An adiabatic demagnetization refrigerator for SIRTF

NASA Technical Reports Server (NTRS)

Timbie, P. T.; Bernstein, G. M.; Richards, P. L.

1989-01-01

An adiabatic demagnetization refrigerator (ADR) has been proposed to cool bolometric infrared detectors on the multiband imaging photometer of the Space Infrared Telescope Facility (SIRTF). One such refrigerator has been built which uses a ferric ammonium alum salt pill suspended by nylon threads in a 3-T solenoid. The resonant modes of this suspension are above 100 Hz. The heat leak to the salt pill is less than 0.5 microW. The system has a hold time at 0.1K of more than 12 h. The cold stage temperature is regulated with a feedback loop that controls the magnetic field. A second, similar refrigerator is being built at a SIRTF prototype to fly on a ballon-borne telescope. It will use a ferromagnetic shield. The possibility of using a high-Tc solenoid-actuated heat switch is also discussed.

Exoplanetary Photometry

NASA Astrophysics Data System (ADS)

Harrington, Joseph

2008-09-01

The Spitzer Space Telescope measured the first photons from exoplanets (Charbonneau et al. 2005, Deming et al. 2005). These secondary eclipses (planet passing behind star) revealed the planet's emitted infrared flux, and under a blackbody assumption provide a brightness temperature in each measured bandpass. Since the initial direct detections, Spitzer has made numerous measurements in the four Infrared Array Camera bandpasses at 3.6, 4.5, 5.7, and 8.0 microns; the Infrared Spectrograph's Blue Peakup Array at 16 microns; and the Multiband Imaging Photometer for Spitzer's 24-micron array. Initial measurements of orbital variation and further photometric study (Harrington et al. 2006, 2007) revealed the extreme day-night variability of some exoplanets, but full orbital phase curves of different planets (Knutson et al. 2007, 2008) demonstrated that not all planets are so variable. This talk will review progress and prospects in exoplanetary photometry.

VizieR Online Data Catalog: YSO candidates in the Magellanic Bridge (Chen+, 2014)

NASA Astrophysics Data System (ADS)

Chen, C.-H. R.; Indebetouw, R.; Muller, E.; Kawamura, A.; Gordon, K. D.; Sewilo, M.; Whitney, B. A.; Fukui, Y.; Madden, S. C.; Meade, M. R.; Meixner, M.; Oliveira, J. M.; Robitaille, T. P.; Seale, J. P.; Shiao, B.; van Loon, J. Th.

2017-06-01

The Spitzer observations of the Bridge were obtained as part of the Legacy Program "Surveying the Agents of Galaxy Evolution in the Tidally-Stripped, Low-Metallicity Small Magellanic Cloud" (SAGE-SMC; Gordon et al. 2011AJ....142..102G). These observations included images taken at 3.6, 4.5, 5.8, and 8.0 um bands with the InfraRed Array Camera (IRAC) and at 24, 70, and 160 um bands with the Multiband Imaging Photometer for Spitzer (MIPS). The details of data processing are given in Gordon et al. (2011AJ....142..102G). To construct multi-wavelength SEDs for sources in the Spitzer catalog, we have expanded it by adding photometry from optical and NIR surveys covering the Bridge, i.e., BRI photometry from the Super COSMOS Sky Surveys (SSS; Hambly et al. 2001MNRAS.326.1279H) and JHKs photometry from the Two Micron All Sky Survey (2MASS; Skrutskie et al. 2006AJ....131.1163S, Cat. VII/233). (5 data files).

New Views of a Familiar Beauty

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Figure 1

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 2Figure 3Figure 4Figure 5

This image composite compares the well-known visible-light picture of the glowing Trifid Nebula (left panel) with infrared views from NASA's Spitzer Space Telescope (remaining three panels). The Trifid Nebula is a giant star-forming cloud of gas and dust located 5,400 light-years away in the constellation Sagittarius.

The false-color Spitzer images reveal a different side of the Trifid Nebula. Where dark lanes of dust are visible trisecting the nebula in the visible-light picture, bright regions of star-forming activity are seen in the Spitzer pictures. All together, Spitzer uncovered 30 massive embryonic stars and 120 smaller newborn stars throughout the Trifid Nebula, in both its dark lanes and luminous clouds. These stars are visible in all the Spitzer images, mainly as yellow or red spots. Embryonic stars are developing stars about to burst into existence. Ten of the 30 massive embryos discovered by Spitzer were found in four dark cores, or stellar 'incubators,' where stars are born. Astronomers using data from the Institute of Radioastronomy millimeter telescope in Spain had previously identified these cores but thought they were not quite ripe for stars. Spitzer's highly sensitive infrared eyes were able to penetrate all four cores to reveal rapidly growing embryos.

Astronomers can actually count the individual embryos tucked inside the cores by looking closely at the Spitzer image taken by its infrared array camera (figure 4). This instrument has the highest spatial resolution of Spitzer's imaging cameras. The Spitzer image from the multiband imaging photometer (figure 5), on the other hand, specializes in detecting cooler materials. Its view highlights the relatively cool core material falling onto the Trifid's growing embryos. The middle panel is a combination of Spitzer data from both of these instruments.

The embryos are thought to have been triggered by a massive 'type O' star, which can be seen as a white spot at the center of the nebula in all four images. Type O stars are the most massive stars, ending their brief lives in explosive supernovas. The small newborn stars probably arose at the same time as the O star, and from the same original cloud of gas and dust.

The Spitzer infrared array camera image is a three-color composite of invisible light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 and 8.0 microns (red). The Spitzer multiband imaging photometer image (figure 3) shows 24-micron emissions. The Spitzer mosaic image combines data from these pictures, showing light of 4.5 microns (blue), 8.0 microns (green) and 24 microns (red). The visible-light image (figure 2) is from the National Optical Astronomy Observatory, Tucson, Ariz.

Riding a Trail of Debris

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Figure 1

This image taken by NASA's Spitzer Space Telescope shows the comet Encke riding along its pebbly trail of debris (long diagonal line) between the orbits of Mars and Jupiter. This material actually encircles the solar system, following the path of Encke's orbit. Twin jets of material can also be seen shooting away from the comet in the short, fan-shaped emission, spreading horizontally from the comet.

Encke, which orbits the Sun every 3.3 years, is well traveled. Having exhausted its supply of fine particles, it now leaves a long trail of larger more gravel-like debris, about one millimeter in size or greater. Every October, Earth passes through Encke's wake, resulting in the well-known Taurid meteor shower.

This image was captured by Spitzer's multiband imaging photometer when Encke was 2.6 times farther away than Earth is from the Sun. It is the best yet mid-infrared view of the comet at this great distance. The data are helping astronomers understand how rotating comets eject particles as they circle the Sun.

The design and application of a multi-band IR imager

NASA Astrophysics Data System (ADS)

Li, Lijuan

2018-02-01

Multi-band IR imaging system has many applications in security, national defense, petroleum and gas industry, etc. So the relevant technologies are getting more and more attention in rent years. As we know, when used in missile warning and missile seeker systems, multi-band IR imaging technology has the advantage of high target recognition capability and low false alarm rate if suitable spectral bands are selected. Compared with traditional single band IR imager, multi-band IR imager can make use of spectral features in addition to space and time domain features to discriminate target from background clutters and decoys. So, one of the key work is to select the right spectral bands in which the feature difference between target and false target is evident and is well utilized. Multi-band IR imager is a useful instrument to collect multi-band IR images of target, backgrounds and decoys for spectral band selection study at low cost and with adjustable parameters and property compared with commercial imaging spectrometer. In this paper, a multi-band IR imaging system is developed which is suitable to collect 4 spectral band images of various scenes at every turn and can be expanded to other short-wave and mid-wave IR spectral bands combination by changing filter groups. The multi-band IR imaging system consists of a broad band optical system, a cryogenic InSb large array detector, a spinning filter wheel and electronic processing system. The multi-band IR imaging system's performance is tested in real data collection experiments.

SIRTF Tools for DIRT

NASA Astrophysics Data System (ADS)

Pound, M. W.; Wolfire, M. G.; Amarnath, N. S.

2003-12-01

The Dust InfraRed ToolBox (DIRT - a part of the Web Infrared ToolShed, or WITS, located at http://dustem.astro.umd.edu) is a Java applet for modeling astrophysical processes in circumstellar shells around young and evolved stars. DIRT has been used by the astrophysics community for about 5 years. Users can automatically and efficiently search grids of pre-calculated models to fit their data. A large set of physical parameters and dust types are included in the model database, which contains over 500,000 models. We are adding new functionality to DIRT to support new missions like SIRTF and SOFIA. A new Instrument module allows for plotting of the model points convolved with the spatial and spectral responses of the selected instrument. This lets users better fit data from specific instruments. Currently, we have implemented modules for the Infrared Array Camera (IRAC) and Multiband Imaging Photometer (MIPS) on SIRTF.

Mysterious Blob Galaxies Revealed

NASA Image and Video Library

2005-01-11

This image composite shows a giant galactic blob (red) and the three merging galaxies NASA's Spitzer Space Telescope discovered within it (yellow). Blobs are intensely glowing clouds of hot hydrogen gas that envelop faraway galaxies. They are about 10 times as large as the galaxies they surround. Visible-light images reveal the vast extent of blobs, but don't provide much information about their host galaxies. Using its heat-seeking infrared eyes, Spitzer was able to see the dusty galaxies tucked inside one well-known blob located 11 billion light-years away. The findings reveal three monstrously bright galaxies, trillions of times brighter than the Sun, in the process of merging together. Spitzer also observed three other blobs located in the same cosmic neighborhood, all of which were found to be glaringly bright. One of these blobs is also known to be a galactic merger, only between two galaxies instead of three. It remains to be seen whether the final two blobs studied also contain mergers. The Spitzer data were acquired by its multiband imaging photometer. The visible-light image was taken by the Blanco Telescope at the Cerro Tololo Inter-American Observatory, Chile. http://photojournal.jpl.nasa.gov/catalog/PIA07220

THE PANCHROMATIC STARBURST IRREGULAR DWARF SURVEY (STARBIRDS): OBSERVATIONS AND DATA ARCHIVE

DOE Office of Scientific and Technical Information (OSTI.GOV)

McQuinn, Kristen B. W.; Mitchell, Noah P.; Skillman, Evan D., E-mail: kmcquinn@astro.umn.edu

2015-06-22

Understanding star formation in resolved low mass systems requires the integration of information obtained from observations at different wavelengths. We have combined new and archival multi-wavelength observations on a set of 20 nearby starburst and post-starburst dwarf galaxies to create a data archive of calibrated, homogeneously reduced images. Named the panchromatic “STARBurst IRregular Dwarf Survey” archive, the data are publicly accessible through the Mikulski Archive for Space Telescopes. This first release of the archive includes images from the Galaxy Evolution Explorer Telescope (GALEX), the Hubble Space Telescope (HST), and the Spitzer Space Telescope (Spitzer) Multiband Imaging Photometer instrument. The datamore » sets include flux calibrated, background subtracted images, that are registered to the same world coordinate system. Additionally, a set of images are available that are all cropped to match the HST field of view. The GALEX and Spitzer images are available with foreground and background contamination masked. Larger GALEX images extending to 4 times the optical extent of the galaxies are also available. Finally, HST images convolved with a 5″ point spread function and rebinned to the larger pixel scale of the GALEX and Spitzer 24 μm images are provided. Future additions are planned that will include data at other wavelengths such as Spitzer IRAC, ground-based Hα, Chandra X-ray, and Green Bank Telescope H i imaging.« less

VizieR Online Data Catalog: Young star forming region NGC 2264 Spitzer sources (Rapson+, 2014)

NASA Astrophysics Data System (ADS)

Rapson, V. A.; Pipher, J. L.; Gutermuth, R. A.; Megeath, S. T.; Allen, T. S.; Myers, P. C.; Allen, L. E.

2017-05-01

We utilize 3.6-8.0 um images of Mon OB1 East obtained with the Spitzer Space Telescope Infrared Array Camera (IRAC; Fazio et al. 2004ApJS..154...10F), 24 um images obtained with the Multi-Band Imaging Photometer (MIPS; Rieke et al. 2004ApJS..154...25R), along with 1-2.5 um NIR data from the Two Micron All Sky Survey (2MASS; Skrutskie et al. 2006AJ....131.1163S, Cat. VII/233) to classify YSOs. These YSOs in Mon OB1 East are classified as either protostars or stars with circumstellar disks by their infrared excess emission above photospheric emission. Spitzer data were gathered as part of two Guaranteed Time Observation programs and one additional program with the goal of studying clustered and distributed star formation throughout Mon OB1 East and comparing the results with those of other molecular clouds. Mon OB1 East was observed by Spitzer in 2004, 2007, and 2008 as part of the Guaranteed Time Observation programs 37 (IRAC data; PI: G. Fazio) and 58 (MIPS data; PI: G. Rieke), as well as program 40006 (IRAC+MIPS data; PI: G. Fazio). (1 data file).

Young Stars Emerge from Orion Head

NASA Image and Video Library

2007-05-17

This image from NASA's Spitzer Space Telescope shows infant stars "hatching" in the head of the hunter constellation, Orion. Astronomers suspect that shockwaves from a supernova explosion in Orion's head, nearly three million years ago, may have initiated this newfound birth. The region featured in this Spitzer image is called Barnard 30. It is located approximately 1,300 light-years away and sits on the right side of Orion's "head," just north of the massive star Lambda Orionis. Wisps of green in the cloud are organic molecules called polycyclic aromatic hydrocarbons. These molecules are formed anytime carbon-based materials are burned incompletely. On Earth, they can be found in the sooty exhaust from automobile and airplane engines. They also coat the grills where charcoal-broiled meats are cooked. Tints of orange-red in the cloud are dust particles warmed by the newly forming stars. The reddish-pink dots at the top of the cloud are very young stars embedded in a cocoon of cosmic gas and dust. Blue spots throughout the image are background Milky Way along this line of sight. This composite includes data from Spitzer's infrared array camera instrument, and multiband imaging photometer instrument. Light at 4.5 microns is shown as blue, 8.0 microns is green, and 24 microns is red. http://photojournal.jpl.nasa.gov/catalog/PIA09411

Young Stars Emerge from Orion's Head

NASA Technical Reports Server (NTRS)

2007-01-01

This image from NASA's Spitzer Space Telescope shows infant stars 'hatching' in the head of the hunter constellation, Orion. Astronomers suspect that shockwaves from a supernova explosion in Orion's head, nearly three million years ago, may have initiated this newfound birth

The region featured in this Spitzer image is called Barnard 30. It is located approximately 1,300 light-years away and sits on the right side of Orion's 'head,' just north of the massive star Lambda Orionis.

Wisps of green in the cloud are organic molecules called polycyclic aromatic hydrocarbons. These molecules are formed anytime carbon-based materials are burned incompletely. On Earth, they can be found in the sooty exhaust from automobile and airplane engines. They also coat the grills where charcoal-broiled meats are cooked.

Tints of orange-red in the cloud are dust particles warmed by the newly forming stars. The reddish-pink dots at the top of the cloud are very young stars embedded in a cocoon of cosmic gas and dust. Blue spots throughout the image are background Milky Way along this line of sight.

This composite includes data from Spitzer's infrared array camera instrument, and multiband imaging photometer instrument. Light at 4.5 microns is shown as blue, 8.0 microns is green, and 24 microns is red.

SPITZER MIPS 24 and 70 {mu}m IMAGING NEAR THE SOUTH ECLIPTIC POLE: MAPS AND SOURCE CATALOGS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, Kimberly S.; Stabenau, Hans F.; Devlin, Mark J.

2010-12-15

We have imaged an 11.5 deg{sup 2} region of sky toward the South Ecliptic Pole (R.A. =04{sup h}43{sup m}, decl. =-53{sup 0}40', J2000) at 24 and 70 {mu}m with MIPS, the Multiband Imaging Photometer for Spitzer. This region is coincident with a field mapped at longer wavelengths by AKARI and BLAST. We discuss our data reduction and source extraction procedures. The median 1{sigma} depths of the maps are 47 {mu}Jy beam{sup -1} at 24 {mu}m and 4.3 mJy beam{sup -1} at 70 {mu}m. At 24 {mu}m, we identify 93,098 point sources with signal-to-noise ratio (S/N) {>=}5 and an additional 63more » resolved galaxies; at 70 {mu}m we identify 891 point sources with S/N {>=}6. From simulations, we determine a false detection rate of 1.8% (1.1%) for the 24 {mu}m (70 {mu}m) catalog. The 24 and 70 {mu}m point-source catalogs are 80% complete at 230 {mu}Jy and 11 mJy, respectively. These mosaic images and source catalogs will be available to the public through the NASA/IPAC Infrared Science Archive.« less

ARC-1988-AC88-0595

NASA Image and Video Library

1988-10-07

Artist: Rick Guidice SIRTF Artwork update - cutaway Space Infrared Telescope Facility's will orbit at 900 kilometers aboard a platform-type spacecraft, providing power, pointing, and communications to Earth. The telescope and its infrared instruments, will reside within a cylindrical cryogen tank. The hollow walls of the tank will contain the superfluid helium that cools the telescope to its operating temperature, a few degrees above absolute zero. SIRTF will carry three versatile instruments to analyze the radiation it collects, the Multiband Imaging Photometer, the Infrared Array Camera, and the Infrared Spectrograph. SIRTF long lifetime - 5 years or more - will permit astronomers of all disciplines to use the facililty to carry out a wide variety of astrophysical programs. It will provide ongoing coverage of variable objects, such as quasars, as well as the capability to study rare and transient events such as comets and supernovae. SIRTF's long lifetime will also allow it to distinguish nearby objects by detecting their gradual motions relative to the more distant background stars.

A Spitzer Infrared Radius for the Transiting Extrasolar Planet HD 209458 b

NASA Technical Reports Server (NTRS)

Richardson, L. Jeremy; Harrington, Joseph; Seager, Sara; Deming, Drake

2007-01-01

We have measured the infrared transit of the extrasolar planet HD 209458 b using the Spitzer Space Telescope. We observed two primary eclipse events (one partial and one complete transit) using the 24 micrometer array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10-second integrations) of the planetary system, recorded before, during, and after transit. We perform optimal photometry on the images and use the local zodiacal light as a short-term flux reference. At this long wavelength, the transit curve has a simple box-like shape, allowing robust solutions for the stellar and planetary radii independent of stellar limb darkening, which is negligible at 24 micrometers. We derive a stellar radius of R(sub *) = 1.06 plus or minus 0.07 solar radius, a planetary radius of R(sub p) = 1.26 plus or minus 0.08 R(sub J), and a stellar mass of 1.17 solar mass. Within the errors, our results agree with the measurements at visible wavelengths. The 24 micrometer radius of the planet therefore does not differ significantly compared to the visible result. We point out the potential for deriving extrasolar transiting planet radii to high accuracy using transit photometry at slightly shorter IR wavelengths where greater photometric precision is possible.

VizieR Online Data Catalog: The YSO population of LDN 1340 in infrared (Kun+, 2016)

NASA Astrophysics Data System (ADS)

Kun, M.; Wolf-Chase, G.; Moor, A.; Apai, D.; Balog, Z.; O'Linger-Luscusk, J.; Moriarty-Schieven, G. H.

2016-07-01

L1340 was observed by the Spitzer Space Telescope using Spitzer's Infrared Array Camera (IRAC) on 2009 March 16 and the Multiband Imaging Photometer for Spitzer (MIPS) on 2008 November 26 (Prog. ID: 50691, PI: G. Fazio). The IRAC observations covered ~1deg2 in all four bands. Moreover, a small part of the cloud, centered on RNO 7, was observed in the four IRAC bands on 2006 September 24 (Prog. ID: 30734, PI: D. Figer). We selected candidate YSOs from the Spitzer Enhanced Imaging Products (SEIP) Source List, containing 19745 point sources in the target field. High angular resolution near-infrared images of two small regions of L1340 were obtained on 2002 October 24 in the JHK bands, using the near-infrared camera Omega-Cass, mounted on the 3.5m telescope at the Calar Alto Observatory, Spain. The results for IRAS 02224+7227 have been shown in Kun et al. (2014, J/ApJ/795/L26). Here we present the results for RNO 7. To classify the evolutionary status of the color-selected candidate YSOs and obtain as complete a picture of the SFR and its YSO population as possible, we supplemented the Spitzer data with photometric data available in public databases. See section 2.3 for further details. (13 data files).

Kepler Supernova Remnant: A View from Spitzer Space Telescope

NASA Image and Video Library

2004-10-06

This Spitzer false-color image is a composite of data from the 24 micron channel of Spitzer's multiband imaging photometer (red), and three channels of its infrared array camera: 8 micron (yellow), 5.6 micron (blue), and 4.8 micron (green). Stars are most prominent in the two shorter wavelengths, causing them to show up as turquoise. The supernova remnant is most prominent at 24 microns, arising from dust that has been heated by the supernova shock wave, and re-radiated in the infrared. The 8 micron data shows infrared emission from regions closely associated with the optically emitting regions. These are the densest regions being encountered by the shock wave, and probably arose from condensations in the surrounding material that was lost by the supernova star before it exploded. The composite above (PIA06908, PIA06909, and PIA06910) represent views of Kepler's supernova remnant taken in X-rays, visible light, and infrared radiation. Each top panel in the composite above shows the entire remnant. Each color in the composite represents a different region of the electromagnetic spectrum, from X-rays to infrared light. The X-ray and infrared data cannot be seen with the human eye. Astronomers have color-coded those data so they can be seen in these images. http://photojournal.jpl.nasa.gov/catalog/PIA06910

Hubble and Spitzer Space Telescope Observations of the Debris Disk around the nearby K Dwarf HD 92945

NASA Astrophysics Data System (ADS)

Golimowski, D. A.; Krist, J. E.; Stapelfeldt, K. R.; Chen, C. H.; Ardila, D. R.; Bryden, G.; Clampin, M.; Ford, H. C.; Illingworth, G. D.; Plavchan, P.; Rieke, G. H.; Su, K. Y. L.

2011-07-01

We present the first resolved images of the debris disk around the nearby K dwarf HD 92945, obtained with the Hubble Space Telescope's (HST 's) Advanced Camera for Surveys. Our F606W (Broad V) and F814W (Broad I) coronagraphic images reveal an inclined, axisymmetric disk consisting of an inner ring about 2farcs0-3farcs0 (43-65 AU) from the star and an extended outer disk whose surface brightness declines slowly with increasing radius approximately 3farcs0-5farcs1 (65-110 AU) from the star. A precipitous drop in the surface brightness beyond 110 AU suggests that the outer disk is truncated at that distance. The radial surface-density profile is peaked at both the inner ring and the outer edge of the disk. The dust in the outer disk scatters neutrally but isotropically, and it has a low V-band albedo of 0.1. This combination of axisymmetry, ringed and extended morphology, and isotropic neutral scattering is unique among the 16 debris disks currently resolved in scattered light. We also present new infrared photometry and spectra of HD 92945 obtained with the Spitzer Space Telescope's Multiband Imaging Photometer and InfraRed Spectrograph. These data reveal no infrared excess from the disk shortward of 30 μm and constrain the width of the 70 μm source to lsim180 AU. Assuming that the dust comprises compact grains of astronomical silicate with a surface-density profile described by our scattered-light model of the disk, we successfully model the 24-350 μm emission with a minimum grain size of a min = 4.5 μm and a size distribution proportional to a -3.7 throughout the disk, but with maximum grain sizes of 900 μm in the inner ring and 50 μm in the outer disk. Together, our HST and Spitzer observations indicate a total dust mass of ~0.001M ⊕. However, our observations provide contradictory evidence of the dust's physical characteristics: its neutral V-I color and lack of 24 μm emission imply grains larger than a few microns, but its isotropic scattering and low albedo suggest a large population of submicron-sized grains. If grains smaller than a few microns are absent, then stellar radiation pressure may be the cause only if the dust is composed of highly absorptive materials like graphite. The dynamical causes of the sharply edged inner ring and outer disk are unclear, but recent models of dust creation and transport in the presence of migrating planets support the notion that the disk indicates an advanced state of planet formation around HD 92945. Based in part on guaranteed observing time awarded by the National Aeronautics and Space Administration (NASA) to the Advanced Camera for Surveys Investigation Definition Team and the Multiband Imaging Photometer for Spitzer Instrument Team.

A Star Close Encounter

NASA Image and Video Library

2006-10-03

The potential planet-forming disk (or "protoplanetary disk") of a sun-like star is being violently ripped away by the powerful winds of a nearby hot O-type star in this image from NASA's Spitzer Space Telescope. At up to 100 times the mass of sun-like stars, O stars are the most massive and energetic stars in the universe. The O star can be seen to the right of the image, as the large orange spot with the white center. To the left, the comet-like structure is actually a neighboring solar system that is being destroyed by the O star's powerful winds and intense ultraviolet light. In a process called "photoevaporation," immense output from the O star heats up the nearby protoplanetary disk so much that gas and dust boil off, and the disk can no longer hold together. Photon (or light) blasts from the O star then strip the potential planet-forming disk off its neighbor star by blowing away evaporated material. This effect is illustrated in the smaller system's comet-like structure. The system is located about 2,450 light-years away in the star-forming cloud IC 1396. The image was taken with Spitzer's multiband imaging photometer instrument at 24 microns. The picture is a pseudo-color stretch representing intensity. Yellow and white represent hot areas, whereas purple and blue represent relatively cooler, fainter regions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang-Condell, Hannah; Chen, Christine H.; Mittal, Tushar

We analyze spectra obtained with the Spitzer Infrared Spectrograph (IRS) of 110 B-, A-, F-, and G-type stars with optically thin infrared excess in the Scorpius–Centaurus OB association. The ages of these stars range from 11 to 17 Myr. We fit the infrared excesses observed in these sources by Spitzer IRS and the Multiband Imaging Photometer for Spitzer (MIPS) to simple dust models according to Mie theory. We find that nearly all of the objects in our study can be fit by one or two belts of dust. Dust around lower mass stars appears to be closer in than aroundmore » higher mass stars, particularly for the warm dust component in the two-belt systems, suggesting a mass-dependent evolution of debris disks around young stars. For those objects with stellar companions, all dust distances are consistent with truncation of the debris disk by the binary companion. The gaps between several of the two-belt systems can place limits on the planets that might lie between the belts, potentially constraining the mass and locations of planets that may be forming around these stars.« less

A TREND BETWEEN COLD DEBRIS DISK TEMPERATURE AND STELLAR TYPE: IMPLICATIONS FOR THE FORMATION AND EVOLUTION OF WIDE-ORBIT PLANETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballering, Nicholas P.; Rieke, George H.; Su, Kate Y. L.

2013-09-20

Cold debris disks trace the limits of planet formation or migration in the outer regions of planetary systems, and thus have the potential to answer many of the outstanding questions in wide-orbit planet formation and evolution. We characterized the infrared excess spectral energy distributions of 174 cold debris disks around 546 main-sequence stars observed by both the Spitzer Infrared Spectrograph and the Multiband Imaging Photometer for Spitzer. We found a trend between the temperature of the inner edges of cold debris disks and the stellar type of the stars they orbit. This argues against the importance of strictly temperature-dependent processesmore » (e.g., non-water ice lines) in setting the dimensions of cold debris disks. Also, we found no evidence that delayed stirring causes the trend. The trend may result from outward planet migration that traces the extent of the primordial protoplanetary disk, or it may result from planet formation that halts at an orbital radius limited by the efficiency of core accretion.« less

The Astronomical Zoo in MIPSGAL I and II

NASA Astrophysics Data System (ADS)

Kuchar, Thomas A.; Mizuno, D.; Shenoy, S.; Paladini, R.; Kraemer, K.; Price, S.; Marleau, F.; Padgett, D.; Indebetouw, R.; Ingalls, J.; Ali, B.; Berriman, B.; Boulanger, F.; Cutri, R.; Latter, W.; Miville-Deschenes, M.; Molinari, S.; Rebull, L.; Testi, L.; Shipman, R.; Martin, P.; Carey, S.; Noriega-Crespo, A.

2006-12-01

The view of the Galactic Plane at 24 µm is breathtaking. A great part of this beauty arises from the complexity of the Interstellar Medium shaped by endless energetic events driven by HII regions, supernova explosions, Wolf-Rayets, Luminous Blue Variables, and evolved and new born massive stars. A sample of these objects is presented in this poster, gathered from the Multiband Imaging Photometer for Spitzer (MIPS) Survey of the Galactic Plane I and II (MIPSGAL; see Carey et al. 2006, this meeting). The global color properties of these objects are derived by combining the data at 24 and 70um with that from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE), and following similar schemes as those used in the Spitzer Surveys of the Magellanic Clouds (Bolatto et al. 2006, astroph-0608561; Meixner et al. 2006, astroph-0606356). This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA in part through an award issued by JPL/Caltech.

Devastated Stellar Neighborhood

NASA Technical Reports Server (NTRS)

2008-01-01

This image from NASA's Spitzer Space Telescope shows the nasty effects of living near a group of massive stars: radiation and winds from the massive stars (white spot in center) are blasting planet-making material away from stars like our sun. The planetary material can be seen as comet-like tails behind three stars near the center of the picture. The tails are pointing away from the massive stellar furnaces that are blowing them outward.

The picture is the best example yet of multiple sun-like stars being stripped of their planet-making dust by massive stars.

The sun-like stars are about two to three million years old, an age when planets are thought to be growing out of surrounding disks of dust and gas. Astronomers say the dust being blown from the stars is from their outer disks. This means that any Earth-like planets forming around the sun-like stars would be safe, while outer planets like Uranus might be nothing more than dust in the wind.

This image shows a portion of the W5 star-forming region, located 6,500 light-years away in the constellation Cassiopeia. It is a composite of infrared data from Spitzer's infrared array camera and multiband imaging photometer. Light with a wavelength of 3.5 microns is blue, while light from the dust of 24 microns is orange-red.

Laser-Sharp Jet Splits Water

NASA Technical Reports Server (NTRS)

2008-01-01

A jet of gas firing out of a very young star can be seen ramming into a wall of material in this infrared image from NASA's Spitzer Space Telescope.

The young star, called HH 211-mm, is cloaked in dust and can't be seen. But streaming away from the star are bipolar jets, color-coded blue in this view. The pink blob at the end of the jet to the lower left shows where the jet is hitting a wall of material. The jet is hitting the wall so hard that shock waves are being generated, which causes ice to vaporize off dust grains. The shock waves are also heating material up, producing energetic ultraviolet radiation. The ultraviolet radiation then breaks the water vapor molecules apart.

The red color at the end of the lower jet represents shock-heated iron, sulfur and dust, while the blue color in both jets denotes shock-heated hydrogen molecules.

HH 211-mm is part of a cluster of about 300 stars, called IC 348, located 1,000 light-years away in the constellation Perseus.

This image is a composite of infrared data from Spitzer's infrared array camera and its multiband imaging photometer. Light with wavelengths of 3.6 and 4.5 microns is blue; 8-micron-light is green; and 24-micron light is red.

A SPITZER VIEW OF STAR FORMATION IN THE CYGNUS X NORTH COMPLEX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beerer, I. M.; Koenig, X. P.; Hora, J. L.

2010-09-01

We present new images and photometry of the massive star-forming complex Cygnus X obtained with the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer for Spitzer (MIPS) on board the Spitzer Space Telescope. A combination of IRAC, MIPS, UKIRT Deep Infrared Sky Survey, and Two Micron All Sky Survey data are used to identify and classify young stellar objects (YSOs). Of the 8231 sources detected exhibiting infrared excess in Cygnus X North, 670 are classified as class I and 7249 are classified as class II. Using spectra from the FAST Spectrograph at the Fred L. Whipple Observatory and Hectospecmore » on the MMT, we spectrally typed 536 sources in the Cygnus X complex to identify the massive stars. We find that YSOs tend to be grouped in the neighborhoods of massive B stars (spectral types B0 to B9). We present a minimal spanning tree analysis of clusters in two regions in Cygnus X North. The fraction of infrared excess sources that belong to clusters with {>=}10 members is found to be 50%-70%. Most class II objects lie in dense clusters within blown out H II regions, while class I sources tend to reside in more filamentary structures along the bright-rimmed clouds, indicating possible triggered star formation.« less

VizieR Online Data Catalog: Star clusters automatically detected in the LMC (Bitsakis+, 2017)

NASA Astrophysics Data System (ADS)

Bitsakis, T.; Bonfini, P.; Gonzalez-Lopezlira, R. A.; Ramirez-Siordia, V. H.; Bruzual, G.; Charlot, S.; Maravelias, G.; Zaritsky, D.

2018-03-01

The archival data used in this work were acquired from several diverse large surveys, which mapped the Magellanic Clouds at various bands. Simons+ (2014AdSpR..53..939S) composed a mosaic using archival data from the Galaxy Evolution Explorer (GALEX) at the near-ultraviolet (NUV) band (λeff=2275Å). The mosaic covers an area of 15deg2 on the LMC. the central ~3x1deg2 of the LMC (the bar-region) was later observed by the Swift Ultraviolet-Optical Telescope (UVOT) Magellanic Clouds Survey (SUMAC; Siegel+ 2014AJ....148..131S). The optical data used here are from the Magellanic Cloud Photometric Survey (MCPS; Zaritsky+ 2004, J/AJ/128/1606). These authors observed the central 64deg2 of the LMC with 3.8-5.2 minute exposures at the Johnson U, B, V, and Gunn i filters of the Las Campanas Swope Telescope. Meixner+ (2006, J/AJ/132/2268) performed a uniform and unbiased imaging survey of the LMC (called Surveying the Agents of a Galaxy's Evolution, or SAGE), covering the central 7deg2 with both the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer (MIPS) on-board the Spitzer Space Telescope. (1 data file).

Interleaved diffusion-weighted EPI improved by adaptive partial-Fourier and multi-band multiplexed sensitivity-encoding reconstruction

PubMed Central

Chang, Hing-Chiu; Guhaniyogi, Shayan; Chen, Nan-kuei

2014-01-01

Purpose We report a series of techniques to reliably eliminate artifacts in interleaved echo-planar imaging (EPI) based diffusion weighted imaging (DWI). Methods First, we integrate the previously reported multiplexed sensitivity encoding (MUSE) algorithm with a new adaptive Homodyne partial-Fourier reconstruction algorithm, so that images reconstructed from interleaved partial-Fourier DWI data are free from artifacts even in the presence of either a) motion-induced k-space energy peak displacement, or b) susceptibility field gradient induced fast phase changes. Second, we generalize the previously reported single-band MUSE framework to multi-band MUSE, so that both through-plane and in-plane aliasing artifacts in multi-band multi-shot interleaved DWI data can be effectively eliminated. Results The new adaptive Homodyne-MUSE reconstruction algorithm reliably produces high-quality and high-resolution DWI, eliminating residual artifacts in images reconstructed with previously reported methods. Furthermore, the generalized MUSE algorithm is compatible with multi-band and high-throughput DWI. Conclusion The integration of the multi-band and adaptive Homodyne-MUSE algorithms significantly improves the spatial-resolution, image quality, and scan throughput of interleaved DWI. We expect that the reported reconstruction framework will play an important role in enabling high-resolution DWI for both neuroscience research and clinical uses. PMID:24925000

The Panchromatic STARBurst IRregular Dwarf Survey (STARBIRDS): Observations and Data Archive

NASA Astrophysics Data System (ADS)

McQuinn, Kristen B. W.; Mitchell, Noah P.; Skillman, Evan D.

2015-06-01

Understanding star formation in resolved low mass systems requires the integration of information obtained from observations at different wavelengths. We have combined new and archival multi-wavelength observations on a set of 20 nearby starburst and post-starburst dwarf galaxies to create a data archive of calibrated, homogeneously reduced images. Named the panchromatic “STARBurst IRregular Dwarf Survey” archive, the data are publicly accessible through the Mikulski Archive for Space Telescopes. This first release of the archive includes images from the Galaxy Evolution Explorer Telescope (GALEX), the Hubble Space Telescope (HST), and the Spitzer Space Telescope (Spitzer) Multiband Imaging Photometer instrument. The data sets include flux calibrated, background subtracted images, that are registered to the same world coordinate system. Additionally, a set of images are available that are all cropped to match the HST field of view. The GALEX and Spitzer images are available with foreground and background contamination masked. Larger GALEX images extending to 4 times the optical extent of the galaxies are also available. Finally, HST images convolved with a 5″ point spread function and rebinned to the larger pixel scale of the GALEX and Spitzer 24 μm images are provided. Future additions are planned that will include data at other wavelengths such as Spitzer IRAC, ground-based Hα, Chandra X-ray, and Green Bank Telescope H i imaging. Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA), and the Canadian Astronomy Data Centre (CADC/NRC/CSA).

The TRICLOBS Dynamic Multi-Band Image Data Set for the Development and Evaluation of Image Fusion Methods

PubMed Central

Hogervorst, Maarten A.; Pinkus, Alan R.

2016-01-01

The fusion and enhancement of multiband nighttime imagery for surveillance and navigation has been the subject of extensive research for over two decades. Despite the ongoing efforts in this area there is still only a small number of static multiband test images available for the development and evaluation of new image fusion and enhancement methods. Moreover, dynamic multiband imagery is also currently lacking. To fill this gap we present the TRICLOBS dynamic multi-band image data set containing sixteen registered visual (0.4–0.7μm), near-infrared (NIR, 0.7–1.0μm) and long-wave infrared (LWIR, 8–14μm) motion sequences. They represent different military and civilian surveillance scenarios registered in three different scenes. Scenes include (military and civilian) people that are stationary, walking or running, or carrying various objects. Vehicles, foliage, and buildings or other man-made structures are also included in the scenes. This data set is primarily intended for the development and evaluation of image fusion, enhancement and color mapping algorithms for short-range surveillance applications. The imagery was collected during several field trials with our newly developed TRICLOBS (TRI-band Color Low-light OBServation) all-day all-weather surveillance system. This system registers a scene in the Visual, NIR and LWIR part of the electromagnetic spectrum using three optically aligned sensors (two digital image intensifiers and an uncooled long-wave infrared microbolometer). The three sensor signals are mapped to three individual RGB color channels, digitized, and stored as uncompressed RGB (false) color frames. The TRICLOBS data set enables the development and evaluation of (both static and dynamic) image fusion, enhancement and color mapping algorithms. To allow the development of realistic color remapping procedures, the data set also contains color photographs of each of the three scenes. The color statistics derived from these photographs can be used to define color mappings that give the multi-band imagery a realistic color appearance. PMID:28036328

The TRICLOBS Dynamic Multi-Band Image Data Set for the Development and Evaluation of Image Fusion Methods.

PubMed

Toet, Alexander; Hogervorst, Maarten A; Pinkus, Alan R

2016-01-01

The fusion and enhancement of multiband nighttime imagery for surveillance and navigation has been the subject of extensive research for over two decades. Despite the ongoing efforts in this area there is still only a small number of static multiband test images available for the development and evaluation of new image fusion and enhancement methods. Moreover, dynamic multiband imagery is also currently lacking. To fill this gap we present the TRICLOBS dynamic multi-band image data set containing sixteen registered visual (0.4-0.7μm), near-infrared (NIR, 0.7-1.0μm) and long-wave infrared (LWIR, 8-14μm) motion sequences. They represent different military and civilian surveillance scenarios registered in three different scenes. Scenes include (military and civilian) people that are stationary, walking or running, or carrying various objects. Vehicles, foliage, and buildings or other man-made structures are also included in the scenes. This data set is primarily intended for the development and evaluation of image fusion, enhancement and color mapping algorithms for short-range surveillance applications. The imagery was collected during several field trials with our newly developed TRICLOBS (TRI-band Color Low-light OBServation) all-day all-weather surveillance system. This system registers a scene in the Visual, NIR and LWIR part of the electromagnetic spectrum using three optically aligned sensors (two digital image intensifiers and an uncooled long-wave infrared microbolometer). The three sensor signals are mapped to three individual RGB color channels, digitized, and stored as uncompressed RGB (false) color frames. The TRICLOBS data set enables the development and evaluation of (both static and dynamic) image fusion, enhancement and color mapping algorithms. To allow the development of realistic color remapping procedures, the data set also contains color photographs of each of the three scenes. The color statistics derived from these photographs can be used to define color mappings that give the multi-band imagery a realistic color appearance.

Multiband super-resolution imaging of graded-index photonic crystal flat lens

NASA Astrophysics Data System (ADS)

Xie, Jianlan; Wang, Junzhong; Ge, Rui; Yan, Bei; Liu, Exian; Tan, Wei; Liu, Jianjun

2018-05-01

Multiband super-resolution imaging of point source is achieved by a graded-index photonic crystal flat lens. With the calculations of six bands in common photonic crystal (CPC) constructed with scatterers of different refractive indices, it can be found that the super-resolution imaging of point source can be realized by different physical mechanisms in three different bands. In the first band, the imaging of point source is based on far-field condition of spherical wave while in the second band, it is based on the negative effective refractive index and exhibiting higher imaging quality than that of the CPC. However, in the fifth band, the imaging of point source is mainly based on negative refraction of anisotropic equi-frequency surfaces. The novel method of employing different physical mechanisms to achieve multiband super-resolution imaging of point source is highly meaningful for the field of imaging.

Stormy Clouds of Star Birth

NASA Technical Reports Server (NTRS)

2004-01-01

Hidden behind a shroud of dust in the constellation Cygnus is an exceptionally bright source of radio emission called DR21. Visible light images reveal no trace of what is happening in this region because of heavy dust obscuration. In fact, visible light is attenuated in DR21 by a factor of more than 10,000,000,000,000,000,000,000,000,000, 000,000,000,000 (ten thousand trillion heptillion).

New images from NASA's Spitzer Space Telescope allow us to peek behind the cosmic veil and pinpoint one of the most massive natal stars yet seen in our Milky Way galaxy. The never-before-seen star is 100,000 times as bright as the Sun. Also revealed for the first time is a powerful outflow of hot gas emanating from this star and bursting through a giant molecular cloud.

This image shows a 24-micron image mosaic, obtained with the Multiband Imaging Photometer aboard Spitzer (MIPS). This image maps the cooler infrared emission from interstellar dust found throughout the interstellar medium. The DR21 complex is clearly seen near the center of the strip, which covers about twice the area of the IRAC image.

Perhaps the most fascinating feature in this image is a long and shadowy linear filament extending towards the 10 o'clock position of DR21. This jet of cold and dense gas, nearly 50 light-years in extent, appears in silhouette against a warmer background. This filament is too long and massive to be a stellar jet and may have formed from a pre-existing molecular cloud core sculpted by DR21's strong winds. Regardless of its true nature, this jet and the numerous other arcs and wisps of cool dust signify the interstellar turbulence normally unseen by the human eye.

The SED Machine: A Robotic Spectrograph for Fast Transient Classification

NASA Astrophysics Data System (ADS)

Blagorodnova, Nadejda; Neill, James D.; Walters, Richard; Kulkarni, Shrinivas R.; Fremling, Christoffer; Ben-Ami, Sagi; Dekany, Richard G.; Fucik, Jason R.; Konidaris, Nick; Nash, Reston; Ngeow, Chow-Choong; Ofek, Eran O.; O’ Sullivan, Donal; Quimby, Robert; Ritter, Andreas; Vyhmeister, Karl E.

2018-03-01

Current time domain facilities are finding several hundreds of transient astronomical events a year. The discovery rate is expected to increase in the future as soon as new surveys such as the Zwicky Transient Facility (ZTF) and the Large Synoptic Sky Survey (LSST) come online. Presently, the rate at which transients are classified is approximately one order or magnitude lower than the discovery rate, leading to an increasing “follow-up drought”. Existing telescopes with moderate aperture can help address this deficit when equipped with spectrographs optimized for spectral classification. Here, we provide an overview of the design, operations and first results of the Spectral Energy Distribution Machine (SEDM), operating on the Palomar 60-inch telescope (P60). The instrument is optimized for classification and high observing efficiency. It combines a low-resolution (R ∼ 100) integral field unit (IFU) spectrograph with “Rainbow Camera” (RC), a multi-band field acquisition camera which also serves as multi-band (ugri) photometer. The SEDM was commissioned during the operation of the intermediate Palomar Transient Factory (iPTF) and has already lived up to its promise. The success of the SEDM demonstrates the value of spectrographs optimized for spectral classification.

High-order multiband encoding in the heart.

PubMed

Cunningham, Charles H; Wright, Graham A; Wood, Michael L

2002-10-01

Spatial encoding with multiband selective excitation (e.g., Hadamard encoding) has been restricted to a small number of slices because the RF pulse becomes unacceptably long when more than about eight slices are encoded. In this work, techniques to shorten multiband RF pulses, and thus allow larger numbers of slices, are investigated. A method for applying the techniques while retaining the capability of adaptive slice thickness is outlined. A tradeoff between slice thickness and pulse duration is shown. Simulations and experiments with the shortened pulses confirmed that motion-induced excitation profile blurring and phase accrual were reduced. The connection between gradient hardware limitations, slice thickness, and flow sensitivity is shown. Excitation profiles for encoding 32 contiguous slices of 1-mm thickness were measured experimentally, and the artifact resulting from errors in timing of RF pulse relative to gradient was investigated. A multiband technique for imaging 32 contiguous 2-mm slices, with adaptive slice thickness, was developed and demonstrated for coronary artery imaging in healthy subjects. With the ability to image high numbers of contiguous slices, using relatively short (1-2 ms) RF pulses, multiband encoding has been advanced further toward practical application. Copyright 2002 Wiley-Liss, Inc.

CHANG-ES X: Spatially Resolved Separation of Thermal Contribution from Radio Continuum Emission in Edge-on Galaxies

NASA Astrophysics Data System (ADS)

Vargas, Carlos J.; Mora-Partiarroyo, Silvia Carolina; Schmidt, Philip; Rand, Richard J.; Stein, Yelena; Walterbos, René A. M.; Wang, Q. Daniel; Basu, Aritra; Patterson, Maria; Kepley, Amanda; Beck, Rainer; Irwin, Judith; Heald, George; Li, Jiangtao; Wiegert, Theresa

2018-02-01

We analyze the application of star formation rate calibrations using Hα and 22 μm infrared (IR) imaging data in predicting the thermal radio component for a test sample of three edge-on galaxies (NGC 891, NGC 3044, and NGC 4631) in the Continuum Halos in Nearby Galaxies—an EVLA Survey (CHANG-ES). We use a mixture of Hα and 24 μm calibration from Calzetti et al. and a linear 22 μm only calibration from Jarrett et al. on the test sample. We apply these relations on a pixel-to-pixel basis to create thermal prediction maps in the two CHANG-ES bands: L and C band (1.5 GHz and 6.0 GHz, respectively). We analyze the resulting nonthermal spectral index maps, and find a characteristic steepening of the nonthermal spectral index with vertical distance from the disk after application of all methods. We find possible evidence of extinction in the 22 μm data as compared to 70 μm Spitzer Multiband Imaging Photometer imaging in NGC 891. We analyze a larger sample of edge-on and face-on galaxy 25–100 μm flux ratios, and find that the ratios for edge-ons are systematically lower by a factor of 1.36, a result we attribute to excess extinction in the mid-IR in edge-ons. We introduce a new calibration for correcting the Hα luminosity for dust when galaxies are edge-on or very dusty.

Stereo Imaging Miniature Endoscope with Single Imaging Chip and Conjugated Multi-Bandpass Filters

NASA Technical Reports Server (NTRS)

Shahinian, Hrayr Karnig (Inventor); Bae, Youngsam (Inventor); White, Victor E. (Inventor); Shcheglov, Kirill V. (Inventor); Manohara, Harish M. (Inventor); Kowalczyk, Robert S. (Inventor)

2018-01-01

A dual objective endoscope for insertion into a cavity of a body for providing a stereoscopic image of a region of interest inside of the body including an imaging device at the distal end for obtaining optical images of the region of interest (ROI), and processing the optical images for forming video signals for wired and/or wireless transmission and display of 3D images on a rendering device. The imaging device includes a focal plane detector array (FPA) for obtaining the optical images of the ROI, and processing circuits behind the FPA. The processing circuits convert the optical images into the video signals. The imaging device includes right and left pupil for receiving a right and left images through a right and left conjugated multi-band pass filters. Illuminators illuminate the ROI through a multi-band pass filter having three right and three left pass bands that are matched to the right and left conjugated multi-band pass filters. A full color image is collected after three or six sequential illuminations with the red, green and blue lights.

Tiny Particles, So Far Away

NASA Image and Video Library

2005-01-10

NASA's Spitzer Space Telescope recently captured these images of the star Vega, located 25 light years away in the constellation Lyra. Spitzer was able to detect the heat radiation from the cloud of dust around the star and found that the debris disc is much larger than previously thought. This side by side comparison, taken by Spitzer's multiband imaging photometer, shows the warm infrared glows from dust particles orbiting the star at wavelengths of 24 microns (figure 2 in blue) and 70 microns (figure 3 in red). Both images show a very large, circular and smooth debris disc. The disc radius extends to at least 815 astronomical units. (One astronomical unit is the distance from Earth to the Sun, which is 150-million kilometers or 93-million miles). Scientists compared the surface brightness of the disc in the infrared wavelengths to determine the temperature distribution of the disc and then infer the corresponding particle size in the disc. Most of the particles in the disc are only a few microns in size, or 100 times smaller than a grain of Earth sand. These fine dust particles originate from collisions of embryonic planets near the star at a radius of approximately 90 astronomical units, and are then blown away by Vega's intense radiation. The mass and short lifetime of these small particles indicate that the disc detected by Spitzer is the aftermath of a large and relatively recent collision, involving bodies perhaps as big as the planet Pluto. The images are 3 arcminutes on each side. North is oriented upward and east is to the left. http://photojournal.jpl.nasa.gov/catalog/PIA07218

Serendipitous discovery of an infrared bow shock near PSR J1549–4848 with Spitzer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhongxiang; Kaplan, David L.; Slane, Patrick

2013-06-01

We report on the discovery of an infrared cometary nebula around PSR J1549–4848 in our Spitzer survey of a few middle-aged radio pulsars. Following the discovery, multi-wavelength imaging and spectroscopic observations of the nebula were carried out. We detected the nebula in Spitzer Infrared Array Camera 8.0, Multiband Imaging Photometer for Spitzer 24 and 70 μm imaging, and in Spitzer IRS 7.5-14.4 μm spectroscopic observations, and also in the Wide-field Infrared Survey Explorer all-sky survey at 12 and 22 μm. These data were analyzed in detail, and we find that the nebula can be described with a standard bow shockmore » shape, and that its spectrum contains polycyclic aromatic hydrocarbon and H{sub 2} emission features. However, it is not certain which object drives the nebula. We analyze the field stars and conclude that none of them can be the associated object because stars with a strong wind or mass ejection that usually produce bow shocks are much brighter than the field stars. The pulsar is approximately 15'' away from the region in which the associated object is expected to be located. In order to resolve the discrepancy, we suggest that a highly collimated wind could be emitted from the pulsar and produce the bow shock. X-ray imaging to detect the interaction of the wind with the ambient medium- and high-spatial resolution radio imaging to determine the proper motion of the pulsar should be carried out, which will help verify the association of the pulsar with the bow shock nebula.« less

A Million Comet Pieces

NASA Technical Reports Server (NTRS)

2006-01-01

[figure removed for brevity, see original site] A Million Comet Pieces (poster version)

This infrared image from NASA's Spitzer Space Telescope shows the broken Comet 73P/Schwassman-Wachmann 3 skimming along a trail of debris left during its multiple trips around the sun. The flame-like objects are the comet's fragments and their tails, while the dusty comet trail is the line bridging the fragments.

Comet 73P /Schwassman-Wachmann 3 began to splinter apart in 1995 during one of its voyages around the sweltering sun. Since then, the comet has continued to disintegrate into dozens of fragments, at least 36 of which can be seen here. Astronomers believe the icy comet cracked due the thermal stress from the sun.

The Spitzer image provides the best look yet at the trail of debris left in the comet's wake after its 1995 breakup. The observatory's infrared eyes were able to see the dusty comet bits and pieces, which are warmed by sunlight and glow at infrared wavelengths. This comet debris ranges in size from pebbles to large boulders. When Earth passes near this rocky trail every year, the comet rubble burns up in our atmosphere, lighting up the sky in meteor showers. In 2022, Earth is expected to cross close to the comet's trail, producing a noticeable meteor shower.

Astronomers are studying the Spitzer image for clues to the comet's composition and how it fell apart. Like NASA's Deep Impact experiment, in which a probe smashed into comet Tempel 1, the cracked Comet 73P/Schwassman-Wachmann 3 provides a perfect laboratory for studying the pristine interior of a comet.

This image was taken from May 4 to May 6 by Spitzer's multi-band imaging photometer, using its 24-micron wavelength channel.

Multi-Band Miniaturized Patch Antennas for a Compact, Shielded Microwave Breast Imaging Array.

PubMed

Aguilar, Suzette M; Al-Joumayly, Mudar A; Burfeindt, Matthew J; Behdad, Nader; Hagness, Susan C

2013-12-18

We present a comprehensive study of a class of multi-band miniaturized patch antennas designed for use in a 3D enclosed sensor array for microwave breast imaging. Miniaturization and multi-band operation are achieved by loading the antenna with non-radiating slots at strategic locations along the patch. This results in symmetric radiation patterns and similar radiation characteristics at all frequencies of operation. Prototypes were fabricated and tested in a biocompatible immersion medium. Excellent agreement was obtained between simulations and measurements. The trade-off between miniaturization and radiation efficiency within this class of patch antennas is explored via a numerical analysis of the effects of the location and number of slots, as well as the thickness and permittivity of the dielectric substrate, on the resonant frequencies and gain. Additionally, we compare 3D quantitative microwave breast imaging performance achieved with two different enclosed arrays of slot-loaded miniaturized patch antennas. Simulated array measurements were obtained for a 3D anatomically realistic numerical breast phantom. The reconstructed breast images generated from miniaturized patch array data suggest that, for the realistic noise power levels assumed in this study, the variations in gain observed across this class of multi-band patch antennas do not significantly impact the overall image quality. We conclude that these miniaturized antennas are promising candidates as compact array elements for shielded, multi-frequency microwave breast imaging systems.

Document Monitor

NASA Technical Reports Server (NTRS)

1988-01-01

The charters of Freedom Monitoring System will periodically assess the physical condition of the U.S. Constitution, Declaration of Independence and Bill of Rights. Although protected in helium filled glass cases, the documents are subject to damage from light vibration and humidity. The photometer is a CCD detector used as the electronic film for the camera system's scanning camera which mechanically scans the document line by line and acquires a series of images, each representing a one square inch portion of the document. Perkin-Elmer Corporation's photometer is capable of detecting changes in contrast, shape or other indicators of degradation with 5 to 10 times the sensitivity of the human eye. A Vicom image processing computer receives the data from the photometer stores it and manipulates it, allowing comparison of electronic images over time to detect changes.

Improved colour matching technique for fused nighttime imagery with daytime colours

NASA Astrophysics Data System (ADS)

Hogervorst, Maarten A.; Toet, Alexander

2016-10-01

Previously, we presented a method for applying daytime colours to fused nighttime (e.g., intensified and LWIR) imagery (Toet and Hogervorst, Opt.Eng. 51(1), 2012). Our colour mapping not only imparts a natural daylight appearance to multiband nighttime images but also enhances the contrast and visibility of otherwise obscured details. As a result, this colourizing method leads to increased ease of interpretation, better discrimination and identification of materials, faster reaction times and ultimately improved situational awareness (Toet e.a., Opt.Eng.53(4), 2014). A crucial step in this colouring process is the choice of a suitable colour mapping scheme. When daytime colour images and multiband sensor images of the same scene are available the colour mapping can be derived from matching image samples (i.e., by relating colour values to sensor signal intensities). When no exact matching reference images are available the colour transformation can be derived from the first-order statistical properties of the reference image and the multiband sensor image (Toet, Info. Fus. 4(3), 2003). In the current study we investigated new colour fusion schemes that combine the advantages of the both methods, using the correspondence between multiband sensor values and daytime colours (1st method) in a smooth transformation (2nd method). We designed and evaluated three new fusion schemes that focus on: i) a closer match with the daytime luminances, ii) improved saliency of hot targets and iii) improved discriminability of materials

A Performance Comparison for Two Versions of the Vulcan Photometer

NASA Technical Reports Server (NTRS)

Borucki, W. J.; Caldwell, D. A.; Koch, D. G.; Jenkins, J. M.; Showen, R. L.

2001-01-01

Analysis of the images produced by the first version (V1) of the Vulcan photometer indicated that two major sources of noise were sky brightness and image motion. To reduce the effect of the sky brightness, a second version (V2) with a longer focal length and a larger format detector was developed and tested. The first version consisted of 15-centimeter (cm) focal length, F/1.5 Aerojet Delft reconnaissance lens, and a 2048 x 2048 format front-illuminated charged coupled device (CCD) with 9 microns micropixels (Mpixels). The second version used a 30-cm focal length, F/2.5 Kodak AeroEktar lens, and a 4096 x 4096 format CCD with 9 micro pixels. Both have a 49-square-degree field of view (FOV) but the area of the sky subtended by each pixel in the V2 version is one-fourth that of the V1 version. This modification substantially reduces the shot noise due to the sky background and allows fainter stars to be monitored for planetary transits. To remove the data gap and consequent signal-level change caused by flipping the photometer around the declination axis and to reduce image movement on the detector, several other modifications were incorporated. These include modifying the mount and stiffening the photometer and autoguider structures to reduce flexure. This paper compares the performance characteristics of each photometer and discusses tests to identify sources of systematic noise.

Is There Anybody Home?

NASA Image and Video Library

2004-12-09

NASA's Spitzer Space Telescope recently captured these infrared images of six older stars with known planets. The yellow, fuzzy blobs are stars circled by disks of dust, or "debris disks," like the one that surrounds our own Sun. Though astronomers had predicted that stars with planets would harbor debris disks, they could not detect such disks until now. Spitzer was able to sense these dusty disks via their warm infrared glows. Specifically, the presence of the disks was inferred from an excess amount of infrared emission relative to what is emitted from the parent star alone. The stars themselves are similar in age and temperature to our Sun. In astronomical terms, they are stellar main sequence stars, with spectral types of F, G, or K. These planet-bearing stars have a median age of four billion years. For reference, our Sun is classified as a G star, with an age of approximately five billion years. The disks surrounding these planetary systems are comprised of cool material, with temperatures less than 100 Kelvin (-173 degrees Celsius). They are10 times farther away from their parent stars than Earth is from the Sun, and are thought to be analogues of the comet-filled Kuiper Belt in our solar system. The contrast scale is the same for each image. The images are approximately 2 arcminutes on each side. North is oriented upward and east is to the left. The pictures were taken with the 70-micron filter of Spitzer's multiband imaging photometer. The telescope resolution at 70 microns is 17 arcseconds and there is no evidence for any emission extended beyond the telescope resolution. http://photojournal.jpl.nasa.gov/catalog/PIA07098

Is There Anybody Home?

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site] Figure 1

NASA's Spitzer Space Telescope recently captured these infrared images of six older stars with known planets. The yellow, fuzzy blobs are stars circled by disks of dust, or 'debris disks,' like the one that surrounds our own Sun. Though astronomers had predicted that stars with planets would harbor debris disks, they could not detect such disks until now.

Spitzer was able to sense these dusty disks via their warm infrared glows. Specifically, the presence of the disks was inferred from an excess amount of infrared emission relative to what is emitted from the parent star alone.

The stars themselves are similar in age and temperature to our Sun. In astronomical terms, they are stellar main sequence stars, with spectral types of F, G, or K. These planet-bearing stars have a median age of four billion years. For reference, our Sun is classified as a G star, with an age of approximately five billion years.

The disks surrounding these planetary systems are comprised of cool material, with temperatures less than 100 Kelvin (-173 degrees Celsius). They are10 times farther away from their parent stars than Earth is from the Sun, and are thought to be analogues of the comet-filled Kuiper Belt in our solar system.

The contrast scale is the same for each image. The images are approximately 2 arcminutes on each side. North is oriented upward and east is to the left. The pictures were taken with the 70-micron filter of Spitzer's multiband imaging photometer. The telescope resolution at 70 microns is 17 arcseconds and there is no evidence for any emission extended beyond the telescope resolution.

Quaternion-Based Texture Analysis of Multiband Satellite Images: Application to the Estimation of Aboveground Biomass in the East Region of Cameroon.

PubMed

Djiongo Kenfack, Cedrigue Boris; Monga, Olivier; Mpong, Serge Moto; Ndoundam, René

2018-03-01

Within the last decade, several approaches using quaternion numbers to handle and model multiband images in a holistic manner were introduced. The quaternion Fourier transform can be efficiently used to model texture in multidimensional data such as color images. For practical application, multispectral satellite data appear as a primary source for measuring past trends and monitoring changes in forest carbon stocks. In this work, we propose a texture-color descriptor based on the quaternion Fourier transform to extract relevant information from multiband satellite images. We propose a new multiband image texture model extraction, called FOTO++, in order to address biomass estimation issues. The first stage consists in removing noise from the multispectral data while preserving the edges of canopies. Afterward, color texture descriptors are extracted thanks to a discrete form of the quaternion Fourier transform, and finally the support vector regression method is used to deduce biomass estimation from texture indices. Our texture features are modeled using a vector composed with the radial spectrum coming from the amplitude of the quaternion Fourier transform. We conduct several experiments in order to study the sensitivity of our model to acquisition parameters. We also assess its performance both on synthetic images and on real multispectral images of Cameroonian forest. The results show that our model is more robust to acquisition parameters than the classical Fourier Texture Ordination model (FOTO). Our scheme is also more accurate for aboveground biomass estimation. We stress that a similar methodology could be implemented using quaternion wavelets. These results highlight the potential of the quaternion-based approach to study multispectral satellite images.

Narrowband NanoSat Scale Photometry for VUV Planetary and Heliophysics missions

NASA Astrophysics Data System (ADS)

Noto, J.; Doe, R. A.; Frey, H. U.

2015-12-01

Remote vacuum ultraviolet (VUV) soundings to support Explorer-class atmospheric research are typically enabled by large aperture, wideband spectrographs carefully pointed to measure a planet's disk and limb regions (i.e. TIMED/GUVI and MAVEN/UVS). An alternate measurement paradigm is to identify key aeronomical emission targets (i.e HI 121.6-nm, OI 135.6-nm, N2 Lyman-Birge-Hopfield band 135 - 155 nm) and create a series of narrowband photometers each with greater in-band sensitivity (relative to a spectrograph) due to enhanced out-of-band rejection and absence of a dispersive element. Recent advances in narrowband VUV coating and PMT miniaturization have enabled design of a dual-channel nanosatellite-scale VUV photometer with flight heritage significantly leveraged from the NASA POLAR UVI imager the Air Force CubeSat Tiny Ionospheric Photometer (CTIP). Herein we present further modeled sensitivity studies and current build status of the dual-channel thermosphere/ionosphere photometer (DTIP) and address notional missions including dayside O/N2 composition, auroral energetics, nightside plasma structuring and peak layer characterization, and hydrogen geocoronal tomographic imaging.

Global Temperature Measurement of Supercooled Water under Icing Conditions using Two-Color Luminescent Images and Multi-Band Filter

NASA Astrophysics Data System (ADS)

Tanaka, Mio; Morita, Katsuaki; Kimura, Shigeo; Sakaue, Hirotaka

2012-11-01

Icing occurs by a collision of a supercooled-water droplet on a surface. It can be seen in any cold area. A great attention is paid in an aircraft icing. To understand the icing process on an aircraft, it is necessary to give the temperature information of the supercooled water. A conventional technique, such as a thermocouple, is not valid, because it becomes a collision surface that accumulates ice. We introduce a dual-luminescent imaging to capture a global temperature distribution of supercooled water under the icing conditions. It consists of two-color luminescent probes and a multi-band filter. One of the probes is sensitive to the temperature and the other is independent of the temperature. The latter is used to cancel the temperature-independent luminescence of a temperature-dependent image caused by an uneven illumination and a camera location. The multi-band filter only selects the luminescent peaks of the probes to enhance the temperature sensitivity of the imaging system. By applying the system, the time-resolved temperature information of a supercooled-water droplet is captured.

Multi-Wavelength Views of Protostars in IC 1396

NASA Technical Reports Server (NTRS)

2003-01-01

[figure removed for brevity, see original site] Click on individual images below for larger view

[figure removed for brevity, see original site]

[figure removed for brevity, see original site]

[figure removed for brevity, see original site]

NASA's Spitzer Space Telescope has captured a glowing stellar nursery within a dark globule that is opaque at visible light. These new images pierce through the obscuration to reveal the birth of new protostars, or embryonic stars, and young stars never before seen.

The Elephant's Trunk Nebula is an elongated dark globule within the emission nebula IC 1396 in the constellation of Cepheus. Located at a distance of 2,450 light-years, the globule is a condensation of dense gas that is barely surviving the strong ionizing radiation from a nearby massive star. The globule is being compressed by the surrounding ionized gas.

The large composite image above is a product of combining data from the observatory's multiband imaging photometer and the infrared array camera. The thermal emission at 24 microns measured by the photometer (red) is combined with near-infrared emission from the camera at 3.6/4.5 microns (blue) and from 5.8/8.0 microns (green). The colors of the diffuse emission and filaments vary, and are a combination of molecular hydrogen (which tends to be green) and polycyclic aromatic hydrocarbon (brown) emissions.

Within the globule, a half dozen newly discovered protostars, or embryonic stars, are easily discernible as the bright red-tinted objects, mostly along the southern rim of the globule. These were previously undetected at visible wavelengths due to obscuration by the thick cloud ('globule body') and by dust surrounding the newly forming stars. The newborn stars form in the dense gas because of compression by the wind and radiation from a nearby massive star (located outside the field of view to the left). The winds from this unseen star are also responsible for producing the spectacular filamentary appearance of the globule itself.

The Spitzer Space Telescope also sees many newly discovered young stars, often enshrouded in dust, which may be starting the nuclear fusion that defines a star. These young stars are too cool to be seen at visible wavelengths. Both the protostars and young stars are bright in the mid-infrared because of their surrounding discs of solid material. A few of the visible-light stars in this image were found to have excess infrared emission, suggesting they are more mature stars surrounded by primordial remnants from their formation, or from crumbling asteroids and comets in their planetary systems.

Amazing Andromeda Galaxy

NASA Technical Reports Server (NTRS)

2006-01-01

The many 'personalities' of our great galactic neighbor, the Andromeda galaxy, are exposed in this new composite image from NASA's Galaxy Evolution Explorer and the Spitzer Space Telescope.

The wide, ultraviolet eyes of Galaxy Evolution Explorer reveal Andromeda's 'fiery' nature -- hotter regions brimming with young and old stars. In contrast, Spitzer's super-sensitive infrared eyes show Andromeda's relatively 'cool' side, which includes embryonic stars hidden in their dusty cocoons.

Galaxy Evolution Explorer detected young, hot, high-mass stars, which are represented in blue, while populations of relatively older stars are shown as green dots. The bright yellow spot at the galaxy's center depicts a particularly dense population of old stars.

Swaths of red in the galaxy's disk indicate areas where Spitzer found cool, dusty regions where stars are forming. These stars are still shrouded by the cosmic clouds of dust and gas that collapsed to form them.

Together, Galaxy Evolution Explorer and Spitzer complete the picture of Andromeda's swirling spiral arms. Hints of pinkish purple depict regions where the galaxy's populations of hot, high-mass stars and cooler, dust-enshrouded stars co-exist.

Located 2.5 million light-years away, the Andromeda is our largest nearby galactic neighbor. The galaxy's entire disk spans about 260,000 light-years, which means that a light beam would take 260,000 years to travel from one end of the galaxy to the other. By comparison, our Milky Way galaxy's disk is about 100,000 light-years across.

This image is a false color composite comprised of data from Galaxy Evolution Explorer's far-ultraviolet detector (blue), near-ultraviolet detector (green), and Spitzer's multiband imaging photometer at 24 microns (red).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballering, Nicholas P.; Su, Kate Y. L.; Rieke, George H.

We investigate whether varying the dust composition (described by the optical constants) can solve a persistent problem in debris disk modeling—the inability to fit the thermal emission without overpredicting the scattered light. We model five images of the β Pictoris disk: two in scattered light from the Hubble Space Telescope ( HST )/Space Telescope Imaging Spectrograph at 0.58 μ m and HST /Wide Field Camera 3 (WFC 3) at 1.16 μ m, and three in thermal emission from Spitzer /Multiband Imaging Photometer for Spitzer (MIPS) at 24 μ m, Herschel /PACS at 70 μ m, and Atacama Large Millimeter/submillimeter Arraymore » at 870 μ m. The WFC3 and MIPS data are published here for the first time. We focus our modeling on the outer part of this disk, consisting of a parent body ring and a halo of small grains. First, we confirm that a model using astronomical silicates cannot simultaneously fit the thermal and scattered light data. Next, we use a simple generic function for the optical constants to show that varying the dust composition can improve the fit substantially. Finally, we model the dust as a mixture of the most plausible debris constituents: astronomical silicates, water ice, organic refractory material, and vacuum. We achieve a good fit to all data sets with grains composed predominantly of silicates and organics, while ice and vacuum are, at most, present in small amounts. This composition is similar to one derived from previous work on the HR 4796A disk. Our model also fits the thermal spectral energy distribution, scattered light colors, and high-resolution mid-IR data from T-ReCS for this disk. Additionally, we show that sub-blowout grains are a necessary component of the halo.« less

Multi-band morpho-Spectral Component Analysis Deblending Tool (MuSCADeT): Deblending colourful objects

NASA Astrophysics Data System (ADS)

Joseph, R.; Courbin, F.; Starck, J.-L.

2016-05-01

We introduce a new algorithm for colour separation and deblending of multi-band astronomical images called MuSCADeT which is based on Morpho-spectral Component Analysis of multi-band images. The MuSCADeT algorithm takes advantage of the sparsity of astronomical objects in morphological dictionaries such as wavelets and their differences in spectral energy distribution (SED) across multi-band observations. This allows us to devise a model independent and automated approach to separate objects with different colours. We show with simulations that we are able to separate highly blended objects and that our algorithm is robust against SED variations of objects across the field of view. To confront our algorithm with real data, we use HST images of the strong lensing galaxy cluster MACS J1149+2223 and we show that MuSCADeT performs better than traditional profile-fitting techniques in deblending the foreground lensing galaxies from background lensed galaxies. Although the main driver for our work is the deblending of strong gravitational lenses, our method is fit to be used for any purpose related to deblending of objects in astronomical images. An example of such an application is the separation of the red and blue stellar populations of a spiral galaxy in the galaxy cluster Abell 2744. We provide a python package along with all simulations and routines used in this paper to contribute to reproducible research efforts. Codes can be found at http://lastro.epfl.ch/page-126973.html

STAR FORMATION ACTIVITY IN A YOUNG GALAXY CLUSTER AT Z = 0.866

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laganá, T. F.; Martins, L. P.; Ulmer, M. P.

2016-07-10

The galaxy cluster RX J1257+4738 at z = 0.866 is one of the highest redshift clusters with a richness of multi-wavelength data, and is thus a good target to study the star formation–density relation at early epochs. Using a sample of spectroscopically confirmed cluster members, we derive the star-formation rates (SFRs) of our galaxies using two methods: (1) the relation between SFR and total infrared luminosity extrapolated from the observed Spitzer Multiband Imaging Photometer for Spitzer 24 μ m imaging data; and (2) spectral energy distribution fitting using the MAGPHYS code, including eight different bands. We show that, for thismore » cluster, the SFR–density relation is very weak and seems to be dominated by the two central galaxies and the SFR presents a mild dependence on stellar mass, with more massive galaxies having higher SFR. However, the specific SFR (SSFR) decreases with stellar mass, meaning that more massive galaxies are forming fewer stars per unit of mass, and thus suggesting that the increase in star-forming members is driven by cluster assembly and infall. If the environment is somehow driving the star formation, one would expect a relation between the SSFR and the cluster centric distance, but that is not the case. A possible scenario to explain this lack of correlation is the contamination by infalling galaxies in the inner part of the cluster, which may be on their initial pass through the cluster center. As these galaxies have higher SFRs for their stellar mass, they enhance the mean SSFR in the center of the cluster.« less

AMPS definition study on Optical Band Imager and Photometer System (OBIPS)

NASA Technical Reports Server (NTRS)

Davis, T. N.; Deehr, C. S.; Hallinan, T. J.; Wescott, E. M.

1975-01-01

A study was conducted to define the characteristics of a modular optical diagnostic system (OBIPS) for AMPS, to provide input to Phase B studies, and to give information useful for experiment planning and design of other instrumentation. The system described consists of visual and UV-band imagers and visual and UV-band photometers; of these the imagers are most important because of their ability to measure intensity as a function of two spatial dimensions and time with high resolution. The various subsystems of OBIPS are in themselves modular with modules having a high degree of interchangeability for versatility, economy, and redundancy.

SIRTF Tools for DIRT

NASA Astrophysics Data System (ADS)

Pound, M. W.; Wolfire, M. G.; Amarnath, N. S.

2004-07-01

The Dust InfraRed ToolBox (DIRT - a part of the Web Infrared ToolShed, or WITS {http://dustem.astro.umd.edu}) is a Java applet for modeling astrophysical processes in circumstellar shells around young and evolved stars. DIRT has been used by the astrophysics community for about 5 years. Users can automatically and efficiently search grids of pre-calculated models to fit their data. A large set of physical parameters and dust types are included in the model database, which contains over 500,000 models. We are adding new functionality to DIRT to support new missions like SIRTF and SOFIA. A new Instrument module allows for plotting of the model points convolved with the spatial and spectral responses of the selected instrument. This lets users better fit data from specific instruments. Currently, we have implemented modules for the Infrared Array Camera (IRAC) and Multiband Imaging Photometer (MIPS) on SIRTF. The models are based on the dust radiation transfer code of Wolfire & Cassinelli (1986) which accounts for multiple grain sizes and compositions. The model outputs are averaged over the instrument bands using the same weighting (νFν = constant) as the SIRTF data pipeline which allows the SIRTF data products to be compared directly with the model database. This work was supported in part by a NASA AISRP grant NAG 5-10751 and the SIRTF Legacy Science Program provided by NASA through an award issued by JPL under NASA contract 1407.

A Matrix Pencil Algorithm Based Multiband Iterative Fusion Imaging Method

NASA Astrophysics Data System (ADS)

Zou, Yong Qiang; Gao, Xun Zhang; Li, Xiang; Liu, Yong Xiang

2016-01-01

Multiband signal fusion technique is a practicable and efficient way to improve the range resolution of ISAR image. The classical fusion method estimates the poles of each subband signal by the root-MUSIC method, and some good results were get in several experiments. However, this method is fragile in noise for the proper poles could not easy to get in low signal to noise ratio (SNR). In order to eliminate the influence of noise, this paper propose a matrix pencil algorithm based method to estimate the multiband signal poles. And to deal with mutual incoherent between subband signals, the incoherent parameters (ICP) are predicted through the relation of corresponding poles of each subband. Then, an iterative algorithm which aimed to minimize the 2-norm of signal difference is introduced to reduce signal fusion error. Applications to simulate dada verify that the proposed method get better fusion results at low SNR.

A Matrix Pencil Algorithm Based Multiband Iterative Fusion Imaging Method

PubMed Central

Zou, Yong Qiang; Gao, Xun Zhang; Li, Xiang; Liu, Yong Xiang

2016-01-01

Multiband signal fusion technique is a practicable and efficient way to improve the range resolution of ISAR image. The classical fusion method estimates the poles of each subband signal by the root-MUSIC method, and some good results were get in several experiments. However, this method is fragile in noise for the proper poles could not easy to get in low signal to noise ratio (SNR). In order to eliminate the influence of noise, this paper propose a matrix pencil algorithm based method to estimate the multiband signal poles. And to deal with mutual incoherent between subband signals, the incoherent parameters (ICP) are predicted through the relation of corresponding poles of each subband. Then, an iterative algorithm which aimed to minimize the 2-norm of signal difference is introduced to reduce signal fusion error. Applications to simulate dada verify that the proposed method get better fusion results at low SNR. PMID:26781194

Two-way multi-band optical/IR transmission measurements in the Persian Gulf coastal region

NASA Astrophysics Data System (ADS)

de Jong, Arie N.; Fritz, Peter J.

2005-10-01

The atmospheric conditions in the Persian Gulf region are significantly different from other places in the world. The particle size distribution may vary daily and during the day. The aerosols can contribute to the amount of rainfall over land, important for the nations around the Gulf. In 2004 NASNGSFC and NRL (Naval Research Laboratory) introduced a proposal to improve the modelling of aerosol transport for the Persian Gulf area. The proposal included a measurement campaign in the UAE (United Arabian Emirates), held in the summer/fall of 2004, sponsored by the DWRS (Department of Water Resources Studies) in Abu Dhabi: UAEz (Unified Aerosol Experiment in the UAE). In this campaign NASA installed a number of multi-spectral sun-photometers at various locations in the UAE (http://aeronet.gsfc.nasa.gov). NRL installed ground based and airborne particle samplers. In addition, TNO (the Netherlands) installed its multi-band opticaUIR transmissometer, in order to collect horizontal, path-integrated transmission data. This device provides additional information on the scattering behaviour of the aerosols compared to the other instruments, which either integrate scattering over the full vertical path (the NASA sun-photometers, providing the Aerosol Optical Depth (AOD)) or sample the particles in-situ (the NRL particle samplers, providing size distribution and composition). This paper deals with our transmission measurement set-up, which was located in a coastal area near Abu Dhabi. This location allowed the investigation of the local variability of the atmospheric conditions: from desert dust to pollution, such as fossil fuel and biomass burning, depending on the wind direction. For logistic reasons a set-up was chosen with a retro-reflector. This choice implies consequences for the calibration procedure and measurement accuracy, which are discussed in detail. Also the effects of path-inhomogeneity and scintillation for such a two-way set-up are considered. Results are presented for the measurement period of two weeks in September, showing interesting transmission effects due to temporal changes in aerosol particle composition. These phenomena cannot be explained by scattering theory for spherical particles. More knowledge is required on the shape and composition of the particles. Comparison of the transmission data with the data from other instruments will be done in a next phase.

Simultaneous Multislice Accelerated Free-Breathing Diffusion-Weighted Imaging of the Liver at 3T.

PubMed

Obele, Chika C; Glielmi, Christopher; Ream, Justin; Doshi, Ankur; Campbell, Naomi; Zhang, Hoi Cheung; Babb, James; Bhat, Himanshu; Chandarana, Hersh

2015-10-01

To perform image quality comparison between accelerated multiband diffusion acquisition (mb2-DWI) and conventional diffusion acquisition (c-DWI) in patients undergoing clinically indicated liver MRI. In this prospective study 22 consecutive patients undergoing clinically indicated liver MRI on a 3-T scanner equipped to perform multiband diffusion-weighed imaging (mb-DWI) were included. DWI was performed with single-shot spin-echo echo-planar technique with fat-suppression in free breathing with matching parameters when possible using c-DWI, mb-DWI, and multiband DWI with a twofold acceleration (mb2-DWI). These diffusion sequences were compared with respect to various parameters of image quality, lesion detectability, and liver ADC measurements. Accelerated mb2-DWI was 40.9% faster than c-DWI (88 vs. 149 s). Various image quality parameter scores were similar or higher on mb2-DWI when compared to c-DWI. The overall image quality score (averaged over the three readers) was significantly higher for mb-2 compared to c-DWI for b = 0 s/mm(2) (3.48 ± 0.52 vs. 3.21 ± 0.54; p = 0.001) and for b = 800 s/mm(2) (3.24 ± 0.76 vs. 3.06 ± 0.86; p = 0.010). Total of 25 hepatic lesions were visible on mb2-DWI and c-DWI, with identical lesion detectability. There was no significant difference in liver ADC between mb2-DWI and c-DWI (p = 0.12). Bland-Altman plot demonstrates lower mean liver ADC with mb2-DWI compared to c-DWI (by 0.043 × 10(-3) mm(2)/s or 3.7% of the average ADC). Multiband technique can be used to increase acquisition speed nearly twofold for free-breathing DWI of the liver with similar or improved overall image quality and similar lesion detectability compared to conventional DWI.

FIR filters for hardware-based real-time multi-band image blending

NASA Astrophysics Data System (ADS)

Popovic, Vladan; Leblebici, Yusuf

2015-02-01

Creating panoramic images has become a popular feature in modern smart phones, tablets, and digital cameras. A user can create a 360 degree field-of-view photograph from only several images. Quality of the resulting image is related to the number of source images, their brightness, and the used algorithm for their stitching and blending. One of the algorithms that provides excellent results in terms of background color uniformity and reduction of ghosting artifacts is the multi-band blending. The algorithm relies on decomposition of image into multiple frequency bands using dyadic filter bank. Hence, the results are also highly dependant on the used filter bank. In this paper we analyze performance of the FIR filters used for multi-band blending. We present a set of five filters that showed the best results in both literature and our experiments. The set includes Gaussian filter, biorthogonal wavelets, and custom-designed maximally flat and equiripple FIR filters. The presented results of filter comparison are based on several no-reference metrics for image quality. We conclude that 5/3 biorthogonal wavelet produces the best result in average, especially when its short length is considered. Furthermore, we propose a real-time FPGA implementation of the blending algorithm, using 2D non-separable systolic filtering scheme. Its pipeline architecture does not require hardware multipliers and it is able to achieve very high operating frequencies. The implemented system is able to process 91 fps for 1080p (1920×1080) image resolution.

Solar System Observing with the Space Infrared Telescope Facility (SIRTF)

NASA Technical Reports Server (NTRS)

Cleve, J. Van; Meadows, V. S.; Stansberry, J.

2003-01-01

SIRTF is NASA's Space Infrared Telescope Facility. Currently planned for launch on 15 Apr 2003, it is the final element in NASA's Great Observatories Program. SIRTF has an 85 cm diameter f/12 lightweight beryllium telescope, cooled to lekss than 5.5K. It is diffraction-limited at 6.5 microns, and has wavelengthcoverage from 3-180 microns. Its estimated lifetime (limited by cryogen) is 2.5 years at minimum, with a goal of 5+ years. SIRTF has three instruments, IRAC, IRS, and MIPS. IRAC (InfraRed Array Camera) provides simultaneous images at wavelengths of 3.6, 4.5, 5.8, and 8.0 microns. IRS (InfraRed Spectrograph) has 4 modules providing low-resolution (R=60-120) spectra from 5.3 to 40 microns, high-resolution (R=600) spectra from 10 to 37 microns, and an autonomous target acquisition system (PeakUp) which includes small-field imaging at 15 microns. MIPS (Multiband Imaging Photometer for SIRTF)} does imaging photometry at 24, 70, and 160 m and low-resolution (R=15-25) spectroscopy (SED) between 55 and 96 microns. The SIRTF Guaranteed Time Observers (GTOs) are planning to observe Outer Solar System satellites and planets, extinct comets and low-albedo asteroids, Centaurs and Kuiper Belt Objects, cometary dust trails, and a few active short-period comets. The GTO programs are listed in detail in the SIRTF Reserved Observations Catalog (ROC). We would like to emphasize that there remain many interesting subjects for the General Observers (GO). Proposal success for the planetary observer community in the first SIRTF GO proposal cycle (GO-1) determines expectations for future GO calls and Solar System use of SIRTF, so we would like promote a strong set of planetary GO-1 proposals. Towards that end, we present this poster, and we will convene a Solar System GO workshop 3.5 months after launch.

M33: A Close Neighbor Reveals its True Size and Splendor (3-color composite)

NASA Technical Reports Server (NTRS)

2009-01-01

One of our closest galactic neighbors shows its awesome beauty in this new image from NASA's Spitzer Space Telescope. M33, also known as the Triangulum Galaxy, is a member of what's known as our Local Group of galaxies. Along with our own Milky Way, this group travels together in the universe, as they are gravitationally bound. In fact, M33 is one of the few galaxies that is moving toward the Milky Way despite the fact that space itself is expanding, causing most galaxies in the universe to grow farther and farther apart.

When viewed with Spitzer's infrared eyes, this elegant spiral galaxy sparkles with color and detail. Stars appear as glistening blue gems (several of which are actually foreground stars in our own galaxy), while dust rich in organic molecules glows green. The diffuse orange-red glowing areas indicate star-forming regions, while small red flecks outside the spiral disk of M33 are most likely distant background galaxies. But not only is this new image beautiful, it also shows M33 to be surprising large bigger than its visible-light appearance would suggest. With its ability to detect cold, dark dust, Spitzer can see emission from cooler material well beyond the visible range of M33's disk. Exactly how this cold material moved outward from the galaxy is still a mystery, but winds from giant stars or supernovas may be responsible.

M33 is located about 2.9 million light-years away in the constellation Triangulum. This is a three-color composite image showing infrared observations from two of Spitzer instruments. Blue represents combined 3.6- and 4.5-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer.

Spitzer Reveals Stellar 'Family Tree'

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] High resolution poster version

Generations of stars can be seen in this new infrared portrait from NASA's Spitzer Space Telescope. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Younger stars line the rims of the cavities, and some can be seen as pink dots at the tips of the elephant-trunk-like pillars. The white knotty areas are where the youngest stars are forming. Red shows heated dust that pervades the region's cavities, while green highlights dense clouds.

W5 spans an area of sky equivalent to four full moons and is about 6,500 light-years away in the constellation Cassiopeia. The Spitzer picture was taken over a period of 24 hours.

Like other massive star-forming regions, such as Orion and Carina, W5 contains large cavities that were carved out by radiation and winds from the region's most massive stars. According to the theory of triggered star-formation, the carving out of these cavities pushes gas together, causing it to ignite into successive generations of new stars.

This image contains some of the best evidence yet for the triggered star-formation theory. Scientists analyzing the photo have been able to show that the ages of the stars become progressively and systematically younger with distance from the center of the cavities.

This is a three-color composite showing infrared observations from two Spitzer instruments. Blue represents 3.6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morales, F. Y.; Bryden, G.; Werner, M. W.

We present dual-band Herschel /PACS imaging for 59 main-sequence stars with known warm dust ( T {sub warm} ∼ 200 K), characterized by Spitzer . Of 57 debris disks detected at Herschel wavelengths (70 and/or 100 and 160 μ m), about half have spectral energy distributions (SEDs) that suggest two-ring disk architectures mirroring that of the asteroid–Kuiper Belt geometry; the rest are consistent with single belts of warm, asteroidal material. Herschel observations spatially resolve the outer/cold dust component around 14 A-type and 4 solar-type stars with two-belt systems, 15 of which for the first time. Resolved disks are typically observedmore » with radii >100 AU, larger than expected from a simple blackbody fit. Despite the absence of narrow spectral features for ice, we find that the shape of the continuum, combined with resolved outer/cold dust locations, can help constrain the grain size distribution and hint at the dust’s composition for each resolved system. Based on the combined Spitzer /IRS+Multiband Imaging Photometer (5-to-70 μ m) and Herschel /PACS (70-to-160 μ m) data set, and under the assumption of idealized spherical grains, we find that over half of resolved outer/cold belts are best fit with a mixed ice/rock composition. Minimum grain sizes are most often equal to the expected radiative blowout limit, regardless of composition. Three of four resolved systems around the solar-type stars, however, tend to have larger minimum grains compared to expectation from blowout ( f {sub MB} = a {sub min}/ a {sub BOS} ∼ 5). We also probe the disk architecture of 39 Herschel -unresolved systems by modeling their SEDs uniformly, and find them to be consistent with 31 single- and 8 two-belt debris systems.« less

Solar System Studies with the Space Infrared Telescope Facility (SIRTF)

NASA Technical Reports Server (NTRS)

Cruikshank, Dale P.; DeVincenzi, Donald L. (Technical Monitor)

1998-01-01

SIRTF (Space Infrared Telescope Facility) is the final element in NASA's 'Great Observatories' program. It consists of an 85-cm cryogenically-cooled observatory for infrared astronomy from space. SIRTF is scheduled for launch in late 2001 or early 2002 on a Delta rocket into a heliocentric orbit trailing the Earth. Data from SIRTF will be processed and disseminated to the community through the SIRTF Science Center (SSC) located at the Infrared Processing and Analysis Center (IPAC) at Caltech. Some 80/% of the total observing time (estimated at a minimum of 7500 hours of integration time per year for the mission lifetime of about 4 years) will be available to the scientific community at large through a system of refereed proposals. Three basic instruments are located in the SIRTF focal plane. The Multiband Imaging Photometer (MIPS), the Infrared Array Camera (IRAC), and the Infrared Spectrometer (IRS), taken together, provide imaging and spectroscopy from 3.5 to 160 microns. Among the solar system studies suited to SIRTF are the following: 1) spectroscopy and radiometry of small bodies from the asteroid main belt, through the Trojan clouds, to the Kuiper Disk; 2) dust distribution in the zodiacal cloud and the Earth's heliocentric dust ring; 3) spectroscopy and radiometry of comets; and 4) spectroscopy and radiometry of planets and their satellites. Searches for, and studies of dust disks around other stars, brown dwarfs, and superplanets will also be conducted with SIRTF. The SORTIE web site (http://ssc.ipac.caltech.edu/sirtf) contains important details and documentation on the project, the spacecraft, the telescope, instruments, and observing procedures. A community-wide workshop for solar system studies with SIRTF is in the planning stages by the author and Martha S. Hanner for the summer of 1999.

SAND: an automated VLBI imaging and analysing pipeline - I. Stripping component trajectories

NASA Astrophysics Data System (ADS)

Zhang, M.; Collioud, A.; Charlot, P.

2018-02-01

We present our implementation of an automated very long baseline interferometry (VLBI) data-reduction pipeline that is dedicated to interferometric data imaging and analysis. The pipeline can handle massive VLBI data efficiently, which makes it an appropriate tool to investigate multi-epoch multiband VLBI data. Compared to traditional manual data reduction, our pipeline provides more objective results as less human interference is involved. The source extraction is carried out in the image plane, while deconvolution and model fitting are performed in both the image plane and the uv plane for parallel comparison. The output from the pipeline includes catalogues of CLEANed images and reconstructed models, polarization maps, proper motion estimates, core light curves and multiband spectra. We have developed a regression STRIP algorithm to automatically detect linear or non-linear patterns in the jet component trajectories. This algorithm offers an objective method to match jet components at different epochs and to determine their proper motions.

Evaluation of nine-frame enhanced multiband photography San Andreas fault zone, Carrizo Plain, California

NASA Technical Reports Server (NTRS)

Wallace, R. E.

1969-01-01

Nine-frame multiband aerial photography of a sample area 4500 feet on a side was processed to enhance spectral contrasts. The area concerned is in the Carrizo Plain, 45 miles west of Bakersfield, California, in sec. 29, T 31 S., R. 21 E., as shown on the Panorama Hills quadrangle topographic map published by the U. S. Geological Survey. The accompany illustrations include an index map showing the location of the Carrizo Plain area; a geologic map of the area based on field studies and examination of black and white aerial photographs; an enhanced multiband aerial photograph; an Aero Ektachrome photograph; black and white aerial photographs; and infrared image in the 8-13 micron band.

VizieR Online Data Catalog: KiDS-ESO-DR3 multi-band source catalog (de Jong+, 2017)

NASA Astrophysics Data System (ADS)

de Jong, J. T. A.; Verdoes Kleijn, G. A.; Erben, T.; Hildebrandt, H.; Kuijken, K.; Sikkema, G.; Brescia, M.; Bilicki, M.; Napolitano, N. R.; Amaro, V.; Begeman, K. G.; Boxhoorn, D. R.; Buddelmeijer, H.; Cavuoti, S.; Getman, F.; Grado, A.; Helmich, E.; Huang, Z.; Irisarri, N.; La Barbera, F.; Longo, G.; McFarland, J. P.; Nakajima, R.; Paolillo, M.; Puddu, E.; Radovich, M.; Rifatto, A.; Tortora, C; Valentijn, E. A.; Vellucci, C.; Vriend, W-J.; Amon, A.; Blake, C.; Choi, A.; Fenech, Conti I.; Herbonnet, R.; Heymans, C.; Hoekstra, H.; Klaes, D.; Merten, J.; Miller, L.; Schneider, P.; Viola, M.

2017-04-01

KiDS-ESO-DR3 contains a multi-band source catalogue encompassing all publicly released tiles, a total of 440 survey tiles including the coadded images, weight maps, masks and source lists of 292 survey tiles of KiDS-ESO-DR3, adding to the 148 tiles released previously (50 in KiDS-ESO-DR1 and 98 in KiDS-ESO-DR2). (1 data file).

'No Organics' Zone Circles Pinwheel

NASA Technical Reports Server (NTRS)

2008-01-01

The Pinwheel galaxy, otherwise known as Messier 101, sports bright reddish edges in this new infrared image from NASA's Spitzer Space Telescope. Research from Spitzer has revealed that this outer red zone lacks organic molecules present in the rest of the galaxy. The red and blue spots outside of the spiral galaxy are either foreground stars or more distant galaxies.

The organics, called polycyclic aromatic hydrocarbons, are dusty, carbon-containing molecules that help in the formation of stars. On Earth, they are found anywhere combustion reactions take place, such as barbeque pits and exhaust pipes. Scientists also believe this space dust has the potential to be converted into the stuff of life.

Spitzer found that the polycyclic aromatic hydrocarbons decrease in concentration toward the outer portion of the Pinwheel galaxy, then quickly drop off and are no longer detected at its very outer rim. According to astronomers, there's a threshold at the rim where the organic material is being destroyed by harsh radiation from stars. Radiation is more damaging at the far reaches of a galaxy because the stars there have less heavy metals, and metals dampen the radiation.

The findings help researchers understand how stars can form in these harsh environments, where polycyclic aromatic hydrocarbons are lacking. Under normal circumstances, the polycyclic aromatic hydrocarbons help cool down star-forming clouds, allowing them to collapse into stars. In regions like the rim of the Pinwheel as well as the very early universe stars form without the organic dust. Astronomers don't know precisely how this works, so the rim of the Pinwheel provides them with a laboratory for examining the process relatively close up.

In this image, infrared light with a wavelength of 3.6 microns is colored blue; 8-micron light is green; and 24-micron light is red. All three of Spitzer's instruments were used in the study: the infrared array camera, the multiband imaging photometer and the infrared spectrograph.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruuge, A; Erdi, Y; Mahmood, U

Purpose: The conformance of Primary Diagnostic Monitors (PDMs) to the DICOM GSDF is increasingly required by several state and city regulators. Our purpose was to quantitatively characterize the luminance performance of the internal, built in photometer of BARCO monitors against an externally calibrated luminance meter. Methods: Thirty one PDMs (BARCO) were included in our analysis. An externally calibrated photometer (RaySafe Solo Light) was used to measure the luminance and illuminance values. Measured monitors were located at various hospital sites, radiology physicians’ offices and radiology reading rooms. All measured PDMs were equipped with the manufacturer’s built-in photometers and connected to Barcomore » MediCal QA web service for manual and automatic quality control measurements. PDM combinations included 1, 2 and 4 monitors depending on the location. TG-18 and SMPTE test patterns were used to evaluate monitor performance. Results: All the PDMs exceeded the luminance ratio of 250:1, as required by NYC PDM guidelines. One PDM failed the NYC requirement for the minimal luminance level of 350 cd/m2. As compared to the external photometer, the difference in measurement of the maximum luminance with the built-in photometer was found to exceed 5% on 6 of the PDM measured, with a maximum deviation of 10%. The age of the monitors that failed was on average 5 years. All monitors passed the luminance uniformity test, which was 30% from the center of the monitor to the 4 corner locations. Four PDMs failed the Gray Scale Display Function (GSDF) calibration. Conclusion: For the consistent display of medical images and continued conformance with the DICOM GSDF standard, it is essential to compare the performance of the built-in photometer with an externally calibrated photometer for monitors that are older than 5 years.« less

Deep-learning derived features for lung nodule classification with limited datasets

NASA Astrophysics Data System (ADS)

Thammasorn, P.; Wu, W.; Pierce, L. A.; Pipavath, S. N.; Lampe, P. D.; Houghton, A. M.; Haynor, D. R.; Chaovalitwongse, W. A.; Kinahan, P. E.

2018-02-01

Only a few percent of indeterminate nodules found in lung CT images are cancer. However, enabling earlier diagnosis is important to avoid invasive procedures or long-time surveillance to those benign nodules. We are evaluating a classification framework using radiomics features derived with a machine learning approach from a small data set of indeterminate CT lung nodule images. We used a retrospective analysis of 194 cases with pulmonary nodules in the CT images with or without contrast enhancement from lung cancer screening clinics. The nodules were contoured by a radiologist and texture features of the lesion were calculated. In addition, sematic features describing shape were categorized. We also explored a Multiband network, a feature derivation path that uses a modified convolutional neural network (CNN) with a Triplet Network. This was trained to create discriminative feature representations useful for variable-sized nodule classification. The diagnostic accuracy was evaluated for multiple machine learning algorithms using texture, shape, and CNN features. In the CT contrast-enhanced group, the texture or semantic shape features yielded an overall diagnostic accuracy of 80%. Use of a standard deep learning network in the framework for feature derivation yielded features that substantially underperformed compared to texture and/or semantic features. However, the proposed Multiband approach of feature derivation produced results similar in diagnostic accuracy to the texture and semantic features. While the Multiband feature derivation approach did not outperform the texture and/or semantic features, its equivalent performance indicates promise for future improvements to increase diagnostic accuracy. Importantly, the Multiband approach adapts readily to different size lesions without interpolation, and performed well with relatively small amount of training data.

Visual enhancement of unmixed multispectral imagery using adaptive smoothing

USGS Publications Warehouse

Lemeshewsky, G.P.; Rahman, Z.-U.; Schowengerdt, R.A.; Reichenbach, S.E.

2004-01-01

Adaptive smoothing (AS) has been previously proposed as a method to smooth uniform regions of an image, retain contrast edges, and enhance edge boundaries. The method is an implementation of the anisotropic diffusion process which results in a gray scale image. This paper discusses modifications to the AS method for application to multi-band data which results in a color segmented image. The process was used to visually enhance the three most distinct abundance fraction images produced by the Lagrange constraint neural network learning-based unmixing of Landsat 7 Enhanced Thematic Mapper Plus multispectral sensor data. A mutual information-based method was applied to select the three most distinct fraction images for subsequent visualization as a red, green, and blue composite. A reported image restoration technique (partial restoration) was applied to the multispectral data to reduce unmixing error, although evaluation of the performance of this technique was beyond the scope of this paper. The modified smoothing process resulted in a color segmented image with homogeneous regions separated by sharpened, coregistered multiband edges. There was improved class separation with the segmented image, which has importance to subsequent operations involving data classification.

Portable real-time color night vision

NASA Astrophysics Data System (ADS)

Toet, Alexander; Hogervorst, Maarten A.

2008-03-01

We developed a simple and fast lookup-table based method to derive and apply natural daylight colors to multi-band night-time images. The method deploys an optimal color transformation derived from a set of samples taken from a daytime color reference image. The colors in the resulting colorized multiband night-time images closely resemble the colors in the daytime color reference image. Also, object colors remain invariant under panning operations and are independent of the scene content. Here we describe the implementation of this method in two prototype portable dual band realtime night vision systems. One system provides co-aligned visual and near-infrared bands of two image intensifiers, the other provides co-aligned images from a digital image intensifier and an uncooled longwave infrared microbolometer. The co-aligned images from both systems are further processed by a notebook computer. The color mapping is implemented as a realtime lookup table transform. The resulting colorised video streams can be displayed in realtime on head mounted displays and stored on the hard disk of the notebook computer. Preliminary field trials demonstrate the potential of these systems for applications like surveillance, navigation and target detection.

Broadly available imaging devices enable high-quality low-cost photometry.

PubMed

Christodouleas, Dionysios C; Nemiroski, Alex; Kumar, Ashok A; Whitesides, George M

2015-09-15

This paper demonstrates that, for applications in resource-limited environments, expensive microplate spectrophotometers that are used in many central laboratories for parallel measurement of absorbance of samples can be replaced by photometers based on inexpensive and ubiquitous, consumer electronic devices (e.g., scanners and cell-phone cameras). Two devices, (i) a flatbed scanner operating in transmittance mode and (ii) a camera-based photometer (constructed from a cell phone camera, a planar light source, and a cardboard box), demonstrate the concept. These devices illuminate samples in microtiter plates from one side and use the RGB-based imaging sensors of the scanner/camera to measure the light transmitted to the other side. The broadband absorbance of samples (RGB-resolved absorbance) can be calculated using the RGB color values of only three pixels per microwell. Rigorous theoretical analysis establishes a well-defined relationship between the absorbance spectrum of a sample and its corresponding RGB-resolved absorbance. The linearity and precision of measurements performed with these low-cost photometers on different dyes, which absorb across the range of the visible spectrum, and chromogenic products of assays (e.g., enzymatic, ELISA) demonstrate that these low-cost photometers can be used reliably in a broad range of chemical and biochemical analyses. The ability to perform accurate measurements of absorbance on liquid samples, in parallel and at low cost, would enable testing, typically reserved for well-equipped clinics and laboratories, to be performed in circumstances where resources and expertise are limited.

Remote sensing of vigor loss in conifers due to dwarf mistletoe

NASA Technical Reports Server (NTRS)

Meyer, M. P.; French, D. W.; Latham, R. P.; Nelson, C. A.; Douglass, R. W.

1971-01-01

The initial operation of a multiband/multidate tower-tramway test site in northeastern Minnesota for the development of specifications for subsequent multiband aerial photography of more extensive study areas was completed. Multiband/multidate configurations suggested by the tower-tramway studies were and will be flown with local equipment over the Togo test site. This site was photographed by the NASA RB57F aircraft in August and September 1971. It appears that, of all the film/filter combinations attempted to date (including optical recombining of several spectral band images via photo enhancement techniques), Ektachrome infrared film with a Wratten 12 filter is the best for detecting dwarf mistletoe, and other tree diseases as well. Using this film/filter combination, infection centers are easily detectable even on the smallest photo scale (1:100,000) obtained on the Togo site.

3D Display Using Conjugated Multiband Bandpass Filters

NASA Technical Reports Server (NTRS)

Bae, Youngsam; White, Victor E.; Shcheglov, Kirill

2012-01-01

Stereoscopic display techniques are based on the principle of displaying two views, with a slightly different perspective, in such a way that the left eye views only by the left eye, and the right eye views only by the right eye. However, one of the major challenges in optical devices is crosstalk between the two channels. Crosstalk is due to the optical devices not completely blocking the wrong-side image, so the left eye sees a little bit of the right image and the right eye sees a little bit of the left image. This results in eyestrain and headaches. A pair of interference filters worn as an optical device can solve the problem. The device consists of a pair of multiband bandpass filters that are conjugated. The term "conjugated" describes the passband regions of one filter not overlapping with those of the other, but the regions are interdigitated. Along with the glasses, a 3D display produces colors composed of primary colors (basis for producing colors) having the spectral bands the same as the passbands of the filters. More specifically, the primary colors producing one viewpoint will be made up of the passbands of one filter, and those of the other viewpoint will be made up of the passbands of the conjugated filter. Thus, the primary colors of one filter would be seen by the eye that has the matching multiband filter. The inherent characteristic of the interference filter will allow little or no transmission of the wrong side of the stereoscopic images.

Contourlet domain multiband deblurring based on color correlation for fluid lens cameras.

PubMed

Tzeng, Jack; Liu, Chun-Chen; Nguyen, Truong Q

2010-10-01

Due to the novel fluid optics, unique image processing challenges are presented by the fluidic lens camera system. Developed for surgical applications, unique properties, such as no moving parts while zooming and better miniaturization than traditional glass optics, are advantages of the fluid lens. Despite these abilities, sharp color planes and blurred color planes are created by the nonuniform reaction of the liquid lens to different color wavelengths. Severe axial color aberrations are caused by this reaction. In order to deblur color images without estimating a point spread function, a contourlet filter bank system is proposed. Information from sharp color planes is used by this multiband deblurring method to improve blurred color planes. Compared to traditional Lucy-Richardson and Wiener deconvolution algorithms, significantly improved sharpness and reduced ghosting artifacts are produced by a previous wavelet-based method. Directional filtering is used by the proposed contourlet-based system to adjust to the contours of the image. An image is produced by the proposed method which has a similar level of sharpness to the previous wavelet-based method and has fewer ghosting artifacts. Conditions for when this algorithm will reduce the mean squared error are analyzed. While improving the blue color plane by using information from the green color plane is the primary focus of this paper, these methods could be adjusted to improve the red color plane. Many multiband systems such as global mapping, infrared imaging, and computer assisted surgery are natural extensions of this work. This information sharing algorithm is beneficial to any image set with high edge correlation. Improved results in the areas of deblurring, noise reduction, and resolution enhancement can be produced by the proposed algorithm.

Multiband selection with linear array detectors

NASA Technical Reports Server (NTRS)

Richard, H. L.; Barnes, W. L.

1985-01-01

Several techniques that can be used in an earth-imaging system to separate the linear image formed after the collecting optics into the desired spectral band are examined. The advantages and disadvantages of the Multispectral Linear Array (MLA) multiple optics, the MLA adjacent arrays, the imaging spectrometer, and the MLA beam splitter are discussed. The beam-splitter design approach utilizes, in addition to relatively broad spectral region separation, a movable Multiband Selection Device (MSD), placed between the exit ports of the beam splitter and a linear array detector, permitting many bands to be selected. The successful development and test of the MSD is described. The device demonstrated the capacity to provide a wide field of view, visible-to-near IR/short-wave IR and thermal IR capability, and a multiplicity of spectral bands and polarization measuring means, as well as a reasonable size and weight at minimal cost and risk compared to a spectrometer design approach.

Photographic photometry with Iris diaphragm photometers

NASA Technical Reports Server (NTRS)

Schaefer, B. E.

1981-01-01

A general method is presented for solving problems encountered in the analysis of Iris diaphragm photometer (IDP) data. The method is used to derive the general shape of the calibration curve, allowing both a more accurate fit to the IDP data for comparison stars and extrapolation to magnitude ranges for which no comparison stars are measured. The profile of starlight incident and the characteristic curve of the plate are both assumed and then used to derive the profile of the star image. An IDP reading is then determined for each star image. A procedure for correcting the effects of a nonconstant background fog level on the plate is also demonstrated. Additional applications of the method are made in the appendix to determine the relation between the radius of a photographic star image and the star's magnitude, and to predict the IDP reading of the 'point of optimum density'.

Segmentation methodology for automated classification and differentiation of soft tissues in multiband images of high-resolution ultrasonic transmission tomography.

PubMed

Jeong, Jeong-Won; Shin, Dae C; Do, Synho; Marmarelis, Vasilis Z

2006-08-01

This paper presents a novel segmentation methodology for automated classification and differentiation of soft tissues using multiband data obtained with the newly developed system of high-resolution ultrasonic transmission tomography (HUTT) for imaging biological organs. This methodology extends and combines two existing approaches: the L-level set active contour (AC) segmentation approach and the agglomerative hierarchical kappa-means approach for unsupervised clustering (UC). To prevent the trapping of the current iterative minimization AC algorithm in a local minimum, we introduce a multiresolution approach that applies the level set functions at successively increasing resolutions of the image data. The resulting AC clusters are subsequently rearranged by the UC algorithm that seeks the optimal set of clusters yielding the minimum within-cluster distances in the feature space. The presented results from Monte Carlo simulations and experimental animal-tissue data demonstrate that the proposed methodology outperforms other existing methods without depending on heuristic parameters and provides a reliable means for soft tissue differentiation in HUTT images.

SPITZER SEARCH FOR DUST DISKS AROUND CENTRAL STARS OF PLANETARY NEBULAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bilikova, Jana; Chu Youhua; Gruendl, Robert A.

2012-05-01

Two types of dust disks have been discovered around white dwarfs (WDs): small dust disks within the Roche limits of their WDs and large dust disks around hot WDs extending to radial distances of 10-10{sup 2} AU. The majority of the latter WDs are central stars of planetary nebulae (CSPNs). We have therefore used archival Spitzer Infrared Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS) observations of PNs to search for CSPNs with IR excesses and to make a comparative investigation of dust disks around stars at different evolutionary stages. We have examined available images of 72 resolvedmore » PNs in the Spitzer archive and found 56 of them large enough for the CSPN to be resolved from the PN. Among these, only 42 CSPNs are visible in IRAC and/or MIPS images and selected for photometric measurements. From the spectral energy distributions (SEDs) of these CSPNs, we find 19 cases with clear IR excess. Of these, seven are [WC]-type stars, two have apparent visual companions that account for the observed excess emission, two are symbiotic CSPNs, and in eight cases the IR excess originates from an extended emitter, likely a dust disk. For some of these CSPNs, we have acquired follow-up Spitzer MIPS images, Infrared Spectrograph spectra, and Gemini NIRI and Michelle spectroscopic observations. The SEDs and spectra show a great diversity in the emission characteristics of the IR excesses, which may imply different mechanisms responsible for the excess emission. For CSPNs whose IR excesses originate from dust continuum, the most likely dust production mechanisms are (1) breakup of bodies in planetesimal belts through collisions and (2) formation of circumstellar dust disks through binary interactions. A better understanding of post-asymptotic giant branch binary evolution as well as debris disk evolution along with its parent star is needed to distinguish between these different origins. Future observations to better establish the physical parameters of the dust disks and the presence of companions are needed for models to discern between the possible dust production mechanisms.« less

DEBRIS DISKS OF MEMBERS OF THE BLANCO 1 OPEN CLUSTER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stauffer, John R.; Noriega-Crespo, Alberto; Rebull, Luisa M.

2010-08-20

We have used the Spitzer Space Telescope to obtain Multiband Imaging Photometer for Spitzer (MIPS) 24 {mu}m photometry for 37 members of the {approx}100 Myr old open cluster Blanco 1. For the brightest 25 of these stars (where we have 3{sigma} uncertainties less than 15%), we find significant mid-IR excesses for eight stars, corresponding to a debris disk detection frequency of about 32%. The stars with excesses include two A stars, four F dwarfs, and two G dwarfs. The most significant linkage between 24 {mu}m excess and any other stellar property for our Blanco 1 sample of stars is withmore » binarity. Blanco 1 members that are photometric binaries show few or no detected 24 {mu}m excesses whereas a quarter of the apparently single Blanco 1 members do have excesses. We have examined the MIPS data for two other clusters of similar age to Blanco 1-NGC 2547 and the Pleiades. The AFGK photometric binary star members of both of these clusters also show a much lower frequency of 24 {mu}m excesses compared to stars that lie near the single-star main sequence. We provide a new determination of the relation between the V - K {sub s} color and K {sub s} - [24] color for main sequence photospheres based on Hyades members observed with MIPS. As a result of our analysis of the Hyades data, we identify three low mass Hyades members as candidates for having debris disks near the MIPS detection limit.« less

Poly-Pattern Compressive Segmentation of ASTER Data for GIS

NASA Technical Reports Server (NTRS)

Myers, Wayne; Warner, Eric; Tutwiler, Richard

2007-01-01

Pattern-based segmentation of multi-band image data, such as ASTER, produces one-byte and two-byte approximate compressions. This is a dual segmentation consisting of nested coarser and finer level pattern mappings called poly-patterns. The coarser A-level version is structured for direct incorporation into geographic information systems in the manner of a raster map. GIs renderings of this A-level approximation are called pattern pictures which have the appearance of color enhanced images. The two-byte version consisting of thousands of B-level segments provides a capability for approximate restoration of the multi-band data in selected areas or entire scenes. Poly-patterns are especially useful for purposes of change detection and landscape analysis at multiple scales. The primary author has implemented the segmentation methodology in a public domain software suite.

Radiometric calibration of spacecraft using small lunar images

USGS Publications Warehouse

Kieffer, Hugh H.; Anderson, James M.; Becker, Kris J.

1999-01-01

In this study, the data reduction steps that can be used to extract the lunar irradiance from low resolution images of the Moon are examined and the attendant uncertainties are quantitatively assessed. The response integrated over an image is compared to a lunar irradiance model being developed from terrestrial multi-band photometric observations over the 350-2500 nm range.

Single-snapshot 2D color measurement by plenoptic imaging system

NASA Astrophysics Data System (ADS)

Masuda, Kensuke; Yamanaka, Yuji; Maruyama, Go; Nagai, Sho; Hirai, Hideaki; Meng, Lingfei; Tosic, Ivana

2014-03-01

Plenoptic cameras enable capture of directional light ray information, thus allowing applications such as digital refocusing, depth estimation, or multiband imaging. One of the most common plenoptic camera architectures contains a microlens array at the conventional image plane and a sensor at the back focal plane of the microlens array. We leverage the multiband imaging (MBI) function of this camera and develop a single-snapshot, single-sensor high color fidelity camera. Our camera is based on a plenoptic system with XYZ filters inserted in the pupil plane of the main lens. To achieve high color measurement precision of this system, we perform an end-to-end optimization of the system model that includes light source information, object information, optical system information, plenoptic image processing and color estimation processing. Optimized system characteristics are exploited to build an XYZ plenoptic colorimetric camera prototype that achieves high color measurement precision. We describe an application of our colorimetric camera to color shading evaluation of display and show that it achieves color accuracy of ΔE<0.01.

Determination of gravity wave parameters in the airglow combining photometer and imager data

NASA Astrophysics Data System (ADS)

Nyassor, Prosper K.; Arlen Buriti, Ricardo; Paulino, Igo; Medeiros, Amauri F.; Takahashi, Hisao; Wrasse, Cristiano M.; Gobbi, Delano

2018-05-01

Mesospheric airglow measurements of two or three layers were used to characterize both vertical and horizontal parameters of gravity waves. The data set was acquired coincidentally from a multi-channel filter (Multi-3) photometer and an all-sky imager located at São João do Cariri (7.4° S, 36.5° W) in the equatorial region from 2001 to 2007. Using a least-square fitting and wavelet analysis technique, the phase and amplitude of each observed wave were determined, as well as the amplitude growth. Using the dispersion relation of gravity waves, the vertical and horizontal wavelengths were estimated and compared to the horizontal wavelength obtained from the keogram analysis of the images observed by an all-sky imager. The results show that both horizontal and vertical wavelengths, obtained from the dispersion relation and keogram analysis, agree very well for the waves observed on the nights of 14 October and 18 December 2006. The determined parameters showed that the observed wave on the night of 18 December 2006 had a period of ˜ 43.8 ± 2.19 min, with the horizontal wavelength of 235.66 ± 11.78 km having a downward phase propagation, whereas that of 14 October 2006 propagated with a period of ˜ 36.00 ± 1.80 min with a horizontal wavelength of ˜ 195 ± 9.80 km, and with an upward phase propagation. The observation of a wave taken by a photometer and an all-sky imager allowed us to conclude that the same wave could be observed by both instruments, permitting the investigation of the two-dimensional wave parameter.

Evaluation of slice accelerations using multiband echo planar imaging at 3 Tesla

PubMed Central

Xu, Junqian; Moeller, Steen; Auerbach, Edward J.; Strupp, John; Smith, Stephen M.; Feinberg, David A.; Yacoub, Essa; Uğurbil, Kâmil

2013-01-01

We evaluate residual aliasing among simultaneously excited and acquired slices in slice accelerated multiband (MB) echo planar imaging (EPI). No in-plane accelerations were used in order to maximize and evaluate achievable slice acceleration factors at 3 Tesla. We propose a novel leakage (L-) factor to quantify the effects of signal leakage between simultaneously acquired slices. With a standard 32-channel receiver coil at 3 Tesla, we demonstrate that slice acceleration factors of up to eight (MB = 8) with blipped controlled aliasing in parallel imaging (CAIPI), in the absence of in-plane accelerations, can be used routinely with acceptable image quality and integrity for whole brain imaging. Spectral analyses of single-shot fMRI time series demonstrate that temporal fluctuations due to both neuronal and physiological sources were distinguishable and comparable up to slice-acceleration factors of nine (MB = 9). The increased temporal efficiency could be employed to achieve, within a given acquisition period, higher spatial resolution, increased fMRI statistical power, multiple TEs, faster sampling of temporal events in a resting state fMRI time series, increased sampling of q-space in diffusion imaging, or more quiet time during a scan. PMID:23899722

THE MULTI-WAVELENGTH EXTREME STARBURST SAMPLE OF LUMINOUS GALAXIES. I. SAMPLE CHARACTERISTICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laag, Edward; Croft, Steve; Canalizo, Gabriela

2010-12-15

This paper introduces the Multi-wavelength Extreme Starburst Sample (MESS), a new catalog of 138 star-forming galaxies (0.1 < z < 0.3) optically selected from the Sloan Digital Sky Survey using emission line strength diagnostics to have a high absolute star formation rate (SFR; minimum 11 M{sub sun} yr{sup -1} with median SFR {approx} 61 M{sub sun} yr{sup -1} based on a Kroupa initial mass function). The MESS was designed to complement samples of nearby star-forming galaxies such as the luminous infrared galaxies (LIRGs) and ultraviolet luminous galaxies (UVLGs). Observations using the Multi-band Imaging Photometer (24, 70, and 160 {mu}m channels)more » on the Spitzer Space Telescope indicate that the MESS galaxies have IR luminosities similar to those of LIRGs, with an estimated median L{sub TIR} {approx} 3 x 10{sup 11} L{sub sun}. The selection criteria for the MESS objects suggest they may be less obscured than typical far-IR-selected galaxies with similar estimated SFRs. Twenty out of 70 of the MESS objects detected in the Galaxy Evolution Explorer FUV band also appear to be UVLGs. We estimate the SFRs based directly on luminosities to determine the agreement for these methods in the MESS. We compare these estimates to the emission line strength technique, since the effective measurement of dust attenuation plays a central role in these methods. We apply an image stacking technique to the Very Large Array FIRST survey radio data to retrieve 1.4 GHz luminosity information for 3/4 of the sample covered by FIRST including sources too faint, and at too high a redshift, to be detected in FIRST. We also discuss the relationship between the MESS objects and samples selected through alternative criteria. Morphologies will be the subject of a forthcoming paper.« less

VizieR Online Data Catalog: YSOs search in LDN 1340 in optical (Kun+, 2016)

NASA Astrophysics Data System (ADS)

Kun, M.; Moor, A.; Szegedi-Elek, E.; Reipurth, B.

2016-08-01

We observed the optical spectra of 23 stars, utilizing several instruments, namely CAFOS with the G-100 grism, installed on the 2.2m telescope of the Calar Alto Observatory, FAST on the 1.5m telescope of the Fred Lawrence Whipple Observatory, ALFOSC with grism 8 on the Nordic Optical Telescope in the Observatorio del Roque de los Muchachos in La Palma, and the low-resolution slit spectrograph operated on the 1m RCC telescope of the Konkoly Observatory between 1999 Aug 07 and 2011 Sep 27 (see table 1). We observed L1340 with the Wide Field Grism Spectrograph 2 (WFGS2), installed on the University of Hawaii 2.2m telescope, on 2011 January 1, October 15, 16, and 18, and 2012 August 10. We covered an area of 30x40arcmin, centered on RA=2:30,DE=72:48(J2000), with a mosaic of 12 overlapping fields. We found 75 stars with Hα emission by examining the images visually. See section 2.2 and table 2. Spitzer L1340 was observed by the Spitzer Space Telescope using Spitzer's Infrared Array Camera (IRAC) on 2009 March 16 and by the Multiband Imaging Photometer for Spitzer (MIPS) on 2008 November 26 (Prog. ID: 50691, PI: G. Fazio). A small part of the cloud, centered on RNO 7, was observed in the four IRAC bands on 2006 September 24 (Prog. ID: 30734, PI: D. Figer). All but eight of the Hα sources have counterparts in the AllWISE Source Catalog (Wright et al. 2010AJ....140.1868W; see II/328). L1340 is situated within Stripe 1260 of the SEGUE survey (Yanny et al. 2009, J/AJ/137/4377). Each of our target stars has a counterpart in the SDSS Data Release 9 (Ahn et al. 2012, V/139) within 1" of the 2MASS position. (6 data files).

An Application of Multi-band Forced Photometry to One Square Degree of SERVS: Accurate Photometric Redshifts and Implications for Future Science

NASA Astrophysics Data System (ADS)

Nyland, Kristina; Lacy, Mark; Sajina, Anna; Pforr, Janine; Farrah, Duncan; Wilson, Gillian; Surace, Jason; Häußler, Boris; Vaccari, Mattia; Jarvis, Matt

2017-05-01

We apply The Tractor image modeling code to improve upon existing multi-band photometry for the Spitzer Extragalactic Representative Volume Survey (SERVS). SERVS consists of post-cryogenic Spitzer observations at 3.6 and 4.5 μm over five well-studied deep fields spanning 18 deg2. In concert with data from ground-based near-infrared (NIR) and optical surveys, SERVS aims to provide a census of the properties of massive galaxies out to z ≈ 5. To accomplish this, we are using The Tractor to perform “forced photometry.” This technique employs prior measurements of source positions and surface brightness profiles from a high-resolution fiducial band from the VISTA Deep Extragalactic Observations survey to model and fit the fluxes at lower-resolution bands. We discuss our implementation of The Tractor over a square-degree test region within the XMM Large Scale Structure field with deep imaging in 12 NIR/optical bands. Our new multi-band source catalogs offer a number of advantages over traditional position-matched catalogs, including (1) consistent source cross-identification between bands, (2) de-blending of sources that are clearly resolved in the fiducial band but blended in the lower resolution SERVS data, (3) a higher source detection fraction in each band, (4) a larger number of candidate galaxies in the redshift range 5 < z < 6, and (5) a statistically significant improvement in the photometric redshift accuracy as evidenced by the significant decrease in the fraction of outliers compared to spectroscopic redshifts. Thus, forced photometry using The Tractor offers a means of improving the accuracy of multi-band extragalactic surveys designed for galaxy evolution studies. We will extend our application of this technique to the full SERVS footprint in the future.

Compact multi-band fluorescent microscope with an electrically tunable lens for autofocusing

PubMed Central

Wang, Zhaojun; Lei, Ming; Yao, Baoli; Cai, Yanan; Liang, Yansheng; Yang, Yanlong; Yang, Xibin; Li, Hui; Xiong, Daxi

2015-01-01

Autofocusing is a routine technique in redressing focus drift that occurs in time-lapse microscopic image acquisition. To date, most automatic microscopes are designed on the distance detection scheme to fulfill the autofocusing operation, which may suffer from the low contrast of the reflected signal due to the refractive index mismatch at the water/glass interface. To achieve high autofocusing speed with minimal motion artifacts, we developed a compact multi-band fluorescent microscope with an electrically tunable lens (ETL) device for autofocusing. A modified searching algorithm based on equidistant scanning and curve fitting is proposed, which no longer requires a single-peak focus curve and then efficiently restrains the impact of external disturbance. This technique enables us to achieve an autofocusing time of down to 170 ms and the reproductivity of over 97%. The imaging head of the microscope has dimensions of 12 cm × 12 cm × 6 cm. This portable instrument can easily fit inside standard incubators for real-time imaging of living specimens. PMID:26601001

scarlet: Source separation in multi-band images by Constrained Matrix Factorization

NASA Astrophysics Data System (ADS)

Melchior, Peter; Moolekamp, Fred; Jerdee, Maximilian; Armstrong, Robert; Sun, Ai-Lei; Bosch, James; Lupton, Robert

2018-03-01

SCARLET performs source separation (aka "deblending") on multi-band images. It is geared towards optical astronomy, where scenes are composed of stars and galaxies, but it is straightforward to apply it to other imaging data. Separation is achieved through a constrained matrix factorization, which models each source with a Spectral Energy Distribution (SED) and a non-parametric morphology, or multiple such components per source. The code performs forced photometry (with PSF matching if needed) using an optimal weight function given by the signal-to-noise weighted morphology across bands. The approach works well if the sources in the scene have different colors and can be further strengthened by imposing various additional constraints/priors on each source. Because of its generic utility, this package provides a stand-alone implementation that contains the core components of the source separation algorithm. However, the development of this package is part of the LSST Science Pipeline; the meas_deblender package contains a wrapper to implement the algorithms here for the LSST stack.

Cloud Screening and Quality Control Algorithm for Star Photometer Data: Assessment with Lidar Measurements and with All-sky Images

NASA Technical Reports Server (NTRS)

Ramirez, Daniel Perez; Lyamani, H.; Olmo, F. J.; Whiteman, D. N.; Navas-Guzman, F.; Alados-Arboledas, L.

2012-01-01

This paper presents the development and set up of a cloud screening and data quality control algorithm for a star photometer based on CCD camera as detector. These algorithms are necessary for passive remote sensing techniques to retrieve the columnar aerosol optical depth, delta Ae(lambda), and precipitable water vapor content, W, at nighttime. This cloud screening procedure consists of calculating moving averages of delta Ae() and W under different time-windows combined with a procedure for detecting outliers. Additionally, to avoid undesirable Ae(lambda) and W fluctuations caused by the atmospheric turbulence, the data are averaged on 30 min. The algorithm is applied to the star photometer deployed in the city of Granada (37.16 N, 3.60 W, 680 ma.s.l.; South-East of Spain) for the measurements acquired between March 2007 and September 2009. The algorithm is evaluated with correlative measurements registered by a lidar system and also with all-sky images obtained at the sunset and sunrise of the previous and following days. Promising results are obtained detecting cloud-affected data. Additionally, the cloud screening algorithm has been evaluated under different aerosol conditions including Saharan dust intrusion, biomass burning and pollution events.

Interleaved EPI based fMRI improved by multiplexed sensitivity encoding (MUSE) and simultaneous multi-band imaging.

PubMed

Chang, Hing-Chiu; Gaur, Pooja; Chou, Ying-hui; Chu, Mei-Lan; Chen, Nan-kuei

2014-01-01

Functional magnetic resonance imaging (fMRI) is a non-invasive and powerful imaging tool for detecting brain activities. The majority of fMRI studies are performed with single-shot echo-planar imaging (EPI) due to its high temporal resolution. Recent studies have demonstrated that, by increasing the spatial-resolution of fMRI, previously unidentified neuronal networks can be measured. However, it is challenging to improve the spatial resolution of conventional single-shot EPI based fMRI. Although multi-shot interleaved EPI is superior to single-shot EPI in terms of the improved spatial-resolution, reduced geometric distortions, and sharper point spread function (PSF), interleaved EPI based fMRI has two main limitations: 1) the imaging throughput is lower in interleaved EPI; 2) the magnitude and phase signal variations among EPI segments (due to physiological noise, subject motion, and B0 drift) are translated to significant in-plane aliasing artifact across the field of view (FOV). Here we report a method that integrates multiple approaches to address the technical limitations of interleaved EPI-based fMRI. Firstly, the multiplexed sensitivity-encoding (MUSE) post-processing algorithm is used to suppress in-plane aliasing artifacts resulting from time-domain signal instabilities during dynamic scans. Secondly, a simultaneous multi-band interleaved EPI pulse sequence, with a controlled aliasing scheme incorporated, is implemented to increase the imaging throughput. Thirdly, the MUSE algorithm is then generalized to accommodate fMRI data obtained with our multi-band interleaved EPI pulse sequence, suppressing both in-plane and through-plane aliasing artifacts. The blood-oxygenation-level-dependent (BOLD) signal detectability and the scan throughput can be significantly improved for interleaved EPI-based fMRI. Our human fMRI data obtained from 3 Tesla systems demonstrate the effectiveness of the developed methods. It is expected that future fMRI studies requiring high spatial-resolvability and fidelity will largely benefit from the reported techniques.

Construction of an Inexpensive Sun Photometer for Measuring Aerosols Optical Depth (AOD) and Comparison Between the Ground Based and Satellite Based Measurements

NASA Astrophysics Data System (ADS)

Mamun, M.; Mondol, P.

2012-12-01

Aerosols influence our weather and climate because they affect the amount of sunlight reaching Earth's surface. An important way of probing the atmosphere from the ground is to measure the effects of the atmosphere on sunlight transmitted through the atmosphere to Earth's surface. These indirect techniques provide information about the entire atmosphere above the observer, not just the atmosphere that can be sampled directly. In response to global issues of air quality and climate change, and to the need to improve the quality of science education, inexpensive atmosphere monitoring instruments have been developed. This paper describes a new kind of inexpensive two channels LED Sun Photometer for monitoring aerosols that provide much better long-term stability than instruments that use expensive interference filters. Here HAZE-SPAN TERC VHS-1 model has been used for constructing sun photometer with light emitting diode as detector. Monitoring Earth's atmosphere is a challenging task. As there is no facility in our country (Bangladesh) for ground based measurement for monitoring aerosol so, this type of study is very essential. This study compares the aerosol optical depth (AOD) retrieved from the Terra and Aqua MODerate Resolution Imaging Spectroradiometers (MODIS) with ground-based measurements from a handheld sun photometer over the region of Rajshahi, Bangladesh for The 15 days duration of June 2012. The results indicate that the Terra and Aqua MODIS AOD retrievals at 550 nm have good correlations with the measurements from the handheld sun photometer. The correlation coefficients r = 0.88 for Terra and r = 0.55 for Aqua where as r = 0.65 for Terra and Aqua themselves. AOD for another wavelength at 625 nm is documented in this study for finding out the relation of AOD at different wavelengths. In this paper it has been described and summarized briefly investigations for four important topics: LEDs used as light detectors, construction of sun photometer and its use, the measurements and monitoring of Aerosol Optical Depth (AOD) by using handheld sun photometer, and the comparison between satellite based and ground based measurements.

Pioneer: First to Jupiter, Saturn, and beyond. Bibliography

NASA Technical Reports Server (NTRS)

1980-01-01

The reference citatons are grouped by experiment. Experiments include: the charged particle instrument experiment; the ultraviolet photometer experiment; imaging experiments; and magnetometer experiments. The asteroid detector experiment and the plasma analyser experiment are also included.

What's Old is New in the Large Magellanic Cloud

NASA Technical Reports Server (NTRS)

2006-01-01

[figure removed for brevity, see original site] Poster Version Large Magellanic Cloud

This vibrant image from NASA's Spitzer Space Telescope shows the Large Magellanic Cloud, a satellite galaxy to our own Milky Way galaxy.

The infrared image, a mosaic of 300,000 individual tiles, offers astronomers a unique chance to study the lifecycle of stars and dust in a single galaxy. Nearly one million objects are revealed for the first time in this Spitzer view, which represents about a 1,000-fold improvement in sensitivity over previous space-based missions. Most of the new objects are dusty stars of various ages populating the Large Magellanic Cloud; the rest are thought to be background galaxies.

The blue color in the picture, seen most prominently in the central bar, represents starlight from older stars. The chaotic, bright regions outside this bar are filled with hot, massive stars buried in thick blankets of dust. The red color around these bright regions is from dust heated by stars, while the red dots scattered throughout the picture are either dusty, old stars or more distant galaxies. The greenish clouds contain cooler interstellar gas and molecular-sized dust grains illuminated by ambient starlight.

Astronomers say this image allows them to quantify the process by which space dust -- the same stuff that makes up planets and even people -- is recycled in a galaxy. The picture shows dust at its three main cosmic hangouts: around the young stars, where it is being consumed (red-tinted, bright clouds); scattered about in the space between stars (greenish clouds); and in expelled shells of material from old stars (randomly-spaced red dots).

The Large Magellanic Cloud, located 160,000 light-years from Earth, is one of a handful of dwarf galaxies that orbit our own Milky Way. It is approximately one-third as wide as the Milky Way, and, if it could be seen in its entirety, would cover the same amount of sky as a grid of about 480 full moons. About one-third of the entire galaxy can be seen in the Spitzer image.

This picture is a composite of infrared light captured by Spitzer. Light with wavelengths of 3.6 (blue) and 8 (green) microns was captured by the telescope's infrared array camera; 24-micron light (red) was detected by the multiband imaging photometer.

What Old is New in the Large Magellanic Cloud

NASA Image and Video Library

2006-09-01

This vibrant image from NASA's Spitzer Space Telescope shows the Large Magellanic Cloud, a satellite galaxy to our own Milky Way galaxy. The infrared image, a mosaic of 300,000 individual tiles, offers astronomers a unique chance to study the lifecycle of stars and dust in a single galaxy. Nearly one million objects are revealed for the first time in this Spitzer view, which represents about a 1,000-fold improvement in sensitivity over previous space-based missions. Most of the new objects are dusty stars of various ages populating the Large Magellanic Cloud; the rest are thought to be background galaxies. The blue color in the picture, seen most prominently in the central bar, represents starlight from older stars. The chaotic, bright regions outside this bar are filled with hot, massive stars buried in thick blankets of dust. The red color around these bright regions is from dust heated by stars, while the red dots scattered throughout the picture are either dusty, old stars or more distant galaxies. The greenish clouds contain cooler interstellar gas and molecular-sized dust grains illuminated by ambient starlight. Astronomers say this image allows them to quantify the process by which space dust -- the same stuff that makes up planets and even people -- is recycled in a galaxy. The picture shows dust at its three main cosmic hangouts: around the young stars, where it is being consumed (red-tinted, bright clouds); scattered about in the space between stars (greenish clouds); and in expelled shells of material from old stars (randomly-spaced red dots). The Large Magellanic Cloud, located 160,000 light-years from Earth, is one of a handful of dwarf galaxies that orbit our own Milky Way. It is approximately one-third as wide as the Milky Way, and, if it could be seen in its entirety, would cover the same amount of sky as a grid of about 480 full moons. About one-third of the entire galaxy can be seen in the Spitzer image. This picture is a composite of infrared light captured by Spitzer. Light with wavelengths of 3.6 (blue) and 8 (green) microns was captured by the telescope's infrared array camera; 24-micron light (red) was detected by the multiband imaging photometer. http://photojournal.jpl.nasa.gov/catalog/PIA07137

Enhanced vibrational spectroscopy, intracellular refractive indexing for label-free biosensing and bioimaging by multiband plasmonic-antenna array.

PubMed

Chen, Cheng-Kuang; Chang, Ming-Hsuan; Wu, Hsieh-Ting; Lee, Yao-Chang; Yen, Ta-Jen

2014-10-15

In this study, we report a multiband plasmonic-antenna array that bridges optical biosensing and intracellular bioimaging without requiring a labeling process or coupler. First, a compact plasmonic-antenna array is designed exhibiting a bandwidth of several octaves for use in both multi-band plasmonic resonance-enhanced vibrational spectroscopy and refractive index probing. Second, a single-element plasmonic antenna can be used as a multifunctional sensing pixel that enables mapping the distribution of targets in thin films and biological specimens by enhancing the signals of vibrational signatures and sensing the refractive index contrast. Finally, using the fabricated plasmonic-antenna array yielded reliable intracellular observation was demonstrated from the vibrational signatures and intracellular refractive index contrast requiring neither labeling nor a coupler. These unique features enable the plasmonic-antenna array to function in a label-free manner, facilitating bio-sensing and imaging development. Copyright © 2014 Elsevier B.V. All rights reserved.

Ground state, collective mode, phase soliton and vortex in multiband superconductors.

PubMed

Lin, Shi-Zeng

2014-12-10

This article reviews theoretical and experimental work on the novel physics in multiband superconductors. Multiband superconductors are characterized by multiple superconducting energy gaps in different bands with interaction between Cooper pairs in these bands. The discovery of prominent multiband superconductors MgB2 and later iron-based superconductors, has triggered enormous interest in multiband superconductors. The most recently discovered superconductors exhibit multiband features. The multiband superconductors possess novel properties that are not shared with their single-band counterpart. Examples include: the time-reversal symmetry broken state in multiband superconductors with frustrated interband couplings; the collective oscillation of number of Cooper pairs between different bands, known as the Leggett mode; and the phase soliton and fractional vortex, which are the main focus of this review. This review presents a survey of a wide range of theoretical exploratory and experimental investigations of novel physics in multiband superconductors. A vast amount of information derived from these studies is shown to highlight unusual and unique properties of multiband superconductors and to reveal the challenges and opportunities in the research on the multiband superconductivity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Christine H.; Mittal, Tushar; Kuchner, Marc

During the Spitzer Space Telescope cryogenic mission, Guaranteed Time Observers, Legacy Teams, and General Observers obtained Infrared Spectrograph (IRS) observations of hundreds of debris disk candidates. We calibrated the spectra of 571 candidates, including 64 new IRAS and Multiband Imaging Photometer for Spitzer (MIPS) debris disks candidates, modeled their stellar photospheres, and produced a catalog of excess spectra for unresolved debris disks. For 499 targets with IRS excess but without strong spectral features (and a subset of 420 targets with additional MIPS 70 μm observations), we modeled the IRS (and MIPS data) assuming that the dust thermal emission was well-describedmore » using either a one- or two-temperature blackbody model. We calculated the probability for each model and computed the average probability to select among models. We found that the spectral energy distributions for the majority of objects (∼66%) were better described using a two-temperature model with warm (T {sub gr} ∼ 100-500 K) and cold (T {sub gr} ∼ 50-150 K) dust populations analogous to zodiacal and Kuiper Belt dust, suggesting that planetary systems are common in debris disks and zodiacal dust is common around host stars with ages up to ∼1 Gyr. We found that younger stars generally have disks with larger fractional infrared luminosities and higher grain temperatures and that higher-mass stars have disks with higher grain temperatures. We show that the increasing distance of dust around debris disks is inconsistent with self-stirred disk models, expected if these systems possess planets at 30-150 AU. Finally, we illustrate how observations of debris disks may be used to constrain the radial dependence of material in the minimum mass solar nebula.« less

Discovery Of An Infrared Bow Shock Associated With Delta Cephei

NASA Astrophysics Data System (ADS)

Remage Evans, Nancy; Marengo, M.; Barmby, P.; Matthews, L. D.; Bono, G.; Welch, D. L.; Romaniello, M.; Huelsman, D.; Su, K. Y. L.; Fazio, G.

2010-05-01

We have obtained Spitzer Infrared Array Camera (IRAC) and Multiband Infrared Photometer for Spitzer (MIPS) observations of a sample of classical Cepheids both to derive infrared Leavitt Laws (Period-Luminosity Relations) and to look for evidence of mass loss in the spectral energy distributions. The MIPS 24 and 70 micron images of Delta Cep were particularly striking, since they show an arc of emission offset about an arcmin from Delta Cep. The emission is shaped like a bow shock and is aligned with the space motion of the Cepheid, implying it is physically related to the star. Bow shock structures of this kind can be formed when ram pressure of the ambient ISM balances the wind from a mass-losing star, raising the intriguing possibility that delta Cep is undergoing mass-loss during the Cepheid phase. Circumstellar emission is not a general feature of our Cepheid observations, but 2 unusual circumstances may make it visible around Delta Cep. If the Cepheid was already surrounded by interstellar matter, mass loss from the star could have created the bow shock. Second, Delta Cep has a physical companion 40" to the South, HD 213317, itself a binary. This B7-8 III-IV star is hot enough that it may produce infrared emission by heating dust within the ejected material. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. P. B. and D. W. both acknowledge research support through Discovery Grants from the Natural Sciences and Engineering Research Council of Canada. N. R. E. acknowledges support from the Chandra X-Ray Center grant NAS8-03060.

Identification of Luminous Infrared Galaxies at 1 <~ z <~ 2.51,2,3,4,

NASA Astrophysics Data System (ADS)

Le Floc'h, E.; Pérez-González, P. G.; Rieke, G. H.; Papovich, C.; Huang, J.-S.; Barmby, P.; Dole, H.; Egami, E.; Alonso-Herrero, A.; Wilson, G.; Miyazaki, S.; Rigby, J. R.; Bei, L.; Blaylock, M.; Engelbracht, C. W.; Fazio, G. G.; Frayer, D. T.; Gordon, K. D.; Hines, D. C.; Misselt, K. A.; Morrison, J. E.; Muzerolle, J.; Rieke, M. J.; Rigopoulou, D.; Su, K. Y. L.; Willner, S. P.; Young, E. T.

2004-09-01

We present preliminary results on 24 μm detections of luminous infrared galaxies at z>~1 with the Multiband Imaging Photometer for Spitzer (MIPS). Observations were performed in the Lockman Hole and the Extended Groth Strip (EGS) and were supplemented by data obtained with the Infrared Array Camera (IRAC) between 3 and 9 μm. The positional accuracy of <~2" for most MIPS/IRAC detections provides unambiguous identifications of their optical counterparts. Using spectroscopic redshifts from the Deep Extragalactic Evolutionary Probe survey, we identify 24 μm sources at z>~1 in the EGS, while the combination of the MIPS/IRAC observations with BVRIJHK ancillary data in the Lockman Hole also shows very clear cases of galaxies with photometric redshifts at 1<~z<~2.5. The observed 24 μm fluxes indicate infrared luminosities greater than 1011 Lsolar, while the data at shorter wavelengths reveal rather red and probably massive (M>~M*) galaxy counterparts. It is the first time that this population of luminous objects is detected up to z~2.5 in the infrared. Our work demonstrates the ability of the MIPS instrument to probe the dusty universe at very high redshift and illustrates how the forthcoming Spitzer deep surveys will offer a unique opportunity to illuminate a dark side of cosmic history not explored by previous infrared experiments. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, operated jointly by Max-Planck-Institut für Astronomie and Instituto de Astrofísica de Andalucia (CSIC). Based on observations made with the Isaac Newton Telescope, operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

A SPITZER MIPS STUDY OF 2.5-2.0 M{sub Sun} STARS IN SCORPIUS-CENTAURUS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Christine H.; Bitner, Martin; Pecaut, Mark

2012-09-10

We have obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) 24 {mu}m and 70 {mu}m observations of 215 nearby, Hipparcos B- and A-type common proper-motion single and binary systems in the nearest OB association, Scorpius-Centaurus. Combining our MIPS observations with those of other ScoCen stars in the literature, we estimate 24 {mu}m B+A-type disk fractions of 17/67 (25{sup +6}{sub -5}%), 36/131 (27{sup +4}{sub -4}%), and 23/95 (24{sup +5}{sub -4}%) for Upper Scorpius ({approx}11 Myr), Upper Centaurus Lupus ({approx}15 Myr), and Lower Centaurus Crux ({approx}17 Myr), respectively, somewhat smaller disk fractions than previously obtained for F- and G-type members.more » We confirm previous IRAS excess detections and present new discoveries of 51 protoplanetary and debris disk systems, with fractional infrared luminosities ranging from L{sub IR}/L{sub *} = 10{sup -6} to 10{sup -2} and grain temperatures ranging from T{sub gr} = 40 to 300 K. In addition, we confirm that the 24 {mu}m and 70 {mu}m excesses (or fractional infrared luminosities) around B+A-type stars are smaller than those measured toward F+G-type stars and hypothesize that the observed disk property dependence on stellar mass may be the result of a higher stellar companion fraction around B- and A-type stars at 10-200 AU. Finally, we note that the majority of the ScoCen 24 {mu}m excess sources also possess 12 {mu}m excess, indicating that Earth-like planets may be forming via collisions in the terrestrial planet zone at {approx}10-100 Myr.« less

The Long-Lived Disks in the η Chamaeleontis Cluster

NASA Astrophysics Data System (ADS)

Sicilia-Aguilar, Aurora; Bouwman, Jeroen; Juhász, Attila; Henning, Thomas; Roccatagliata, Veronica; Lawson, Warrick A.; Acke, Bram; Feigelson, Eric D.; Tielens, A. G. G. M.; Decin, Leen; Meeus, Gwendolyn

2009-08-01

We present Infrared Spectrograph spectra and revised Multiband Imaging Photometer photometry for the 18 members of the η Chamaeleontis cluster. Aged 8 Myr, the η Cha cluster is one of the few nearby regions within the 5-10 Myr age range, during which the disk fraction decreases dramatically and giant planet formation must come to an end. For the 15 low-mass members, we measure a disk fraction ~50%, high for their 8 Myr age, and four of the eight disks lack near-IR excesses, consistent with the empirical definition of "transition" disks. Most of the disks are comparable to geometrically flat disks. The comparison with regions of different ages suggests that at least some of the "transition" disks may represent the normal type of disk around low-mass stars. Therefore, their flattened structure and inner holes may be related to other factors (initial masses of the disk and the star, environment, binarity), rather than to pure time evolution. We analyze the silicate dust in the disk atmosphere, finding moderate crystalline fractions (~10%-30%) and typical grain sizes ~1-3 μm, without any characteristic trend in the composition. These results are common to other regions of different ages, suggesting that the initial grain processing occurs very early in the disk lifetime (<1 Myr). Large grain sizes in the disk atmosphere cannot be used as a proxy for age, but are likely related to higher disk turbulence. The dust mineralogy varies between the 8-12 μm and the 20-30 μm features, suggesting high temperature dust processing and little radial mixing. Finally, the analysis of IR and optical data on the B9 star η Cha reveals that it is probably surrounded by a young debris disk with a large inner hole, instead of being a classical Be star.

Probing the Physical Properties of High Redshift Optically Obscured Galaxies in the Bootes NOAO Deep Wide Field Survey using the Infrared Spectrograph on Spitzer

NASA Astrophysics Data System (ADS)

Higdon, S. J. U.; Weedman, D.; Higdon, J. L.; Houck, J. R.; Soifer, B. T.; Armus, L.; Charmandaris, V.; Herter, T. L.; Brandl, B. R.; Brown, M. J. I.; Dey, A.; Jannuzi, B.; Le Floc'h, E.; Rieke, M.

2004-12-01

We have surveyed a field covering 8.4 degrees2 within the NOAO Deep Wide Field Survey region in Boötes with the Multiband Imaging Photometer on the Spitzer Space Telescope to a limiting 24 um flux density of 0.3 mJy, identifying ˜ 22,000 point sources. Thirty one sources from this survey with F(24 um) > 0.75 mJy , which are optically ``invisible'' (R > 26) or very faint (I > 24) have been observed with the low-resolution modules of the Infrared Spectrograph on SST. The spectra were extracted using the IRS SMART spectral analysis package in order to optimize their signal to noise. A suite of mid-IR spectral templates of well known galaxies, observed as part of the IRS GTO program, is used to perform formal fits to the spectral energy distribution of the Boötes sources. These fits enable us to measure their redshift, to calculate the depth of the 9.7 um silicate feature along with the strength of 7.7 um PAH, as well as to estimate their bolometric luminosities. We compare the mid-IR slope, the measured PAH luminosity, and the optical depth of these sources with those of galaxies in the local Universe. As a result we are able to estimate the contribution of a dust enshrouded active nucleus to the mid-IR and bolometric luminosity of these systems. This work is based [in part] on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. Support for this work was provided by NASA through Contract Number 1257184 issued by JPL/Caltech.

Stellar Occultation Studies of the Solar System

NASA Technical Reports Server (NTRS)

Elliot, James L.

1998-01-01

Earth-based observations of stellar occultations provide extremely high spatial resolution for bodies in the outer solar system, about 10,000 times better than that of traditional imaging observations. Stellar occultation data can be used to establish the structure of atmospheres and rings of solar system bodies at high spatial resolution. Airborne occultation observations are particularly effective, since the controlled mobility of the observing platform allows the observer to fly within the optimum part of the occultation shadow for most events that are visible from Earth. Airborne observations are carried out above any clouds and are nearly free of scintillation noise from the Earth's atmosphere. KAO occultation observations resulted in the first detection of gravity waves in the Martian atmosphere, discovery of the Uranian rings, the first detection of Pluto's atmosphere, the first Earth-based investigations of Triton's atmosphere, and the discovery of narrow jets from Chiron's nucleus. The first SOFIA occultation opportunity will be an investigation of Pluto's atmospheric structure in November, 2002, and will resolve a problem that has lingered since the KAO discovery observation fourteen years earlier. We plan to continue our successful airborne occultation program with the greatly enhanced capability provided by SOFIA. We propose here to replace our KAO occultation photometer with one having twice the throughput, half the noise, a somewhat wider wavelength range, four times the field of view, and ten times the frame rate to optimize its performance and to capitalize on the larger collecting area offered by SOFIA. It will also allow for simultaneous visible and IR occultation observations, greatly enriching the results that we can obtain from occultations. We call this new imaging occultation photometer HOPI (High-speed Occultation Photometer and Imager). HOPI will provide a signal-to-noise ratio two to four times that of our present photometer for a given event, will permit useful observations of the more numerous events involving fainter stars, and will allow higher time resolution observations to be made. HOPI's characteristics also make it an ideal instrument for initial and ongoing evaluations of the SOFIA telescope's performance.

Geologic studies of Yellowstone National Park imagery using an electronic image enhancement system

NASA Technical Reports Server (NTRS)

Smedes, H. W.

1970-01-01

The image enhancement system is described, as well as the kinds of enhancement attained. Results were obtained from various kinds of remote sensing imagery (mainly black and white multiband, color, color infrared, thermal infrared, and side-looking K-band radar) of parts of Yellowstone National Park. Possible additional fields of application of these techniques are considered.

Collation of earth resources data collected by ERIM airborne sensors

NASA Technical Reports Server (NTRS)

Hasell, P. G., Jr.

1975-01-01

Earth resources imagery from nine years of data collection with developmental airborne sensors is cataloged for reference. The imaging sensors include single and multiband line scanners and side-looking radars. The operating wavelengths of the sensors include ultraviolet, visible and infrared band scanners, and X- and L-band radar. Imagery from all bands (radar and scanner) were collected at some sites and many sites had repeated coverage. The multiband scanner data was radiometrically calibrated. Illustrations show how the data can be used in earth resource investigations. References are made to published reports which have made use of the data in completed investigations. Data collection sponsors are identified and a procedure described for gaining access to the data.

Test of the MarsSedEx Settling Tube Photometer during the 2nd Swiss Parabolic Flight Campaign

NASA Astrophysics Data System (ADS)

Kuhn, Nikolaus J.; Kuhn, Brigitte; Rüegg, Hans-Rudolf; Zimmermann, Lukas

2017-04-01

Gravity affects flow hydraulics and thus limits the application of simple models for sediment transport developed for Earth on Mars. The significance of the differences in sediment settling has been demonstrated for sand-sized particles by measuring settling velocities using video-imaging during parabolic flights. This approach does not work for finer particles because they cannot be distinguished individually on a video. Tracking of fine sediment clouds is also difficult using videos because changes in density are not captured. Photometers, on the other hand, are able to capture differences in turbidity and offer the potential to measure the settling behaviour of clouds of fine and differently-sized sediment particles. In this study, the feasibility of using a settling-tube photometer used for the rapid assessment of settling velocities developed by the University of Basel during a parabolic flight with reduced gravity is presented. In addition, the potential of the results generated in this Martian-analogue environment to support the identification sediments containing traces of life on Mars is discussed.

An Application of Multi-band Forced Photometry to One Square Degree of SERVS: Accurate Photometric Redshifts and Implications for Future Science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nyland, Kristina; Lacy, Mark; Sajina, Anna

We apply The Tractor image modeling code to improve upon existing multi-band photometry for the Spitzer Extragalactic Representative Volume Survey (SERVS). SERVS consists of post-cryogenic Spitzer observations at 3.6 and 4.5 μ m over five well-studied deep fields spanning 18 deg{sup 2}. In concert with data from ground-based near-infrared (NIR) and optical surveys, SERVS aims to provide a census of the properties of massive galaxies out to z  ≈ 5. To accomplish this, we are using The Tractor to perform “forced photometry.” This technique employs prior measurements of source positions and surface brightness profiles from a high-resolution fiducial band from themore » VISTA Deep Extragalactic Observations survey to model and fit the fluxes at lower-resolution bands. We discuss our implementation of The Tractor over a square-degree test region within the XMM Large Scale Structure field with deep imaging in 12 NIR/optical bands. Our new multi-band source catalogs offer a number of advantages over traditional position-matched catalogs, including (1) consistent source cross-identification between bands, (2) de-blending of sources that are clearly resolved in the fiducial band but blended in the lower resolution SERVS data, (3) a higher source detection fraction in each band, (4) a larger number of candidate galaxies in the redshift range 5 <  z  < 6, and (5) a statistically significant improvement in the photometric redshift accuracy as evidenced by the significant decrease in the fraction of outliers compared to spectroscopic redshifts. Thus, forced photometry using The Tractor offers a means of improving the accuracy of multi-band extragalactic surveys designed for galaxy evolution studies. We will extend our application of this technique to the full SERVS footprint in the future.« less

Multiband multi-echo imaging of simultaneous oxygenation and flow timeseries for resting state connectivity.

PubMed

Cohen, Alexander D; Nencka, Andrew S; Lebel, R Marc; Wang, Yang

2017-01-01

A novel sequence has been introduced that combines multiband imaging with a multi-echo acquisition for simultaneous high spatial resolution pseudo-continuous arterial spin labeling (ASL) and blood-oxygenation-level dependent (BOLD) echo-planar imaging (MBME ASL/BOLD). Resting-state connectivity in healthy adult subjects was assessed using this sequence. Four echoes were acquired with a multiband acceleration of four, in order to increase spatial resolution, shorten repetition time, and reduce slice-timing effects on the ASL signal. In addition, by acquiring four echoes, advanced multi-echo independent component analysis (ME-ICA) denoising could be employed to increase the signal-to-noise ratio (SNR) and BOLD sensitivity. Seed-based and dual-regression approaches were utilized to analyze functional connectivity. Cerebral blood flow (CBF) and BOLD coupling was also evaluated by correlating the perfusion-weighted timeseries with the BOLD timeseries. These metrics were compared between single echo (E2), multi-echo combined (MEC), multi-echo combined and denoised (MECDN), and perfusion-weighted (PW) timeseries. Temporal SNR increased for the MECDN data compared to the MEC and E2 data. Connectivity also increased, in terms of correlation strength and network size, for the MECDN compared to the MEC and E2 datasets. CBF and BOLD coupling was increased in major resting-state networks, and that correlation was strongest for the MECDN datasets. These results indicate our novel MBME ASL/BOLD sequence, which collects simultaneous high-resolution ASL/BOLD data, could be a powerful tool for detecting functional connectivity and dynamic neurovascular coupling during the resting state. The collection of more than two echoes facilitates the use of ME-ICA denoising to greatly improve the quality of resting state functional connectivity MRI.

Autographic theme extraction

USGS Publications Warehouse

Edson, D.; Colvocoresses, Alden P.

1973-01-01

Remote-sensor images, including aerial and space photographs, are generally recorded on film, where the differences in density create the image of the scene. With panchromatic and multiband systems the density differences are recorded in shades of gray. On color or color infrared film, with the emulsion containing dyes sensitive to different wavelengths, a color image is created by a combination of color densities. The colors, however, can be separated by filtering or other techniques, and the color image reduced to monochromatic images in which each of the separated bands is recorded as a function of the gray scale.

A consideration of the use of optical fibers to remotely couple photometers to telescopes

NASA Technical Reports Server (NTRS)

Heacox, William D.

1988-01-01

The possible use of optical fibers to remotely couple photometers to telescopes is considered. Such an application offers the apparent prospect of enhancing photometric stability as a consequence of the benefits of remote operation and decreased sensitivity to image details. A properly designed fiber optic coupler will probably show no significant changes in optical transmisssion due to normal variations in the fiber configuration. It may be more difficult to eliminate configuration-dependent effects on the pupil of the transmitted beam, and thus achieve photometric stability to guiding and seeing errors. In addition, there is some evidence for significant changes in the optical throughputs of fibers over the temperature range normally encountered in astronomical observatories.

21 CFR 862.2300 - Colorimeter, photometer, or spectrophotometer for clinical use.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Colorimeter, photometer, or spectrophotometer for... Clinical Laboratory Instruments § 862.2300 Colorimeter, photometer, or spectrophotometer for clinical use. (a) Identification. A colorimeter, a photometer, or a spectrophotometer for clinical use is an...

21 CFR 862.2300 - Colorimeter, photometer, or spectrophotometer for clinical use.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Colorimeter, photometer, or spectrophotometer for... Clinical Laboratory Instruments § 862.2300 Colorimeter, photometer, or spectrophotometer for clinical use. (a) Identification. A colorimeter, a photometer, or a spectrophotometer for clinical use is an...

Design and performances of microcameras and photometers instruments on TARANIS satellite for an advanced characterization of Transient Luminous Event in the upper atmosphere

NASA Astrophysics Data System (ADS)

Le Mer-Dachard, Fanny; Cansot, Elodie; Hébert, Philippe; Farges, Thomas; Ravel, Karen; Gaillac, Stéphanie

2015-10-01

The TARANIS mission aims at studying upper atmosphere coupling with a scientific nadir-pointing microsatellite - CNES Myriade family - at a low-altitude orbit (700 km). The main objectives are to measure the occurrence of Transient Luminous Event (TLE), impulsive energetic optical phenomena generated by storms according to recently discovered process, and Terrestrial Gamma-ray Flash (TGF), their emissions and trigger factors. TARANIS instruments are currently in manufacturing, assembly, integration and testing phase. The MicroCameras and Photometers instruments (MCP) are in charge of the remote sensing of the sprites and the lightning in optical wavelengths. MicroCameras instrument [MCP-MC] is an imager in the visible and Photometers instrument [MCP-PH] is a radiometer with four bands from UV to NIR, able to detect TLEs on-board and to trigger the whole payload. The satellite will provide a complete survey of the atmosphere in low resolution together with a high resolution data of sites of interest automatically detected on board. For MC and PH instruments, CEA defined scientific needs and is in charge of processing data and providing scientific results. CNES described the technical requirements of these two instruments and will run in-flight commissioning. Design, manufacturing and testing is under responsibility of Sodern for MicroCameras and Bertin Technologies for Photometers. This article shortly describes physical characteristics of TLEs and presents the final design of these instruments and first measured performances.

Image change detection systems, methods, and articles of manufacture

DOEpatents

Jones, James L.; Lassahn, Gordon D.; Lancaster, Gregory D.

2010-01-05

Aspects of the invention relate to image change detection systems, methods, and articles of manufacture. According to one aspect, a method of identifying differences between a plurality of images is described. The method includes loading a source image and a target image into memory of a computer, constructing source and target edge images from the source and target images to enable processing of multiband images, displaying the source and target images on a display device of the computer, aligning the source and target edge images, switching displaying of the source image and the target image on the display device, to enable identification of differences between the source image and the target image.

Advanced Concurrent-Multiband, Multibeam, Aperture-Synthesis with Intelligent Processing for Urban Operation Sensing

DTIC Science & Technology

2012-04-09

signatures (RSS), in particular, despeckling, superresolution and convergence rate, for a variety of admissible 115 imaging array sensor...attain the superresolution performances in the resulting SSP estimates (3.4), we propose the VA inspired approach [13], [14] to specify the POCS

Remote Sensing Classification of Grass Seed Cropping Practices in Western Oregon

USDA-ARS?s Scientific Manuscript database

Multiband Landsat images and multi-temporal MODIS 16-day composite NDVI were classified into 16 categories representing the primary crop rotation options and stand establishment conditions present in western Oregon grass seed fields. Mismatch in resolution between MODIS and Landsat data was resolved...

A Real Time System for Multi-Sensor Image Analysis through Pyramidal Segmentation

DTIC Science & Technology

1992-01-30

A Real Time Syte for M~ulti- sensor Image Analysis S. E I0 through Pyramidal Segmentation/ / c •) L. Rudin, S. Osher, G. Koepfler, J.9. Morel 7. ytu...experiments with reconnaissance photography, multi- sensor satellite imagery, medical CT and MRI multi-band data have shown a great practi- cal potential...C ,SF _/ -- / WSM iS-I-0-d41-40450 $tltwt, kw" I (nor.- . Z-97- A real-time system for multi- sensor image analysis through pyramidal segmentation

The gravitational lens system Q0957+561 in the ultraviolet

NASA Technical Reports Server (NTRS)

Dolan, J. F.; Michalitsianos, A. G.; Thompson, R. W.; Boyd, P. T.; Wolinski, K. G.; Bless, R. C.; Nelson, M. J.; Percival, J. W.; Taylor, M. J.; Elliot, J. L.

1995-01-01

Photometric and polarimetric observations of both images of the gravitationally lensed quasar Q0957+561 (z(sub em) = 1.41) were obtained in the UV in 1993 with the High Speed Photometer on board the Hubble Space Photometer on board the Hubble Space Telescope. The images exhibited no significant polarization in a bandpass centered on 2770 A (observer's frame); p less than or = 3.2 % (2 sigma upper limit) in each image. The ratio of the flux density in image A to that in image B in late 1993 had a constant valuee, 1.021 +/- 0.008, in four different UV bandpass between 1400 A and 3040 A observer's frame). These results are consistent with the prediction of the gravitation lens interpretation that the photometric ratio of the images measured simultaneously should be independent of frequency. Reprocessed archival spectra of the two images obtained between 1981 and 1983 by the International Ultraviolet Explorer (IUE) show that the photometric ratio of A to B varies between 0.96 and 2.0 in the Ly alpha emission line, and between 0.77 and 1.8 in the O VI lambda 1037 emission line (quasar rest frame). The photometric ratio of A to B at any single epoch is often significantly different in the two emission lines. Accepting the system as a gravitational lens implies that in the quasar the flux in the Ly alpha emsisson line can vary independently of the flux in the 0 IV emission line.

Validation and understanding of Moderate Resolution Imaging Spectroradiometer aerosol products (C5) using ground-based measurements from the handheld Sun photometer network in China

Treesearch

Zhanqing Li; Feng Niu; Kwon-Ho Lee; Jinyuan Xin; Wei Min Hao; Bryce L. Nordgren; Yuesi Wang; Pucai Wang

2007-01-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) currently provides the most extensive aerosol retrievals on a global basis, but validation is limited to a small number of ground stations. This study presents a comprehensive evaluation of Collection 4 and 5 MODIS aerosol products using ground measurements from the Chinese Sun Hazemeter Network (CSHNET). The...

'Peony Nebula' Star Settles for Silver Medal

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Poster Version Movie

If our galaxy, the Milky Way, were to host its own version of the Olympics, the title for the brightest known star would go to a massive star called Eta Carina. However, a new runner-up now the second-brightest star in our galaxy has been discovered in the galaxy's dusty and frenzied interior. This image from NASA's Spitzer Space Telescope shows the new silver medalist, circled in the inset above, in the central region of our Milky Way.

Dubbed the 'Peony nebula' star, this blazing ball of gas shines with the equivalent light of 3.2 million suns. The reigning champ, Eta Carina, produces the equivalent of 4.7 million suns worth of light though astronomers say these estimates are uncertain, and it's possible that the Peony nebula star could be even brighter than Eta Carina.

If the Peony star is so bright, why doesn't it stand out more in this view? The answer is dust. This star is located in a very dusty region jam packed with stars. In fact, there could be other super bright stars still hidden deep in the stellar crowd. Spitzer's infrared eyes allowed it to pierce the dust and assess the Peony nebula star's true brightness. Likewise, infrared data from the European Southern Observatory's New Technology Telescope in Chile were integral in calculating the Peony nebula star's luminosity.

The Peony nebula, which surrounds the Peony nebular star, is the reddish cloud of dust in and around the white circle.

The movie begins by showing a stretch of the dusty and frenzied central region of our Milky Way galaxy. It then zooms in to reveal the 'Peony nebula' star the new second-brightest star in the Milky Way, discovered in part by NASA's Spitzer Space Telescope.

This is a three-color composite showing infrared observations from two Spitzer instruments. Blue represents 3.6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer.

Examining the infrared variable star population discovered in the Small Magellanic Cloud using the SAGE-SMC survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polsdofer, Elizabeth; Marengo, M.; Seale, J.

2015-02-01

We present our study on the infrared variability of point sources in the Small Magellanic Cloud (SMC). We use the data from the Spitzer Space Telescope Legacy Program “Surveying the Agents of Galaxy Evolution in the Tidally Stripped, Low Metallicity Small Magellanic Cloud” (SAGE-SMC) and the “Spitzer Survey of the Small Magellanic Cloud” (S{sup 3}MC) survey, over three different epochs, separated by several months to 3 years. Variability in the thermal infrared is identified using a combination of Spitzer’s InfraRed Array Camera 3.6, 4.5, 5.8, and 8.0 μm bands, and the Multiband Imaging Photometer for Spitzer 24 μm band. Anmore » error-weighted flux difference between each pair of three epochs (“variability index”) is used to assess the variability of each source. A visual source inspection is used to validate the photometry and image quality. Out of ∼2 million sources in the SAGE-SMC catalog, 814 meet our variability criteria. We matched the list of variable star candidates to the catalogs of SMC sources classified with other methods, available in the literature. Carbon-rich Asymptotic Giant Branch (AGB) stars make up the majority (61%) of our variable sources, with about a third of all of our sources being classified as extreme AGB stars. We find a small, but significant population of oxygen-rich (O-rich) AGB (8.6%), Red Supergiant (2.8%), and Red Giant Branch (<1%) stars. Other matches to the literature include Cepheid variable stars (8.6%), early type stars (2.8%), Young-stellar objects (5.8%), and background galaxies (1.2%). We found a candidate OH maser star, SSTISAGE1C J005212.88-730852.8, which is a variable O-rich AGB star, and would be the first OH/IR star in the SMC, if confirmed. We measured the infrared variability of a rare RV Tau variable (a post-AGB star) that has recently left the AGB phase. 59 variable stars from our list remain unclassified.« less

Photometer Tracks The Sun

NASA Technical Reports Server (NTRS)

Matsumoto, Tak; Mina, Cesar; Russell, Philip; Van Ark, William

1988-01-01

Airborne Sun-tracking photometer enables observations of Sun during much greater portion of flights than previously possible, without special maneuvers of airplane. Instrument occupies dome atop airplane. Fiberglass dome protects photometer and rotates to aim photometer in azimuth and elevation to track Sun. Provides controlled environment for instrument, including mechanical and electronic parts. Instrument calibrated without removing it from airplane.

MicroCameras and Photometers (MCP) on board the TARANIS satellite

NASA Astrophysics Data System (ADS)

Farges, T.; Hébert, P.; Le Mer-Dachard, F.; Ravel, K.; Gaillac, S.

2017-12-01

TARANIS (Tool for the Analysis of Radiations from lightNing and Sprites) is a CNES micro satellite. Its main objective is to study impulsive transfers of energy between the Earth atmosphere and the space environment. It will be sun-synchronous at an altitude of 700 km. It will be launched in 2019 for at least 2 years. Its payload is composed of several electromagnetic instruments in different wavelengths (from gamma-rays to radio waves including optical). TARANIS instruments are currently in calibration and qualification phase. The purpose is to present the MicroCameras and Photometers (MCP) design, to show its performances after its recent characterization and at last to discuss the scientific objectives and how we want to answer it with the MCP observations. The MicroCameras, developed by Sodern, are dedicated to the spatial description of TLEs and their parent lightning. They are able to differentiate sprite and lightning thanks to two narrow bands ([757-767 nm] and [772-782 nm]) that provide simultaneous pairs of images of an Event. Simulation results of the differentiation method will be shown. After calibration and tests, the MicroCameras are now delivered to the CNES for integration on the payload. The Photometers, developed by Bertin Technologies, will provide temporal measurements and spectral characteristics of TLEs and lightning. There are key instrument because of their capability to detect on-board TLEs and then switch all the instruments of the scientific payload in their high resolution acquisition mode. Photometers use four spectral bands in the [170-260 nm], [332-342 nm], [757-767 nm] and [600-900 nm] and have the same field of view as cameras. The on-board TLE detection algorithm remote-controlled parameters have been tuned before launch using the electronic board and simulated or real events waveforms. After calibration, the Photometers are now going through the environmental tests. They will be delivered to the CNES for integration on the payload in September 2017.

GLACiAR: GaLAxy survey Completeness AlgoRithm

NASA Astrophysics Data System (ADS)

Carrasco, Daniela; Trenti, Michele; Mutch, Simon; Oesch, Pascal

2018-05-01

GLACiAR (GaLAxy survey Completeness AlgoRithm) estimates the completeness and selection functions in galaxy surveys. Tailored for multiband imaging surveys aimed at searching for high-redshift galaxies through the Lyman Break technique, the code can nevertheless be applied broadly. GLACiAR generates artificial galaxies that follow Sérsic profiles with different indexes and with customizable size, redshift and spectral energy distribution properties, adds them to input images, and measures the recovery rate.

Comets Kick up Dust in Helix Nebula

NASA Technical Reports Server (NTRS)

2007-01-01

This infrared image from NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye.

The nebula, located about 700 light-years away in the constellation Aquarius, belongs to a class of objects called planetary nebulae. Discovered in the 18th century, these colorful beauties were named for their resemblance to gas-giant planets like Jupiter.

Planetary nebulae are the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years.

In Spitzer's infrared view of the Helix nebula, the eye looks more like that of a green monster's. Infrared light from the outer gaseous layers is represented in blues and greens. The white dwarf is visible as a tiny white dot in the center of the picture. The red color in the middle of the eye denotes the final layers of gas blown out when the star died.

The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star. Before the star died, its comets and possibly planets would have orbited the star in an orderly fashion. But when the star blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, resulting in an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded.

So far, the Helix nebula is one of only a few dead-star systems in which evidence for comet survivors has been found.

This image is made up of data from Spitzer's infrared array camera and multiband imaging photometer. Blue shows infrared light of 3.6 to 4.5 microns; green shows infrared light of 5.8 to 8 microns; and red shows infrared light of 24 microns.

On the analysis of large data sets

NASA Astrophysics Data System (ADS)

Ruch, Gerald T., Jr.

We present a set of tools and techniques for performing detailed comparisons between computational models with high dimensional parameter spaces and large sets of archival data. By combining a principal component analysis of a large grid of samples from the model with an artificial neural network, we create a powerful data visualization tool as well as a way to robustly recover physical parameters from a large set of experimental data. Our techniques are applied in the context of circumstellar disks, the likely sites of planetary formation. An analysis is performed applying the two layer approximation of Chiang et al. (2001) and Dullemond et al. (2001) to the archive created by the Spitzer Space Telescope Cores to Disks Legacy program. We find two populations of disk sources. The first population is characterized by the lack of a puffed up inner rim while the second population appears to contain an inner rim which casts a shadow across the disk. The first population also exhibits a trend of increasing spectral index while the second population exhibits a decreasing trend in the strength of the 20 mm silicate emission feature. We also present images of the giant molecular cloud W3 obtained with the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer (MIPS) on board the Spitzer Space Telescope. The images encompass the star forming regions W3 Main, W3(OH), and a region that we refer to as the Central Cluster which encloses the emission nebula IC 1795. We present a star count analysis of the point sources detected in W3. The star count analysis shows that the stellar population of the Central Cluster, when compared to that in the background, contains an over density of sources. The Central Cluster also contains an excess of sources with colors consistent with Class II Young Stellar Objects (YSOs). A analysis of the color-color diagrams also reveals a large number of Class II YSOs in the Central Cluster. Our results suggest that an earlier epoch of star formation created the Central Cluster, created a cavity, and triggered the active star formation in the W3 Main and W3(OH) regions. We also detect a new outflow and its candidate exciting star.

Shadows and Dust: Mid-Infrared Extinction Mapping of the Initial Conditions of Massive Star and Star Cluster Formation

NASA Astrophysics Data System (ADS)

Tan, Jonathan

We describe a research plan to develop and extend the mid-infrared (MIR) extinction mapping technique presented by Butler & Tan (2009), who studied Infrared Dark Clouds (IRDCs) using Spitzer Space Telescope Infrared Array Camera (IRAC) 8 micron images. This method has the ability to probe the detailed spatial structure of very high column density regions, i.e. the gas clouds thought to represent the initial conditions for massive star and star cluster formation. We will analyze the data Spitzer obtained at other wavelengths, i.e. the IRAC bands at 3.6, 4.5 and 5.8 microns, and the Multiband Imaging Photometer (MIPS) bands, especially at 24 microns. This will allow us to measure the dust extinction law across the MIR and search for evidence of dust grain evolution, e.g. grain growth and ice mantle formation, as a function of gas density and column density. We will also study the detailed structure of the extinction features, including individual cores that may form single stars or close binaries, especially focusing on those cores that may form massive stars. By studying independent dark cores in a given IRDC, we will be able to test if they have a common minimum observed intensity, which we will then attribute to the foreground. This is a new method that should allow us to more accurately map distant, high column density IRDCs, probing more extreme regimes of star formation. We will combine MIR extinction mapping, which works best at high column densities, with near- IR mapping based on 2MASS images of star fields, which is most useful at lower columns that probe the extended giant molecular cloud structure. This information is crucial to help understand the formation process of IRDCs, which may be the rate limiting step for global galactic star formation rates. We will use our new extinction mapping methods to analyze large samples of IRDCs and thus search the Galaxy for the most extreme examples of high column density cores and assess the global star formation efficiency in dense gas. We will estimate the ability of future NASA missions, such as JWST, to carry out MIR extinction mapping science. We will develop the results of this research into an E/PO presentation to be included in the various public outreach events organized and courses taught by the PI.

A Photometer for Measuring Population Growth in Yeast.

ERIC Educational Resources Information Center

Tatina, Robert; Hartley, Tamela; Thomas, Danita

1999-01-01

Describes the construction and use of an inexpensive, portable photometer designed specifically for estimating population sizes in yeast cultures. Suggests activities for use with the photometer. (WRM)

The Role of Thermodynamic Processes in the Evolution of Single and Multi-banding within Winter Storms

NASA Astrophysics Data System (ADS)

Ganetis, Sara Anne

Mesoscale precipitation bands within Northeast U.S. (NEUS) winter storms result in heterogeneous spatial and temporal snowfall. Several studies have provided analysis of snowbands focusing on larger, meso-beta scale bands with lengths (L) > 200 km known as single bands. NEUS winter storms can also exhibit multiple bands with meso-beta scale (L < 200 km) and similar spatial orientation and when ≥ 3 occur are termed multi-bands; however, the genesis and evolution of multi-bands is less well understood. Unlike single bands, there is no multi-bands climatological study. In addition, there has been little detailed thermodynamic analysis of snowbands. This dissertation utilizes radar observations, reanalyses, and high-resolution model simulations to explore the thermodynamic evolution of single and multi-bands. Bands are identified within 20 cool season (October-April) NEUS storms. The 110-case dataset was classified using a combination of automated and manual methods into: single band only (SINGLE), multi-bands only (MULTI), both single and multi-bands (BOTH), and non-banded (NONE). Multi-bands occur with the presence of a single band in 55.4% of times used in this study, without the presence of a single band 18.1% of the time, and precipitation exhibits no banded characteristics 23.8% of the time. Most MULTI events occur in the northeast quadrant of a developing cyclone poleward of weak-midlevel forcing along a warm front, whereas multi-bands associated with BOTH events mostly occur in the northwest quadrant of mature cyclones associated with strong mid-level frontogenesis and conditional symmetric instability. The non-banded precipitation associated with NONE events occur in the eastern quadrants of developing and mature cyclones lacking mid-level forcing to concentrate the precipitation into bands. A high-resolution mesoscale model is used to explore the evolution of single and multi-bands based on two case studies, one of a single band and one of multi-bands. The multi-bands form in response to intermittent mid-level frontogenetical forcing in a conditionally unstable environment. The bands within their genesis location southeast of the single band move northwest towards the single band by 700-hPa steering flow. This allows for the formation of new multi-bands within the genesis region, unlike the single band that remains fixed to a 700-hPa frontogenesis maximum. Latent heating within the band is shown to increase the intensity and duration of single and multi-bands through decreased geopotential height below the heating maximum that leads to increased convergence within the band.

Raman lidar and sun photometer measurements of aerosols and water vapor during the ARM RCS experiment

NASA Technical Reports Server (NTRS)

Ferrare, R. A.; Whiteman, D. N.; Melfi, S. H.; Evans, K. D.; Holben, B. N.

1995-01-01

The first Atmospheric Radiation Measurement (ARM) Remote Cloud Study (RCS) Intensive Operations Period (IOP) was held during April 1994 at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site near Lamont, Oklahoma. This experiment was conducted to evaluate and calibrate state-of-the-art, ground based remote sensing instruments and to use the data acquired by these instruments to validate retrieval algorithms developed under the ARM program. These activities are part of an overall plan to assess general circulation model (GCM) parameterization research. Since radiation processes are one of the key areas included in this parameterization research, measurements of water vapor and aerosols are required because of the important roles these atmospheric constituents play in radiative transfer. Two instruments were deployed during this IOP to measure water vapor and aerosols and study their relationship. The NASA/Goddard Space Flight Center (GSFC) Scanning Raman Lidar (SRL) acquired water vapor and aerosol profile data during 15 nights of operations. The lidar acquired vertical profiles as well as nearly horizontal profiles directed near an instrumented 60 meter tower. Aerosol optical thickness, phase function, size distribution, and integrated water vapor were derived from measurements with a multiband automatic sun and sky scanning radiometer deployed at this site.

Analysis of remote sensing data for evaluation of vegetation resources

NASA Technical Reports Server (NTRS)

1970-01-01

Research has centered around: (1) completion of a study on the use of remote sensing techniques as an aid to multiple use management; (2) determination of the information transfer at various image resolution levels for wildland areas; and (3) determination of the value of small scale multiband, multidate photography for the analysis of vegetation resources. In addition, a substantial effort was made to upgrade the automatic image classification and spectral signature acquisition capabilities of the laboratory. It was found that: (1) Remote sensing techniques should be useful in multiple use management to provide a first-cut analysis of an area. (2) Imagery with 400-500 feet ground resolvable distance (GRD), such as that expected from ERTS-1, should allow discriminations to be made between woody vegetation, grassland, and water bodies with approximately 80% accuracy. (3) Barley and wheat acreages in Maricopa County, Arizona could be estimated with acceptable accuracies using small scale multiband, multidate photography. Sampling errors for acreages of wheat, barley, small grains (wheat and barley combined), and all cropland were 13%, 11%, 8% and 3% respectively.

Radar data processing and analysis

NASA Technical Reports Server (NTRS)

Ausherman, D.; Larson, R.; Liskow, C.

1976-01-01

Digitized four-channel radar images corresponding to particular areas from the Phoenix and Huntington test sites were generated in conjunction with prior experiments performed to collect X- and L-band synthetic aperture radar imagery of these two areas. The methods for generating this imagery are documented. A secondary objective was the investigation of digital processing techniques for extraction of information from the multiband radar image data. Following the digitization, the remaining resources permitted a preliminary machine analysis to be performed on portions of the radar image data. The results, although necessarily limited, are reported.

Excitation-resolved cone-beam x-ray luminescence tomography.

PubMed

Liu, Xin; Liao, Qimei; Wang, Hongkai; Yan, Zhuangzhi

2015-07-01

Cone-beam x-ray luminescence computed tomography (CB-XLCT), as an emerging imaging technique, plays an important role in in vivo small animal imaging studies. However, CB-XLCT suffers from low-spatial resolution due to the ill-posed nature of reconstruction. We improve the imaging performance of CB-XLCT by using a multiband excitation-resolved imaging scheme combined with principal component analysis. To evaluate the performance of the proposed method, the physical phantom experiment is performed with a custom-made XLCT/XCT imaging system. The experimental results validate the feasibility of the method, where two adjacent nanophosphors (with an edge-to-edge distance of 2.4 mm) can be located.

Low-cost, high-performance and efficiency computational photometer design

NASA Astrophysics Data System (ADS)

Siewert, Sam B.; Shihadeh, Jeries; Myers, Randall; Khandhar, Jay; Ivanov, Vitaly

2014-05-01

Researchers at the University of Alaska Anchorage and University of Colorado Boulder have built a low cost high performance and efficiency drop-in-place Computational Photometer (CP) to test in field applications ranging from port security and safety monitoring to environmental compliance monitoring and surveying. The CP integrates off-the-shelf visible spectrum cameras with near to long wavelength infrared detectors and high resolution digital snapshots in a single device. The proof of concept combines three or more detectors into a single multichannel imaging system that can time correlate read-out, capture, and image process all of the channels concurrently with high performance and energy efficiency. The dual-channel continuous read-out is combined with a third high definition digital snapshot capability and has been designed using an FPGA (Field Programmable Gate Array) to capture, decimate, down-convert, re-encode, and transform images from two standard definition CCD (Charge Coupled Device) cameras at 30Hz. The continuous stereo vision can be time correlated to megapixel high definition snapshots. This proof of concept has been fabricated as a fourlayer PCB (Printed Circuit Board) suitable for use in education and research for low cost high efficiency field monitoring applications that need multispectral and three dimensional imaging capabilities. Initial testing is in progress and includes field testing in ports, potential test flights in un-manned aerial systems, and future planned missions to image harsh environments in the arctic including volcanic plumes, ice formation, and arctic marine life.

Space telescope phase B definition study. Volume 2A: Science instruments, high speed point/area photometer

NASA Technical Reports Server (NTRS)

1976-01-01

The analysis and preliminary design of a high speed point/area photometer for the space telescope are summarized. The scientific objectives, photometer requirements, and design concepts are presented.

A MAGELLAN MIKE AND SPITZER MIPS STUDY OF 1.5-1.0 M{sub sun} STARS IN SCORPIUS-CENTAURUS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Christine H.; Bitner, Martin A.; Mamajek, Eric E.

2011-09-10

We obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) 24 {mu}m and 70 {mu}m observations of 182 nearby, Hipparcos F- and G-type common proper motion single and binary systems in the nearest OB association, Scorpius-Centaurus. We also obtained Magellan/MIKE R {approx} 50,000 visual spectra at 3500-10500 A for 181 candidate ScoCen stars in single and binary systems. Combining our MIPS observations with those of other ScoCen stars in the literature, we estimate 24 {mu}m F+G-type disk fractions of 9/27 (33% {+-} 11%), 21/67 (31% {+-} 7%), and 25/71 (35% {+-} 7%) for Upper Scorpius ({approx}10 Myr), Upper Centaurusmore » Lupus ({approx}15 Myr), and Lower Centaurus Crux ({approx}17 Myr), respectively. We confirm previous IRAS and MIPS excess detections and present new discoveries of 41 protoplanetary and debris disk systems, with fractional infrared luminosities ranging from L{sub IR}/L{sub *} = 10{sup -5} to 10{sup -2} and grain temperatures ranging from T{sub gr} = 40-300 K. We searched for an increase in 24 {mu}m excess at an age of 15-20 Myr, consistent with the onset of debris production predicted by coagulation N-body simulations of outer planetary systems. We found such an increase around 1.5 M{sub sun} stars but discovered a decrease in the 24 {mu}m excess around 1.0 M{sub sun} stars. We additionally discovered that the 24 {mu}m excess around 1.0 M{sub sun} stars is larger than predicted by self-stirred models. Finally, we found a weak anti-correlation between fractional infrared luminosity (L{sub IR}/L{sub *}) and chromospheric activity (R'{sub HK}), that may be the result of differences in stellar properties, such as mass, luminosity, and/or winds.« less

The Secondary Eclipse and Transit of HD 209458b at 24 micron

NASA Astrophysics Data System (ADS)

Harrington, J.; Luszcz, S.; Deming, D.; Richardson, L. J.; Seager, S.

2005-08-01

We used the Multiband Imaging Photometer on the Spitzer Space Telescope to obtain 24-micron lightcurves for one secondary eclipse and half a transit of extrasolar planet HD 209458b behind/in front of its star. Optimal photometric extraction of the total system brightness gives S/N of ˜100 per 10-sec exposure. We measure the deficit of planetary flux in secondary eclipse at 55 ± 10 μ Jy, or 0.260 ± 0.046% of the stellar flux, giving a brightness temperature of 1130 ± 150 K. The secondary eclipse occurs within 7 min (1σ ) of the mid-time between transits, essentially eliminating the hypothesis that HD 209458b's radius is inflated by tidal dissipation due to an elliptical orbit. Such an orbit would have required a second planet in a resonant orbit. This measurement and a similar, simultaneously-submitted result for TrES-1 by Charbonneau et al. (2005) are the first direct measurements of radiation from confirmed extrasolar planets. We measure a preliminary transit depth of 1.559 ± 0.065% of the stellar flux. The stellar limb-darkening curve is flat to within the errors, as expected for this wavelength. Adopting a stellar radius of 1.18 ± 0.10 R⊙ (Cody and Sasselov 2002) gives a planetary radius of 1.43 ± 0.13 RJ, consistent with that derived from optical measurements. The large error bar prevents us from ruling out a significant wavelength dependence of the eclipsing radius, as might be be expected if a particulate coma were responsible for the inflated optical radius. Spitzer has acquired an additional complete transit; updated results will be presented at the conference. This work was supported by the NASA Origins of Solar Systems program and the Spitzer Space Telescope. LJR is an NRC research associate.

Revealing evolved massive stars with Spitzer

NASA Astrophysics Data System (ADS)

Gvaramadze, V. V.; Kniazev, A. Y.; Fabrika, S.

2010-06-01

Massive evolved stars lose a large fraction of their mass via copious stellar wind or instant outbursts. During certain evolutionary phases, they can be identified by the presence of their circumstellar nebulae. In this paper, we present the results of a search for compact nebulae (reminiscent of circumstellar nebulae around evolved massive stars) using archival 24-μm data obtained with the Multiband Imaging Photometer for Spitzer. We have discovered 115 nebulae, most of which bear a striking resemblance to the circumstellar nebulae associated with luminous blue variables (LBVs) and late WN-type (WNL) Wolf-Rayet (WR) stars in the Milky Way and the Large Magellanic Cloud (LMC). We interpret this similarity as an indication that the central stars of detected nebulae are either LBVs or related evolved massive stars. Our interpretation is supported by follow-up spectroscopy of two dozen of these central stars, most of which turn out to be either candidate LBVs (cLBVs), blue supergiants or WNL stars. We expect that the forthcoming spectroscopy of the remaining objects from our list, accompanied by the spectrophotometric monitoring of the already discovered cLBVs, will further increase the known population of Galactic LBVs. This, in turn, will have profound consequences for better understanding the LBV phenomenon and its role in the transition between hydrogen-burning O stars and helium-burning WR stars. We also report on the detection of an arc-like structure attached to the cLBV HD 326823 and an arc associated with the LBV R99 (HD 269445) in the LMC. Partially based on observations collected at the German-Spanish Astronomical Centre, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC). E-mail: vgvaram@mx.iki.rssi.ru (VVG); akniazev@saao.ac.za (AYK); fabrika@sao.ru (SF)

VizieR Online Data Catalog: Candidate eruptive young stars in Lynds 1340 (Kun+, 2014)

NASA Astrophysics Data System (ADS)

Kun, M.; Apai, D.; O'Linger-Luscusk, J.; Moor, A.; Stecklum, B.; Szegedi-Elek, E.; Wolf-Chase, G.

2016-07-01

Lynds 1340 was observed by the Spitzer Space Telescope using the Infrared Array Camera (IRAC) on 2009 March 16 and the Multiband Imaging Photometer (MIPS) for Spitzer on 2008 November 26 (Prog. ID: 50691, PI: G. Fazio). The observations covered ~1deg2 in each band. We obtained low-resolution optical spectra for the star coinciding with IRAS 02224+7227 on 2003 February 5 using CAFOS with the G-100 grism on the 2.2m Telescope of the Calar Alto Observatory, and on 2004 December 11 using FAST on the 1.5m FLWO Telescope. High angular resolution JHK images, centered on the same star, were obtained on 2002 October 24 using the near-infrared camera Omega-Cass, mounted on the 3.5m Telescope of the Calar Alto Observatory. We performed a new search for Hα emission stars in L1340 using the Wide Field Grism Spectrograph 2 installed on the University of Hawaii 2.2m Telescope. We observed 2MASS J02263797+7304575 on 2011 October 16 and detected a Hα emission with EW(Hα)=-80Å in its spectrum. The Ks magnitude of 2MASS J02325605+7246055 was measured on the images obtained on 2010 October 18, during the monitoring program of V1180 Cas (Kun et al. 2011, J/ApJ/733/L8), using the MAGIC camera on the 2.2m Telescope of the Calar Alto Observatory. Narrow-band images through [SII] and Hα filters, as well as broad R-band images containing the environment of 2MASSJ02325605+7246055, were obtained with the Schmidt Telescope of the Thuringer Landessternwarte (TLS), Tautenburg in 2011 May, June, and September. Spectra of the nebula and the two brightest HH knots were obtained using the TLS medium-resolution Nasmyth spectrograph (R~700) in 2011 November. BVRCIC photometric observations of IRAS 02224+7227 were performed with the 1m Ritchey-Chretien-Coude (RCC) Telescope of the Konkoly Observatory at three epochs between 2001 and 2011. We measured the RC and IC magnitudes of IRAS 02224+7227 and 2MASSJ02263797+7304575 at several epochs between 2011 January and 2014 June on the images collected with the wide-field camera on the Schmidt Telescope of the Konkoly Observatory to monitor the light variations of V1180 Cas (Kun et al. 2011, J/ApJ/733/L8). L1340 is situated within Stripe 1260 of the SEGUE survey (Yanny et al. 2009, J/AJ/137/4377), thus its entire area was observed in the ugriz bands in 2005 November-December. Each target star has high-quality 3.4, 4.6, 12, and 22um fluxes in the AllWISE data base. (1 data file).

Computer processing of Mars Odyssey THEMIS IR imaging, MGS MOLA altimetry and Mars Express stereo imaging to locate Airy-0, the Mars prime meridian reference

NASA Astrophysics Data System (ADS)

Duxbury, Thomas; Neukum, Gerhard; Smith, David E.; Christensen, Philip; Neumann, Gregory; Albee, Arden; Caplinger, Michael; Seregina, N. V.; Kirk, Randolph L.

The small crater Airy-0 was selected from Mariner 9 images to be the reference for the Mars prime meridian. Initial analyses were made in year 2000 to tie Viking Orbiter and Mars Orbiter Camera images of Airy-0 to the evolving Mars Orbiter Laser Altimeter global digital terrain model to improve the location accuracy of Airy-0. Based upon this tie and radiometric tracking of landers / rovers from earth, new expressions for the Mars spin axis direction, spin rate and prime meridian epoch value were produced to define the orientation of the Martian surface in inertial space over time. Now that the Mars Global Surveyor mission and the Mars Orbiter Laser Altimeter global digital terrain model are complete, a more exhaustive study has been performed to determine the location of Airy-0 relative to the global terrain grid. THEMIS IR image cubes of the Airy and Gale crater regions were tied to the global terrain grid using precision stereo photogrammetric image processing techniques. The Airy-0 location was determined to be within 50 meters of the currently defined IAU prime meridian, with this offset at the limiting absolute accuracy of the global terrain grid. Additional outputs of this study were a controlled multi-band photomosaic of Airy, precision alignment and geometric models of the ten THEMIS IR bands and a controlled multi-band photomosaic of Gale crater used to validate the Mars Surface Laboratory operational map products supporting their successful landing on Mars.

Magnetic Resonance Imaging Measurement of Transmission of Arterial Pulsation to the Brain on Propranolol Versus Amlodipine.

PubMed

Webb, Alastair J S; Rothwell, Peter M

2016-06-01

Cerebral arterial pulsatility is associated with leukoaraiosis and depends on central arterial pulsatility and arterial stiffness. The effect of antihypertensive drugs on transmission of central arterial pulsatility to the cerebral circulation is unknown, partly because of limited methods of assessment. In a technique-development pilot study, 10 healthy volunteers were randomized to crossover treatment with amlodipine and propranolol. At baseline and on each drug, we assessed aortic (Sphygmocor) and middle cerebral artery pulsatility (TCDtranscranial ultrasound). We also performed whole-brain, 3-tesla multiband blood-oxygen level dependent magnetic resonance imaging (multiband factor 6, repetition time=0.43s), concurrent with a novel method of continuous noninvasive blood pressure monitoring. Drug effects on relationships between cardiac cycle variation in blood pressure and blood-oxygen level dependent imaging were determined (fMRI Expert Analysis Tool, fMRIB Software Library [FEAT-FSL]). Aortic pulsatility was similar on amlodipine (27.3 mm Hg) and propranolol (27.9 mm Hg, P diff=0.33), while MCA pulsatility increased nonsignificantly more from baseline on propranolol (+6%; P=0.09) than amlodipine (+1.5%; P=0.58). On magnetic resonance imaging, cardiac frequency blood pressure variations were found to be significantly more strongly associated with blood-oxygen level dependent imaging on propranolol than amlodipine. We piloted a novel method of assessment of arterial pulsatility with concurrent high-frequency blood-oxygen level dependent magnetic resonance imaging and noninvasive blood pressure monitoring. This method was able to identify greater transmission of aortic pulsation on propranolol than amlodipine, which warrants further investigation. © 2016 American Heart Association, Inc.

An inexpensive and stable LED Sun photometer for measuring the water vapor column over South Texas from 1990 to 2001

NASA Astrophysics Data System (ADS)

Mims, Forrest M.

2002-07-01

A Sun photometer that uses near-infrared light-emitting diodes (LEDs) as spectrally-selective photodetectors has measured total column water vapor in South Texas since February 1990. The 12 years of solar noon observations to date are correlated with upper air soundings at Del Rio, Texas (r2 = 0.75), and highly correlated with measurements by a Microtops II filter Sun photometer (r2 = 0.94). LEDs are inexpensive and have far better long term stability than the interference filters in conventional Sun photometers. The LED Sun photometer therefore provides an inexpensive, stable and portable means for measuring column water vapor.

Miniaturised wireless smart tag for optical chemical analysis applications.

PubMed

Steinberg, Matthew D; Kassal, Petar; Tkalčec, Biserka; Murković Steinberg, Ivana

2014-01-01

A novel miniaturised photometer has been developed as an ultra-portable and mobile analytical chemical instrument. The low-cost photometer presents a paradigm shift in mobile chemical sensor instrumentation because it is built around a contactless smart card format. The photometer tag is based on the radio-frequency identification (RFID) smart card system, which provides short-range wireless data and power transfer between the photometer and a proximal reader, and which allows the reader to also energise the photometer by near field electromagnetic induction. RFID is set to become a key enabling technology of the Internet-of-Things (IoT), hence devices such as the photometer described here will enable numerous mobile, wearable and vanguard chemical sensing applications in the emerging connected world. In the work presented here, we demonstrate the characterisation of a low-power RFID wireless sensor tag with an LED/photodiode-based photometric input. The performance of the wireless photometer has been tested through two different model analytical applications. The first is photometry in solution, where colour intensity as a function of dye concentration was measured. The second is an ion-selective optode system in which potassium ion concentrations were determined by using previously well characterised bulk optode membranes. The analytical performance of the wireless photometer smart tag is clearly demonstrated by these optical absorption-based analytical experiments, with excellent data agreement to a reference laboratory instrument. © 2013 Elsevier B.V. All rights reserved.

MULTIBAND OPTICAL OBSERVATION OF THE P/2010 A2 DUST TAIL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Junhan; Ishiguro, Masateru; Hanayama, Hidekazu

2012-02-10

An inner main-belt asteroid, P/2010 A2, was discovered on 2010 January 6. Based on its orbital elements, it is considered that the asteroid belongs to the Flora collisional family, where S-type asteroids are common, while showing a comet-like dust tail. Although analysis of images taken by the Hubble Space Telescope and Rosetta spacecraft suggested that the dust tail resulted from a recent head-on collision between asteroids, an alternative idea of ice sublimation was suggested based on the morphological fitting of ground-based images. Here, we report a multiband observation of P/2010 A2 made on 2010 January with a 105 cm telescopemore » at the Ishigakijima Astronomical Observatory. Three broadband filters, g', R{sub c} , and I{sub c} , were employed for the observation. The unique multiband data reveal that the reflectance spectrum of the P/2010 A2 dust tail resembles that of an Sq-type asteroid or that of ordinary chondrites rather than that of an S-type asteroid. Due to the large error of the measurement, the reflectance spectrum also resembles the spectra of C-type asteroids, even though C-type asteroids are uncommon in the Flora family. The reflectances relative to the g' band (470 nm) are 1.096 {+-} 0.046 at the R{sub c} band (650 nm) and 1.131 {+-} 0.061 at the I{sub c} band (800 nm). We hypothesize that the parent body of P/2010 A2 was originally S-type but was then shattered upon collision into scattering fresh chondritic particles from the interior, thus forming the dust tail.« less

Comparing Aerosol Retrievals from Ground-Based Instruments at the Impact-Pm Field Campaign

NASA Astrophysics Data System (ADS)

Kupinski, M.; Bradley, C. L.; Kalashnikova, O. V.; Xu, F.; Diner, D. J.; Clements, C. B.; Camacho, C.

2016-12-01

Detection of aerosol types, components having different size and chemical composition, over urban areas is important for understanding their impact on health and climate. In particular, sustained contact with size-differentiated airborne particulate matter: PM10 and PM2.5 can lead to adverse health effects such as asthma attacks, heart and lung diseases, and premature mortality. Multi-angular polarimetric measurements have been advocated in recent years as an additional tool to better understand and retrieve the aerosol properties needed for improved predictions of aerosol impart on air quality and climate. We deployed the ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI) for accurate spectropolarimetric and radiance measurements co-located with the AERONET CIMEL sun photometer and a Halo Doppler 18 m resolution lidar from San José State University at the Garland-Fresno Air Quality supersite in Fresno, CA on July 7 during the Imaging Polarimetric Assessment and Characterization of Tropospheric Particulate Matter (ImPACT-PM) field experiment. GroundMSPI sampled the atmospheric scattering phase function in and 90 degrees out of the principal plane every 15 minutes in an automated manner, utilizing the 2-axis gimbal mount in elevation and azimuth. The goal of this work is verify atmospheric measurement of GroundMSPI with the coincident CIMEL sun photometer and ground-based lidar. Diffuse-sky radiance measurements of GroundMSPI are compared with the CIMEL sun photometer throughout the day. AERONET aerosol parameters such as size, shape, and index of refraction as well as lidar aerosol extinction profiles will be used in a forward radiative transfer model to compare with GroundMSPI observations and optimize these parameters to best match GroundMSPI data.

The Hubble Space Telescope high speed photometer

NASA Technical Reports Server (NTRS)

Vancitters, G. W., Jr.; Bless, R. C.; Dolan, J. F.; Elliot, J. L.; Robinson, E. L.; White, R. L.

1988-01-01

The Hubble Space Telescope will provide the opportunity to perform precise astronomical photometry above the disturbing effects of the atmosphere. The High Speed Photometer is designed to provide the observatory with a stable, precise photometer with wide dynamic range, broad wavelenth coverage, time resolution in the microsecond region, and polarimetric capability. Here, the scientific requirements for the instrument are examined, the unique design features of the photometer are explored, and the improvements to be expected over the performance of ground-based instruments are projected.

CCD Photometer Installed on the Telescope - 600 OF the Shamakhy Astrophysical Observatory: I. Adjustment of CCD Photometer with Optics - 600

NASA Astrophysics Data System (ADS)

Lyuty, V. M.; Abdullayev, B. I.; Alekberov, I. A.; Gulmaliyev, N. I.; Mikayilov, Kh. M.; Rustamov, B. N.

2009-12-01

Short description of optical and electric scheme of CCD photometer with camera U-47 installed on the Cassegrain focus of ZEISS-600 telescope of the ShAO NAS Azerbaijan is provided. The reducer of focus with factor of reduction 1.7 is applied. It is calculated equivalent focal distances of a telescope with a focus reducer. General calculations of optimum distance from focal plane and t sizes of optical filters of photometer are presented.

ASTER First Views of Red Sea, Ethiopia - Thermal-Infrared TIR Image monochrome

NASA Image and Video Library

2000-03-11

ASTER succeeded in acquiring this image at night, which is something Visible/Near Infrared VNIR) and Shortwave Infrared (SWIR) sensors cannot do. The scene covers the Red Sea coastline to an inland area of Ethiopia. White pixels represent areas with higher temperature material on the surface, while dark pixels indicate lower temperatures. This image shows ASTER's ability as a highly sensitive, temperature-discerning instrument and the first spaceborne TIR multi-band sensor in history. The size of image: 60 km x 60 km approx., ground resolution 90 m x 90 m approximately. http://photojournal.jpl.nasa.gov/catalog/PIA02452

Airborne tracking sunphotometer apparatus and system

NASA Technical Reports Server (NTRS)

Matsumoto, Yutaka (Inventor); Mina, Cesar (Inventor); Russell, Philip B. (Inventor); Vanark, William B. (Inventor)

1987-01-01

An airborne tracking Sun photometer apparatus has a rotatable dome. An azimuth drive motor is connected to rotate the dome. The dome has an equatorial slot. A cylindrical housing is pivotally mounted inside the dome at the equatorial slot. A photometer is mounted in the housing to move in the equatorial slot as the housing pivots. The photometer has an end facing from the slot with an optical flat transparent window. An elevation drive motor is connected to pivot the cylindrical housing. The rotatable dome is mounted in the bulkhead of an aircraft to extend from the interior of the aircraft. A Sun sensor causes the photometer to track the Sun automatically. Alternatively, the photometer may be oriented manually or by computer.

Influence of the spectral power distribution of a LED on the illuminance responsivity of a photometer

NASA Astrophysics Data System (ADS)

Sametoglu, Ferhat

2008-09-01

The measurement accuracy in the photometric quantities measured through photometer head is determined by the value of the spectral mismatch correction factor ( c( St, Ss)), which is defined as a function of spectral power distribution of light sources, besides illuminance responsivity of the photometer head used. This factor is more important when photometric quantities of the light-emitting diode (LED) style optical sources, which radiate within relatively narrow spectral bands as compared with that of other optical sources, are being measured. Variations of the illuminance responsivities of various V( λ)-adopted photometer heads are discussed. High-power-colored LEDs, manufactured by Lumileds Lighting Co., were used as light sources and their relative spectral power distributions (RSPDs) were measured using a spectrometer-based optical setup. Dependences of the c( St, Ss) factors of three types of photometer heads ( f1'=1.4%, f1'=0.8% and f1'=0.5%) with wavelength and influences of the factors on the illuminance responsivities of photometer heads are presented.

Analysis of lithology: Vegetation mixes in multispectral images

NASA Technical Reports Server (NTRS)

Adams, J. B.; Smith, M.; Adams, J. D.

1982-01-01

Discrimination and identification of lithologies from multispectral images is discussed. Rock/soil identification can be facilitated by removing the component of the signal in the images that is contributed by the vegetation. Mixing models were developed to predict the spectra of combinations of pure end members, and those models were refined using laboratory measurements of real mixtures. Models in use include a simple linear (checkerboard) mix, granular mixing, semi-transparent coatings, and combinations of the above. The use of interactive computer techniques that allow quick comparison of the spectrum of a pixel stack (in a multiband set) with laboratory spectra is discussed.

ASTER First Views of Rift Valley, Ethiopia - Thermal-Infrared TIR Image color

NASA Image and Video Library

2000-03-11

This image is a color composite covering the Rift Valley inland area of Ethiopia (south of the region shown in PIA02452). The color difference of this image reflects the distribution of different rocks with different amounts of silicon dioxide. It is inferred that the area with whitish color is covered with basalt and the pinkish area in the center contain sandesite. This is the first spaceborne, multi-band TIR image in history that enables geologists to distinguish between rocks with similar compositions. The size of image: 60 km x 60 km approx., ground resolution 90 m x 90 m approximately. http://photojournal.jpl.nasa.gov/catalog/PIA02453

VizieR Online Data Catalog: KiDS-ESO-DR2 multi-band source catalog (de Jong+, 2015)

NASA Astrophysics Data System (ADS)

de Jong, J. T. A.; Verdoes Kleijn, G. A.; Boxhoorn, D. R.; Buddelmeijer, H.; Capaccioli, M.; Getman, F.; Grado, A.; Helmich, E.; Huang, Z.; Irisarri, N.; Kuijken, K.; La Barbera, F.; McFarland, J. P.; Napolitano, N. R.; Radovich, M.; Sikkema, G.; Valentijn, E. A.; Begeman, K. G.; Brescia, M.; Cavuoti, S.; Choi, A.; Cordes, O.-M.; Covone, G.; Dall'Ora, M.; Hildebrandt, H.; Longo, G.; Nakajima, R.; Paolillo, M.; Puddu, E.; Rifatto, A.; Tortora, C.; van Uitert, E.; Buddendiek, A.; Harnois-Deraps, J.; Erben, T.; Eriksen, M. B.; Heymans, C.; Hoekstra, H.; Joachimi, B.; Kitching, T. D.; Klaes, D.; Koopmans, L. V. E.; Koehlinger, F.; Roy, N.; Sifon, C.; Schneider, P.; Sutherland, W. J.; Viola, M.; Vriend, W.-J.

2016-10-01

KiDS data releases consist of ~1 square degree tiles that have been successfully observed in all four survey filters (u,g,r,i). The second data release (KiDS-ESO-DR2) was available in February 2015 and contains imaging data, masks and single-band source lists for all tiles observed in all four filters for which observations were completed during the second year of regular operations (1 October 2012 to 31 September 2013), a total of 98 tiles. Apart from the data products mentioned above, KiDS-ESO-DR2 also provides a multi-band source catalogue based on the combined set of 148 tiles released in the first two data releases. A complete list of all tiles with data quality parameters can be found on the KiDS website: http://kids.strw.leidenuniv.nl/DR2/ (1 data file).

First Solar System Results Of The Spitzer Space Telescope, Including Imaging And Spectroscopy Of The Principal Uranian Satellites, Phoebe, And Rhea

NASA Astrophysics Data System (ADS)

van Cleve, J.; Cruikshank, D. P.; Stansberry, J. A.; Burgdorf, M. J.; Devost, D.; Emery, J. P.; Fazio, G.; Fernandez, Y. R.; Glaccum, W.; Grillmair, C.; Houck, J. R.; Meadows, V. S.; Morris, P.; Reach, W. T.; Reitsema, H.; Rieke, G. H.; Werner, M. W.

2004-05-01

The Spitzer Space Telescope, formerly known as SIRTF, is now operational and delivers unprecedented sensitivity for the observation of Solar System targets. Spitzer has three instruments, IRAC, IRS, and MIPS. IRAC (InfraRed Array Camera) provides simultaneous images at wavelengths of 3.6, 4.5, 5.8, and 8.0 μ m. IRS (InfraRed Spectrograph) has 4 modules providing low-resolution (R=60-120) spectra from 5.3 to 40 μ m, high-resolution (R=600) spectra from 10 to 37 μ m, and an autonomous target acquisition system (PeakUp) which includes small-field imaging at 15 μ m. MIPS (Multiband Imaging Photometer for SIRTF) does imaging photometry at 24, 70, and 160 μ m and low-resolution (R=15-25) spectroscopy (SED) between 55 and 96 μ m. Guaranteed Time Observer (GTO) programs include the moons of the outer Solar System, Pluto, Centaurs, Kuiper Belt Objects, and comets. For example, the "IRS Moons and Planets" program is now examining the principal satellites of outer Solar System planets, as well as Uranus and Neptune, using all SIRTF instruments. IRAC photometry will establish the hitherto unknown albedo of these cold objects at wavelengths between 3.5 and 8 μ m, IRS will do reflectance spectrosopy at wavelengths between 5.3 and 15 μ m, and thermal emission spectroscopy between 10 and 40 μ m. Combined with MIPS photometry and SED measurements, these data will provide compositional information, albedo, and thermal properties of these objects. The observations of Uranus and Neptune will be used to monitor changes in Uranus and Neptune atmospheres with season [1,2], for trace composition data, and for precise straylight subtraction for observations of their innermost principal satellites. We will observe Titan to compare spectra of the hemisphere centered on the "continent" seen in near-IR Hubble images [3] to spectra of other Titan longitudes, and interpret these differences in terms of surface composition and temperature. The poster will represent the first Solar System results of SIRTF, including but not limited to: 1. Photometry of the principal Uranian satellites between 3.6 and 15 μ m and interpretation in terms of surface composition, temperature, and thermal inertia. 2. Images and spectra of Phoebe and Rhea, and such other moons of Saturn as are scheduled for observation between March 1 and the beginning of this conference. 3. Images and spectra of Neptune and Triton, if those observations are scheduled between April 29 and the beginning of this conference. References: [1] Hammel H. B., Young, L. A, Hackwell J., Lynch D. K., Russell R., and Orton G. S. (1992) Icarus, 99, 347. [2] Hammel, H. B., Rages K., Lockwood G. W., Karkoschka E., and de Pater I. (2001) Icarus, 153, 229. [3] Smith, P. H., Lemmon, M. T., Lorenz, R. D., Sromovsky, L. A., Caldwell, J. J., and Allison, M. D. (1996) Icarus, 119, 336.

An Astronomical Test of CCD Photometric Precision

NASA Technical Reports Server (NTRS)

Koch, David G.; Dunham, Edward W.; Borucki, William J.; Jenkins, Jon M.

2001-01-01

Ground-based differential photometry is limited to a precision of order 10(exp -3) because of atmospheric effects. A space-based photometer should be limited only by the inherent instrument precision and shot noise. Laboratory tests have shown that a precision of order 10-5 is achievable with commercially available charged coupled devices (CCDs). We have proposed to take this one step further by performing measurements at a telescope using a Wollaston prism as a beam splitter First-order atmospheric effects (e.g., extinction) will appear to be identical in the two images of each star formed by the prism and will be removed in the data analysis. This arrangement can determine the precision that is achievable under the influence of second-order atmospheric effects (e.g., variable point-spread function (PSF) from seeing). These telescopic observations will thus provide a lower limit to the precision that can be realized by a space-based differential photometer.

BOMBOLO: a Multi-Band, Wide-field, Near UV/Optical Imager for the SOAR 4m Telescope

NASA Astrophysics Data System (ADS)

Angeloni, R.; Guzmán, D.; Puzia, T. H.; Infante, L.

2014-10-01

BOMBOLO is a new multi-passband visitor instrument for SOAR observatory. The first fully Chilean instrument of its kind, it is a three-arms imager covering the near-UV and optical wavelengths. The three arms work simultaneously and independently, providing synchronized imaging capability for rapid astronomical events. BOMBOLO will be able to address largely unexplored events in the minute-to-second timescales, with the following leading science cases: 1) Simultaneous Multiband Flickering Studies of Accretion Phenomena; 2) Near UV/Optical Diagnostics of Stellar Evolutionary Phases; 3) Exoplanetary Transits and 4) Microlensing Follow-Up. BOMBOLO optical design consists of a wide field collimator feeding two dychroics at 390 and 550 nm. Each arm encompasses a camera, filter wheel and a science CCD230-42, imaging a 7 x 7 arcmin field of view onto a 2k x 2k image. The three CCDs will have different coatings to optimise the efficiencies of each camera. The detector controller to run the three cameras will be Torrent (the NOAO open-source system) and a PanView application will run the instrument and produce the data-cubes. The instrument is at Conceptual Design stage, having been approved by the SOAR Board of Directors as a visitor instrument in 2012 and having been granted full funding from CONICYT, the Chilean State Agency of Research, in 2013. The Design Phase is starting now and will be completed in late 2014, followed by a construction phase in 2015 and 2016A, with expected Commissioning in 2016B and 2017A.

Lander and rover exploration on the lunar surface: A study for SELENE-B mission

NASA Astrophysics Data System (ADS)

Selene-B Rover Science Group; Sasaki, S.; Sugihara, T.; Saiki, K.; Akiyama, H.; Ohtake, M.; Takeda, H.; Hasebe, N.; Kobayashi, M.; Haruyama, J.; Shirai, K.; Kato, M.; Kubota, T.; Kunii, Y.; Kuroda, Y.

The SELENE-B, a lunar landing mission, has been studied in Japan, where a scientific investigation plan is proposed using a robotic rover and a static lander. The main theme to be investigated is to clarify the lunar origin and evolution, especially for early crustal formation process probably from the ancient magma ocean. The highest priority is placed on a direct in situ geology at a crater central peak, “a window to the interior”, where subcrustal materials are exposed and directly accessed without drilling. As a preliminary study was introduced by Sasaki et al. [Sasaki, S., Kubota, T., Okada, T. et al. Scientific exploration of lunar surface using a rover in Japanse future lunar mission. Adv. Space Res. 30, 1921 1926, 2002.], the rover and lander are jointly used, where detailed analyses of the samples collected by the rover are conducted at the lander. Primary scientific instruments are a multi-band stereo imager, a gamma-ray spectrometer, and a sampling tool on the rover, and a multi-spectral telescopic imager, a sampling system, and a sample analysis package with an X-ray spectrometer/diffractometer, a multi-band microscope as well as a sample cleaning and grinding device on the lander.

The design of common aperture and multi-band optical system based on day light telescope

NASA Astrophysics Data System (ADS)

Chen, Jiao; Wang, Ling; Zhang, Bo; Teng, Guoqi; Wang, Meng

2017-02-01

As the development of electro-optical weapon system, the technique of common path and multi-sensor are used popular, and becoming a trend. According to the requirement of miniaturization and lightweight for electro-optical stabilized sighting system, a day light telescope/television viewing-aim system/ laser ranger has been designed in this thesis, which has common aperture. Thus integration scheme of multi-band and common aperture has been adopted. A day light telescope has been presented, which magnification is 8, field of view is 6°, and distance of exit pupil is more than 20mm. For 1/3" CCD, television viewing-aim system which has 156mm focal length, has been completed. In addition, laser ranging system has been designed, with 10km raging distance. This paper outlines its principle which used day light telescope as optical reference of correcting the optical axis. Besides, by means of shared objective, reserved image with inverting prism and coating beam-splitting film on the inclined plane of the cube prism, the system has been applied to electro-optical weapon system, with high-resolution of imaging and high-precision ranging.

The Imager for Sprites and Upper Atmospheric Lightning (ISUAL)

NASA Astrophysics Data System (ADS)

Frey, H. U.; Mende, S. B.; Harris, S. E.; Heetderks, H.; Takahashi, Y.; Su, H.-T.; Hsu, R.-R.; Chen, A. B.; Fukunishi, H.; Chang, Y.-S.; Lee, L.-C.

2016-08-01

The Imager for Sprites and Upper Atmospheric Lightning (ISUAL) was the first specifically dedicated instrument to observe lightning-induced transient luminous events (TLE): sprites, elves, halos, and gigantic jets from space. The Imager is an intensified CCD system operating in the visible wavelength region with a filter wheel to select from six positions with filters. The Imager has a 5° × 20° (vertical times horizontal) field of view. The spectrophotometer (SP) is populated with six photometers with individual filters for emissions from the far ultraviolet to the near infrared. An array photometer with two channels operating in the blue and red provides altitude profiles of the emission over 16 altitude bins each. The Associated Electronics Package (AEP) controls instrument functions and interfaces with the spacecraft. ISUAL was launched 21 May 2004 into a Sun-synchronous 890 km orbit on the Formosat-2 satellite and has successfully been collecting data ever since. ISUAL is running on the nightside of the orbit and is pointed to the east of the orbit down toward the limb. The instrument runs continuously and writes data to a circular buffer. Whenever the SP detects a sudden signal increase above a preset threshold, a trigger signal is generated that commands the system to keep the data for about 400 ms starting from ~50 ms before the trigger. Over its lifetime of ~11 years the system recorded thousands of TLE and also successfully observed aurora and airglow.

Low-latitude Ionospheric Research using the CIRCE Mission

NASA Astrophysics Data System (ADS)

Dymond, K.; Nicholas, A. C.; Budzien, S. A.; Stephan, A. W.

2016-12-01

The Coordinated Ionospheric Reconstruction Cubesat Experiment (CIRCE) is a dual-satellite mission consisting of two 6U CubeSats actively maintaining a lead-follow configuration in the same orbit with a launch planned for the 2018-2019 time frame. These nano-satellites will each feature two 1U ultraviolet photometers, observing the 135.6 nm emission of atomic oxygen at nighttime. The primary objective is to characterize the two-dimensional distribution of electrons in the Equatorial Ionization Anomaly (EIA). The methodology used to reconstruct the nighttime ionosphere employs continuous UV photometry from four distinct viewing angles in combination with an additional data source, such as in situ plasma density measurements or a wide-band beacon data, with advanced image space reconstruction algorithm tomography techniques. The COSMIC/FORMOSAT-3 (CF3) constellation featured six Tiny Ionospheric Photometers, a compact UV sensor design which served as the pathfinder for the CIRCE instruments. The TIP instruments on the CF3 satellites demonstrated detection of ionospheric bubbles before they had penetrated the peak of the F-region ionosphere. We present our mission concept, simulations illustrating the imaging capability of the sensor suite, and a range of science questions addressable using such a system.

Where Galactic Snakes Live

NASA Image and Video Library

2006-10-27

This infrared image from NASA's Spitzer Space Telescope shows what astronomers are referring to as a "snake" (upper left) and its surrounding stormy environment. The sinuous object is actually the core of a thick, sooty cloud large enough to swallow dozens of solar systems. In fact, astronomers say the "snake's belly" may be harboring beastly stars in the process of forming. The galactic creepy crawler to the right of the snake is another thick cloud core, in which additional burgeoning massive stars might be lurking. The colorful regions below the two cloud cores are less dense cloud material, in which dust has been heated by starlight and glows with infrared light. Yellow and orange dots throughout the image are monstrous developing stars; the red star on the "belly" of the snake is 20 to 50 times as massive as our sun. The blue dots are foreground stars. The red ball at the bottom left is a "supernova remnant," the remains of massive star that died in a fiery blast. Astronomers speculate that radiation and winds from the star before it died, in addition to a shock wave created when it exploded, might have played a role in creating the snake. Spitzer was able to spot the two black cloud cores using its heat-seeking infrared vision. The objects are hiding in the dusty plane of our Milky Way galaxy, invisible to optical telescopes. Because their heat, or infrared light, can sneak through the dust, they first showed up in infrared images from past missions. The cloud cores are so thick with dust that if you were to somehow transport yourself into the middle of them, you would see nothing but black, not even a star in the sky. Now, that's spooky! Spitzer's view of the region provides the best look yet at the massive embryonic stars hiding inside the snake. Astronomers say these observations will ultimately help them better understand how massive stars form. By studying the clustering and range of masses of the stellar embryos, they hope to determine if the stars were born in the same way that our low-mass sun was formed - out of a collapsing cloud of gas and dust - or by another mechanism in which the environment plays a larger role. The snake is located about 11,000 light-years away in the constellation Sagittarius. This false-color image is a composite of infrared data taken by Spitzer's infrared array camera and multiband imaging photometer. Blue represents 3.6-micron light; green shows light of 8 microns; and red is 24-micron light. http://photojournal.jpl.nasa.gov/catalog/PIA01318

Where Galactic Snakes Live

NASA Technical Reports Server (NTRS)

2006-01-01

This infrared image from NASA's Spitzer Space Telescope shows what astronomers are referring to as a 'snake' (upper left) and its surrounding stormy environment. The sinuous object is actually the core of a thick, sooty cloud large enough to swallow dozens of solar systems. In fact, astronomers say the 'snake's belly' may be harboring beastly stars in the process of forming.

The galactic creepy crawler to the right of the snake is another thick cloud core, in which additional burgeoning massive stars might be lurking. The colorful regions below the two cloud cores are less dense cloud material, in which dust has been heated by starlight and glows with infrared light. Yellow and orange dots throughout the image are monstrous developing stars; the red star on the 'belly' of the snake is 20 to 50 times as massive as our sun. The blue dots are foreground stars.

The red ball at the bottom left is a 'supernova remnant,' the remains of massive star that died in a fiery blast. Astronomers speculate that radiation and winds from the star before it died, in addition to a shock wave created when it exploded, might have played a role in creating the snake.

Spitzer was able to spot the two black cloud cores using its heat-seeking infrared vision. The objects are hiding in the dusty plane of our Milky Way galaxy, invisible to optical telescopes. Because their heat, or infrared light, can sneak through the dust, they first showed up in infrared images from past missions. The cloud cores are so thick with dust that if you were to somehow transport yourself into the middle of them, you would see nothing but black, not even a star in the sky. Now, that's spooky!

Spitzer's new view of the region provides the best look yet at the massive embryonic stars hiding inside the snake. Astronomers say these observations will ultimately help them better understand how massive stars form. By studying the clustering and range of masses of the stellar embryos, they hope to determine if the stars were born in the same way that our low-mass sun was formed - out of a collapsing cloud of gas and dust - or by another mechanism in which the environment plays a larger role.

The snake is located about 11,000 light-years away in the constellation Sagittarius.

This false-color image is a composite of infrared data taken by Spitzer's infrared array camera and multiband imaging photometer. Blue represents 3.6-micron light; green shows light of 8 microns; and red is 24-micron light.

Behavioral modeling and digital compensation of nonlinearity in DFB lasers for multi-band directly modulated radio-over-fiber systems

NASA Astrophysics Data System (ADS)

Li, Jianqiang; Yin, Chunjing; Chen, Hao; Yin, Feifei; Dai, Yitang; Xu, Kun

2014-11-01

The envisioned C-RAN concept in wireless communication sector replies on distributed antenna systems (DAS) which consist of a central unit (CU), multiple remote antenna units (RAUs) and the fronthaul links between them. As the legacy and emerging wireless communication standards will coexist for a long time, the fronthaul links are preferred to carry multi-band multi-standard wireless signals. Directly-modulated radio-over-fiber (ROF) links can serve as a lowcost option to make fronthaul connections conveying multi-band wireless signals. However, directly-modulated radioover- fiber (ROF) systems often suffer from inherent nonlinearities from directly-modulated lasers. Unlike ROF systems working at the single-band mode, the modulation nonlinearities in multi-band ROF systems can result in both in-band and cross-band nonlinear distortions. In order to address this issue, we have recently investigated the multi-band nonlinear behavior of directly-modulated DFB lasers based on multi-dimensional memory polynomial model. Based on this model, an efficient multi-dimensional baseband digital predistortion technique was developed and experimentally demonstrated for linearization of multi-band directly-modulated ROF systems.

Advancing RF pulse design using an open-competition format: Report from the 2015 ISMRM challenge.

PubMed

Grissom, William A; Setsompop, Kawin; Hurley, Samuel A; Tsao, Jeffrey; Velikina, Julia V; Samsonov, Alexey A

2017-10-01

To advance the best solutions to two important RF pulse design problems with an open head-to-head competition. Two sub-challenges were formulated in which contestants competed to design the shortest simultaneous multislice (SMS) refocusing pulses and slice-selective parallel transmission (pTx) excitation pulses, subject to realistic hardware and safety constraints. Short refocusing pulses are needed for spin echo SMS imaging at high multiband factors, and short slice-selective pTx pulses are needed for multislice imaging in ultra-high field MRI. Each sub-challenge comprised two phases, in which the first phase posed problems with a low barrier of entry, and the second phase encouraged solutions that performed well in general. The Challenge ran from October 2015 to May 2016. The pTx Challenge winners developed a spokes pulse design method that combined variable-rate selective excitation with an efficient method to enforce SAR constraints, which achieved 10.6 times shorter pulse durations than conventional approaches. The SMS Challenge winners developed a time-optimal control multiband pulse design algorithm that achieved 5.1 times shorter pulse durations than conventional approaches. The Challenge led to rapid step improvements in solutions to significant problems in RF excitation for SMS imaging and ultra-high field MRI. Magn Reson Med 78:1352-1361, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

A Simple Photometer to Study Skylight

ERIC Educational Resources Information Center

McIntosh Gordon

2006-01-01

A simple photometer constructed from an LED and an op amp can be used to measure light in a number of physical situations. A variety of LEDs exist to investigate different wavelength ranges. Combined with an inexpensive transit, the LED photometer can be used to carry out skylight studies and atmospheric optical depth measurements. The activities…

Simple photometer circuits using modular electronic components

NASA Technical Reports Server (NTRS)

Wampler, J. E.

1975-01-01

Operational and peak holding amplifiers are discussed as useful circuits for bioluminescence assays. Circuit diagrams are provided. While analog methods can give a good integration on short time scales, digital methods were found best for long term integration in bioluminescence assays. Power supplies, a general photometer circuit with ratio capability, and variations in the basic photometer design are also considered.

An evaluation of multiband photography for rock discrimination. [sedimentary rocks of Front Range, Colorado

NASA Technical Reports Server (NTRS)

Lee, K. (Principal Investigator); Raines, G. L.

1974-01-01

The author has identified the following significant results. With the advent of ERTS and Skylab satellites, multiband imagery and photography have become readily available to geologists. The ability of multiband photography to discriminate sedimentary rocks was examined. More than 8600 in situ measurements of band reflectance of the sedimentary rocks of the Front Range, Colorado, were acquired. Statistical analysis of these measurements showed that: (1) measurements from one site can be used at another site 100 miles away; (2) there is basically only one spectral reflectance curve for these rocks, with constant amplitude differences between the curves; and (3) the natural variation is so large that at least 150 measurements per formation are required to select best filters. These conclusions are supported by subjective tests with aerial multiband photography. The designed multiband photography concept for rock discrimination is not a practical method of improving sedimentary rock discrimination capabilities.

Evaluation of a Portable Photometer for Estimating Diesel Particulate Matter Concentrations in an Underground Limestone Mine

PubMed Central

Watts, Winthrop F.; Gladis, David D.; Schumacher, Matthew F.; Ragatz, Adam C.; Kittelson, David B.

2010-01-01

A low cost, battery-operated, portable, real-time aerosol analyzer is not available for monitoring diesel particulate matter (DPM) concentrations in underground mines. This study summarizes a field evaluation conducted at an underground limestone mine to evaluate the potential of the TSI AM 510 portable photometer (equipped with a Dorr-Oliver cyclone and 1.0-μm impactor) to qualitatively track time-weighted average mass and elemental, organic, and total carbon (TC) measurements associated with diesel emissions. The calibration factor corrected correlation coefficient (R2) between the underground TC and photometer measurements was 0.93. The main issues holding back the use of a photometer for real-time estimation of DPM in an underground mine are the removal of non-DPM-associated particulate matter from the aerosol stream using devices, such as a cyclone and/or impactor and calibration of the photometer to mine-specific aerosol. PMID:20410071

Error analysis of integrated water vapor measured by CIMEL photometer

NASA Astrophysics Data System (ADS)

Berezin, I. A.; Timofeyev, Yu. M.; Virolainen, Ya. A.; Frantsuzova, I. S.; Volkova, K. A.; Poberovsky, A. V.; Holben, B. N.; Smirnov, A.; Slutsker, I.

2017-01-01

Water vapor plays a key role in weather and climate forming, which leads to the need for continuous monitoring of its content in different parts of the Earth. Intercomparison and validation of different methods for integrated water vapor (IWV) measurements are essential for determining the real accuracies of these methods. CIMEL photometers measure IWV at hundreds of ground-based stations of the AERONET network. We analyze simultaneous IWV measurements performed by a CIMEL photometer, an RPG-HATPRO MW radiometer, and a FTIR Bruker 125-HR spectrometer at the Peterhof station of St. Petersburg State University. We show that the CIMEL photometer calibrated by the manufacturer significantly underestimates the IWV obtained by other devices. We may conclude from this intercomparison that it is necessary to perform an additional calibration of the CIMEL photometer, as well as a possible correction of the interpretation technique for CIMEL measurements at the Peterhof site.

The NIST Detector-Based Luminous Intensity Scale

PubMed Central

Cromer, C. L.; Eppeldauer, G.; Hardis, J. E.; Larason, T. C.; Ohno, Y.; Parr, A. C.

1996-01-01

The Système International des Unités (SI) base unit for photometry, the candela, has been realized by using absolute detectors rather than absolute sources. This change in method permits luminous intensity calibrations of standard lamps to be carried out with a relative expanded uncertainty (coverage factor k = 2, and thus a 2 standard deviation estimate) of 0.46 %, almost a factor-of-two improvement. A group of eight reference photometers has been constructed with silicon photodiodes, matched with filters to mimic the spectral luminous efficiency function for photopic vision. The wide dynamic range of the photometers aid in their calibration. The components of the photometers were carefully measured and selected to reduce the sources of error and to provide baseline data for aging studies. Periodic remeasurement of the photometers indicate that a yearly recalibration is required. The design, characterization, calibration, evaluation, and application of the photometers are discussed. PMID:27805119

A new optimal seam method for seamless image stitching

NASA Astrophysics Data System (ADS)

Xue, Jiale; Chen, Shengyong; Cheng, Xu; Han, Ying; Zhao, Meng

2017-07-01

A novel optimal seam method which aims to stitch those images with overlapping area more seamlessly has been propos ed. Considering the traditional gradient domain optimal seam method and fusion algorithm result in bad color difference measurement and taking a long time respectively, the input images would be converted to HSV space and a new energy function is designed to seek optimal stitching path. To smooth the optimal stitching path, a simplified pixel correction and weighted average method are utilized individually. The proposed methods exhibit performance in eliminating the stitching seam compared with the traditional gradient optimal seam and high efficiency with multi-band blending algorithm.

VizieR Online Data Catalog: Merging galaxies with tidal tails in COSMOS to z=1 (Wen+, 2016)

NASA Astrophysics Data System (ADS)

Wen, Z. Z.; Zheng, X. Z.

2017-02-01

Our study utilizes the public data and catalogs from multi-band deep surveys of the COSMOS field. The UltraVISTA survey (McCracken+ 2012, J/A+A/544/A156) provides ultra-deep near-IR imaging observations of this field in the Y,J,H, and Ks-band, as well as a narrow band (NB118). The HST/ACS I-band imaging data are publicly available, allowing us to measure morphologies in the rest-frame optical for galaxies at z<=1. The HST/ACS I-band images reach a 5σ depth of 27.2 magnitude for point sources. (1 data file).

Omega Centauri Looks Radiant in Infrared

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Poster Version

A cluster brimming with millions of stars glistens like an iridescent opal in this image from NASA's Spitzer Space Telescope. Called Omega Centauri, the sparkling orb of stars is like a miniature galaxy. It is the biggest and brightest of the 150 or so similar objects, called globular clusters, that orbit around the outside of our Milky Way galaxy. Stargazers at southern latitudes can spot the stellar gem with the naked eye in the constellation Centaurus.

Globular clusters are some of the oldest objects in our universe. Their stars are over 12 billion years old, and, in most cases, formed all at once when the universe was just a toddler. Omega Centauri is unusual in that its stars are of different ages and possess varying levels of metals, or elements heavier than boron. Astronomers say this points to a different origin for Omega Centauri than other globular clusters: they think it might be the core of a dwarf galaxy that was ripped apart and absorbed by our Milky Way long ago.

In this new view of Omega Centauri, Spitzer's infrared observations have been combined with visible-light data from the National Science Foundation's Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory in Chile. Visible-light data with a wavelength of .55 microns is colored blue, 3.6-micron infrared light captured by Spitzer's infrared array camera is colored green and 24-micron infrared light taken by Spitzer's multiband imaging photometer is colored red.

Where green and red overlap, the color yellow appears. Thus, the yellow and red dots are stars revealed by Spitzer. These stars, called red giants, are more evolved, larger and dustier. The stars that appear blue were spotted in both visible and 3.6-micron-, or near-, infrared light. They are less evolved, like our own sun. Some of the red spots in the picture are distant galaxies beyond our own.

Spitzer found very little dust around any but the most luminous, coolest red giants, implying that the dimmer red giants do not form significant amounts of dust. The space between the stars in Omega Centauri was also found to lack dust, which means the dust is rapidly destroyed or leaves the cluster.

Deep 1.1 mm-wavelength imaging of the GOODS-S field by AzTEC/ASTE - II. Redshift distribution and nature of the submillimetre galaxy population

NASA Astrophysics Data System (ADS)

Yun, Min S.; Scott, K. S.; Guo, Yicheng; Aretxaga, I.; Giavalisco, M.; Austermann, J. E.; Capak, P.; Chen, Yuxi; Ezawa, H.; Hatsukade, B.; Hughes, D. H.; Iono, D.; Johnson, S.; Kawabe, R.; Kohno, K.; Lowenthal, J.; Miller, N.; Morrison, G.; Oshima, T.; Perera, T. A.; Salvato, M.; Silverman, J.; Tamura, Y.; Williams, C. C.; Wilson, G. W.

2012-02-01

We report the results of the counterpart identification and a detailed analysis of the physical properties of the 48 sources discovered in our deep 1.1-mm wavelength imaging survey of the Great Observatories Origins Deep Survey-South (GOODS-S) field using the AzTEC instrument on the Atacama Submillimeter Telescope Experiment. One or more robust or tentative counterpart candidate is found for 27 and 14 AzTEC sources, respectively, by employing deep radio continuum, Spitzer/Multiband Imaging Photometer for Spitzer and Infrared Array Camera, and Large APEX Bolometer Camera 870 μm data. Five of the sources (10 per cent) have two robust counterparts each, supporting the idea that these galaxies are strongly clustered and/or heavily confused. Photometric redshifts and star formation rates (SFRs) are derived by analysing ultraviolet(UV)-to-optical and infrared(IR)-to-radio spectral energy distributions (SEDs). The median redshift of zmed˜ 2.6 is similar to other earlier estimates, but we show that 80 per cent of the AzTEC-GOODS sources are at z≥ 2, with a significant high-redshift tail (20 per cent at z≥ 3.3). Rest-frame UV and optical properties of AzTEC sources are extremely diverse, spanning 10 mag in the i- and K-band photometry (a factor of 104 in flux density) with median values of i= 25.3 and K= 22.6 and a broad range of red colour (i-K= 0-6) with an average value of i-K≈ 3. These AzTEC sources are some of the most luminous galaxies in the rest-frame optical bands at z≥ 2, with inferred stellar masses M*= (1-30) × 1010 M⊙ and UV-derived SFRs of SFRUV≳ 101-3 M⊙ yr-1. The IR-derived SFR, 200-2000 M⊙ yr-1, is independent of z or M*. The resulting specific star formation rates, SSFR ≈ 1-100 Gyr-1, are 10-100 times higher than similar mass galaxies at z= 0, and they extend the previously observed rapid rise in the SSFR with redshift to z= 2-5. These galaxies have a SFR high enough to have built up their entire stellar mass within their Hubble time. We find only marginal evidence for an active galactic nucleus (AGN) contribution to the near-IR and mid-IR SEDs, even among the X-ray detected sources, and the derived M* and SFR show little dependence on the presence of an X-ray bright AGN.

Rotating wedge filter photometer for high altitude sounding rocket application.

PubMed

Holm, C; Maehlum, B N; Narheim, B T

1972-02-01

A scanning photometer is described, utilizing a rotating wedge interference filter as the wavelength scanning element around 6300 A. A detailed description of the filter production is given, emphasizing the procedure for in situ wavelength control during fabrication. Subsequently, the complete photometer is briefly described, and some results from its applications on an auroral sounding rocket flight are presented.

The Pierce-Blitzstein Photometer - The PBPHOT

NASA Astrophysics Data System (ADS)

Ambruster, Carol; Hull, A. B.; Koch, R. H.; Mitchell, R. J.; Smith, R. E.

2009-01-01

This report describes the inception, development and extensive use (over 50 years) of the simultaneous 2-source, pulse-counting photometer named after the two astronomers in this paper's title. These men are not, however, the only personalities associated with the lifetime of the photometer from 1952 to 2007 and the contributions of other people are explicitly recognized. The embellishments and upgrades over time of the original conceptions are detailed for both the optical/mechanical/electrical hardware and the software. The opportunities and limitations of the three observing stations where this photometer and its prototypes were tested and functioned and the telescopes upon which they were mounted are also discussed and compared.

Evaluation of the MODIS Aerosol Retrievals over Ocean and Land during CLAMS.

NASA Astrophysics Data System (ADS)

Levy, R. C.; Remer, L. A.; Martins, J. V.; Kaufman, Y. J.; Plana-Fattori, A.; Redemann, J.; Wenny, B.

2005-04-01

The Chesapeake Lighthouse Aircraft Measurements for Satellites (CLAMS) experiment took place from 10 July to 2 August 2001 in a combined ocean-land region that included the Chesapeake Lighthouse [Clouds and the Earth's Radiant Energy System (CERES) Ocean Validation Experiment (COVE)] and the Wallops Flight Facility (WFF), both along coastal Virginia. This experiment was designed mainly for validating instruments and algorithms aboard the Terra satellite platform, including the Moderate Resolution Imaging Spectroradiometer (MODIS). Over the ocean, MODIS retrieved aerosol optical depths (AODs) at seven wavelengths and an estimate of the aerosol size distribution. Over the land, MODIS retrieved AOD at three wavelengths plus qualitative estimates of the aerosol size. Temporally coincident measurements of aerosol properties were made with a variety of sun photometers from ground sites and airborne sites just above the surface. The set of sun photometers provided unprecedented spectral coverage from visible (VIS) to the solar near-infrared (NIR) and infrared (IR) wavelengths. In this study, AOD and aerosol size retrieved from MODIS is compared with similar measurements from the sun photometers. Over the nearby ocean, the MODIS AOD in the VIS and NIR correlated well with sun-photometer measurements, nearly fitting a one-to-one line on a scatterplot. As one moves from ocean to land, there is a pronounced discontinuity of the MODIS AOD, where MODIS compares poorly to the sun-photometer measurements. Especially in the blue wavelength, MODIS AOD is too high in clean aerosol conditions and too low under larger aerosol loadings. Using the Second Simulation of the Satellite Signal in the Solar Spectrum (6S) radiative code to perform atmospheric correction, the authors find inconsistency in the surface albedo assumptions used by the MODIS lookup tables. It is demonstrated how the high bias at low aerosol loadings can be corrected. By using updated urban/industrial aerosol climatology for the MODIS lookup table over land, it is shown that the low bias for larger aerosol loadings can also be corrected. Understanding and improving MODIS retrievals over the East Coast may point to strategies for correction in other locations, thus improving the global quality of MODIS. Improvements in regional aerosol detection could also lead to the use of MODIS for monitoring air pollution.

Developing a Stand Alone Sun Photometer for Ships and Buoys

NASA Technical Reports Server (NTRS)

Porter, John N.

1997-01-01

During November and December 1995 the first Aerosol Characterization Experiment (ACE 1) was carried to characterize the aerosol physical and optical properties in the clean marine atmosphere near Tasmania in the South Pacific. As part of this effort, and with funding from this proposal, we installed a sun photometer on the R/V Discoverer and a spectro-photometer on the NOAA C-130 aircraft.

Implementation of a Low-Cost Automated LED Photometer for Enzymatic Reaction Detection to Teach Basic Bioelectronics Technologies in Vocational High Schools

ERIC Educational Resources Information Center

Chen, Huai-Yi; Nieh, Hwa-Ming; Yang, Ming-Feng; Chou, Yu-Kung; Chung, Jui-Hsu; Liou, Je-Wen

2016-01-01

This study proposes a home-assembled, low-cost blue light-emitting diode (LED) photometer that uses simple and low-cost hardware and software, costing about US $150. This 425-nm wavelength photometer is controlled by an 89C51 microcontroller chip. Glucose concentration detection experiments involving enzyme coupling reactions were carried out to…

Hyperspectral Sun Photometer for Atmospheric Characterization and Vicarious Calibrations

NASA Technical Reports Server (NTRS)

Pagnutti, Mary; Ryan, Robert; Holekamp, Kara

2008-01-01

A hyperspectral sun photometer and associated methods have been developed and demonstrated. Accurate sun photometer calibration is critical to properly measure the solar irradiance and characterize the atmosphere. Traditional sun photometer calibration requires solar observations over several hours. In contrast, the procedures for operating this photometer entail less data acquisition time and embody a more direct approach to calibration. The scientific value of the measurement data produced by this instrument is not adversely affected by atmospheric instability. In addition, this instrument yields hyperspectral data covering a large spectral range (350-2,500 nm) not available from most traditional sun photometers. The hyperspectral sun photometer components include (1) a commercially available spectroradiometer that has been laboratory-calibrated and (2) a commercially available reflectance standard panel that exhibits nearly Lambertian 99% reflectance. The spectroradiometer is positioned above, and aimed downward at, the panel. The procedure for operating this instrument calls for a series of measurements: one in which the panel is fully illuminated by the sun, one in which a shade is positioned between the panel and the sun, and two in which the shade is positioned to cast a shadow to either side of the panel. The total sequence of measurements can be performed in less than a minute. From these measurements, the total radiance, the diffuse radiance, and the direct solar radiance are calculated. The direct solar irradiance is calculated from the direct solar radiance and the known reflectance factor of the panel as a function of the solar zenith angle. Atmospheric characteristics are estimated from the optical depth at various wavelengths calculated from (1) the direct solar irradiance obtained as described above, (2) the air mass along a column from the measurement position to the Sun, and (3) the top-of-atmosphere solar irradiance. The instrumentation used to implement the sun photometer is the same as that used to characterize targets used in radiometric vicarious calibrations. Utilizing this type of sun photometer thus reduces the amount of instrumentation and labor required to perform these studies.

Multi-band transmission color filters for multi-color white LEDs based visible light communication

NASA Astrophysics Data System (ADS)

Wang, Qixia; Zhu, Zhendong; Gu, Huarong; Chen, Mengzhu; Tan, Qiaofeng

2017-11-01

Light-emitting diodes (LEDs) based visible light communication (VLC) can provide license-free bands, high data rates, and high security levels, which is a promising technique that will be extensively applied in future. Multi-band transmission color filters with enough peak transmittance and suitable bandwidth play a pivotal role for boosting signal-noise-ratio in VLC systems. In this paper, multi-band transmission color filters with bandwidth of dozens nanometers are designed by a simple analytical method. Experiment results of one-dimensional (1D) and two-dimensional (2D) tri-band color filters demonstrate the effectiveness of the multi-band transmission color filters and the corresponding analytical method.

Electron-boson spectral density function of correlated multiband systems obtained from optical data: Ba0.6K0.4Fe2As2 and LiFeAs.

PubMed

Hwang, Jungseek

2016-03-31

We introduce an approximate method which can be used to simulate the optical conductivity data of correlated multiband systems for normal and superconducting cases by taking advantage of a reversed process in comparison to a usual optical data analysis, which has been used to extract the electron-boson spectral density function from measured optical spectra of single-band systems, like cuprates. We applied this method to optical conductivity data of two multiband pnictide systems (Ba0.6K0.4Fe2As2 and LiFeAs) and obtained the electron-boson spectral density functions. The obtained electron-boson spectral density consists of a sharp mode and a broad background. The obtained spectral density functions of the multiband systems show similar properties as those of cuprates in several aspects. We expect that our method helps to reveal the nature of strong correlations in the multiband pnictide superconductors.

WE-G-18C-07: Accelerated Water/fat Separation in MRI for Radiotherapy Planning Using Multi-Band Imaging Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crijns, S; Stemkens, B; Sbrizzi, A

Purpose: Dixon sequences are used to characterize disease processes, obtain good fat or water separation in cases where fat suppression fails and to obtain pseudo-CT datasets. Dixon's method uses at least two images acquired with different echo times and thus requires prolonged acquisition times. To overcome associated problems (e.g., for DCE/cine-MRI), we propose to use a method for water/fat separation based on spectrally selective RF pulses. Methods: Two alternating RF pulses were used, that imposes a fat selective phase cycling over the phase encoding lines, which results in a spatial shift for fat in the reconstructed image, identical to thatmore » in CAIPIRINHA. Associated aliasing artefacts were resolved using the encoding power of a multi-element receiver array, analogous to SENSE. In vivo measurements were performed on a 1.5T clinical MR-scanner in a healthy volunteer's legs, using a four channel receiver coil. Gradient echo images were acquired with TE/TR = 2.3/4.7ms, flip angle 20°, FOV 45×22.5cm{sup 2}, matrix 480×216, slice thickness 5mm. Dixon images were acquired with TE,1/TE,2/TR=2.2/4.6/7ms. All image reconstructions were done in Matlab using the ReconFrame toolbox (Gyrotools, Zurich, CH). Results: RF pulse alternation yields a fat image offset from the water image. Hence the water and fat images fold over, which is resolved using in-plane SENSE reconstruction. Using the proposed technique, we achieved excellent water/fat separation comparable to Dixon images, while acquiring images at only one echo time. Conclusion: The proposed technique yields both inphase water and fat images at arbitrary echo times and requires only one measurement, thereby shortening the acquisition time by a factor 2. In future work the technique may be extended to a multi-band water/fat separation sequence that is able to achieve single point water/fat separation in multiple slices at once and hence yields higher speed-up factors.« less

Absolute calibration of ultraviolet filter photometry

NASA Technical Reports Server (NTRS)

Bless, R. C.; Fairchild, T.; Code, A. D.

1972-01-01

The essential features of the calibration procedure can be divided into three parts. First, the shape of the bandpass of each photometer was determined by measuring the transmissions of the individual optical components and also by measuring the response of the photometer as a whole. Secondly, each photometer was placed in the essentially-collimated synchrotron radiation bundle maintained at a constant intensity level, and the output signal was determined from about 100 points on the objective. Finally, two or three points on the objective were illuminated by synchrotron radiation at several different intensity levels covering the dynamic range of the photometers. The output signals were placed on an absolute basis by the electron counting technique described earlier.

REMOTE SENSING IN OCEANOGRAPHY.

DTIC Science & Technology

remote sensing from satellites. Sensing of oceanographic variables from aircraft began with the photographing of waves and ice. Since then remote measurement of sea surface temperatures and wave heights have become routine. Sensors tested for oceanographic applications include multi-band color cameras, radar scatterometers, infrared spectrometers and scanners, passive microwave radiometers, and radar imagers. Remote sensing has found its greatest application in providing rapid coverage of large oceanographic areas for synoptic and analysis and

Multiband Fourier Analysis and Interstellar Reddening of the Variable Stars in the Globular Cluster NGC 6402 (M14)

NASA Astrophysics Data System (ADS)

Weinschenk, Sedrick; Murphy, Brian; Villiger, Nathan J.

2018-01-01

We present a detailed study of the variable stars in the globular cluster NGC 6402 (M14). Approximately 1500 B and V band images were collected from July 2016 to August 2017 using the SARA Consortium Jacobus Kaptyen 1-meter telescope located in the Canary Islands. Using difference image analysis, we were able to identify 145 probable variable stars, confirming the 133 previously known variables and adding 12 new variables. The variables consisted of 117 RR Lyrae stars, 18 long period variables, 2 eclipsing variables, 6 Cepheid variables, and 2 SX Phoenix variables. Of the RR Lyrae variables 55 were of fundamental mode RR0 stars, of which 18 exhibited the Blazhko effect, 57 were of 1st overtone RR1, of which 7 appear to exhibit the Blazhko effect, 1 2nd overtone RR2, and 2 double mode variables. We found an average period of 0.59016 days for RR0 stars and 0.30294 days for RR1 stars. Using the multiband light curves of both the RR0 and RR1 variables we found an average E(B-V) of 0.604 with a scatter of 0.15 magnitudes. Using Fourier decomposition of the RR Lyrae light curves we also determined the metallicity and distance of the NGC 6402.

Aerosol and Surface Parameter Retrievals for a Multi-Angle, Multiband Spectrometer

NASA Technical Reports Server (NTRS)

Broderick, Daniel

2012-01-01

This software retrieves the surface and atmosphere parameters of multi-angle, multiband spectra. The synthetic spectra are generated by applying the modified Rahman-Pinty-Verstraete Bidirectional Reflectance Distribution Function (BRDF) model, and a single-scattering dominated atmosphere model to surface reflectance data from Multiangle Imaging SpectroRadiometer (MISR). The aerosol physical model uses a single scattering approximation using Rayleigh scattering molecules, and Henyey-Greenstein aerosols. The surface and atmosphere parameters of the models are retrieved using the Lavenberg-Marquardt algorithm. The software can retrieve the surface and atmosphere parameters with two different scales. The surface parameters are retrieved pixel-by-pixel while the atmosphere parameters are retrieved for a group of pixels where the same atmosphere model parameters are applied. This two-scale approach allows one to select the natural scale of the atmosphere properties relative to surface properties. The software also takes advantage of an intelligent initial condition given by the solution of the neighbor pixels.

Dynamic image fusion and general observer preference

NASA Astrophysics Data System (ADS)

Burks, Stephen D.; Doe, Joshua M.

2010-04-01

Recent developments in image fusion give the user community many options for ways of presenting the imagery to an end-user. Individuals at the US Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate have developed an electronic system that allows users to quickly and efficiently determine optimal image fusion algorithms and color parameters based upon collected imagery and videos from environments that are typical to observers in a military environment. After performing multiple multi-band data collections in a variety of military-like scenarios, different waveband, fusion algorithm, image post-processing, and color choices are presented to observers as an output of the fusion system. The observer preferences can give guidelines as to how specific scenarios should affect the presentation of fused imagery.

The Herschel Space Observatory, Opening the Far Infrared

NASA Astrophysics Data System (ADS)

Pearson, John C.

2009-06-01

The Herschel Space Observatory (Herschel) is a multi user observatory operated by the European Space Agency with a significant NASA contribution. Herschel features a passively cooled 3.5 meter telescope expected to operate near 78 Kelvin and three cryogenic instruments covering the 670 to 57 μm spectral region. The mission life time, determined by the consumption of 2500 liters of liquid helium, is expected to be at least 3.5 years with at least 3 years of operational lifetime in an L2 orbit. The three payload instruments are the Spectral and Photometric Imaging Receiver (SPIRE), Photodetector Array Camera and Spectrometer (PACS), and the Heterodyne Instrument for Far Infrared (HIFI). SPIRE covers 200-670 μm and is a three band bolometer based photometer and a two band imaging Martin-Puplett FTS with a spectral resolution of up to 600. PACS covers 57-200 μm and is a three band bolometer based photometer and a grating slit spectrometer illuminating photoconductor arrays in two bands with a resolution of up to 5000. HIFI covers 480-1272 GHz and 1440-1910 GHz and is a series of seven dual polarization heterodyne receivers with a spectral resolution up to 5×10^6. The observatory performance, selected science program and upcoming opportunities will be discussed.

Real time 3D photometry

NASA Astrophysics Data System (ADS)

Fernandez-Balbuena, A. A.; Vazquez-Molini, D.; García-Botella, A.; Romo, J.; Serrano, Ana

2017-09-01

The photometry and radiometry measurement is a well-developed field. The necessity of measuring optical systems performance involves the use of several techniques like Gonio-photometry. The Gonio photometers are a precise measurement tool that is used in the lighting area like office, luminaire head car lighting, concentrator /collimator measurement and all the designed and fabricated optical systems that works with light. There is one disadvantage in this kind of measurements that obtain the intensity polar curves and the total flux of the optical system. In the industry, there are good Gonio photometers that are precise and reliable but they are very expensive and the measurement time is long. In industry the cost can be of minor importance but measuring time that is around 30 minutes is of major importance due to trained staff cost. We have designed a system to measure photometry in real time; it consists in a curved screen to get a huge measurement angle and a CCD. The system to be measured projects light onto the screen and the CCD records a video of the screen obtaining an image of the projected profile. A complex calibration permits to trace screen data (x,y,z) to intensity polar curve (I,αγ). This intensity is obtained in candels (cd) with an image + processing time below one second.

Distributing coil elements in three dimensions enhances parallel transmission multiband RF performance: A simulation study in the human brain at 7 Tesla.

PubMed

Wu, Xiaoping; Tian, Jinfeng; Schmitter, Sebastian; Vaughan, J Tommy; Uğurbil, Kâmil; Van de Moortele, Pierre-François

2016-06-01

We explore the advantages of using a double-ring radiofrequency (RF) array and slice orientation to design parallel transmission (pTx) multiband (MB) pulses for simultaneous multislice (SMS) imaging with whole-brain coverage at 7 Tesla (T). A double-ring head array with 16 elements split evenly in two rings stacked in the z-direction was modeled and compared with two single-ring arrays consisting of 8 or 16 elements. The array performance was evaluated by designing band-specific pTx MB pulses with local specific absorption rate (SAR) control. The impact of slice orientations was also investigated. The double-ring array consistently and significantly outperformed the other two single-ring arrays, with peak local SAR reduced by up to 40% at a fixed excitation error of 0.024. For all three arrays, exciting sagittal or coronal slices yielded better RF performance than exciting axial or oblique slices. A double-ring RF array can be used to drastically improve SAR versus excitation fidelity tradeoff for pTx MB pulse design for brain imaging at 7 T; therefore, it is preferable against single-ring RF array designs when pursuing various biomedical applications of pTx SMS imaging. In comparing the stripline arrays, coronal and sagittal slices are more advantageous than axial and oblique slices for pTx MB pulses. Magn Reson Med 75:2464-2472, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

RARE/Turbo Spin Echo Imaging with Simultaneous MultiSlice Wave-CAIPI

PubMed Central

Eichner, Cornelius; Bhat, Himanshu; Grant, P. Ellen; Wald, Lawrence L.; Setsompop, Kawin

2014-01-01

Purpose To enable highly accelerated RARE/Turbo Spin Echo (TSE) imaging using Simultaneous MultiSlice (SMS) Wave-CAIPI acquisition with reduced g-factor penalty. Methods SMS Wave-CAIPI incurs slice shifts across simultaneously excited slices while playing sinusoidal gradient waveforms during the readout of each encoding line. This results in an efficient k-space coverage that spreads aliasing in all three dimensions to fully harness the encoding power of coil sensitivities. The novel MultiPINS radiofrequency (RF) pulses dramatically reduce the power deposition of multiband (MB) refocusing pulse, thus allowing high MB factors within the Specific Absorption Rate (SAR) limit. Results Wave-CAIPI acquisition with MultiPINS permits whole brain coverage with 1 mm isotropic resolution in 70 seconds at effective MB factor 13, with maximum and average g-factor penalties of gmax=1.34 and gavg=1.12, and without √R penalty. With blipped-CAIPI, the g-factor performance was degraded to gmax=3.24 and gavg=1.42; a 2.4-fold increase in gmax relative to Wave-CAIPI. At this MB factor, the SAR of the MultiBand and PINS pulses are 4.2 and 1.9 times that of the MultiPINS pulse, while the peak RF power are 19.4 and 3.9 times higher. Conclusion Combination of the two technologies, Wave-CAIPI and MultiPINS pulse, enables highly accelerated RARE/TSE imaging with low SNR penalty at reduced SAR. PMID:25640187

Use of pattern recognition for unaliasing simultaneously acquired slices in simultaneous multislice MR fingerprinting.

PubMed

Jiang, Yun; Ma, Dan; Bhat, Himanshu; Ye, Huihui; Cauley, Stephen F; Wald, Lawrence L; Setsompop, Kawin; Griswold, Mark A

2017-11-01

The purpose of this study is to accelerate an MR fingerprinting (MRF) acquisition by using a simultaneous multislice method. A multiband radiofrequency (RF) pulse was designed to excite two slices with different flip angles and phases. The signals of two slices were driven to be as orthogonal as possible. The mixed and undersampled MRF signal was matched to two dictionaries to retrieve T 1 and T 2 maps of each slice. Quantitative results from the proposed method were validated with the gold-standard spin echo methods in a phantom. T 1 and T 2 maps of in vivo human brain from two simultaneously acquired slices were also compared to the results of fast imaging with steady-state precession based MRF method (MRF-FISP) with a single-band RF excitation. The phantom results showed that the simultaneous multislice imaging MRF-FISP method quantified the relaxation properties accurately compared to the gold-standard spin echo methods. T 1 and T 2 values of in vivo brain from the proposed method also matched the results from the normal MRF-FISP acquisition. T 1 and T 2 values can be quantified at a multiband acceleration factor of two using our proposed acquisition even in a single-channel receive coil. Further acceleration could be achieved by combining this method with parallel imaging or iterative reconstruction. Magn Reson Med 78:1870-1876, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Berkeley extreme-ultraviolet airglow rocket spectrometer: BEARS.

PubMed

Cotton, D M; Chakrabarti, S

1992-09-20

We describe the Berkeley extreme-UV airglow rocket spectrometer, which is a payload designed to test several thermospheric remote-sensing concepts by measuring the terrestrial O I far-UV and extreme-UV dayglow and the solar extreme-UV spectrum simultaneously. The instrument consisted of two near-normal Rowland mount spectrometers and a Lyman-alpha photometer. The dayglow spectrometer covered two spectral regions from 980 to 1040 A and from 1300 to 1360 A with 1.5-A resolution. The solar spectrometer had a bandpass of 250-1150 A with an ~ 10-A resolution. All three spectra were accumulated by using a icrochannel-plate-intensified, two-dimensional imaging detector with three separate wedge-and strip anode readouts. The hydrogen Lyman-alpha photometer was included to monitor the solar Lyman-alpha irradiance and geocoronal Lyman-alpha emissions. The instrument was designed, fabricated, and calibrated at the University of California, Berkeley and was successfully launched on 30 September 1988 aboard the first test flight of a four-stage sounding rocket, Black Brant XII.

Facility Instrumentation for SOFIA: Technical Specifications and Scientific Goals

NASA Astrophysics Data System (ADS)

Stacey, G. J.

2000-05-01

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is NASA's next generation airborne observatory consisting of a 2.5 m telescope in a modified Boeing 747 SP. First light is expected in late 2002. Three "Facility Class" instruments were among the first generation of instruments selected to fly on SOFIA. These instruments, currently under development are (1) a 5 to 38 um imaging photometer based on twin As:Si and Sb:Sb BIB arrays (FORCAST), (2) a 40 to 300 um photometer based on three arrays of bolometers, and (3) a 17 to 210 um eschelle grating spectrometer based on an Sb:Sb BIB array and a Ge:Sb and stressed Ge:Ga array of photoconductors. I will discuss both the technical aspects of these facility instruments, and some of the exciting new science that is possible with these ground breaking instruments on an airborne 2.5 meter telescope. Science topics include circumstellar debris disks, star formation, the Galactic Center, and distant galaxies.

Estimation of 557.7 nm Emission Altitude using Co-located Lidars and Photometers over Arecibo

NASA Astrophysics Data System (ADS)

Franco, E.; Raizada, S.; Lautenbach, J.; Brum, C. G. M.

2017-12-01

Airglow at 557.7 nm (green line emission) is generated through the Barth mechanism in the E-region altitude and is sometimes associated with red line (630.0 nm) originating at F-region altitudes. Photons at 557.7 nm are produced through the quenching of excited atomic oxygen atoms, O(1S), while 630.0 nm results through the de-excitation of O(1D) atoms. Even though, the contribution of the green line from F-region is negligible and the significant component comes from the mesosphere, this uncertainty gives rise to a question related to its precise altitude. Previous studies have shown that perturbations generated by atmospheric gravity Waves (GWs) alter the airglow intensity and can be used for studying dynamics of the region where it originates. The uncertainty in the emission altitude of green line can be resolved by using co-located lidars, which provide altitude resolved metal densities. At Arecibo, the resonance lidars tuned to Na and K resonance wavelengths at 589 nm and 770 nm can be used in conjunction with simultaneous measurements from green line photometer to resolve this issue. Both photometer and lidars have narrow field of view as compared to airglow imagers, and hence provide an added advantage that these instruments sample same GW spectrum. Hence, correlation between density perturbations inferred from lidars and airglow intensity perturbations can shed light on the exact altitude of green line emission.

Ionospheric Remote Sensing using GPS Radio Occultation and Ultraviolet Photometry aboard the ISS

NASA Astrophysics Data System (ADS)

Budzien, S. A.; Powell, S. P.; O'Hanlon, B.; Humphreys, T.; Bishop, R. L.; Stephan, A. W.; Gross, J.; Chakrabarti, S.

2017-12-01

The GPS Radio Occultation and Ultraviolet Photometer Co-located (GROUP-C) experiment launched to the International Space Station (ISS) on February 19, 2017 as part of the Space Test Program Houston #5 payload (STP-H5). After early orbit testing, GROUP-C began routine science operations in late April. GROUP-C includes a high-sensitivity far-ultraviolet photometer measuring horizontal nighttime ionospheric gradients and an advanced software-defined GPS receiver providing ionospheric electron density profiles, scintillation measurements, and lower atmosphere profiles. GROUP-C and a companion experiment, the Limb-Imaging Ionospheric and Thermospheric Extreme-Ultraviolet Spectrograph (LITES), offer a unique capability to study spatial and temporal variability of the thermosphere and ionosphere using multi-sensor approaches, including ionospheric tomography. Data are collected continuously across low- and mid-latitudes as the ISS orbit precesses through all local times every 60 days. The GROUP-C GPS sensor routinely collects dual-frequency GPS occultations, makes targeted raw signal captures of GPS and Galileo occultations, and includes multiple antennas to characterize multipath in the ISS environment. The UV photometer measures the 135.6 nm ionospheric recombination airglow emision along the nightside orbital track. We present the first analysis of ionospheric observations, discuss the challenges and opportunities of remote sensing from the ISS platform, and explore how these new data help address questions regarding the complex and dynamic features of the low and middle latitude ionosphere-thermosphere relevant to the upcoming GOLD and ICON missions.

Compact CPW-fed spiral-patch monopole antenna with tuneable frequency for multiband applications

NASA Astrophysics Data System (ADS)

Beigi, P.; Nourinia, J.; Zehforoosh, Y.

2018-04-01

A frequency reconfigurable monopole antenna with coplanar waveguide-fed with four switchable for multiband application is reported. The monopole antenna includes square-spiral patch and two L-shaped elements. The number of frequency resonances are increased by adding square spiral. In the reported antenna, two PIN diodes are used to achieve the multiband operation. PIN diodes embedded on the spiral patch can control the frequency resonance when they are forward-biased or in those off-state. The final designed antenna, with compact size of 20 × 20 ×1 mm3, has been fabricated on an inexpensive FR4 substrate. All experimental and simulation results are acceptable suggesting that the reported antenna is a good candidate for multiband applications.

Fair comparison of complexity between a multi-band CAP and DMT for data center interconnects.

PubMed

Wei, J L; Sanchez, C; Giacoumidis, E

2017-10-01

We present, to the best of our knowledge, the first known detailed analysis and fair comparison of complexity of a 56 Gb/s multi-band carrierless amplitude and phase (CAP) and discrete multi-tone (DMT) over 80 km dispersion compensation fiber-free single-mode fiber links based on intensity modulation and direct detection for data center interconnects. We show that the matched finite impulse response filters and inverse fast Fourier transform (IFFT)/FFT take the majority of the complexity of the multi-band CAP and DMT, respectively. The choice of the multi-band CAP sub-band count and the DMT IFFT/FFT size makes significant impact on the system complexity or performance, and trade-off must be considered.

A multichannel fiber optic photometer present performance and future developments

NASA Technical Reports Server (NTRS)

Barwig, H.; Schoembs, R.; Huber, G.

1988-01-01

A three channel photometer for simultaneous multicolor observations was designed with the aim of making possible highly efficient photometry of fast variable objects like cataclysmic variables. Experiences with this instrument over a period of three years are presented. Aspects of the special techniques applied are discussed with respect to high precision photometry. In particular, the use of fiber optics is critically analyzed. Finally, the development of a new photometer concept is discussed.

Characteristics of CMEs observed in the heliosphere using Helios photometer data. [coronal mass ejection

NASA Technical Reports Server (NTRS)

Webb, D. F.; Jackson, B. V.

1992-01-01

The zodiacal light photometers on the two Helios spacecraft have been used to detect and study mass ejections and other phenomena emanating from the sun and traversing the heliosphere within 1 AU. We have recently compiled a complete list of all of the significant white light transient events detected from the 90-deg photometers on both Helios spacecraft. This is a preliminary report on the long-term frequency of occurrence of these events; it emphasizes newly processed data from Helios-l from 1975 through 1982 and viewed south of the ecliptic. With the large Helios photometer data base, we will be able to identify the fraction of the 90 deg events which are heliospheric CMEs and determine their characteristics.

A white super-stable source for the metrology of astronomical photometers

NASA Astrophysics Data System (ADS)

Wildi, F. P.; Deline, A.; Chazelas, B.

2015-09-01

The testing of photometers and in particular the testing of high precision photometers for the detection of planetary transits requires a light source which photometric stability is to par or better than the goal stability of the photometer to be tested. In the frame of the CHEOPS mission, a comprehensive calibration bench has been developed. Aside from measuring the sensibility of the CHEOPS payload to the different environmental conditions, this bench will also be used to test the relative accuracy of the payload. A key element of this bench is an extremely stable light source that is used to create an artificial star which is then projected into the payload's telescope. We present here the development of this payload and the performance achieved.

Single and multi-band electromagnetic induced transparency-like metamaterials with coupled split ring resonators

NASA Astrophysics Data System (ADS)

Bagci, Fulya; Akaoglu, Baris

2017-08-01

We present a metamaterial configuration exhibiting single and multi-band electromagnetic induced transparency (EIT)-like properties. The unit cell of the single band EIT-like metamaterial consists of a multi-split ring resonator surrounded by a split ring resonator. The multi-split ring resonator acts as a quasi-dark or dark resonator, depending on the polarization of the incident wave, and the split ring resonator serves as the bright resonator. Combination of these two resonators results in a single band EIT-like transmission inside the stop band. EIT-like transmission phenomenon is also clearly observed in the measured transmission spectrum at almost the same frequencies for vertical and horizontal polarized waves, and the numerical results are verified for normal incidence. Moreover, multi-band transmission windows are created within a wide band by combining the two slightly different single band EIT-like metamaterial unit cells that exhibit two different coupling strengths inside a supercell configuration. Group indices as high as 123 for single band and 488 for tri-band transmission, accompanying with high transmission rates (over 80%), are achieved, rendering the metamaterial very suitable for multi-band slow light applications. It is shown that the group delay of the propagating wave can be increased and dynamically controlled by changing the polarization angle. Multi-band EIT-like transmission is also verified experimentally, and a good agreement with simulations is obtained. The proposed novel methodology for obtaining multi-band EIT, which takes advantage of a supercell configuration by hosting slightly different configured unit cells, can be utilized for easily formation and manipulation of multi-band transmission windows inside a stop band.

Chiral anomaly enhancement and photoirradiation effects in multiband touching fermion systems

NASA Astrophysics Data System (ADS)

Ezawa, Motohiko

2017-05-01

Multiband touchings together with the emergence of fermions exhibiting linear dispersions have recently been predicted and realized in various materials. We first investigate the Adler-Bell-Jackiw chiral anomaly in these multiband touching semimetals when they are described by the pseudospin operator in high-dimensional representation. By evaluating the Chern number, we show that the anomalous Hall effect is enhanced depending on the magnitude of the pseudospin. It is also confirmed by the analysis of the Landau levels when magnetic field is applied. Namely, charge pumping occurs from one multiband touching point to another through multichannel Landau levels in the presence of parallel electric and magnetic fields. We also show a pair annihilation of two multiband touching points by photoirradiation. Furthermore, we propose generalizations of Dirac semimetals, multiple Weyl semimetals, and loop-nodal semimetals to those composed of fermions carrying pseudospins in high-dimensional representation. Finally we investigate the three-band touching protected by the C3 symmetry. We show that the three-band touching point is broken into two Weyl points by photoirradiation.

MIRA: review of inputs from updated results of the phobos mission

NASA Astrophysics Data System (ADS)

Moroz, V. I.; Korablev, O. I.; Rodin, A. V.; Titov, D. V.

1999-01-01

The future Mars International Reference Atmosphere (MIRA) is intended to replace the present COSPAR Mars Reference Model compiled in 1979 on the basis of Mariner 9 and Viking 1,2 missions results. At the moment, several sources of the post-Viking data potentially useful for MIRA are available. Among them is a data set obtained during Phobos mission in 1989. The interpretation of these data has undergone thorough refinement, so final recommendations for MIRA can be made. The principal points are: 1) vertical profile of water vapor with a ``knee'' at the height about 25 km retrieved in the spring equinox season near equator; 2) variations of water vapor column density including peculiarities on the slopes of high mountains; 3) vertical profiles of ozone; 4) new estimates of CO abundance; 5) surface pressure/height mapping (CO2 altimetry) in selected regions; 6) optical depths of aerosols; 7) vertical profiles of aerosol between surface and 40 km; 8) properties of high altitude ice layers and clouds above mountains; 9) microphysical properties of aerosol particles (size, composition, and number density estimates). The data have been obtained by means of instruments AUGUSTE (UV and NIR spectrometers for limb sounding of the atmosphere using solar occultations), ISM (NIR scanning spectrometer), TERMOSKAN (thermal IR scanning radiometer), KRFM (near-UV and visible multi-band photometer). The observations were performed in equatorial regions during northern spring (solar aerocentric longitudes 8° < Ls < 18°).

VizieR Online Data Catalog: UBVRIz light curves of 51 Type II supernovae (Galbany+, 2016)

NASA Astrophysics Data System (ADS)

Galbany, L.; Hamuy, M.; Phillips, M. M.; Suntzeff, N. B.; Maza, J.; de Jaeger, T.; Moraga, T.; Gonzalez-Gaitan, S.; Krisciunas, K.; Morrell, N. I.; Thomas-Osip, J.; Krzeminski, W.; Gonzalez, L.; Antezana, R.; Wishnjewski, M.; McCarthy, P.; Anderson, J. P.; Gutierrez, C. P.; Stritzinger, M.; Folatelli, G.; Anguita, C.; Galaz, G.; Green, E. M.; Impey, C.; Kim, Y.-C.; Kirhakos, S.; Malkan, M. A.; Mulchaey, J. S.; Phillips, A. C.; Pizzella, A.; Prosser, C. F.; Schmidt, B. P.; Schommer, R. A.; Sherry, W.; Strolger, L.-G.; Wells, L. A.; Williger, G. M.

2016-08-01

This paper presents a sample of multi-band, visual-wavelength light curves of 51 type II supernovae (SNe II) observed from 1986 to 2003 in the course of four different surveys: the Cerro Tololo Supernova Survey, the Calan Tololo Supernova Program (C&T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernovae Survey (CATS). Near-infrared photometry and optical spectroscopy of this set of SNe II will be published in two companion papers. A list of the SNe II used in this study is presented in Table1. The first object in our list is SN 1986L and it is the only SN observed with photoelectric techniques (by M.M.P and S.K., using the Cerro Tololo Inter-American Observatory (CTIO) 0.9m equipped with a photometer and B and V filters). The remaining SNe were observed using a variety of telescopes equipped with CCD detectors and UBV(RI)KCz filters (see Table5). The magnitudes for the photometric sequences of the 51 SNe II are listed in Table4. In every case, these sequences were derived from observations of Landolt standards (see Appendix D in Hamuy et al. 2001ApJ...558..615H for the definition of the z band and Stritzinger et al. 2002AJ....124.2100S for the description of the z-band standards). Table5 lists the resulting UBVRIz magnitudes for the 51 SNe. (3 data files).

Infrared studies of the circumsolar and night sky, April 1968 - 30 November 1971

NASA Technical Reports Server (NTRS)

Peterson, A. W.

1972-01-01

A program is summarized of infrared studies of the circumsolar and night sky conducted between April, 1968, and November 30, 1971, at the University of New Mexico. In addition to observations performed at Capillo Peak Observatory in New Mexico, airborne observations from the Ames Research Center's CV990 were performed in 1968, and eclipses in Siberia (1968) and southern Mexico (1970) were observed. Two dual-channel filter photometers covering wavelengths in the 0.8 to 4.8 micron range were constructed for the aircraft and eclipse observations. A single channel differential photometer was constructed for daytime circumsolar observations. Two large-aperture (12 inch and 24 inch) photometers have been constructed for twilight and night sky photometry. Finally, a small spectrograph for eclipse work has been constructed. It has been used for airglow observations also. Other specialized instrumentation include a four-axis mounting for radial scanning with the eclipse photometers and a 14-inch diameter collimator for use with a black body in calibration of the photometers. The observations performed are included.

A novel multi-band SAR data technique for fully automatic oil spill detection in the ocean

NASA Astrophysics Data System (ADS)

Del Frate, Fabio; Latini, Daniele; Taravat, Alireza; Jones, Cathleen E.

2013-10-01

With the launch of the Italian constellation of small satellites for the Mediterranean basin observation COSMO-SkyMed and the German TerraSAR-X missions, the delivery of very high-resolution SAR data to observe the Earth day or night has remarkably increased. In particular, also taking into account other ongoing missions such as Radarsat or those no longer working such as ALOS PALSAR, ERS-SAR and ENVISAT the amount of information, at different bands, available for users interested in oil spill analysis has become highly massive. Moreover, future SAR missions such as Sentinel-1 are scheduled for launch in the very next years while additional support can be provided by Uninhabited Aerial Vehicle (UAV) SAR systems. Considering the opportunity represented by all these missions, the challenge is to find suitable and adequate image processing multi-band procedures able to fully exploit the huge amount of data available. In this paper we present a new fast, robust and effective automated approach for oil-spill monitoring starting from data collected at different bands, polarizations and spatial resolutions. A combination of Weibull Multiplicative Model (WMM), Pulse Coupled Neural Network (PCNN) and Multi-Layer Perceptron (MLP) techniques is proposed for achieving the aforementioned goals. One of the most innovative ideas is to separate the dark spot detection process into two main steps, WMM enhancement and PCNN segmentation. The complete processing chain has been applied to a data set containing C-band (ERS-SAR, ENVISAT ASAR), X-band images (Cosmo-SkyMed and TerraSAR-X) and L-band images (UAVSAR) for an overall number of more than 200 images considered.

Tri-band optical coherence tomography for lipid and vessel spectroscopic imaging

NASA Astrophysics Data System (ADS)

Yu, Luoqin; Kang, Jiqiang; Wang, Xie; Wei, Xiaoming; Chan, Kin-Tak; Lee, Nikki P.; Wong, Kenneth K. Y.

2016-03-01

Optical coherence tomography (OCT) has been utilized for various functional imaging applications. One of its highlights comes from spectroscopic imaging, which can simultaneously obtain both morphologic and spectroscopic information. Assisting diagnosis and therapeutic intervention of coronary artery disease is one of the major directions in spectroscopic OCT applications. Previously Tanaka et al. have developed a spectral domain OCT (SDOCT) to image lipid distribution within blood vessel [1]. In the meantime, Fleming et al. have demonstrated optical frequency domain imaging (OFDI) by a 1.3-μm swept source and quadratic discriminant analysis model [2]. However, these systems suffered from burdensome computation as the optical properties' variation was calculated from a single-band illumination that provided limited contrast. On the other hand, multi-band OCT facilitates contrast enhancement with separated wavelength bands, which further offers an easier way to distinguish different materials. Federici and Dubois [3] and Tsai and Chan [4] have demonstrated tri-band OCT systems to further enhance the image contrast. However, these previous work provided under-explored functional properties. Our group has reported a dual-band OCT system based on parametrically amplified Fourier domain mode-locked (FDML) laser with time multiplexing scheme [5] and a dual-band FDML laser OCT system with wavelength-division multiplexing [6]. Fiber optical parametric amplifier (OPA) can be ideally incorporated in multi-band spectroscopic OCT system as it has a broad amplification window and offers an additional output range at idler band, which is phase matched with the signal band. The sweeping ranges can thus overcome traditional wavelength bands that are limited by intra-cavity amplifiers in FDML lasers. Here, we combines the dual-band FDML laser together with fiber OPA, which consequently renders a simultaneous tri-band output at 1.3, 1.5, and 1.6 μm, for intravascular applications. Lipid and blood vessel distribution can be subsequently visualized with the tri-band OCT system by ex vivo experiments using porcine artery model with artificial lipid plaques.

Anatomy of a Busted Comet

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Poster Version (Figure 1)

NASA's Spitzer Space Telescope captured the picture on the left of comet Holmes in March 2008, five months after the comet suddenly erupted and brightened a millionfold overnight. The contrast of the picture has been enhanced on the right to show the anatomy of the comet.

Every six years, comet 17P/Holmes speeds away from Jupiter and heads inward toward the sun, traveling the same route typically without incident. However, twice in the last 116 years, in November 1892 and October 2007, comet Holmes mysteriously exploded as it approached the asteroid belt. Astronomers still do not know the cause of these eruptions.

Spitzer's infrared picture at left hand side of figure 1, reveals fine dust particles that make up the outer shell, or coma, of the comet. The nucleus of the comet is within the bright whitish spot in the center, while the yellow area shows solid particles that were blown from the comet in the explosion. The comet is headed away from the sun, which lies beyond the right-hand side of figure 1.

The contrast-enhanced picture on the right shows the comet's outer shell, and strange filaments, or streamers, of dust. The streamers and shell are a yet another mystery surrounding comet Holmes. Scientists had initially suspected that the streamers were small dust particles ejected from fragments of the nucleus, or from hyerpactive jets on the nucleus, during the October 2007 explosion. If so, both the streamers and the shell should have shifted their orientation as the comet followed its orbit around the sun. Radiation pressure from the sun should have swept the material back and away from it. But pictures of comet Holmes taken by Spitzer over time show the streamers and shell in the same configuration, and not pointing away from the sun. The observations have left astronomers stumped.

The horizontal line seen in the contrast-enhanced picture is a trail of debris that travels along with the comet in its orbit.

The Spitzer picture was taken with the spacecraft's multiband imaging photometer at an infrared wavelength of 24 microns.

Space Surveillance Tech Area Benefits From University Partnerships

NASA Astrophysics Data System (ADS)

Cole, K.; Voss, D.; Pietruszewski, A.; King, L.; Hohnstadt, P.; Feirstine, K.; Crassidis, J.; D'Angelo, M.; Linares, R.

2011-09-01

The University Nanosat Program (UNP) is a two year small satellite competition held among leading universities across the nation. In the past 12 years UNP has involved 27 universities and over 5000 students in a variety of engineering fields and other disciplines, in the process of designing and managing the development of a satellite. The UNP is a partnership between the Air Force Office of Scientific Research (AFOSR), the Air Force Research Laboratory (AFRL), and the American Institute of Aeronautics and Astronautics (AIAA). The program’s primary purpose is to help train engineering students in satellite design, fabrication, and testing by requiring them to build the satellite themselves through the mentorship of their Principle Investigator, industry mentors, and a series of six program reviews managed by the AFRL Program Office. Each university-built satellite attempts to further a specific technology or perform a scientific mission. Technologies advanced through the program include all aspects of small satellite designs including structures, propulsion, imaging, navigation and have helped further science payloads such as energetic particle detectors, plasma probes, photometers, and many others. This paper will discuss the educational impact on students involved in a hands-on, hardware focused program, with emphasis given to two UNP satellites relevant to Space Surveillance Technologies. The most recent winner of the UNP competition, Michigan Technological University’s Oculus-ASR, is a calibration instrument for AMOS’ telescopic non-resolved object characterization program. Another example is the University of Buffalo, which is calibrating with the AFRL MESSA program in the current competition cycle. The University of Buffalo’s nanosatellite is being designed to collect multi-band photometric data of glinting geostationary space objects. Both these satellites are excellent examples of the relevance and quality of innovation and technology that can be produced from an educational program. Finally, the paper will discuss how corporate and government sponsors are a critical part of launching a successful educational flight experiment, and are key benefactors from the data gleaned from a successful mission. These strong partnerships result in students working on relevant projects with mission driven requirements resulting in a better educational program and a greater return on the investment of external partners.

Observations of starburst galaxies: Science and supporting technology

NASA Astrophysics Data System (ADS)

Laag, Edward Aric

In chapter 1 we report on the development of wavefront reconstruction and control algorithms for multi-conjugate adaptive optics (MCAO) and the results of testing them in the laboratory under conditions that simulate an 8 meter class telescope. The UCO/Lick Observatory Laboratory for Adaptive Optics Multi-Conjugate testbed allows us to test wide field of view adaptive optics systems as they might be instantiated in the near future on giant telescopes. In particular, we have been investigating the performance of MCAO using five laser beacons for wavefront sensing and a minimum variance algorithm for control of two conjugate deformable mirrors. We have demonstrated improved Strehl ratio and enlarged field of view performance when compared to conventional AO techniques. We have demonstrated improved MCAO performance with the implementation of a routine that minimizes the generalized isoplanatism when turbulent layers do not correspond to deformable mirror conjugate altitudes. Finally, we have demonstrated suitability of the system for closed-loop operation when configured to feed back conditional mean estimates of wavefront residuals rather than the directly measured residuals. This technique has recently been referred to as the "pseudo-open-loop" control law in the literature. Chapter 2 introduces the Multi-wavelength Extreme Starburst Sample (MESS), a new catalog of 138 star-forming galaxies (0.1 < z < 0.3) optically selected from the SDSS using emission line strength diagnostics to have SFR ≥ 50 M⊙ yr-1 based on a Kroupa IMF. The MESS was designed to complement samples of nearby star forming galaxies such as the luminous infrared galaxies (LIRGs), and ultraviolet luminous galaxies (UVLGs). Observations using the multiband imaging photometer (MIPS; 24, 70, and 160mum channels) on the Spitzer Space Telescope indicate the MESS galaxies have IR luminosities similar to those of LIRGs, with an estimated median LTIR ˜ 3 x 1011 L⊙ . The selection criteria for the MESS suggests they may be less obscured than typical far-IR selected galaxies with similar estimated SFRs. We estimate the SFRs based directly on luminosities to determine the agreement for these methods in the MESS.

Far-Infrared Extragalactic Surveys: Past, Present, and Future

NASA Technical Reports Server (NTRS)

Moseley, Samuel H., Jr.; Fisher, Richard R. (Technical Monitor)

2001-01-01

As much as one third of the luminosity of the local universe is emitted in the far infrared. In order to understand the history of energy release in the universe, it is crucial to characterize this rest-frame far-infrared contribution from the present back to the era of initial galaxy formation. Over the redshift range from 0 to 10, this energy is received in the 80 micrometers to 1 mm spectral region. In the 1980's the Infrared Astronomy Satellite (IRAS) all-sky survey provided the first comprehensive view of the far infrared emission from the local universe. The diffuse background measurements by Cosmic Background Explorer Satellite (COBE) have provided constraints on the integral contributions from the high redshift universe. In the past five years, submillimeter measurements made using the SCUBA instrument have revealed powerful high redshift sources. To develop a clear history of energy release in the universe, we need numbers and redshifts of representative populations of energetically important objects. The near future will bring the Space Infrared Telescope Facility Multiband Imaging Photometer (SIRTF)(MIPS) survey, which will cover about 100 square degrees at wavelengths out to 160 micrometers, providing a large sample of energetically important galaxies out to z of approx.3. In 2005, the Japanese IRIS survey will provide a 160 micrometers full sky survey, which will provide larger samples of the high z galaxy populations and will find intrinsically rare high luminosity objects. The SPIRE instrument on the FIRST facility will extend these surveys to longer wavelengths, providing a view of the universe at higher redshifts in three spectral bands. A concept for an all-sky submillimeter survey is under development, called the Survey of Infrared Cosmic Evolution (SIRCE). With a 2 m cryogenic telescope, it can map the entire sky to the confusion limit in the 100 to 500 micrometers range in six months. This survey will provide photometric redshifts, number counts, and will find the most luminous objects in the universe. In the next decade, the opening of the submillimeter, combined with the near infrared capability of NGST will provide us with a clear picture of energy release in the early universe.

The Last Gasp of Gas Giant Planet Formation: A Spitzer Study of the 5 Myr Old Cluster NGC 2362

NASA Astrophysics Data System (ADS)

Currie, Thayne; Lada, Charles J.; Plavchan, Peter; Robitaille, Thomas P.; Irwin, Jonathan; Kenyon, Scott J.

2009-06-01

Expanding upon the Infrared Array Camera (IRAC) survey from Dahm & Hillenbrand, we describe Spitzer IRAC and Multiband Imaging Photometer for Spitzer observations of the populous, 5 Myr old open cluster NGC 2362. We analyze the mid-IR colors of cluster members and compared their spectral energy distributions (SEDs) to star+circumstellar disk models to constrain the disk morphologies and evolutionary states. Early/intermediate-type confirmed/candidate cluster members either have photospheric mid-IR emission or weak, optically thin IR excess emission at λ >= 24 μm consistent with debris disks. Few late-type, solar/subsolar-mass stars have primordial disks. The disk population around late-type stars is dominated by disks with inner holes (canonical "transition disks") and "homologously depleted" disks. Both types of disks represent an intermediate stage between primordial disks and debris disks. Thus, in agreement with previous results, we find that multiple paths for the primordial-to-debris disk transition exist. Because these "evolved primordial disks" greatly outnumber primordial disks, our results undermine standard arguments in favor of a lsim105 yr timescale for the transition based on data from Taurus-Auriga. Because the typical transition timescale is far longer than 105 yr, these data also appear to rule out standard ultraviolet photoevaporation scenarios as the primary mechanism to explain the transition. Combining our data with other Spitzer surveys, we investigate the evolution of debris disks around high/intermediate-mass stars and investigate timescales for giant planet formation. Consistent with Currie et al., the luminosity of 24 μm emission in debris disks due to planet formation peaks at ≈10-20 Myr. If the gas and dust in disks evolve on similar timescales, the formation timescale for gas giant planets surrounding early-type, high/intermediate-mass (gsim1.4 M sun) stars is likely 1-5 Myr. Most solar/subsolar-mass stars detected by Spitzer have SEDs that indicate their disks may be actively leaving the primordial disk phase. Thus, gas giant planet formation may also occur by ~5 Myr around solar/subsolar-mass stars as well.

Star Formation in Henize 206

NASA Image and Video Library

2004-03-08

This image from NASA Spitzer Space Telescope, shows the wispy filamentary structure of Henize 206, is a four-color composite mosaic created by combining data from an infrared array camera IRAC. The LMC is a small satellite galaxy gravitationally bound to our own Milky Way. Yet the gravitational effects are tearing the companion to shreds in a long-playing drama of 'intergalactic cannibalism.' These disruptions lead to a recurring cycle of star birth and star death. Astronomers are particularly interested in the LMC because its fractional content of heavy metals is two to five times lower than is seen in our solar neighborhood. [In this context, 'heavy elements' refer to those elements not present in the primordial universe. Such elements as carbon, oxygen and others are produced by nucleosynthesis and are ejected into the interstellar medium via mass loss by stars, including supernova explosions.] As such, the LMC provides a nearby cosmic laboratory that may resemble the distant universe in its chemical composition. The primary Spitzer image, showing the wispy filamentary structure of Henize 206, is a four-color composite mosaic created by combining data from an infrared array camera (IRAC) at near-infrared wavelengths and the mid-infrared data from a multiband imaging photometer (MIPS). Blue represents invisible infrared light at wavelengths of 3.6 and 4.5 microns. Note that most of the stars in the field of view radiate primarily at these short infrared wavelengths. Cyan denotes emission at 5.8 microns, green depicts the 8.0 micron light, and red is used to trace the thermal emission from dust at 24 microns. The separate instrument images are included as insets to the main composite. An inclined ring of emission dominates the central and upper regions of the image. This delineates a bubble of hot, x-ray emitting gas that was blown into space when a massive star died in a supernova explosion millions of years ago. The shock waves from that explosion impacted a cloud of nearby hydrogen gas, compressed it, and started a new generation of star formation. The death of one star led to the birth of many new stars. This is particularly evident in the MIPS inset, where the 24-micron emission peaks correspond to newly formed stars. The ultraviolet and visible-light photons from the new stars are absorbed by surrounding dust and re-radiated at longer infrared wavelengths, where it is detected by Spitzer. This emission nebula was cataloged by Karl Henize (HEN-eyes) while spending 1948-1951 in South Africa doing research for his Ph.D. dissertation at the University of Michigan. Henize later became a NASA astronaut and, at age 59, became the oldest rookie to fly on the Space Shuttle during an eight-day flight of the Challenger in 1985. He died just short of his 67th birthday in 1993 while attempting to climb the north face of Mount Everest, the world's highest peak. http://photojournal.jpl.nasa.gov/catalog/PIA05517

Photometer Performance Assessment in Kepler Science Data Processing

NASA Technical Reports Server (NTRS)

Li, Jie; Allen, Christopher; Bryson, Stephen T.; Caldwell, Douglas A.; Chandrasekaran, Hema; Clarke, Bruce D.; Gunter, Jay P.; Jenkins, Jon M.; Klaus, Todd C.; Quintana, Elisa V.;

Photometric redshift estimation via deep learning. Generalized and pre-classification-less, image based, fully probabilistic redshifts

NASA Astrophysics Data System (ADS)

D'Isanto, A.; Polsterer, K. L.

2018-01-01

Context. The need to analyze the available large synoptic multi-band surveys drives the development of new data-analysis methods. Photometric redshift estimation is one field of application where such new methods improved the results, substantially. Up to now, the vast majority of applied redshift estimation methods have utilized photometric features. Aims: We aim to develop a method to derive probabilistic photometric redshift directly from multi-band imaging data, rendering pre-classification of objects and feature extraction obsolete. Methods: A modified version of a deep convolutional network was combined with a mixture density network. The estimates are expressed as Gaussian mixture models representing the probability density functions (PDFs) in the redshift space. In addition to the traditional scores, the continuous ranked probability score (CRPS) and the probability integral transform (PIT) were applied as performance criteria. We have adopted a feature based random forest and a plain mixture density network to compare performances on experiments with data from SDSS (DR9). Results: We show that the proposed method is able to predict redshift PDFs independently from the type of source, for example galaxies, quasars or stars. Thereby the prediction performance is better than both presented reference methods and is comparable to results from the literature. Conclusions: The presented method is extremely general and allows us to solve of any kind of probabilistic regression problems based on imaging data, for example estimating metallicity or star formation rate of galaxies. This kind of methodology is tremendously important for the next generation of surveys.

Design and realization of photoelectric instrument binocular optical axis parallelism calibration system

NASA Astrophysics Data System (ADS)

Ying, Jia-ju; Chen, Yu-dan; Liu, Jie; Wu, Dong-sheng; Lu, Jun

2016-10-01

The maladjustment of photoelectric instrument binocular optical axis parallelism will affect the observe effect directly. A binocular optical axis parallelism digital calibration system is designed. On the basis of the principle of optical axis binocular photoelectric instrument calibration, the scheme of system is designed, and the binocular optical axis parallelism digital calibration system is realized, which include four modules: multiband parallel light tube, optical axis translation, image acquisition system and software system. According to the different characteristics of thermal infrared imager and low-light-level night viewer, different algorithms is used to localize the center of the cross reticle. And the binocular optical axis parallelism calibration is realized for calibrating low-light-level night viewer and thermal infrared imager.

FRIT characterized hierarchical kernel memory arrangement for multiband palmprint recognition

NASA Astrophysics Data System (ADS)

Kisku, Dakshina R.; Gupta, Phalguni; Sing, Jamuna K.

2015-10-01

In this paper, we present a hierarchical kernel associative memory (H-KAM) based computational model with Finite Ridgelet Transform (FRIT) representation for multispectral palmprint recognition. To characterize a multispectral palmprint image, the Finite Ridgelet Transform is used to achieve a very compact and distinctive representation of linear singularities while it also captures the singularities along lines and edges. The proposed system makes use of Finite Ridgelet Transform to represent multispectral palmprint image and it is then modeled by Kernel Associative Memories. Finally, the recognition scheme is thoroughly tested with a benchmarking multispectral palmprint database CASIA. For recognition purpose a Bayesian classifier is used. The experimental results exhibit robustness of the proposed system under different wavelengths of palm image.

Fast Dynamic 3D MRSI with Compressed Sensing and Multiband Excitation Pulses for Hyperpolarized 13C Studies

PubMed Central

Larson, Peder E. Z.; Hu, Simon; Lustig, Michael; Kerr, Adam B.; Nelson, Sarah J.; Kurhanewicz, John; Pauly, John M.; Vigneron, Daniel B.

2010-01-01

Hyperpolarized 13C MRSI can detect not only the uptake of the pre-polarized molecule but also its metabolic products in vivo, thus providing a powerful new method to study cellular metabolism. Imaging the dynamic perfusion and conversion of these metabolites provides additional tissue information but requires methods for efficient hyperpolarization usage and rapid acquisitions. In this work, we have developed a time-resolved 3D MRSI method for acquiring hyperpolarized 13C data by combining compressed sensing methods for acceleration and multiband excitation pulses to efficiently use the magnetization. This method achieved a 2 sec temporal resolution with full volumetric coverage of a mouse, and metabolites were observed for up to 60 sec following injection of hyperpolarized [1-13C]-pyruvate. The compressed sensing acquisition used random phase encode gradient blips to create a novel random undersampling pattern tailored to dynamic MRSI with sampling incoherency in four (time, frequency and two spatial) dimensions. The reconstruction was also tailored to dynamic MRSI by applying a temporal wavelet sparsifying transform in order to exploit the inherent temporal sparsity. Customized multiband excitation pulses were designed with a lower flip angle for the [1-13C]-pyruvate substrate given its higher concentration than its metabolic products ([1-13C]-lactate and [1-13C]-alanine), thus using less hyperpolarization per excitation. This approach has enabled the monitoring of perfusion and uptake of the pyruvate, and the conversion dynamics to lactate and alanine throughout a volume with high spatial and temporal resolution. PMID:20939089

The High Speed Photometer for the Space Telescope

NASA Technical Reports Server (NTRS)

Bless, R. C.

1982-01-01

An overview of the high speed photometer (HSP), its optics and detectors, its electronics, its mechanical structure, and some observational considerations are presented. The capabilities and limitations of the HSP are outlined.

Lunar and Planetary Science XXXV: Future Missions to the Moon

NASA Technical Reports Server (NTRS)

2004-01-01

This document contained the following topics: A Miniature Mass Spectrometer Module; SELENE Gamma Ray Spectrometer Using Ge Detector Cooled by Stirling Cryocooler; Lunar Elemental Composition and Investigations with D-CIXS X-Ray Mapping Spectrometer on SMART-1; X-Ray Fluorescence Spectrometer Onboard the SELENE Lunar Orbiter: Its Science and Instrument; Detectability of Degradation of Lunar Impact Craters by SELENE Terrain Camera; Study of the Apollo 16 Landing Site: As a Standard Site for the SELENE Multiband Imager; Selection of Targets for the SMART-1 Infrared Spectrometer (SIR); Development of a Telescopic Imaging Spectrometer for the Moon; The Lunar Seismic Network: Mission Update.

An International Haze-Monitoring Network for Students.

NASA Astrophysics Data System (ADS)

Mims, Forrest M., III

1999-07-01

The Global Learning and Observations to Benefit the Environment (GLOBE) Program is an international network of schools in 71 countries that monitors up to 20 environmental parameters. Recently GLOBE added a haze-monitoring program to its measurement protocols. This network has the potential of providing important data about changes in the aerosol optical depth of the atmosphere caused by weather fronts, industrial and automobile pollution, and smoke from forest and brush fires and volcanic eruptions. Initially, monitoring will be conducted with an inexpensive, single-channel (520 nm) sun photometer. Unlike conventional sun photometers that use interference filters that are subject to unpredictable and rapid degradation, the GLOBE instrument uses a common light-emitting diode (LED) as a spectrally selective detector. Annual calibrations of two LED sun photometers at Mauna Loa Observatory since 1992 show that these instruments have insignificant degradation when compared to filter sun photometers. Some 175 prototype versions of a kit LED sun photometer have been assembled and tested by students from 16 countries at the University of the Nations and by more than 130 high school teachers in various pilot studies. These studies have demonstrated that even inexperienced students and teachers can quickly assemble a sun photometer from a kit of parts and perform a reliable angley calibration. The pilot studies have also demonstrated that sun photometery provides a convenient means for allowing students to perform hands-on science while they learn about various topics in history, electronics, algebra, statistics, graphing, and meteorology.

On-board data processing for the near infrared spectrograph and photometer instrument (NISP) of the EUCLID mission

NASA Astrophysics Data System (ADS)

Bonoli, Carlotta; Balestra, Andrea; Bortoletto, Favio; D'Alessandro, Maurizio; Farinelli, Ruben; Medinaceli, Eduardo; Stephen, John; Borsato, Enrico; Dusini, Stefano; Laudisio, Fulvio; Sirignano, Chiara; Ventura, Sandro; Auricchio, Natalia; Corcione, Leonardo; Franceschi, Enrico; Ligori, Sebastiano; Morgante, Gianluca; Patrizii, Laura; Sirri, Gabriele; Trifoglio, Massimo; Valenziano, Luca

2016-07-01

The Near Infrared Spectrograph and Photometer (NISP) is one of the two instruments on board the EUCLID mission now under implementation phase; VIS, the Visible Imager is the second instrument working on the same shared optical beam. The NISP focal plane is based on a detector mosaic deploying 16x, 2048x2048 pixels^2 HAWAII-II HgCdTe detectors, now in advanced delivery phase from Teledyne Imaging Scientific (TIS), and will provide NIR imaging in three bands (Y, J, H) plus slit-less spectroscopy in the range 0.9÷2.0 micron. All the NISP observational modes will be supported by different parametrization of the classic multi-accumulation IR detector readout mode covering the specific needs for spectroscopic, photometric and calibration exposures. Due to the large number of deployed detectors and to the limited satellite telemetry available to ground, a consistent part of the data processing, conventionally performed off-line, will be accomplished on board, in parallel with the flow of data acquisitions. This has led to the development of a specific on-board, HW/SW, data processing pipeline, and to the design of computationally performing control electronics, suited to cope with the time constraints of the NISP acquisition sequences during the sky survey. In this paper we present the architecture of the NISP on-board processing system, directly interfaced to the SIDECAR ASICs system managing the detector focal plane, and the implementation of the on-board pipe-line allowing all the basic operations of input frame averaging, final frame interpolation and data-volume compression before ground down-link.

Fabrication and characterization of multiband solar cells based on highly mismatched alloys

NASA Astrophysics Data System (ADS)

López, N.; Braña, A. F.; García Núñez, C.; Hernández, M. J.; Cervera, M.; Martínez, M.; Yu, K. M.; Walukiewicz, W.; García, B. J.

2015-10-01

Multiband solar cells are one type of third generation photovoltaic devices in which an increase of the power conversion efficiency is achieved through the absorption of low energy photons while preserving a large band gap that determines the open circuit voltage. The ability to absorb photons from different parts of the solar spectrum originates from the presence of an intermediate energy band located within the band gap of the material. This intermediate band, acting as a stepping stone allows the absorption of low energy photons to transfer electrons from the valence band to the conduction band by a sequential two photons absorption process. It has been demonstrated that highly mismatched alloys offer a potential to be used as a model material system for practical realization of multiband solar cells. Dilute nitride GaAs1-xNx highly mismatched alloy with low mole fraction of N is a prototypical multiband semiconductor with a well-defined intermediate band. Currently, we are using chemical beam epitaxy to synthesize dilute nitride highly mismatched alloys. The materials are characterized by a variety of structural and optical methods to optimize their properties for multiband photovoltaic devices.

Low-latitude ionospheric research using the CIRCE Mission: instrumentation overview

NASA Astrophysics Data System (ADS)

Dymond, K. F.; Nicholas, A. C.; Budzien, S. A.; Stephan, A. W.; Marquis, P.; Brown, C. M.; Finne, T.; Wolfram, K. D.

2017-08-01

The Coordinated Ionospheric Reconstruction Cubesat Experiment (CIRCE) is a dual-satellite mission consisting of two 6U CubeSats actively maintaining a lead-follow configuration in the same orbit with a launch planned for the 2018-2019 time-frame. These nanosatellites will each feature two 1U size ultraviolet photometers, observing the 135.6 nm emission of atomic oxygen at nighttime. The primary objective is to characterize the two-dimensional distribution of electrons in the orbital plane of the vehicles with special emphasis on studying the morphology of the Equatorial Ionization Anomaly (EIA). The methodology used to reconstruct the nighttime ionosphere employs continuous UV photometry from four distinct viewing angles in combination with an additional data source, such as in situ plasma density measurements or a wide-band beacon data, with advanced image space reconstruction algorithm tomography techniques. The COSMIC/FORMOSAT-3 (CF3) constellation featured six Tiny Ionospheric Photometers, compact UV sensors which served as the pathfinder for the CIRCE instruments. The TIP instruments on the CF3 satellites demonstrated detection of ionospheric bubbles before they had penetrated the peak of the F-region ionosphere, showed the temporal evolution of the EIA, and observed a Medium Scale Travelling Ionospheric Disturbance. We present our mission concept, some pertinent information regarding the instrument design, the results of simulations illustrating the imaging capability of the sensor suite, and a range of science questions addressable using such a system.

GOES Satellite Data Validation Via Hand-held 4 LED Sun Photometer at Norfolk State University

NASA Technical Reports Server (NTRS)

Reynolds, Arthur, Jr.; Jackson, Tyrone; Reynolds, Kevin; Davidson, Cassy; Coope-Pabis, Barbara

2005-01-01

Sun photometry is a passive means of measuring a quantity of light radiation. The GIFTS- IOMI/GLOBE Water Vapor/Haze Sun photometer contains four light emitting diodes (LEDs), which are used to convert photocurrent to voltage. The intensity of the incoming and outgoing radiation as detected on the Earth s surface can be affected by aerosols and gases in the atmosphere. The focus of this research is primarily on aerosol and water vapor particles that absorb and reemit energy. Two LEDs in the photometer correspond to light scattered at 530 nm (green spectrum) and 620 nm (red spectrum). They collect data pertaining to aerosols that scatter light. The other two LEDs detect the light scattered by water vapor at wavelengths of 820 nm and 920 nm. The water vapor measurements will be compared to data collected by the Geostationary Observation Environmental Satellite (GOES). Before a comparison can be made, the extraterrestrial constant (ET), which is intrinsic to each sun photometer, must be measured. This paper will present determination of the ET constant, from which the aerosol optical thickness (AOT) can be computed for comparison to the GOES satellite to ascertain the reliability of the sun photometer.

Using precise word timing information improves decoding accuracy in a multiband-accelerated multimodal reading experiment.

PubMed

Vu, An T; Phillips, Jeffrey S; Kay, Kendrick; Phillips, Matthew E; Johnson, Matthew R; Shinkareva, Svetlana V; Tubridy, Shannon; Millin, Rachel; Grossman, Murray; Gureckis, Todd; Bhattacharyya, Rajan; Yacoub, Essa

2016-01-01

The blood-oxygen-level-dependent (BOLD) signal measured in functional magnetic resonance imaging (fMRI) experiments is generally regarded as sluggish and poorly suited for probing neural function at the rapid timescales involved in sentence comprehension. However, recent studies have shown the value of acquiring data with very short repetition times (TRs), not merely in terms of improvements in contrast to noise ratio (CNR) through averaging, but also in terms of additional fine-grained temporal information. Using multiband-accelerated fMRI, we achieved whole-brain scans at 3-mm resolution with a TR of just 500 ms at both 3T and 7T field strengths. By taking advantage of word timing information, we found that word decoding accuracy across two separate sets of scan sessions improved significantly, with better overall performance at 7T than at 3T. The effect of TR was also investigated; we found that substantial word timing information can be extracted using fast TRs, with diminishing benefits beyond TRs of 1000 ms.

Multiband optical variability of the blazar OJ 287 during its outbursts in 2015-2016

NASA Astrophysics Data System (ADS)

Gupta, Alok C.; Agarwal, Aditi; Mishra, Alka; Gaur, H.; Wiita, P. J.; Gu, M. F.; Kurtanidze, O. M.; Damljanovic, G.; Uemura, M.; Semkov, E.; Strigachev, A.; Bachev, R.; Vince, O.; Zhang, Z.; Villarroel, B.; Kushwaha, P.; Pandey, A.; Abe, T.; Chanishvili, R.; Chigladze, R. A.; Fan, J. H.; Hirochi, J.; Itoh, R.; Kanda, Y.; Kawabata, M.; Kimeridze, G. N.; Kurtanidze, S. O.; Latev, G.; Dimitrova, R. V. Muñoz; Nakaoka, T.; Nikolashvili, M. G.; Shiki, K.; Sigua, L. A.; Spassov, B.

2017-03-01

We present recent optical photometric observations of the blazar OJ 287 taken during 2015 September-2016 May. Our intense observations of the blazar started in 2015 November and continued until 2016 May and included detection of the large optical outburst in 2015 December that was predicted using the binary black hole model for OJ 287. For our observing campaign, we used a total of nine ground-based optical telescopes of which one is in Japan, one is in India, three are in Bulgaria, one is in Serbia, one is in Georgia, and two are in the USA. These observations were carried out in 102 nights with a total of ∼1000 image frames in BVRI bands, though the majority were in the R band. We detected a second comparably strong flare in 2016 March. In addition, we investigated multiband flux variations, colour variations, and spectral changes in the blazar on diverse time-scales as they are useful in understanding the emission mechanisms. We briefly discuss the possible physical mechanisms most likely responsible for the observed flux, colour, and spectral variability.

Concerning the use of multifunctional photometer - polarimeter for studying the invasion of cosmic bodies into the Earth's atmosphere

NASA Astrophysics Data System (ADS)

Geraimchuk, M. D.; Vidmachenko, A. P.; Nevodovskyi, P. V.; Steklov, O. F.

2018-05-01

Main astronomical observatory of the National Academy of Sciences of Ukraine together with the National Technical University of Ukraine "KPI" for many years working on the development of photometers-polarimeters for the study of cosmic bodies and Earth's atmosphere. We proposed an option of the development of a multipurpose panoramic photometer-polarimeter, which takes into account the shortcomings of the previous versions of the instrument and also allows for the registration of tracks of bolides, and study of their tails, and weak meteor phenomena.

University of New Hampshire's Project SMART 2017: Marine and Environmental Science for High School Students

NASA Astrophysics Data System (ADS)

Goelzer, J.; Varner, R. K.; Levergood, R.; Sullivan, F.; Palace, M. W.; Haney, J. F.; Rock, B. N.; Smith, C. W.

2017-12-01

The month long residential Marine and Environmental Science research program for high school students at the University of New Hampshire connects students with university researchers. This educational program provides upper level high school students who are considering majors in the earth and environmental sciences with the opportunity to perform field work and conduct authentic research. This year's program introduced students to four modules exploring topics ranging from forest ecology to island ecosystems. The unifying theme between modules was the use of spectroscopy and remote sensing as a method of assessing the characteristics of ecosystems. Students constructed their own photometers utilizing eight specific Light Emitting Diodes (LEDs) spanning a wavelength range from 400 to 1200 nm. An Ultra Violet (UV) LED, four visible LEDs, and three different infrared LEDs were selected to detect light reflected by plant pigments and tissues. Students collected data using their photometers and compared results to an actual Analytical Spectral Device (ASD) reflectance data, mounted eight photometers on an unmanned aerial system (UAS) to collect forest canopy data and collected data from island rock pools. The students compared their photometer readings to data collected using a fluorometer to identify the presence of phycocyanin produced by cyanobacteria and chlorophyll produced by algae in the rock pools. Students found that the photometer data were comparable to the ASD data for several wavelengths, but recommended several changes. It was determined that to be useful for forest health assessment, two of the three infrared LEDs had the incorrect gain settings, and that for rock pool studies, the infrared LEDs were not necessary. Based on the student findings, we will refine the photometers for next year's program. The photometers constructed this summer will be utilized in high schools classes during the 2017-2018 school year. This low cost project will bring what is normally a university level STEM experience into the high school classroom with university faculty, students and staff collaborating with high school teachers and students.

Large and small-scale structures in Saturn's rings

NASA Astrophysics Data System (ADS)

Albers, N.; Rehnberg, M. E.; Brown, Z. L.; Sremcevic, M.; Esposito, L. W.

2017-09-01

Observations made by the Cassini spacecraft have revealed both large and small scale structures in Saturn's rings in unprecedented detail. Analysis of high-resolution measurements by the Cassini Ultraviolet Spectrograph (UVIS) High Speed Photometer (HSP) and the Imaging Science Subsystem (ISS) show an abundance of intrinsic small-scale structures (or clumping) seen across the entire ring system. These include self-gravity wakes (50-100m), sub-km structure at the A and B ring edges, and "straw"/"ropy" structures (1-3km).

Multiband electronic transport in α-Yb 1₋xSr x AlB 4 [ x = 0, 0.19(3)] single crystals

DOE PAGES

Ryu, Hyejin; Abeykoon, Milinda; Bozin, Emil; ...

2016-08-19

Here we report on the evidence for the multiband electronic transport in α- YbAlB 4 and α-Yb 0.81(2)Sr 0.19(3)AlB 4. Multiband transport reveals itself below 10 K in both compounds via Hall effect measurements, whereas anisotropic magnetic ground state sets in below 3 K in α-Yb 0.81(2)Sr 0.19(3)AlB 4. Our results show that Sr 2+ substitution enhances conductivity, but does not change the quasiparticle mass of bands induced by heavy fermion hybridization.

Spitzer observations of NGC 2264: the nature of the disk population

NASA Astrophysics Data System (ADS)

Teixeira, P. S.; Lada, C. J.; Marengo, M.; Lada, E. A.

2012-04-01

Aims: NGC 2264 is a young cluster with a rich circumstellar disk population which makes it an ideal target for studying the evolution of stellar clusters. Our goal is to study the star formation history of NGC 2264 and to analyse the primordial disk evolution of its members. Methods: The study presented is based on data obtained with the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer for Spitzer (MIPS) on board the Spitzer Space Telescope, combined with deep near-infrared (NIR) ground-based FLAMINGOS imaging and previously published optical data. Results: We build NIR dust extinction maps of the molecular cloud associated with the cluster, and determine it to have a mass of 2.1 × 103 M⊙ above an AV of 7 mag. Using a differential Ks-band luminosity function (KLF) of the cluster, we estimate the size of the population of NGC 2264, within the area observed by FLAMINGOS, to be 1436 ± 242 members. The star formation efficiency is ≥ ~25%. We identify the disk population and divide it into 3 groups based on their spectral energy distribution slopes from 3.6 μm to 8 μm and on the 24 μm excess emission: (i) optically thick inner disks, (ii) anaemic inner disks, and (iii) disks with inner holes, or transition disks. We analyse the spatial distribution of these sources and find that sources with thick disks segregate into sub-clusterings, whereas sources with anaemic disks do not. Furthermore, sources with anaemic disks are found to be unembedded (i.e., with AV < 3 mag), whereas the clustered sources with thick disks are still embedded within the parental cloud. Conclusions: NGC 2264 has undergone more than one star-forming event, where the anaemic and extincted thick disk population appear to have formed in separate episodes: the sources with anaemic disks are more evolved and have had time to disperse and populate a halo of the cluster. We also find tentative evidence of triggered star-formation in the Fox Fur Nebula. In terms of disk evolution, our findings support the emerging disk evolution paradigm of two distinct evolutionary paths for primordial optically thick disks: a homologous one where the disk emission decreases uniformly at NIR and mid-infrared (MIR) wavelengths, and a radially differential one where the emission from the inner region of the disk decreases more rapidly than from the outer region (forming transition disks).

Determination of nocturnal aerosol properties from a combination of lunar photometer and lidar observations

NASA Astrophysics Data System (ADS)

Li, Donghui; Li, Zhengqiang; Lv, Yang; Zhang, Ying; Li, Kaitao; Xu, Hua

2015-10-01

Aerosol plays a key role in the assessment of global climate change and environmental health, while observation is one of important way to deepen the understanding of aerosol properties. In this study, the newly instrument - lunar photometer is used to measure moonlight and nocturnal column aerosol optical depth (AOD, τ) is retrieved. The AOD algorithm is test and verified with sun photometer both in high and low aerosol loading. Ångström exponent (α) and fine/coarse mode AOD (τf, τc) 1 is derived from spectral AOD. The column aerosol properties (τ, α, τf, τc) inferred from the lunar photometer is analyzed based on two month measurement in Beijing. Micro-pulse lidar has advantages in retrieval of aerosol vertical distribution, especially in night. However, the typical solution of lidar equation needs lidar ratio(ratio of aerosol backscatter and extinction coefficient) assumed in advance(Fernald method), or constrained by AOD2. Yet lidar ratio is varied with aerosol type and not easy to fixed, and AOD is used of daylight measurement, which is not authentic when aerosol loading is different from day and night. In this paper, the nocturnal AOD measurement from lunar photometer combined with mie scattering lidar observations to inverse aerosol extinction coefficient(σ) profile in Beijing is discussed.

TOWARD CHARACTERIZATION OF THE TYPE IIP SUPERNOVA PROGENITOR POPULATION: A STATISTICAL SAMPLE OF LIGHT CURVES FROM Pan-STARRS1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanders, N. E.; Soderberg, A. M.; Chornock, R.

2015-02-01

In recent years, wide-field sky surveys providing deep multiband imaging have presented a new path for indirectly characterizing the progenitor populations of core-collapse supernovae (SNe): systematic light-curve studies. We assemble a set of 76 grizy-band Type IIP SN light curves from Pan-STARRS1, obtained over a constant survey program of 4 yr and classified using both spectroscopy and machine-learning-based photometric techniques. We develop and apply a new Bayesian model for the full multiband evolution of each light curve in the sample. We find no evidence of a subpopulation of fast-declining explosions (historically referred to as ''Type IIL'' SNe). However, we identify a highly significantmore » relation between the plateau phase decay rate and peak luminosity among our SNe IIP. These results argue in favor of a single parameter, likely determined by initial stellar mass, predominantly controlling the explosions of red supergiants. This relation could also be applied for SN cosmology, offering a standardizable candle good to an intrinsic scatter of ≲ 0.2 mag. We compare each light curve to physical models from hydrodynamic simulations to estimate progenitor initial masses and other properties of the Pan-STARRS1 Type IIP SN sample. We show that correction of systematic discrepancies between modeled and observed SN IIP light-curve properties and an expanded grid of progenitor properties are needed to enable robust progenitor inferences from multiband light-curve samples of this kind. This work will serve as a pathfinder for photometric studies of core-collapse SNe to be conducted through future wide-field transient searches.« less

A pulse-mode two channel rocket photometer

NASA Astrophysics Data System (ADS)

Petkov, N. P.

Benefits of vertical profile measurements of nighttime emission in the upper atmosphere are discussed. The block diagram of a two-channel rocket photometer with a common pulse operating mode for both channels is described. The requirements and features of the basic units are determined.

AEGIS-X: Deep Chandra Imaging of the Central Groth Strip

NASA Astrophysics Data System (ADS)

Nandra, K.; Laird, E. S.; Aird, J. A.; Salvato, M.; Georgakakis, A.; Barro, G.; Perez-Gonzalez, P. G.; Barmby, P.; Chary, R.-R.; Coil, A.; Cooper, M. C.; Davis, M.; Dickinson, M.; Faber, S. M.; Fazio, G. G.; Guhathakurta, P.; Gwyn, S.; Hsu, L.-T.; Huang, J.-S.; Ivison, R. J.; Koo, D. C.; Newman, J. A.; Rangel, C.; Yamada, T.; Willmer, C.

2015-09-01

We present the results of deep Chandra imaging of the central region of the Extended Groth Strip, the AEGIS-X Deep (AEGIS-XD) survey. When combined with previous Chandra observations of a wider area of the strip, AEGIS-X Wide (AEGIS-XW), these provide data to a nominal exposure depth of 800 ks in the three central ACIS-I fields, a region of approximately 0.29 deg2. This is currently the third deepest X-ray survey in existence; a factor ∼ 2-3 shallower than the Chandra Deep Fields (CDFs), but over an area ∼3 times greater than each CDF. We present a catalog of 937 point sources detected in the deep Chandra observations, along with identifications of our X-ray sources from deep ground-based, Spitzer, GALEX, and Hubble Space Telescope imaging. Using a likelihood ratio analysis, we associate multiband counterparts for 929/937 of our X-ray sources, with an estimated 95% reliability, making the identification completeness approximately 94% in a statistical sense. Reliable spectroscopic redshifts for 353 of our X-ray sources are available predominantly from Keck (DEEP2/3) and MMT Hectospec, so the current spectroscopic completeness is ∼38%. For the remainder of the X-ray sources, we compute photometric redshifts based on multiband photometry in up to 35 bands from the UV to mid-IR. Particular attention is given to the fact that the vast majority the X-ray sources are active galactic nuclei and require hybrid templates. Our photometric redshifts have mean accuracy of σ =0.04 and an outlier fraction of approximately 5%, reaching σ =0.03 with less than 4% outliers in the area covered by CANDELS . The X-ray, multiwavelength photometry, and redshift catalogs are made publicly available.

Star Observations by Asteroid Multiband Imaging Camera (AMICA) on Hayabusa (MUSES-C) Cruising Phase

NASA Astrophysics Data System (ADS)

Saito, J.; Hashimoto, T.; Kubota, T.; Hayabusa AMICA Team

Muses-C is the first Japanese asteroid mission and also a technology demonstration one to the S-type asteroid, 25143 Itokawa (1998SF36). It was launched at May 9, 2003, and renamed Hayabusa after the spacecraft was confirmed to be on the interplanetary orbit. This spacecraft has the event of the Earth-swingby for gravitational assist in the way to Itokawa on 2004 May. The arrival to Itokawa is scheduled on 2005 summer. During the visit to Itokawa, the remote-sensing observation with AMICA, NIRS (Near Infrared Spectrometer), XRS (X-ray Fluorescence Spectrometer), and LIDAR are performed, and the spacecraft descends and collects the surface samples at the touch down to the surface. The captured asteroid sample will be returned to the Earth in the middle of 2007. The telescopic optical navigation camera (ONC-T) with seven bandpass filters (and one wide-band filter) and polarizers is called AMICA (Asteroid Multiband Imaging CAmera) when ONC-T is used for scientific observations. The AMICA's seven bandpass filters are nearly equivalent to the seven filters of the ECAS (Eight Color Asteroid Survey) system. Obtained spectroscopic data will be compared with previously obtained ECAS observations. AMICA also has four polarizers, which are located on one edge of the CCD chip (covering 1.1 x 1.1 degrees each). Using the polarizers of AMICA, we can obtain polarimetric information of the target asteroid's surface. Since last November, we planned the test observations of some stars and planets by AMICA and could successfully obtain these images. Here, we briefly report these observations and its calibration by the ground-based observational data. In addition, we also present a current status of AMICA.

VizieR Online Data Catalog: Improved multi-band photometry from SERVS (Nyland+, 2017)

NASA Astrophysics Data System (ADS)

Nyland, K.; Lacy, M.; Sajina, A.; Pforr, J.; Farrah, D.; Wilson, G.; Surace, J.; Haussler, B.; Vaccari, M.; Jarvis, M.

2017-07-01

The Spitzer Extragalactic Representative Volume Survey (SERVS) sky footprint includes five well-studied astronomical deep fields with abundant multi-wavelength data spanning an area of ~18deg2 and a co-moving volume of ~0.8Gpc3. The five deep fields included in SERVS are the XMM-LSS field, Lockman Hole (LH), ELAIS-N1 (EN1), ELAIS-S1 (ES1), and Chandra Deep Field South (CDFS). SERVS provides NIR, post-cryogenic imaging in the 3.6 and 4.5um Spitzer/IRAC bands to a depth of ~2uJy. IRAC dual-band source catalogs generated using traditional catalog extraction methods are described in Mauduit+ (2012PASP..124..714M). The Spitzer IRAC data are complemented by ground-based NIR observations from the VISTA Deep Extragalactic Observations (VIDEO; Jarvis+ 2013MNRAS.428.1281J) survey in the south in the Z, Y, J, H, and Ks bands and UKIRT Infrared Deep Sky Survey (UKIDSS; Lawrence+ 2007, see II/319) in the north in the J and K bands. SERVS also provides substantial overlap with infrared data from SWIRE (Lonsdale+ 2003PASP..115..897L) and the Herschel Multitiered Extragalactic Survey (HerMES; Oliver+ 2012, VIII/95). As shown in Figure 1, one square degree of the XMM-LSS field overlaps with ground-based optical data from the Canada-France-Hawaii Telescope Legacy Survey Deep field 1 (CFHTLS-D1). The CFHTLS-D1 region is centered at RAJ2000=02:25:59, DEJ2000=-04:29:40 and includes imaging through the filter set u', g', r', i', and z'. Thus, in combination with the NIR data from SERVS and VIDEO that overlap with the CFHTLS-D1 region, multi-band imaging over a total of 12 bands is available. (2 data files).

Quantification of Optical and Physical Properties of Combustion-Generated Carbonaceous Aerosols (

PubMed Central

Perera, Inoka Eranda; Litton, Charles D.

2016-01-01

A series of experiments were conducted to quantify and characterize the optical and physical properties of combustion-generated aerosols during both flaming and smoldering combustion of three materials common to underground mines—Pittsburgh Seam coal, Styrene Butadiene Rubber (a common mine conveyor belt material), and Douglas-fir wood—using a combination of analytical and gravimetric measurements. Laser photometers were utilized in the experiments for continuous measurement of aerosol mass concentrations and for comparison to measurements made using gravimetric filter samples. The aerosols of interest lie in the size range of tens to a few hundred nanometers, out of range of the standard photometer calibration. To correct for these uncertainties, the photometer mass concentrations were compared to gravimetric samples to determine if consistent correlations existed. The response of a calibrated and modified combination ionization/photoelectric smoke detector was also used. In addition, the responses of this sensor and a similar, prototype ionization/photoelectric sensor, along with discrete angular scattering, total scattering, and total extinction measurements, were used to define in real time the size, morphology, and radiative transfer properties of these differing aerosols that are generally in the form of fractal aggregates. SEM/TEM images were also obtained in order to compare qualitatively the real-time, continuous experimental measurements with the visual microscopic measurements. These data clearly show that significant differences exist between aerosols from flaming and from smoldering combustion and that these differences produce very different scattering and absorption signatures. The data also indicate that ionization/photoelectric sensors can be utilized to measure continuously and in real time aerosol properties over a broad spectrum of applications related to adverse environmental and health effects. PMID:27546898

Quantification of Optical and Physical Properties of Combustion-Generated Carbonaceous Aerosols (

PubMed

Perera, Inoka Eranda; Litton, Charles D

2015-03-01

A series of experiments were conducted to quantify and characterize the optical and physical properties of combustion-generated aerosols during both flaming and smoldering combustion of three materials common to underground mines-Pittsburgh Seam coal, Styrene Butadiene Rubber (a common mine conveyor belt material), and Douglas-fir wood-using a combination of analytical and gravimetric measurements. Laser photometers were utilized in the experiments for continuous measurement of aerosol mass concentrations and for comparison to measurements made using gravimetric filter samples. The aerosols of interest lie in the size range of tens to a few hundred nanometers, out of range of the standard photometer calibration. To correct for these uncertainties, the photometer mass concentrations were compared to gravimetric samples to determine if consistent correlations existed. The response of a calibrated and modified combination ionization/photoelectric smoke detector was also used. In addition, the responses of this sensor and a similar, prototype ionization/photoelectric sensor, along with discrete angular scattering, total scattering, and total extinction measurements, were used to define in real time the size, morphology, and radiative transfer properties of these differing aerosols that are generally in the form of fractal aggregates. SEM/TEM images were also obtained in order to compare qualitatively the real-time, continuous experimental measurements with the visual microscopic measurements. These data clearly show that significant differences exist between aerosols from flaming and from smoldering combustion and that these differences produce very different scattering and absorption signatures. The data also indicate that ionization/photoelectric sensors can be utilized to measure continuously and in real time aerosol properties over a broad spectrum of applications related to adverse environmental and health effects.

TIMED solar EUV experiment: preflight calibration results for the XUV photometer system

NASA Astrophysics Data System (ADS)

Woods, Thomas N.; Rodgers, Erica M.; Bailey, Scott M.; Eparvier, Francis G.; Ucker, Gregory J.

1999-10-01

The Solar EUV Experiment (SEE) on the NASA Thermosphere, Ionosphere, and Mesosphere Energetics and Dynamics (TIMED) mission will measure the solar vacuum ultraviolet (VUV) spectral irradiance from 0.1 to 200 nm. To cover this wide spectral range two different types of instruments are used: a grating spectrograph for spectra between 25 and 200 nm with a spectral resolution of 0.4 nm and a set of silicon soft x-ray (XUV) photodiodes with thin film filters as broadband photometers between 0.1 and 35 nm with individual bandpasses of about 5 nm. The grating spectrograph is called the EUV Grating Spectrograph (EGS), and it consists of a normal- incidence, concave diffraction grating used in a Rowland spectrograph configuration with a 64 X 1024 array CODACON detector. The primary calibrations for the EGS are done using the National Institute for Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF-III) in Gaithersburg, Maryland. In addition, detector sensitivity and image quality, the grating scattered light, the grating higher order contributions, and the sun sensor field of view are characterized in the LASP calibration laboratory. The XUV photodiodes are called the XUV Photometer System (XPS), and the XPS includes 12 photodiodes with thin film filters deposited directly on the silicon photodiodes' top surface. The sensitivities of the XUV photodiodes are calibrated at both the NIST SURF-III and the Physikalisch-Technische Bundesanstalt (PTB) electron storage ring called BESSY. The other XPS calibrations, namely the electronics linearity and field of view maps, are performed in the LASP calibration laboratory. The XPS and solar sensor pre-flight calibration results are primarily discussed as the EGS calibrations at SURF-III have not yet been performed.

Passband switchable microwave photonic multiband filter

PubMed Central

Ge, Jia; Fok, Mable P.

2015-01-01

A reconfigurable microwave photonic (MWP) multiband filter with selectable and switchable passbands is proposed and experimentally demonstrated, with a maximum of 12 simultaneous passbands evenly distributed from 0 to 10 GHz. The scheme is based on the generation of tunable optical comb lines using a two-stage Lyot loop filter, such that various filter tap spacings and spectral combinations are obtained for the configuration of the MWP filter. Through polarization state adjustment inside the Lyot loop filter, an optical frequency comb with 12 different comb spacings is achieved, which corresponds to a MWP filter with 12 selectable passbands. Center frequencies of the filter passbands are switchable, while the number of simultaneous passbands is tunable from 1 to 12. Furthermore, the MWP multiband filter can either work as an all-block, single-band or multiband filter with various passband combinations, which provide exceptional operation flexibility. All the passbands have over 30 dB sidelobe suppression and 3-dB bandwidth of 200 MHz, providing good filter selectivity. PMID:26521693

Passband switchable microwave photonic multiband filter.

PubMed

Ge, Jia; Fok, Mable P

2015-11-02

A reconfigurable microwave photonic (MWP) multiband filter with selectable and switchable passbands is proposed and experimentally demonstrated, with a maximum of 12 simultaneous passbands evenly distributed from 0 to 10 GHz. The scheme is based on the generation of tunable optical comb lines using a two-stage Lyot loop filter, such that various filter tap spacings and spectral combinations are obtained for the configuration of the MWP filter. Through polarization state adjustment inside the Lyot loop filter, an optical frequency comb with 12 different comb spacings is achieved, which corresponds to a MWP filter with 12 selectable passbands. Center frequencies of the filter passbands are switchable, while the number of simultaneous passbands is tunable from 1 to 12. Furthermore, the MWP multiband filter can either work as an all-block, single-band or multiband filter with various passband combinations, which provide exceptional operation flexibility. All the passbands have over 30 dB sidelobe suppression and 3-dB bandwidth of 200 MHz, providing good filter selectivity.

LITES and GROUP-C Mission Update: Ionosphere and Thermosphere Sensing from the ISS

NASA Astrophysics Data System (ADS)

Stephan, A. W.; Budzien, S. A.; Chakrabarti, S.; Hysell, D. L.; Powell, S. P.; Finn, S. C.; Cook, T.; Bishop, R. L.

2016-12-01

The Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) and GPS Radio Occultation and Ultraviolet Photometer Co-located (GROUP-C) experiments are scheduled for launch to the International Space Station (ISS) in November 2016 as part of the Space Test Program Houston #5 payload (STP-H5). The two experiments provide technical development and risk-reduction for future space weather sensors suitable for ionospheric specification, space situational awareness, and data products for global ionosphere assimilative models. The combined instrument suite of these experiments offers a unique capability to study spatial and temporal variability of the thermosphere and ionosphere using multi-sensor and tomographic approaches. LITES is an imaging spectrograph that spans 60-140 nm and continuously acquires limb profiles of the ionosphere and thermosphere from 150-350 km altitude. GROUP-C includes a high-sensitivity far-ultraviolet photometer measuring horizontal ionospheric gradients and an advanced GPS receiver providing ionospheric electron density profiles and scintillation measurements. High-cadence limb images and nadir photometry from GROUP-C/LITES are combined to tomographically reconstruct high-fidelity two-dimensional volume emission rates within the ISS orbital plane. The GPS occultation receiver provides independent measurements to calibrate and validate advanced daytime ionospheric algorithms and nighttime tomography. The vantage from the ISS on the lower portion of the thermosphere and ionosphere will yield measurements complementary to the NASA GOLD and ICON missions which are expected to fly during the STP-H5 mission. We present a mission status update and available early orbit observations, and the opportunities for using these new data to help address questions regarding the complex and dynamic features of the low and middle latitude ionosphere-thermosphere system that have important implications for operational systems.

Characteristics of an aerosol photometer while automatically controlling chamber dilution-air flow rate.

PubMed

O'Shaughnessy, P T; Hemenway, D R

2000-10-01

Trials were conducted to determine those factors that affect the accuracy of a direct-reading aerosol photometer when automatically controlling airflow rate within an exposure chamber to regulate airborne dust concentrations. Photometer response was affected by a shift in the aerosol size distribution caused by changes in chamber flow rate. In addition to a dilution effect, flow rate also determined the relative amount of aerosol lost to sedimentation within the chamber. Additional calculations were added to a computer control algorithm to compensate for these effects when attempting to automatically regulate flow based on a proportional-integral-derivative (PID) feedback control algorithm. A comparison between PID-controlled trials and those performed with a constant generator output rate and dilution-air flow rate demonstrated that there was no significant decrease in photometer accuracy despite the many changes in flow rate produced when using PID control. Likewise, the PID-controlled trials produced chamber aerosol concentrations within 1% of a desired level.

Input-output Transfer Function Analysis of a Photometer Circuit Based on an Operational Amplifier.

PubMed

Hernandez, Wilmar

2008-01-09

In this paper an input-output transfer function analysis based on the frequencyresponse of a photometer circuit based on operational amplifier (op amp) is carried out. Opamps are universally used in monitoring photodetectors and there are a variety of amplifierconnections for this purpose. However, the electronic circuits that are usually used to carryout the signal treatment in photometer circuits introduce some limitations in theperformance of the photometers that influence the selection of the op amps and otherelectronic devices. For example, the bandwidth, slew-rate, noise, input impedance and gain,among other characteristics of the op amp, are often the performance limiting factors ofphotometer circuits. For this reason, in this paper a comparative analysis between twophotodiode amplifier circuits is carried out. One circuit is based on a conventional currentto-voltage converter connection and the other circuit is based on a robust current-to-voltageconverter connection. The results are satisfactory and show that the photodiode amplifierperformance can be improved by using robust control techniques.

Multiband Photonic Phased-Array Antenna

NASA Technical Reports Server (NTRS)

Tang, Suning

2015-01-01

A multiband phased-array antenna (PAA) can reduce the number of antennas on shipboard platforms while offering significantly improved performance. Crystal Research, Inc., has developed a multiband photonic antenna that is based on a high-speed, optical, true-time-delay beamformer. It is capable of simultaneously steering multiple independent radio frequency (RF) beams in less than 1,000 nanoseconds. This high steering speed is 3 orders of magnitude faster than any existing optical beamformer. Unlike other approaches, this technology uses a single controlling device per operation band, eliminating the need for massive optical switches, laser diodes, and fiber Bragg gratings. More importantly, only one beamformer is needed for all antenna elements.

Multi-band phase shifter design using modified slotline configuration

NASA Astrophysics Data System (ADS)

Kulandhaisamy, Indhumathi; Rajendran, Dinesh Babu; Kanagasabai, Malathi; Gurusamy, Gunasekaran; Moorthy, Balaji; George, Jithila V.; Lawrance, Livya

2017-01-01

In this paper, an analog multiband phase shifter using slotline configuration is proposed. To implement the design, a pair of modified Split Ring Resonator (SRR) is employed. The periodic property of SRR provides multiband characteristics, whether the coupling slot gives the phase variations over the bands. The operation is well explained with an equivalent circuit model and its characteristics have been studied both in simulation and measurement. The prototype operates in 1.77-2.16, 3.5-3.97, 5.08-5.33, 6.43-6.93, and 8.01-8.59 GHz frequency bands which can be utilized for GSM, GPS, WLAN, C-band, and X-band applications, respectively.

Multiangle Imaging Spectroradiometer (MISR) Global Aerosol Optical Depth Validation Based on 2 Years of Coincident Aerosol Robotic Network (AERONET) Observations

NASA Technical Reports Server (NTRS)

Kahn, Ralph A.; Gaitley, Barbara J.; Martonchik, John V.; Diner, David J.; Crean, Kathleen A.; Holben, Brent

2005-01-01

Performance of the Multiangle Imaging Spectroradiometer (MISR) early postlaunch aerosol optical thickness (AOT) retrieval algorithm is assessed quantitatively over land and ocean by comparison with a 2-year measurement record of globally distributed AERONET Sun photometers. There are sufficient coincident observations to stratify the data set by season and expected aerosol type. In addition to reporting uncertainty envelopes, we identify trends and outliers, and investigate their likely causes, with the aim of refining algorithm performance. Overall, about 2/3 of the MISR-retrieved AOT values fall within [0.05 or 20% x AOT] of Aerosol Robotic Network (AERONET). More than a third are within [0.03 or 10% x AOT]. Correlation coefficients are highest for maritime stations (approx.0.9), and lowest for dusty sites (more than approx.0.7). Retrieved spectral slopes closely match Sun photometer values for Biomass burning and continental aerosol types. Detailed comparisons suggest that adding to the algorithm climatology more absorbing spherical particles, more realistic dust analogs, and a richer selection of multimodal aerosol mixtures would reduce the remaining discrepancies for MISR retrievals over land; in addition, refining instrument low-light-level calibration could reduce or eliminate a small but systematic offset in maritime AOT values. On the basis of cases for which current particle models are representative, a second-generation MISR aerosol retrieval algorithm incorporating these improvements could provide AOT accuracy unprecedented for a spaceborne technique.

Aerosol Optical Depth Determinations for BOREAS

NASA Technical Reports Server (NTRS)

Wrigley, R. C.; Livingston, J. M.; Russell, P. B.; Guzman, R. P.; Ried, D.; Lobitz, B.; Peterson, David L. (Technical Monitor)

1994-01-01

Automated tracking sun photometers were deployed by NASA/Ames Research Center aboard the NASA C-130 aircraft and at a ground site for all three Intensive Field Campaigns (IFCs) of the Boreal Ecosystem-Atmosphere Study (BOREAS) in central Saskatchewan, Canada during the summer of 1994. The sun photometer data were used to derive aerosol optical depths for the total atmospheric column above each instrument. The airborne tracking sun photometer obtained data in both the southern and northern study areas at the surface prior to takeoff, along low altitude runs near the ground tracking sun photometer, during ascents to 6-8 km msl, along remote sensing flightlines at altitude, during descents to the surface, and at the surface after landing. The ground sun photometer obtained data from the shore of Candle Lake in the southern area for all cloud-free times. During the first IFC in May-June ascents and descents of the airborne tracking sun photometer indicated the aerosol optical depths decreased steadily from the surface to 3.5 kni where they leveled out at approximately 0.05 (at 525 nm), well below levels caused by the eruption of Mt. Pinatubo. On a very clear day, May 31st, surface optical depths measured by either the airborne or ground sun photometers approached those levels (0.06-0.08 at 525 nm), but surface optical depths were often several times higher. On June 4th they increased from 0.12 in the morning to 0.20 in the afternoon with some evidence of brief episodes of pollen bursts. During the second IFC surface aerosol optical depths were variable in the extreme due to smoke from western forest fires. On July 20th the aerosol optical depth at 525 nm decreased from 0.5 in the morning to 0.2 in the afternoon; they decreased still further the next day to 0.05 and remained consistently low throughout the day to provide excellent conditions for several remote sensing missions flown that day. Smoke was heavy for the early morning of July 24th but cleared partially by 10:30 local time and cleared fully by 11:30. Heavy smoke characterized the rest of the IFC in both study areas.

ASTER's First Views of Red Sea, Ethiopia - Thermal-Infrared (TIR) Image (monochrome)

NASA Technical Reports Server (NTRS)

2000-01-01

ASTER succeeded in acquiring this image at night, which is something Visible/Near Infrared VNIR) and Shortwave Infrared (SWIR) sensors cannot do. The scene covers the Red Sea coastline to an inland area of Ethiopia. White pixels represent areas with higher temperature material on the surface, while dark pixels indicate lower temperatures. This image shows ASTER's ability as a highly sensitive, temperature-discerning instrument and the first spaceborne TIR multi-band sensor in history.

The size of image: 60 km x 60 km approx., ground resolution 90 m x 90 m approximately.

The ASTER instrument was built in Japan for the Ministry of International Trade and Industry. A joint United States/Japan Science Team is responsible for instrument design, calibration, and data validation. ASTER is flying on the Terra satellite, which is managed by NASA's Goddard Space Flight Center, Greenbelt, MD.

A software reconfigurable optical multiband UWB system utilizing a bit-loading combined with adaptive LDPC code rate scheme

NASA Astrophysics Data System (ADS)

He, Jing; Dai, Min; Chen, Qinghui; Deng, Rui; Xiang, Changqing; Chen, Lin

2017-07-01

In this paper, an effective bit-loading combined with adaptive LDPC code rate algorithm is proposed and investigated in software reconfigurable multiband UWB over fiber system. To compensate the power fading and chromatic dispersion for the high frequency of multiband OFDM UWB signal transmission over standard single mode fiber (SSMF), a Mach-Zehnder modulator (MZM) with negative chirp parameter is utilized. In addition, the negative power penalty of -1 dB for 128 QAM multiband OFDM UWB signal are measured at the hard-decision forward error correction (HD-FEC) limitation of 3.8 × 10-3 after 50 km SSMF transmission. The experimental results show that, compared to the fixed coding scheme with the code rate of 75%, the signal-to-noise (SNR) is improved by 2.79 dB for 128 QAM multiband OFDM UWB system after 100 km SSMF transmission using ALCR algorithm. Moreover, by employing bit-loading combined with ALCR algorithm, the bit error rate (BER) performance of system can be further promoted effectively. The simulation results present that, at the HD-FEC limitation, the value of Q factor is improved by 3.93 dB at the SNR of 19.5 dB over 100 km SSMF transmission, compared to the fixed modulation with uncoded scheme at the same spectrum efficiency (SE).

Photometer for detection of sodium day airglow.

NASA Technical Reports Server (NTRS)

Mcmahon, D. J.; Manring, E. R.; Patty, R. R.

1973-01-01

Description of a photometer for daytime ground-based measurements of sodium airglow emission. The photometer described can be characterized by the following principal features: (1) a narrow (4.5-A) interference filter for initial discrimination; (2) cooled photomultiplier detector to reduce noise from dark current fluctuations and chopping to eliminate the average dark current; (3) a sodium vapor resonance cell to provide an effective bandpass comparable to the Doppler line width; (4) separate detection of all light transmitted by the interference filter to evaluate the Rayleigh and Mie components within the Doppler width of the resonance cell; and (5) temperature quenching of the resonance cell to evaluate and account for instrumental imperfections.

Diethylenetriaminepentaacetic acid-gadolinium (DTPA-Gd)-conjugated polysuccinimide derivatives as magnetic resonance imaging contrast agents.

PubMed

Lee, Ha Young; Jee, Hye Won; Seo, Sung Mi; Kwak, Byung Kook; Khang, Gilson; Cho, Sun Hang

2006-01-01

Biocompatible polysuccinimide (PSI) derivatives conjugated with diethylenetriaminepentaacetic acid gadolinium (DTPA-Gd) were prepared as magnetic resonance imaging (MRI) contrast agents. In this study, we synthesized PSI derivatives incorporating methoxy-poly(ethylene glycol) (mPEG) as hydrophilic ligand, hexadecylamine as hydrophobic ligand, and DTPA-Gd as contrast agent. PSI was synthesized by the polycondensation polymerization of aspartic acid. All the synthesized materials were characterized by proton nuclear magnetic resonance (1H NMR). Critical micellization concentrations were determined using fluorescent probes (pyrene). Micelle size and shape were measured by electro-photometer light scattering (ELS) and atomic force microscopy (AFM). The formed micelle size ranged from 100 to 300 nm. The T1-weighted MR images of the phantom prepared with PSI-mPEG-C16-(DTPA-Gd) were obtained in a 3.0 T clinical MR imager, and the conjugates showed a great potential as MRI contrast agents.

Microparticle analysis system and method

NASA Technical Reports Server (NTRS)

Morrison, Dennis R. (Inventor)

2007-01-01

A device for analyzing microparticles is provided which includes a chamber with an inlet and an outlet for respectively introducing and dispensing a flowing fluid comprising microparticles, a light source for providing light through the chamber and a photometer for measuring the intensity of light transmitted through individual microparticles. The device further includes an imaging system for acquiring images of the fluid. In some cases, the device may be configured to identify and determine a quantity of the microparticles within the fluid. Consequently, a method for identifying and tracking microparticles in motion is contemplated herein. The method involves flowing a fluid comprising microparticles in laminar motion through a chamber, transmitting light through the fluid, measuring the intensities of the light transmitted through the microparticles, imaging the fluid a plurality of times and comparing at least some of the intensities of light between different images of the fluid.

Ten-color Gegenschein-zodiacal light photometer. [onboard Skylab

NASA Technical Reports Server (NTRS)

Sparrow, J. G.; Weinberg, J. L.; Hahn, R. C.

1977-01-01

A ten-color Fabry photometer was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, F region airglow, and spacecraft corona. A brief description is given of the design, calibration, and performance of the instrument.

Sensitive Small Area Photometer

ERIC Educational Resources Information Center

Levenson, M. D.

1970-01-01

Describes a simple photometer capable of measuring small light intensities over small areas. The inexpensive, easy-to- construct instrument is intended for use in a student laboratory to measure the light intensities in a diffraction experiment from single or multiple slits. Typical experimental results are presented along with the theoretical…

LARSPEC spectroradiometer-multiband radiometer data formats

NASA Technical Reports Server (NTRS)

Biehl, L. L.

1982-01-01

The data base software system, LARSPEC, is discussed and the data base format for agronomic, meteorological, spectroradiometer, and multiband radiometer data is described. In addition, the contents and formats of each record of data and the wavelength tables are listed and the codes used for some of the parameters are described.

Multi-band gap and new solar cell options workshop

NASA Technical Reports Server (NTRS)

Hutchby, J.; Timmons, M.; Olson, J. M.

1993-01-01

Discussions of the multi-band gap (MBG) and new solar cell options workshop are presented. Topics discussed include: greater than 2 terminal cells; radiation damage preventing development of MBG cells for space; lattice matching; measurement of true performance; future of II-VI materials in MBG devices; and quaternaries.

Evaluation of AirMSPI photopolarimetric retrievals of smoke properties with in-situ observations collected during the ImPACT-PM field campaign

NASA Astrophysics Data System (ADS)

Kalashnikova, O. V.; Garay, M. J.; Xu, F.; Seidel, F.; Diner, D. J.; Seinfeld, J.; Bates, K. H.; Kong, W.; Kenseth, C.; Cappa, C. D.

2017-12-01

We introduce and evaluate an approach for obtaining closure between in situ and polarimetric remote sensing observations of smoke properties obtained during the collocated CIRPAS Twin Otter and ER-2 aircraft measurements of the Lebec fire event on July 8, 2016. We investigate the utility of multi-angle, spectropolarimetric remote sensing imagery to evaluate the relative contribution of organics, non-organic and black carbon particles to smoke particulate composition. The remote sensing data were collected during the Imaging Polarimetric and Characterization of Tropospheric Particular Matter (ImPACT-PM) field campaign by the Airborne Multiangle SpectroPolarimetric Imager (AirMSPI), which flew on NASA's high-altitude ER-2 aircraft. The ImPACT-PM field campaign was a joint JPL/Caltech effort to combine measurements from the Terra Multi-angle Imaging SpectroRadiometer (MISR), AirMSPI, in situ airborne measurements, and a chemical transport model to validate remote sensing retrievals of different types of airborne particulate matter with a particular emphasis on carbonaceous aerosols. The in-situ aerosol data were collected with a suite of Caltech instruments on board the CIRPAS Twin Otter aircraft and included the Aerosol Mass Spectrometer (AMS), the Differential Mobility Analyzer (DMA), and the Single Particle Soot Photometer (SP-2). The CIRPAS Twin Otter aircraft was also equipped with the Particle Soot Absorption Photometer (PSAP), nephelometer, a particle counter, and meteorological sensors. We found that the multi-angle polarimetric observations are capable of fire particulate emission monitoring by particle type as inferred from the in-situ airborne measurements. Modeling of retrieval sensitivities show that the characterization of black carbon is the most challenging. The work aims at evaluating multi-angle, spectropolarimetric capabilities for particulate matter characterization in support of the Multi-Angle Imager for Aerosols (MAIA) satellite investigation, which is currently in development under NASA's third Earth Venture Instrument Program.

Filter type rotor for multistation photometer

DOEpatents

Shumate, II, Starling E.

1977-07-12

A filter type rotor for a multistation photometer is provided. The rotor design combines the principle of cross-flow filtration with centrifugal sedimentation so that these occur simultaneously as a first stage of processing for suspension type fluids in an analytical type instrument. The rotor is particularly useful in whole-blood analysis.

21 CFR 862.2300 - Colorimeter, photometer, or spectrophotometer for clinical use.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Colorimeter, photometer, or spectrophotometer for clinical use. 862.2300 Section 862.2300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES...

21 CFR 862.2300 - Colorimeter, photometer, or spectrophotometer for clinical use.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Colorimeter, photometer, or spectrophotometer for clinical use. 862.2300 Section 862.2300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES...

21 CFR 862.2300 - Colorimeter, photometer, or spectrophotometer for clinical use.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Colorimeter, photometer, or spectrophotometer for clinical use. 862.2300 Section 862.2300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES...

A Hybrid Algorithm for Period Analysis from Multiband Data with Sparse and Irregular Sampling for Arbitrary Light-curve Shapes

NASA Astrophysics Data System (ADS)

Saha, Abhijit; Vivas, A. Katherina

2017-12-01

Ongoing and future surveys with repeat imaging in multiple bands are producing (or will produce) time-spaced measurements of brightness, resulting in the identification of large numbers of variable sources in the sky. A large fraction of these are periodic variables: compilations of these are of scientific interest for a variety of purposes. Unavoidably, the data sets from many such surveys not only have sparse sampling, but also have embedded frequencies in the observing cadence that beat against the natural periodicities of any object under investigation. Such limitations can make period determination ambiguous and uncertain. For multiband data sets with asynchronous measurements in multiple passbands, we wish to maximally use the information on periodicity in a manner that is agnostic of differences in the light-curve shapes across the different channels. Given large volumes of data, computational efficiency is also at a premium. This paper develops and presents a computationally economic method for determining periodicity that combines the results from two different classes of period-determination algorithms. The underlying principles are illustrated through examples. The effectiveness of this approach for combining asynchronously sampled measurements in multiple observables that share an underlying fundamental frequency is also demonstrated.

Multiband Study of Radio Sources of the Rcr Catalogue with Virtual Observatory Tools

NASA Astrophysics Data System (ADS)

Zhelenkova, O. P.; Soboleva, N. S.; Majorova, E. K.; Temirova, A. V.

We present early results of our multiband study of the RATAN Cold Revised (RCR) catalogue obtained from seven cycles of the ``Cold'' survey carried with the RATAN-600 radio telescope at 7.6 cm in 1980--1999, at the declination of the SS 433 source. We used the 2MASS and LAS UKIDSS infrared surveys, the DSS-II and SDSS DR7 optical surveys, as well as the USNO-B1 and GSC-II catalogues, the VLSS, TXS, NVSS, FIRST and GB6 radio surveys to accumulate information about the sources. For radio sources that have no detectable optical candidate in optical or infrared catalogues, we additionally looked through images in several bands from the SDSS, LAS UKIDSS, DPOSS, 2MASS surveys and also used co-added frames in different bands. We reliably identified 76% of radio sources of the RCR catalogue. We used the ALADIN and SAOImage DS9 scripting capabilities, interoperability services of ALADIN and TOPCAT, and also other Virtual Observatory (VO) tools and resources, such as CASJobs, NED, Vizier, and WSA, for effective data access, visualization and analysis. Without VO tools it would have been problematic to perform our study.

Independent polarization and multi-band THz absorber base on Jerusalem cross

NASA Astrophysics Data System (ADS)

Arezoomand, Afsaneh Saee; Zarrabi, Ferdows B.; Heydari, Samaneh; Gandji, Navid P.

2015-10-01

In this paper, we present the design and simulation of a single and multi-band perfect metamaterial absorber (MA) in the THz region base on Jerusalem cross (JC) and metamaterial load in unit cells. The structures consist of dual metallic layers for allowing near-perfect absorption with absorption peak of more than 99%. In this novel design, four-different shape of Jerusalem cross is presented and by adding L, U and W shape loaded to first structure, we tried to achieve a dual-band absorber. In addition, by good implementation of these loaded, we are able to control the absorption resonance at second resonance at 0.9, 0.7 and 0.85 THz respectively. In the other hand, we achieved a semi stable designing at first resonance between 0.53 and 0.58 THz. The proposed absorber has broadband polarization angle. The surface current modeled and proved the broadband polarization angle at prototype MA. The LC resonance of the metamaterial for Jerusalem cross and modified structures are extracting from equivalent circuit. As a result, proposed MA is useful for THz medical imaging and communication systems and the dual-band absorber has applications in many scientific and technological areas.

Sentinel-2: State of the Image Quality Calibration at the End of the Commissioning

NASA Astrophysics Data System (ADS)

Tremas, Thierry; Lonjou, Vincent; Lacherade, Sophie; Gaudel-Vacaresse, Angelique; Languille, Florie

2016-08-01

This article summarizes the activity of CNES during the In Orbit Calibration Phase of Sentinel 2A as well as the transfer of production of GIPP (Ground Image Processing Parameters) from CNES to ESRIN. The state of the main calibration parameters and performances, few months before PDGS is declared fully operational, are listed and explained.In radiometry a special attention is paid to the absolute calibration using the on-board diffuser, and the vicarious calibration methods using instrumented or statistically well characterized sites and inter- comparisons with other sensors. Regarding geometry, the presentation focuses on the performances of absolute location with and without reference points. The requirements of multi-band and multi-temporal registration are exposed. Finally, the construction and the rule of the GRI (Ground Reference Images) in the future are explained.

VizieR Online Data Catalog: GLASS. VI. MCS J0416.1-2403 HFF imaging & spectra (Hoag+, 2016)

NASA Astrophysics Data System (ADS)

Hoag, A.; Huang, K.-H.; Treu, T.; Bradac, M.; Schmidt, K. B.; Wang, X.; Brammer, G. B.; Broussard, A.; Amorin, R.; Castellano, M.; Fontana, A.; Merlin, E.; Schrabback, T.; Trenti, M.; Vulcani, B.

2017-02-01

The Grism Lens-Amplified Survey from Space (GLASS; GO-13459, PI: Treu; Schmidt+ 2014ApJ...782L..36S; Treu+ 2015, J/ApJ/812/114) observed 10 massive galaxy clusters with the HST WFC3-IR G102 and G141 grism between 2013 December and 2015 January. Each of the clusters targeted by GLASS has deep multi-band HST imaging from the Hubble Frontier Fields (HFF) in 2014 September and/or from CLASH (ESO VIMOS large program CLASH-VLT; 186.A-0798; PI: P. Rosati; Balestra+, 2016, J/ApJS/224/33). We also use mid-IR imaging data acquired with the IRAC on board the Spitzer Space Telescope obtained by the DDT program #90258 (PI: Soifer; P. Capak+ 2016, in prep.) and #80168 (PI: Bouwens). (2 data files).

Multistage, multiseasonal and multiband imagery to identify and qualify non-forest vegetation resources

NASA Technical Reports Server (NTRS)

Driscoll, R. S.; Francis, R. E.

1970-01-01

A description of space and supporting aircraft photography for the interpretation and analyses of non-forest (shrubby and herbaceous) native vegetation is presented. The research includes the development of a multiple sampling technique to assign quantitative area values of specific plant community types included within an assigned space photograph map unit. Also, investigations of aerial film type, scale, and season of photography for identification and quantity measures of shrubby and herbaceous vegetation were conducted. Some work was done to develop automated interpretation techniques with film image density measurement devices.

Detection and mapping of volcanic rock assemblages and associated hydrothermal alteration with Thermal Infrared Multiband Scanner (TIMS) data Comstock Lode Mining District, Virginia City, Nevada

NASA Technical Reports Server (NTRS)

Taranik, James V.; Hutsinpiller, Amy; Borengasser, Marcus

1986-01-01

Thermal Infrared Multispectral Scanner (TIMS) data were acquired over the Virginia City area on September 12, 1984. The data were acquired at approximately 1130 hours local time (1723 IRIG). The TIMS data were analyzed using both photointerpretation and digital processing techniques. Karhuen-Loeve transformations were utilized to display variations in radiant spectral emittance. The TIMS image data were compared with color infrared metric camera photography, LANDSAT Thematic Mapper (TM) data, and key areas were photographed in the field.

Parallel LC circuit model for multi-band absorption and preliminary design of radiative cooling.

PubMed

Feng, Rui; Qiu, Jun; Liu, Linhua; Ding, Weiqiang; Chen, Lixue

2014-12-15

We perform a comprehensive analysis of multi-band absorption by exciting magnetic polaritons in the infrared region. According to the independent properties of the magnetic polaritons, we propose a parallel inductance and capacitance(PLC) circuit model to explain and predict the multi-band resonant absorption peaks, which is fully validated by using the multi-sized structure with identical dielectric spacing layer and the multilayer structure with the same strip width. More importantly, we present the application of the PLC circuit model to preliminarily design a radiative cooling structure realized by merging several close peaks together. This omnidirectional and polarization insensitive structure is a good candidate for radiative cooling application.

Tunable multiband plasmonic response of indium antimonide touching microrings in the terahertz range.

PubMed

Moridsadat, Maryam; Golmohammadi, Saeed; Baghban, Hamed

2018-06-01

In this paper, we propose a terahertz (THz) plasmonic structure that supports three resonance modes, including the charge transfer plasmon (CTP), the bonding dipole-dipole plasmon, and the antibonding dipole-dipole plasmon, which can be strongly tuned by geometrical parameters, passively, and the temperature, actively. The structure exhibits a considerable thermal sensitivity of more than 0.01 THz/K. The introduced multiband and tunable THz plasmonic structures offer important applications in thermal switches, thermo-optical modulators, broadband filters, design of multifunctional molecules originating from the multiband specification of the proposed structure, and improvement in plasmonic sensor applications stemming from a detailed study of the CTP mode.

Geocoronal imaging with Dynamics Explorer

NASA Technical Reports Server (NTRS)

Rairden, R. L.; Frank, L. A.; Craven, J. D.

1986-01-01

The ultraviolet photometer of the University of Iowa spin-scan auroral imaging instrumentation on board Dynamics Explorer-1 has returned numerous hydrogen Lyman alpha images of the geocorona from altitudes of 570 km to 23,300 km (1.09 R sub E to 4.66 R sub E geocentric radial distance). The hydrogen density gradient is shown by a plot of the zenith intensities throughout this range, which decrease to near celestial background values as the spacecraft approaches apogee. Characterizing the upper geocorona as optically thin (single-scattering), the zenith intensity is converted directly to vertical column density. This approximation loses its validity deeper in the geocorona, where the hydrogen is demonstrated to be optically thick in that there is no Lyman alpha limb brightening. Further study of the geocoronal hydrogen distribution will require computer modeling of the radiative transfer.

A spectrographic study of the aurora and the relation to solar wind pressure pulses.

NASA Astrophysics Data System (ADS)

Stockton-Chalk, A. B.; Lanchester, B. S.; Ivchenko, N.; Lummerzheim, D.; Throp, K.

SIF (Spectrographic Imaging Facility) is a Southampton University / University College London collaboration. The platform consists of a High Throughput Imaging Echelle Spectrograph, HiTIES, two photometers and a narrow angle auroral imager. The spectrograph has a mosaic filter; each of the three spectral panels are centred over/near important spectral features: Hbeta (486.1nm), N2+(470.9nm), N2+(465.2nm), thus allowing studies of proton and electron aurorae. The platform has been successfully deployed in Svalbard since November 1999. The purpose of the experiment was to take spectrographic measurements to study the relationship between proton and electron precipitation and to understand the nature of the precipitating spectrum of protons, both in energy and angular distributions. We present a study of the aurora observed in relation to solar wind pressure pulses.

Tunable multi-band absorption in metasurface of graphene ribbons based on composite structure

NASA Astrophysics Data System (ADS)

Ning, Renxia; Jiao, Zheng; Bao, Jie

2017-05-01

A tunable multiband absorption based on a graphene metasurface of composite structure at mid-infrared frequency was investigated by the finite difference time domain method. The composite structure were composed of graphene ribbons and a gold-MgF2 layer which was sandwiched in between two dielectric slabs. The permittivity of graphene is discussed with different chemical potential to obtain tunable absorption. And the absorption of the composite structure can be tuned by the chemical potential of graphene at certain frequencies. The impedance matching was used to study the perfect absorption of the structure in our paper. The results show that multi-band absorption can be obtained and some absorption peaks of the composite structure can be tuned through the changing not only of the width of graphene ribbons and gaps, but also the dielectric and the chemical potential of graphene. However, another peak was hardly changed by parameters due to a different resonant mechanism in proposed structure. This flexibily tunable multiband absorption may be applied to optical communications such as optical absorbers, mid infrared stealth devices and filters.

Advanced imaging research and development at DARPA

NASA Astrophysics Data System (ADS)

Dhar, Nibir K.; Dat, Ravi

2012-06-01

Advances in imaging technology have huge impact on our daily lives. Innovations in optics, focal plane arrays (FPA), microelectronics and computation have revolutionized camera design. As a result, new approaches to camera design and low cost manufacturing is now possible. These advances are clearly evident in visible wavelength band due to pixel scaling, improvements in silicon material and CMOS technology. CMOS cameras are available in cell phones and many other consumer products. Advances in infrared imaging technology have been slow due to market volume and many technological barriers in detector materials, optics and fundamental limits imposed by the scaling laws of optics. There is of course much room for improvements in both, visible and infrared imaging technology. This paper highlights various technology development projects at DARPA to advance the imaging technology for both, visible and infrared. Challenges and potentials solutions are highlighted in areas related to wide field-of-view camera design, small pitch pixel, broadband and multiband detectors and focal plane arrays.

Single Lens Dual-Aperture 3D Imaging System: Color Modeling

NASA Technical Reports Server (NTRS)

Bae, Sam Y.; Korniski, Ronald; Ream, Allen; Fritz, Eric; Shearn, Michael

2012-01-01

In an effort to miniaturize a 3D imaging system, we created two viewpoints in a single objective lens camera. This was accomplished by placing a pair of Complementary Multi-band Bandpass Filters (CMBFs) in the aperture area. Two key characteristics about the CMBFs are that the passbands are staggered so only one viewpoint is opened at a time when a light band matched to that passband is illuminated, and the passbands are positioned throughout the visible spectrum, so each viewpoint can render color by taking RGB spectral images. Each viewpoint takes a different spectral image from the other viewpoint hence yielding a different color image relative to the other. This color mismatch in the two viewpoints could lead to color rivalry, where the human vision system fails to resolve two different colors. The difference will be closer if the number of passbands in a CMBF increases. (However, the number of passbands is constrained by cost and fabrication technique.) In this paper, simulation predicting the color mismatch is reported.

VizieR Online Data Catalog: SG1120-1202 members HST imaging & 24um fluxes (Monroe+, 2017)

NASA Astrophysics Data System (ADS)

Monroe, J. T.; Tran, K.-V. H.; Gonzalez, A. H.

2017-09-01

We employ HST imaging of an ~8'x12' mosaic across three filters: F390W (WFC3/UVIS), F606W (ACS/WFC), and F814W (ACS/WFC) for a total of 44 pointings (combined primary and parallels) during cycles 14 (GO 10499) and 19 (GO 12470). We use the Spitzer MIPS 24um fluxes from Saintonge+ (2008ApJ...685L.113S) and Tran+ (2009ApJ...705..809T). The 24um observations were retrieved from the Spitzer archive. For details on spectroscopy from multi-band ground-based observations using Magellan (in 2006), MMT, and VLT/VIMOS (in 2003), we refer the reader to Tran+ (2009ApJ...705..809T). (1 data file).

Design and implementation of a multiband digital filter using FPGA to extract the ECG signal in the presence of different interference signals.

PubMed

Aboutabikh, Kamal; Aboukerdah, Nader

2015-07-01

In this paper, we propose a practical way to synthesize and filter an ECG signal in the presence of four types of interference signals: (1) those arising from power networks with a fundamental frequency of 50Hz, (2) those arising from respiration, having a frequency range from 0.05 to 0.5Hz, (3) muscle signals with a frequency of 25Hz, and (4) white noise present within the ECG signal band. This was done by implementing a multiband digital filter (seven bands) of type FIR Multiband Least Squares using a digital programmable device (Cyclone II EP2C70F896C6 FPGA, Altera), which was placed on an education and development board (DE2-70, Terasic). This filter was designed using the VHDL language in the Quartus II 9.1 design environment. The proposed method depends on Direct Digital Frequency Synthesizers (DDFS) designed to synthesize the ECG signal and various interference signals. So that the synthetic ECG specifications would be closer to actual ECG signals after filtering, we designed in a single multiband digital filter instead of using three separate digital filters LPF, HPF, BSF. Thus all interference signals were removed with a single digital filter. The multiband digital filter results were studied using a digital oscilloscope to characterize input and output signals in the presence of differing sinusoidal interference signals and white noise. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Multi-Band Uncertainty Set Based Robust SCUC With Spatial and Temporal Budget Constraints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dai, Chenxi; Wu, Lei; Wu, Hongyu

2016-11-01

The dramatic increase of renewable energy resources in recent years, together with the long-existing load forecast errors and increasingly involved price sensitive demands, has introduced significant uncertainties into power systems operation. In order to guarantee the operational security of power systems with such uncertainties, robust optimization has been extensively studied in security-constrained unit commitment (SCUC) problems, for immunizing the system against worst uncertainty realizations. However, traditional robust SCUC models with single-band uncertainty sets may yield over-conservative solutions in most cases. This paper proposes a multi-band robust model to accurately formulate various uncertainties with higher resolution. By properly tuning band intervalsmore » and weight coefficients of individual bands, the proposed multi-band robust model can rigorously and realistically reflect spatial/temporal relationships and asymmetric characteristics of various uncertainties, and in turn could effectively leverage the tradeoff between robustness and economics of robust SCUC solutions. The proposed multi-band robust SCUC model is solved by Benders decomposition (BD) and outer approximation (OA), while taking the advantage of integral property of the proposed multi-band uncertainty set. In addition, several accelerating techniques are developed for enhancing the computational performance and the convergence speed. Numerical studies on a 6-bus system and the modified IEEE 118-bus system verify the effectiveness of the proposed robust SCUC approach for enhancing uncertainty modeling capabilities and mitigating conservativeness of the robust SCUC solution.« less

Design and analysis of a multi-passband complex filter for the multiband cognitive radar system

NASA Astrophysics Data System (ADS)

Lee, Hua-Chin; Ting, Der-Hong; Tsao, Ya-Lan

2017-05-01

Multiband cognitive radar systems, operating in a variety of frequency bands and combining the different channels into a joint system, can provide significant flexibility and capability to detect and track hostile targets. This paper proposes a multi-passband complex filter (MPCF) architecture and the related circuit design for a multiband cognitive radar system. By operating under the 5.8GHz UNII band, the sensing part detects the current usage of frequency bands from 5.15GHz to 5.825GHz and provides the information of unused channels. The multiband cognitive radar system uses the whole unused channels and eliminates the used channels by using an on-chip MPCF in order to be coexistent with the Wi-Fi standard. The MPCF filters out the unwanted channels and leave the wanted channels. It dynamically changes the bandwidth of frequency from 20MHz to 80MHz using the 0.18μm CMOS technology. The MPCF is composed of the combination of 5th-order Chebyshev low-pass filters and high-pass filters, and the overall inband ripple of the MPCF is 1.2dB. The consuming current is 21.7mA at 1.8V power supply and the 20MHz bandwidth noise is 55.5nV. The total harmonic distortion (THD) is 45dB at 25MHz and the adjacent channel rejection is 24dB. The result of the MPCF guarantees the performance requirements of the multiband cognitive radar system.

Build Your Own Photometer: A Guided-Inquiry Experiment to Introduce Analytical Instrumentation

ERIC Educational Resources Information Center

Wang, Jessie J.; Nun´ez, Jose´ R. Rodríguez; Maxwell, E. Jane; Algar, W. Russ

2016-01-01

A guided-inquiry project designed to teach students the basics of spectrophotometric instrumentation at the second year level is presented. Students design, build, program, and test their own single-wavelength, submersible photometer using low-cost light-emitting diodes (LEDs) and inexpensive household items. A series of structured prelaboratory…

Techniques of Photometry and Astrometry with APASS, Gaia, and Pan-STARRs Results (Abstract)

NASA Astrophysics Data System (ADS)

Green, W.

2017-12-01

(Abstract only) The databases with the APASS DR9, Gaia DR1, and the Pan-STARRs 3pi DR1 data releases are publicly available for use. There is a bit of data-mining involved to download and manage these reference stars. This paper discusses the use of these databases to acquire accurate photometric references as well as techniques for improving results. Images are prepared in the usual way: zero, dark, flat-fields, and WCS solutions with Astrometry.net. Images are then processed with Sextractor to produce an ASCII table of identifying photometric features. The database manages photometics catalogs and images converted to ASCII tables. Scripts convert the files into SQL and assimilate them into database tables. Using SQL techniques, each image star is merged with reference data to produce publishable results. The VYSOS has over 13,000 images of the ONC5 field to process with roughly 100 total fields in the campaign. This paper provides the overview for this daunting task.

Synoptic maps of heliospheric Thomson scattering brightness from 1974-1985 as observed by the Helios photometers

NASA Technical Reports Server (NTRS)

Hick, P.; Jackson, B. V.; Schwenn, R.

1992-01-01

We display the electron Thomson scattering intensity of the inner heliosphere as observed by the zodiacal light photometers on board the Helios spacecraft in the form of synoptic maps. The technique extrapolates the brightness information from each photometer sector near the Sun and constructs a latitude/longitude map at a given solar height. These data are unique in that they give a determination of heliospheric structures out of the ecliptic above the primary region of solar wind acceleration. The spatial extent of bright, co-rotating heliospheric structures is readily observed in the data north and south of the ecliptic plane where the Helios photometer coverage is most complete. Because the technique has been used on the complete Helios data set from 1974 to 1985, we observe the change in our synoptic maps with solar cycle. Bright structures are concentrated near the heliospheric equator at solar minimum, while at solar maximum bright structures are found at far higher heliographic latitudes. A comparison of these maps with other forms of synoptic data are shown for two available intervals.

Star Formation in the DR21 Region (B)

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site] Annotated mosaic

Hidden behind a shroud of dust in the constellation Cygnus is an exceptionally bright source of radio emission called DR21. Visible light images reveal no trace of what is happening in this region because of heavy dust obscuration. In fact, visible light is attenuated in DR21 by a factor of more than 10,000,000,000,000,000,000,000,000,000,000,000,000,000 (ten thousand trillion heptillion).

New images from NASA's Spitzer Space Telescope allow us to peek behind the cosmic veil and pinpoint one of the most massive natal stars yet seen in our Milky Way galaxy. The never-before-seen star is 100,000 times as bright as the Sun. Also revealed for the first time is a powerful outflow of hot gas emanating from this star and bursting through a giant molecular cloud.

The upper image is a large-scale mosaic assembled from individual photographs obtained with the InfraRed Array Camera (IRAC) aboard Spitzer. The image covers an area about two times that of a full moon. The mosaic is a composite of images obtained at mid-infrared wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). The brightest infrared cloud near the top center corresponds to DR21, which presumably contains a cluster of newly forming stars at a distance of 10,000 light-years.

Protruding out from DR21 toward the bottom left of the image is a gaseous outflow (green), containing both carbon monoxide and molecular hydrogen. Data from the Spitzer spectrograph, which breaks light into its constituent individual wavelengths, indicate the presence of hot steam formed as the outflow heats the surrounding molecular gas. Outflows are physical signatures of processes that create supersonic beams, or jets, of gas. They are usually accompanied by discs of material around the new star, which likely contain the materials from which future planetary systems are formed. Additional newborn stars, depicted in green, can be seen surrounding the DR21 region.

The red filaments stretching across this image denote the presence of polycyclic aromatic hydrocarbons. These organic molecules, comprised of carbon and hydrogen, are excited by surrounding interstellar radiation and become luminescent at wavelengths near 8.0 microns. The complex pattern of filaments is caused by an intricate combination of radiation pressure, gravity and magnetic fields. The result is a tapestry in which winds, outflows and turbulence move and shape the interstellar medium.

To the lower left of the mosaic is a large bubble of gas and dust, which may represent the remnants of a past generation of stars.

The lower panel shows a 24-micron image mosaic, obtained with the Multiband Imaging Photometer aboard Spitzer (MIPS). This image maps the cooler infrared emission from interstellar dust found throughout the interstellar medium. The DR21 complex is clearly seen near the center of the strip, which covers about twice the area of the IRAC image.

Perhaps the most fascinating feature in this image is a long and shadowy linear filament extending towards the 10 o'clock position of DR21. This jet of cold and dense gas, nearly 50 light-years in extent, appears in silhouette against a warmer background. This filament is too long and massive to be a stellar jet and may have formed from a pre-existing molecular cloud core sculpted by DR21's strong winds. Regardless of its true nature, this jet and the numerous other arcs and wisps of cool dust signify the interstellar turbulence normally unseen by the human eye.

An efficient intensity-based ready-to-use X-ray image stitcher.

PubMed

Wang, Junchen; Zhang, Xiaohui; Sun, Zhen; Yuan, Fuzhen

2018-06-14

The limited field of view of the X-ray image intensifier makes it difficult to cover a large target area with a single X-ray image. X-ray image stitching techniques have been proposed to produce a panoramic X-ray image. This paper presents an efficient intensity-based X-ray image stitcher, which does not rely on accurate C-arm motion control or auxiliary devices and hence is ready to use in clinic. The stitcher consumes sequentially captured X-ray images with overlap areas and automatically produces a panoramic image. The gradient information for optimization of image alignment is obtained using a back-propagation scheme so that it is convenient to adopt various image warping models. The proposed stitcher has the following advantages over existing methods: (1) no additional hardware modification or auxiliary markers are needed; (2) it is robust against feature-based approaches; (3) arbitrary warping models and shapes of the region of interest are supported; (4) seamless stitching is achieved using multi-band blending. Experiments have been performed to confirm the effectiveness of the proposed method. The proposed X-ray image stitcher is efficient, accurate and ready to use in clinic. Copyright © 2018 John Wiley & Sons, Ltd.

Young stellar population and ongoing star formation in the H II complex Sh2-252

NASA Astrophysics Data System (ADS)

Jose, Jessy; Pandey, A. K.; Samal, M. R.; Ojha, D. K.; Ogura, K.; Kim, J. S.; Kobayashi, N.; Goyal, A.; Chauhan, N.; Eswaraiah, C.

2013-07-01

In this paper, an extensive survey of the star-forming complex Sh2-252 has been undertaken with an aim to explore its hidden young stellar population as well as to understand the structure and star formation history for the first time. This complex is composed of five prominent embedded clusters associated with the subregions A, C, E, NGC 2175s and Teu 136. We used Two Micron All Sky Survey-near-infrared and Spitzer-Infrared Array Camera, Multiband Imaging Photometer for Spitzer photometry to identify and classify the young stellar objects (YSOs) by their infrared (IR) excess emission. Using the IR colour-colour criteria, we identified 577 YSOs, of which, 163 are Class I, 400 are Class II and 14 are transition disc YSOs, suggesting a moderately rich number of YSOs in this complex. Spatial distribution of the candidate YSOs shows that they are mostly clustered around the subregions in the western half of the complex, suggesting enhanced star formation activity towards its west. Using the spectral energy distribution and optical colour-magnitude diagram-based age analyses, we derived probable evolutionary status of the subregions of Sh2-252. Our analysis shows that the region A is the youngest (˜0.5 Myr), the regions B, C and E are of similar evolutionary stage (˜1-2 Myr) and the clusters NGC 2175s and Teu 136 are slightly evolved (˜2-3 Myr). Morphology of the region in the 1.1 mm map shows a semicircular shaped molecular shell composed of several clumps and YSOs bordering the western ionization front of Sh2-252. Our analyses suggest that next generation star formation is currently under way along this border and that possibly fragmentation of the matter collected during the expansion of the H II region as one of the major processes is responsible for such stars. We observed the densest concentration of YSOs (mostly Class I, ˜0.5 Myr) at the western outskirts of the complex, within a molecular clump associated with water and methanol masers and we suggest that it is indeed a site of cluster formation at a very early evolutionary stage, sandwiched between the two relatively evolved CH II regions A and B.

A robust Multi-Band Water Index (MBWI) for automated extraction of surface water from Landsat 8 OLI imagery

NASA Astrophysics Data System (ADS)

Wang, Xiaobiao; Xie, Shunping; Zhang, Xueliang; Chen, Cheng; Guo, Hao; Du, Jinkang; Duan, Zheng

2018-06-01

Surface water is vital resources for terrestrial life, while the rapid development of urbanization results in diverse changes in sizes, amounts, and quality of surface water. To accurately extract surface water from remote sensing imagery is very important for water environment conservations and water resource management. In this study, a new Multi-Band Water Index (MBWI) for Landsat 8 Operational Land Imager (OLI) images is proposed by maximizing the spectral difference between water and non-water surfaces using pure pixels. Based on the MBWI map, the K-means cluster method is applied to automatically extract surface water. The performance of MBWI is validated and compared with six widely used water indices in 29 sites of China. Results show that our proposed MBWI performs best with the highest accuracy in 26 out of the 29 test sites. Compared with other water indices, the MBWI results in lower mean water total errors by a range of 9.31%-25.99%, and higher mean overall accuracies and kappa coefficients by 0.87%-3.73% and 0.06-0.18, respectively. It is also demonstrated for MBWI in terms of robustly discriminating surface water from confused backgrounds that are usually sources of surface water extraction errors, e.g., mountainous shadows and dark built-up areas. In addition, the new index is validated to be able to mitigate the seasonal and daily influences resulting from the variations of the solar condition. MBWI holds the potential to be a useful surface water extraction technology for water resource studies and applications.

A Geostatistical Data Fusion Technique for Merging Remote Sensing and Ground-Based Observations of Aerosol Optical Thickness

NASA Technical Reports Server (NTRS)

Chatterjee, Abhishek; Michalak, Anna M.; Kahn, Ralph A.; Paradise, Susan R.; Braverman, Amy J.; Miller, Charles E.

2010-01-01

Particles in the atmosphere reflect incoming sunlight, tending to cool the Earth below. Some particles, such as soot, also absorb sunlight, which tens to warm the ambient atmosphere. Aerosol optical depth (AOD) is a measure of the amount of particulate matter in the atmosphere, and is a key input to computer models that simulate and predict Earth's changing climate. The global AOD products from the Multi-angle Imaging SpectroRadiometer (MISR) and the MODerate resolution Imaging Spectroradiometer (MODIS), both of which fly on the NASA Earth Observing System's Terra satellite, provide complementary views of the particles in the atmosphere. Whereas MODIS offers global coverage about four times as frequent as MISR, the multi-angle data makes it possible to separate the surface and atmospheric contributions to the observed top-of-atmosphere radiances, and also to more effectively discriminate particle type. Surface-based AERONET sun photometers retrieve AOD with smaller uncertainties than the satellite instruments, but only at a few fixed locations. So there are clear reasons to combine these data sets in a way that takes advantage of their respective strengths. This paper represents an effort at combining MISR, MODIS and AERONET AOD products over the continental US, using a common spatial statistical technique called kriging. The technique uses the correlation between the satellite data and the "ground-truth" sun photometer observations to assign uncertainty to the satellite data on a region-by-region basis. The larger fraction of the sun photometer variance that is duplicated by the satellite data, the higher the confidence assigned to the satellite data in that region. In the Western and Central US, MISR AOD correlation with AERONET are significantly higher than those with MODIS, likely due to bright surfaces in these regions, which pose greater challenges for the single-view MODIS retrievals. In the east, MODIS correlations are higher, due to more frequent sampling of the varying AOD. These results demonstrate how the MISR and MODIS aerosol products are complementary. The underlying technique also provides one method for combining these products in such a way that takes advantage of the strengths of each, in the places and times when they are maximal, and in addition, yields an estimate of the associated uncertainties in space and time.

Compact light-emitting-diode sun photometer for atmospheric optical depth measurements.

PubMed

Acharya, Y B; Jayaraman, A; Ramachandran, S; Subbaraya, B H

1995-03-01

A new compact light-emitting diode (LED) sun photometer, in which a LED is used as a spectrally selective photodetector as well as a nonlinear feedback element in the operational amplifier, has been developed. The output voltage that is proportional to the logarithm of the incident solar intensity permits the direct measurement of atmospheric optical depths in selected spectral bands. Measurements made over Ahmedabad, India, show good agreement, within a few percent, of optical depths derived with a LED as a photodetector in a linear mode and with a LED as both a photodetector and a feedback element in an operational amplifier in log mode. The optical depths are also found to compare well with those obtained simultaneously with a conventional filter photometer.

Programmable Spectral Source and Design Tool for 3D Imaging Using Complementary Bandpass Filters

NASA Technical Reports Server (NTRS)

Bae, Youngsam (Inventor); Korniski, Ronald J. (Inventor); Ream, Allen (Inventor); Shearn, Michael J. (Inventor); Shahinian, Hrayr Karnig (Inventor); Fritz, Eric W. (Inventor)

2017-01-01

An endoscopic illumination system for illuminating a subject for stereoscopic image capture, includes a light source which outputs light; a first complementary multiband bandpass filter (CMBF) and a second CMBF, the first and second CMBFs being situated in first and second light paths, respectively, where the first CMBF and the second CMBF filter the light incident thereupon to output filtered light; and a camera which captures video images of the subject and generates corresponding video information, the camera receiving light reflected from the subject and passing through a pupil CMBF pair and a detection lens. The pupil CMBF includes a first pupil CMBF and a second pupil CMBF, the first pupil CMBF being identical to the first CMBF and the second pupil CMBF being identical to the second CMBF, and the detection lens includes one unpartitioned section that covers both the first pupil CMBF and the second pupil CMBF.

Seamless image stitching by homography refinement and structure deformation using optimal seam pair detection

NASA Astrophysics Data System (ADS)

Lee, Daeho; Lee, Seohyung

2017-11-01

We propose an image stitching method that can remove ghost effects and realign the structure misalignments that occur in common image stitching methods. To reduce the artifacts caused by different parallaxes, an optimal seam pair is selected by comparing the cross correlations from multiple seams detected by variable cost weights. Along the optimal seam pair, a histogram of oriented gradients is calculated, and feature points for matching are detected. The homography is refined using the matching points, and the remaining misalignment is eliminated using the propagation of deformation vectors calculated from matching points. In multiband blending, the overlapping regions are determined from a distance between the matching points to remove overlapping artifacts. The experimental results show that the proposed method more robustly eliminates misalignments and overlapping artifacts than the existing method that uses single seam detection and gradient features.

PERIODOGRAMS FOR MULTIBAND ASTRONOMICAL TIME SERIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

VanderPlas, Jacob T.; Ivezic, Željko

This paper introduces the multiband periodogram, a general extension of the well-known Lomb–Scargle approach for detecting periodic signals in time-domain data. In addition to advantages of the Lomb–Scargle method such as treatment of non-uniform sampling and heteroscedastic errors, the multiband periodogram significantly improves period finding for randomly sampled multiband light curves (e.g., Pan-STARRS, DES, and LSST). The light curves in each band are modeled as arbitrary truncated Fourier series, with the period and phase shared across all bands. The key aspect is the use of Tikhonov regularization which drives most of the variability into the so-called base model common tomore » all bands, while fits for individual bands describe residuals relative to the base model and typically require lower-order Fourier series. This decrease in the effective model complexity is the main reason for improved performance. After a pedagogical development of the formalism of least-squares spectral analysis, which motivates the essential features of the multiband model, we use simulated light curves and randomly subsampled SDSS Stripe 82 data to demonstrate the superiority of this method compared to other methods from the literature and find that this method will be able to efficiently determine the correct period in the majority of LSST’s bright RR Lyrae stars with as little as six months of LSST data, a vast improvement over the years of data reported to be required by previous studies. A Python implementation of this method, along with code to fully reproduce the results reported here, is available on GitHub.« less

Geocoronal imaging with Dynamics Explorer - A first look

NASA Technical Reports Server (NTRS)

Rairden, R. L.; Frank, L. A.; Craven, J. D.

1983-01-01

The ultraviolet photometer of the University of Iowa spin-scan auroral imaging instrumentation on board Dynamics Explorer-1 has returned numerous hydrogen Lyman alpha images of the geocorona from altitudes of 570 km to 23,300 km (1.09 R sub E to 4.66 R sub E geocentric radial distance). The hydrogen density gradient is shown by a plot of the zenith intensities throughout this range, which decrease to near celestial background values as the spacecraft approaches apogee. Characterizing the upper geocorona as optically thin (single-scattering), the zenith intensity is converted directly to vertical column density. This approximation loses its validity deeper in the geocorona, where the hydrogen is demonstrated to be optically thick in that there is no Lyman alpha limb brightening. Further study of the geocoronal hydrogen distribution will require computer modeling of the radiative transfer. Previously announced in STAR as N83-20889

High-spatial-resolution K-band Imaging of Select K2 Campaign Fields

NASA Astrophysics Data System (ADS)

Colón, Knicole D.; Howell, Steve B.; Ciardi, David R.; Barclay, Thomas

2017-12-01

NASA's K2 mission began observing fields along the ecliptic plane in 2014. Each observing campaign lasts approximately 80 days, during which high-precision optical photometry of select astrophysical targets is collected by the Kepler spacecraft. Due to the 4 arcsec pixel scale of the Kepler photometer, significant blending between the observed targets can occur (especially in dense fields close to the Galactic plane). We undertook a program to use the Wide Field Camera (WFCAM) on the 3.8 m United Kingdom InfraRed Telescope (UKIRT) to collect high-spatial-resolution near-infrared images of targets in select K2 campaign fields, which we report here. These 0.4 arcsec resolution K-band images offer the opportunity to perform a variety of science, including vetting exoplanet candidates by identifying nearby stars blended with the target star and estimating the size, color, and type of galaxies observed by K2.

Satellite measurements of large-scale air pollution - Methods

NASA Technical Reports Server (NTRS)

Kaufman, Yoram J.; Ferrare, Richard A.; Fraser, Robert S.

1990-01-01

A technique for deriving large-scale pollution parameters from NIR and visible satellite remote-sensing images obtained over land or water is described and demonstrated on AVHRR images. The method is based on comparison of the upward radiances on clear and hazy days and permits simultaneous determination of aerosol optical thickness with error Delta tau(a) = 0.08-0.15, particle size with error + or - 100-200 nm, and single-scattering albedo with error + or - 0.03 (for albedos near 1), all assuming accurate and stable satellite calibration and stable surface reflectance between the clear and hazy days. In the analysis of AVHRR images of smoke from a forest fire, good agreement was obtained between satellite and ground-based (sun-photometer) measurements of aerosol optical thickness, but the satellite particle sizes were systematically greater than those measured from the ground. The AVHRR single-scattering albedo agreed well with a Landsat albedo for the same smoke.

The Design and Analysis of a Novel Split-H-Shaped Metamaterial for Multi-Band Microwave Applications

PubMed Central

Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2014-01-01

This paper presents the design and analysis of a novel split-H-shaped metamaterial unit cell structure that is applicable in a multi-band frequency range and that exhibits negative permeability and permittivity in those frequency bands. In the basic design, the separate split-square resonators are joined by a metal link to form an H-shaped unit structure. Moreover, an analysis and a comparison of the 1 × 1 array and 2 × 2 array structures and the 1 × 1 and 2 × 2 unit cell configurations were performed. All of these configurations demonstrate multi-band operating frequencies (S-band, C-band, X-band and Ku-band) with double-negative characteristics. The equivalent circuit model and measured result for each unit cell are presented to validate the resonant behavior. The commercially available finite-difference time-domain (FDTD)-based simulation software, Computer Simulation Technology (CST) Microwave Studio, was used to obtain the reflection and transmission parameters of each unit cell. This is a novel and promising design in the electromagnetic paradigm for its simplicity, scalability, double-negative characteristics and multi-band operation. PMID:28788116

The Design and Analysis of a Novel Split-H-Shaped Metamaterial for Multi-Band Microwave Applications.

PubMed

Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2014-07-02

This paper presents the design and analysis of a novel split-H-shaped metamaterial unit cell structure that is applicable in a multi-band frequency range and that exhibits negative permeability and permittivity in those frequency bands. In the basic design, the separate split-square resonators are joined by a metal link to form an H-shaped unit structure. Moreover, an analysis and a comparison of the 1 × 1 array and 2 × 2 array structures and the 1 × 1 and 2 × 2 unit cell configurations were performed. All of these configurations demonstrate multi-band operating frequencies (S-band, C-band, X-band and K u -band) with double-negative characteristics. The equivalent circuit model and measured result for each unit cell are presented to validate the resonant behavior. The commercially available finite-difference time-domain (FDTD)-based simulation software, Computer Simulation Technology (CST) Microwave Studio, was used to obtain the reflection and transmission parameters of each unit cell. This is a novel and promising design in the electromagnetic paradigm for its simplicity, scalability, double-negative characteristics and multi-band operation.

AOT Retrieval Procedure for Distributed Measurements With Low-Cost Sun Photometers

NASA Astrophysics Data System (ADS)

Toledo, F.; Garrido, C.; Díaz, M.; Rondanelli, R.; Jorquera, S.; Valdivieso, P.

2018-01-01

We propose a new application of inexpensive light-emitting diode (LED)-based Sun photometers, consisting of measuring the aerosol optical thickness (AOT) with high resolution within metropolitan scales. Previously, these instruments have been used at continental scales by the GLOBE program, but this extension is already covered by more expensive and higher-precision instruments of the AERONET global network. For this we built an open source two-channeled LED-based Sun photometer based on previous developments, with improvements in the hardware, software, and modifications on the calibration procedure. Among these we highlight the use of MODTRAN to characterize the effect introduced by using LED sensors in the AOT retrieval, an open design available for the scientific community and a calibration procedure that takes advantage of a CIMEL Sun photometer located within the city, enables the intercomparison of several LED Sun photometers with a common reference. We estimated the root-mean-square error in the AOT retrieved by the prototypes as 0.006 at the 564 nm and 0.009 at the 408 nm. This error is way under the magnitude of the AOT daily cycle variability measured by us in our campaigns, even for distances closer than 15 km. In addition to inner city campaigns, we also show aerosol-tracing applications by measuring AOT variations from the city of Santiago to the Andes glaciers. Measuring AOT at high spatial resolution in urban areas can improve our understanding of urban scale aerosol circulation, providing information for solar energy planning, health policies, and climatological studies, among others.

Rapid and precise determination of ATP using a modified photometer

USGS Publications Warehouse

Shultz, David J.; Stephens, Doyle W.

1980-01-01

An inexpensive delay timer was designed to modify a commercially available ATP photometer which allows a disposable tip pipette to be used for injecting either enzyme or sample into the reaction cuvette. The disposable tip pipette is as precise and accurate as a fixed-needle syringe but eliminates the problem of sample contamination and decreases analytical time. (USGS)

Evaluation of an aerosol photometer for monitoring welding fume levels in a shipyard.

PubMed

Glinsmann, P W; Rosenthal, F S

1985-07-01

A direct reading aerosol photometer (Sibata P-5 Digital Dust Indicator) was used to assess fume levels from welding and burning operations in a shipyard. The photometer was calibrated with gravimetric analysis of filter samples collected simultaneously with instrument readings. A six-fold difference between calibration factors for personal and area samples was found. This difference can be explained by expected changes in particle size distributions in welding fume. Monitoring of various work situations was performed in order to assess the value of the photometer for the measurement of fume. Measurements categorized by enclosure of space and quality of ventilation indicated the presence of high fume levels in semi-enclosed and enclosed spaces. The build up of welding fume in an enclosed space occurred over several minutes after the arc was struck. Decay likewise required several minutes. During welding, wide fluctuations of fume concentrations were found. Thus a single reading was not adequate to characterize average fume levels. Although this type of instrument is useful for locating areas with high fume levels and monitoring the effectiveness of ventilation, the uncertainty in calibration factors makes accurate determinations of fume levels difficult.

Homogenization limit for a multiband effective mass model in heterostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morandi, O., E-mail: morandi@ipcms.unistra.fr

We study the homogenization limit of a multiband model that describes the quantum mechanical motion of an electron in a quasi-periodic crystal. In this approach, the distance among the atoms that constitute the material (lattice parameter) is considered a small quantity. Our model include the description of materials with variable chemical composition, intergrowth compounds, and heterostructures. We derive the effective multiband evolution system in the framework of the kp approach. We study the well posedness of the mathematical problem. We compare the effective mass model with the standard kp models for uniform and non-uniforms crystals. We show that in themore » limit of vanishing lattice parameter, the particle density obtained by the effective mass model, converges to the exact probability density of the particle.« less

Waveguide transition with vacuum window for multiband dynamic nuclear polarization systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rybalko, Oleksandr; Bowen, Sean; Zhurbenko, Vitaliy

2016-05-15

A low loss waveguide transition section and oversized microwave vacuum window covering several frequency bands (94 GHz, 140 GHz, 188 GHz) is presented. The transition is compact and was optimized for multiband Dynamic Nuclear Polarization (DNP) systems in a full-wave simulator. The window is more broadband than commercially available windows, which are usually optimized for single band operation. It is demonstrated that high-density polyethylene with urethane adhesive can be used as a low loss microwave vacuum window in multiband DNP systems. The overall assembly performance and dimensions are found using full-wave simulations. The practical aspects of the window implementation inmore » the waveguide are discussed. To verify the design and simulation results, the window is tested experimentally at the three frequencies of interest.« less

Multiband phase-modulated radio over IsOWC link with balanced coherent homodyne detection

NASA Astrophysics Data System (ADS)

Zong, Kang; Zhu, Jiang

2017-11-01

In this paper, we present a multiband phase-modulated radio over intersatellite optical wireless communication (IsOWC) link with balanced coherent homodyne detection. The proposed system can provide high linearity for transparent transport of multiband radio frequency (RF) signals and better receiver sensitivity than intensity modulated with direct detection (IM/DD) system. The exact analytical expression of signal to noise and distortion ratio (SNDR) is derived considering the third-order intermodulation product and amplifier spontaneous emission (ASE) noise. Numerical results of SNDR with various number of subchannels and modulation index are given. Results indicate that the optimal modulation index exists to maximize the SNDR. With the same system parameters, the value of the optimal modulation index will decrease with the increase of number of subchannels.

Star Formation in Henize 206

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site] IRA-MIPS Composite

[figure removed for brevity, see original site] Visible

[figure removed for brevity, see original site] IRAC

[figure removed for brevity, see original site] MIPS

The LMC is a small satellite galaxy gravitationally bound to our own Milky Way. Yet the gravitational effects are tearing the companion to shreds in a long-playing drama of 'intergalactic cannibalism.' These disruptions lead to a recurring cycle of star birth and star death.

Astronomers are particularly interested in the LMC because its fractional content of heavy metals is two to five times lower than is seen in our solar neighborhood. [In this context, 'heavy elements' refer to those elements not present in the primordial universe. Such elements as carbon, oxygen and others are produced by nucleosynthesis and are ejected into the interstellar medium via mass loss by stars, including supernova explosions.] As such, the LMC provides a nearby cosmic laboratory that may resemble the distant universe in its chemical composition.

The primary Spitzer image, showing the wispy filamentary structure of Henize 206, is a four-color composite mosaic created by combining data from an infrared array camera (IRAC) at near-infrared wavelengths and the mid-infrared data from a multiband imaging photometer (MIPS). Blue represents invisible infrared light at wavelengths of 3.6 and 4.5 microns. Note that most of the stars in the field of view radiate primarily at these short infrared wavelengths. Cyan denotes emission at 5.8 microns, green depicts the 8.0 micron light, and red is used to trace the thermal emission from dust at 24 microns. The separate instrument images are included as insets to the main composite.

An inclined ring of emission dominates the central and upper regions of the image. This delineates a bubble of hot, x-ray emitting gas that was blown into space when a massive star died in a supernova explosion millions of years ago. The shock waves from that explosion impacted a cloud of nearby hydrogen gas, compressed it, and started a new generation of star formation. The death of one star led to the birth of many new stars. This is particularly evident in the MIPS inset, where the 24-micron emission peaks correspond to newly formed stars. The ultraviolet and visible-light photons from the new stars are absorbed by surrounding dust and re-radiated at longer infrared wavelengths, where it is detected by Spitzer.

This emission nebula was cataloged by Karl Henize (HEN-eyes) while spending 1948-1951 in South Africa doing research for his Ph.D. dissertation at the University of Michigan. Henize later became a NASA astronaut and, at age 59, became the oldest rookie to fly on the Space Shuttle during an eight-day flight of the Challenger in 1985. He died just short of his 67th birthday in 1993 while attempting to climb the north face of Mount Everest, the world's highest peak.

DCMDN: Deep Convolutional Mixture Density Network

NASA Astrophysics Data System (ADS)

D'Isanto, Antonio; Polsterer, Kai Lars

2017-09-01

Deep Convolutional Mixture Density Network (DCMDN) estimates probabilistic photometric redshift directly from multi-band imaging data by combining a version of a deep convolutional network with a mixture density network. The estimates are expressed as Gaussian mixture models representing the probability density functions (PDFs) in the redshift space. In addition to the traditional scores, the continuous ranked probability score (CRPS) and the probability integral transform (PIT) are applied as performance criteria. DCMDN is able to predict redshift PDFs independently from the type of source, e.g. galaxies, quasars or stars and renders pre-classification of objects and feature extraction unnecessary; the method is extremely general and allows the solving of any kind of probabilistic regression problems based on imaging data, such as estimating metallicity or star formation rate in galaxies.

Analysis research for earth resource information systems - Where do we stand

NASA Technical Reports Server (NTRS)

Landgrebe, D. A.

1974-01-01

Discussion of the state of the technology of earth resources information systems relative to future operational implementation. The importance of recognizing the difference between systems with image orientation and systems with numerical orientation is illustrated in an example concerning the effect of noise on multiband multispectral data obtained in an agricultural experiment. It is suggested that the data system hardware portion of the total earth resources information system be designed in terms of a numerical orientation; it is argued, however, that this choise is entirely compatible with image-oriented analysis tasks. Some aspects of interfacing such an advanced technology with an operational user community in such a way as to accommodate the user's need for flexibility and yet provide the services needed on a cost-effective basis are discussed.

Automated site characterization for robotic sample acquisition systems

NASA Astrophysics Data System (ADS)

Scholl, Marija S.; Eberlein, Susan J.

1993-04-01

A mobile, semiautonomous vehicle with multiple sensors and on-board intelligence is proposed for performing preliminary scientific investigations on extraterrestrial bodies prior to human exploration. Two technologies, a hybrid optical-digital computer system based on optical correlator technology and an image and instrument data analysis system, provide complementary capabilities that might be part of an instrument package for an intelligent robotic vehicle. The hybrid digital-optical vision system could perform real-time image classification tasks using an optical correlator with programmable matched filters under control of a digital microcomputer. The data analysis system would analyze visible and multiband imagery to extract mineral composition and textural information for geologic characterization. Together these technologies would support the site characterization needs of a robotic vehicle for both navigational and scientific purposes.

Investigation of the utility of ERTS-1 imagery for updating land use and resource data in Guatemala

NASA Technical Reports Server (NTRS)

Garcia, L. E. (Principal Investigator)

1973-01-01

The author has identified the following significant results. An intensive analysis of the imagery received has been completed and findings are reported. Conclusions are restricted by receipt of only limited amounts of cloud-free coverage of test areas. In most cases the interpretation findings were as anticipated from previous experience with multiband images. Band 7 provides promising indication of some economically important environmental communities. It also permits viewing through thin cirrus cloud layers for features of medium to high contrast. Band 4 provides information of submerged reefs and of movement of suspended sediment bodies in water areas. ERTS-1 bulk images have positional mapping accuracy adequate for representation at 1:1,000,000 scale maps. Cloud cover is a true constraint to useable satellite coverage.

III-V infrared research at the Jet Propulsion Laboratory

NASA Astrophysics Data System (ADS)

Gunapala, S. D.; Ting, D. Z.; Hill, C. J.; Soibel, A.; Liu, John; Liu, J. K.; Mumolo, J. M.; Keo, S. A.; Nguyen, J.; Bandara, S. V.; Tidrow, M. Z.

2009-08-01

Jet Propulsion Laboratory is actively developing the III-V based infrared detector and focal plane arrays (FPAs) for NASA, DoD, and commercial applications. Currently, we are working on multi-band Quantum Well Infrared Photodetectors (QWIPs), Superlattice detectors, and Quantum Dot Infrared Photodetector (QDIPs) technologies suitable for high pixel-pixel uniformity and high pixel operability large area imaging arrays. In this paper we report the first demonstration of the megapixel-simultaneously-readable and pixel-co-registered dual-band QWIP focal plane array (FPA). In addition, we will present the latest advances in QDIPs and Superlattice infrared detectors at the Jet Propulsion Laboratory.

The Retrieval of Ozone Profiles from Limb Scatter Measurements: Results from the Shuttle Ozone Limb Sounding Experiment

NASA Technical Reports Server (NTRS)

McPeters, Richard D.; Janz, Scott J.; Hilsenrath, Ernest; Brown, Tammy L.; Flittner, David E.; Heath, Donald F.

1999-01-01

Two instruments were flown on shuttle flight STS-87 to test a new technique for inferring the ozone vertical profile using measurements of scattered sunlight from the Earth's limb. The instruments were an ultraviolet imaging spectrometer designed to measure ozone between 30 and 50 km, and a multi-filter imaging photometer that uses 600 nm radiances to measure ozone between 15 km and 35 km. Two orbits of limb data were obtained on December 2, 1997. For the scans analyzed the ozone profile was measured from 15 km to 50 km with approximately 3 km vertical resolution. Comparisons with a profile from an ozonesonde launched from Ascension Island showed agreement mostly within +/- 5%. The tropopause at 15 km was clearly detected.

Multi-use lunar telescopes

NASA Technical Reports Server (NTRS)

Drummond, Mark; Hine, Butler; Genet, Russell; Genet, David; Talent, David; Boyd, Louis; Trueblood, Mark; Filippenko, Alexei V. (Editor)

1991-01-01

The objective of multi-use telescopes is to reduce the initial and operational costs of space telescopes to the point where a fair number of telescopes, a dozen or so, would be affordable. The basic approach is to develop a common telescope, control system, and power and communications subsystem that can be used with a wide variety of instrument payloads, i.e., imaging CCD cameras, photometers, spectrographs, etc. By having such a multi-use and multi-user telescope, a common practice for earth-based telescopes, development cost can be shared across many telescopes, and the telescopes can be produced in economical batches.

A long Saharan dust event over the western Mediterranean: Lidar, Sun photometer observations, and regional dust modeling

NASA Astrophysics Data System (ADS)

PéRez, C.; Nickovic, S.; Baldasano, J. M.; Sicard, M.; Rocadenbosch, F.; Cachorro, V. E.

2006-08-01

A long Saharan dust event affected the western Mediterranean in the period 12-28 June 2002. Dust was present mainly between 1- and 5-km height affecting most parts of the Iberian Peninsula and reaching western/central Europe. Intensive backscatter lidar observations over Barcelona (Spain) and Sun photometer data from two stations (El Arenosillo, Spain, and Avignon, France) are used to evaluate different configurations the Dust Regional Atmospheric Modeling (DREAM) system. DREAM currently operates dust forecasts over the Mediterranean region (http://www.bsc.es/projects/earthscience/DREAM/) considering four particle size bins while only the first two are relevant for long-range transport analysis since their life time is larger than 12 hours. A more detailed bin method is implemented, and two different dust distributions at sources are compared to the operational version. Evaluations are performed at two wavelengths (532 and 1064 nm). The dust horizontal and vertical structure simulated by DREAM shows very good qualitative agreement when compared to SeaWIFS satellite images and lidar height-time displays over Barcelona. When evaluating the modeled aerosol optical depth (AOD) against Sun photometer data, significant improvements are achieved with the use of the new detailed bin method. In general, the model underpredicts the AOD for increasing Ångström exponents because of the influence of anthropogenic pollution in the boundary layer. In fact, the modeled AOD is highly anticorrelated with the observed Ångström exponents. Avignon shows higher influence of small anthropogenic aerosols which explains the better results of the model at the wavelength of 1064 nm over this location. The uncertainties of backscatter lidar inversions (20-30%) are in the same order of magnitude as the differences between the model experiments. Better model results are obtained when comparing to lidar because most of the anthropogenic effect is removed.

Early-stage young stellar objects in the Small Magellanic Cloud

NASA Astrophysics Data System (ADS)

Oliveira, J. M.; van Loon, J. Th.; Sloan, G. C.; Sewiło, M.; Kraemer, K. E.; Wood, P. R.; Indebetouw, R.; Filipović, M. D.; Crawford, E. J.; Wong, G. F.; Hora, J. L.; Meixner, M.; Robitaille, T. P.; Shiao, B.; Simon, J. D.

2013-02-01

We present new observations of 34 young stellar object (YSO) candidates in the Small Magellanic Cloud (SMC). The photometric selection required sources to be bright at 24 and 70 μm (to exclude evolved stars and galaxies). The anchor of the analysis is a set of Spitzer Infrared Spectrograph (IRS) spectra, supplemented by ground-based 3-5 μm spectra, Spitzer Infrared Array Camera and Multiband Imaging Photometer for Spitzer photometry, near-infrared (IR) imaging and photometry, optical spectroscopy and radio data. The sources' spectral energy distributions and spectral indices are consistent with embedded YSOs; prominent silicate absorption is observed in the spectra of at least 10 sources, silicate emission is observed towards four sources. Polycyclic aromatic hydrocarbon (PAH) emission is detected towards all but two sources. Based on band ratios (in particular the strength of the 11.3-μm and the weakness of the 8.6-μm bands) PAH emission towards SMC YSOs is dominated by predominantly small neutral grains. Ice absorption is observed towards 14 sources in the SMC. The comparison of H2O and CO2 ice column densities for SMC, Large Magellanic Cloud and Galactic samples suggests that there is a significant H2O column density threshold for the detection of CO2 ice. This supports the scenario proposed by Oliveira et al., where the reduced shielding in metal-poor environments depletes the H2O column density in the outer regions of the YSO envelopes. No CO ice is detected towards the SMC sources. Emission due to pure rotational 0-0 transitions of molecular hydrogen is detected towards the majority of SMC sources, allowing us to estimate rotational temperatures and H2 column densities. All but one source are spectroscopically confirmed as SMC YSOs. Based on the presence of ice absorption, silicate emission or absorption and PAH emission, the sources are classified and placed in an evolutionary sequence. Of the 33 YSOs identified in the SMC, 30 sources populate different stages of massive stellar evolution. The presence of ice- and/or silicate-absorption features indicates sources in the early embedded stages; as a source evolves, a compact H ii region starts to emerge, and at the later stages the source's IR spectrum is completely dominated by PAH and fine-structure emission. The remaining three sources are classified as intermediate-mass YSOs with a thick dusty disc and a tenuous envelope still present. We propose one of the SMC sources is a D-type symbiotic system, based on the presence of Raman, H and He emission lines in the optical spectrum, and silicate emission in the IRS spectrum. This would be the first dust-rich symbiotic system identified in the SMC.

Observing the Edge of the Inner Radiation Belt: the South Atlantic Anomaly Seen with Photometers in Low Earth Orbit

NASA Astrophysics Data System (ADS)

Schaefer, R. K.; Wolven, B. C.; Paxton, L.; Romeo, G.; Selby, C.; Hsieh, S. W.

2013-12-01

The South Atlantic Anomaly (SAA) is a region where the Earth's inner radiation belt dips down and bathes low earth orbit satellites with energetic charged particles sometimes causing problems for satellite operations. We will describe data from a series of UV spectrographic imagers (DMSP/SSUSI) that remain on through 4 daily SAA passages. Using spectrographic information, we are able to separate, study, and remove the detector counts due to energetic (~ 1 MeV and above) particle hits. We have made a model of the SAA at Defense Meteorological Satellite Program altitudes (~850 km), and we are able to monitor the intensity of the SAA over the long term (> a decade). Using this window into the inner radiation belt, we are able to see seasonal and solar cycle variations in intensity. In this talk we will describe the techniques, the model, and show results of our study, and and indicate directions for future development and usefulness of using SSUSI as an inner radiation belt particle intensity monitor. Nighttime 427 nm Photometer count rates as seen by SSUSI binned onto a 3 x 3 degree grid and accumulated over the year 2006. The classic shape of the South Atlantic Anomaly is clearly traced by the data.

1997 Report to the Congress on Ballistic Missile Defense.

DTIC Science & Technology

1997-10-01

Infrared Arrays • Quantum Well Infrared Photodector (QWIP) Focal Plane Array (FPA) • Staring Si Impurity Band Conduction Extremely Sensitive Focal...to be flown on STRV lc/d include a Quantum Well Infrared Photometer (QWIP) sensor and a multifunctional compos- ite structure. The Space Technology...Peoples Republic of China Platinum Silicide Quick Reaction Program Quick Response Program Quantum Well Infrared Photometer Research and

ARC-2007-ACD07-0073-047

NASA Image and Video Library

2007-04-14

Lunar CRater Observation and Sensing Satellite (LCROSS) and P.I. at NASA Ames Research Center - close up of Total Luminance Photometer: Metal shake table close up. Shows two units bolted on. The left one is the lens, sensor electronics and photometer sensor. The right is the digital electronics unit for the instrument. The two units, along with their cabling is one of the LCROSS science insruments.

ARC-2007-ACD07-0073-046

NASA Image and Video Library

2007-04-14

Lunar CRater Observation and Sensing Satellite (LCROSS) and P.I. at NASA Ames Research Center - Total Luminance Photometer shake test in N-244 (EEL) : Metal shake table close up. Shows two units bolted on. The left one is the lens, sensor electronics and photometer sensor. The right is the digital electronics unit for the instrument. The two units, along with their cabling is one of the LCROSS science insruments.

Using a Homemade Flame Photometer to Measure Sodium Concentration in a Sports Drink

ERIC Educational Resources Information Center

LaFratta, Christopher N.; Jain, Swapan; Pelse, Ian; Simoska, Olja; Elvy, Karina

2013-01-01

The purpose of this experiment was to create a simple and inexpensive flame photometer to measure the concentration of sodium in beverages, such as Gatorade. We created a nebulizer using small tubing and sprayed the sample into the base of a Bunsen burner. Adjacent to the flame was a photodiode with a filter specific for the emission of the sodium…

Using Project-Based Learning to Design, Build, and Test Student-Made Photometer by Measuring the Unknown Concentration of Colored Substances

ERIC Educational Resources Information Center

Diawati, Chansyanah; Liliasari; Setiabudi, Agus; Buchari

2018-01-01

Students learned the principles and practice of photometry through project-based learning. They addressed the challenge of measuring the unknown concentration of a colored substance using a photometer they were required to design, build, and test. Then, they used that instrument to carry out the experiment and fulfill the challenge. A photometer…

Machine-learned Identification of RR Lyrae Stars from Sparse, Multi-band Data: The PS1 Sample

NASA Astrophysics Data System (ADS)

Sesar, Branimir; Hernitschek, Nina; Mitrović, Sandra; Ivezić, Željko; Rix, Hans-Walter; Cohen, Judith G.; Bernard, Edouard J.; Grebel, Eva K.; Martin, Nicolas F.; Schlafly, Edward F.; Burgett, William S.; Draper, Peter W.; Flewelling, Heather; Kaiser, Nick; Kudritzki, Rolf P.; Magnier, Eugene A.; Metcalfe, Nigel; Tonry, John L.; Waters, Christopher

2017-05-01

RR Lyrae stars may be the best practical tracers of Galactic halo (sub-)structure and kinematics. The PanSTARRS1 (PS1) 3π survey offers multi-band, multi-epoch, precise photometry across much of the sky, but a robust identification of RR Lyrae stars in this data set poses a challenge, given PS1's sparse, asynchronous multi-band light curves (≲ 12 epochs in each of five bands, taken over a 4.5 year period). We present a novel template fitting technique that uses well-defined and physically motivated multi-band light curves of RR Lyrae stars, and demonstrate that we get accurate period estimates, precise to 2 s in > 80 % of cases. We augment these light-curve fits with other features from photometric time-series and provide them to progressively more detailed machine-learned classification models. From these models, we are able to select the widest (three-fourths of the sky) and deepest (reaching 120 kpc) sample of RR Lyrae stars to date. The PS1 sample of ˜45,000 RRab stars is pure (90%) and complete (80% at 80 kpc) at high galactic latitudes. It also provides distances that are precise to 3%, measured with newly derived period-luminosity relations for optical/near-infrared PS1 bands. With the addition of proper motions from Gaia and radial velocity measurements from multi-object spectroscopic surveys, we expect the PS1 sample of RR Lyrae stars to become the premier source for studying the structure, kinematics, and the gravitational potential of the Galactic halo. The techniques presented in this study should translate well to other sparse, multi-band data sets, such as those produced by the Dark Energy Survey and the upcoming Large Synoptic Survey Telescope Galactic plane sub-survey.

Superconductivity between standard types: Multiband versus single-band materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vagov, A.; Shanenko, A. A.; Milošević, M. V.

In the nearest vicinity of the critical temperature, types I and II of conventional single-band superconductors interchange at the Ginzburg-Landau parameter κ = 1/√2. At lower temperatures this point unfolds into a narrow but finite interval of κ’s, shaping an intertype (transitional) domain in the (κ,T ) plane. In the present work, based on the extended Ginzburg-Landau formalism, we show that the same picture of the two standard types with the transitional domain in between applies also to multiband superconductors. However, the intertype domain notably widens in the presence of multiple bands and can become extremely large when the systemmore » has a significant disparity between the band parameters. It is concluded that many multiband superconductors, such as recently discovered borides and iron-based materials, can belong to the intertype regime.« less

Comparison of Aerosol Optical Properties and Water Vapor Among Ground and Airborne Lidars and Sun Photometers During TARFOX

NASA Technical Reports Server (NTRS)

Ferrare, R.; Ismail, S.; Browell, E.; Brackett, V.; Clayton, M.; Kooi, S.; Melfi, S. H.; Whiteman, D.; Schwemmer, G.; Evans, K.

2000-01-01

We compare aerosol optical thickness (AOT) and precipitable water vapor (PWV) measurements derived from ground and airborne lidars and sun photometers during the Tropospheric Aerosol Radiative Forcing Observational Experiment. Such comparisons are important to verify the consistency between various remote sensing measurements before employing them in any assessment of the impact of aerosols on the global radiation balance. Total scattering ratio and extinction profiles measured by the ground-based NASA Goddard Space Flight Center scanning Raman lidar system, which operated from Wallops Island, Virginia (37.86 deg N, 75.51 deg W); are compared with those measured by the Lidar Atmospheric Sensing Experiment (LASE) airborne lidar system aboard the NASA ER-2 aircraft. Bias and root-mean-square differences indicate that these measurements generally agreed within about 10%. Aerosol extinction profiles and estimates of AOT are derived from both lidar measurements using a value for the aerosol extinction/backscattering ratio S(sub a) = 60 sr for the aerosol extinction/backscattering ratio, which was determined from the Raman lidar measurements. The lidar measurements of AOT are found to be generally within 25% of the AOT measured by the NASA Ames Airborne Tracking Sun Photometer (AATS-6). However, during certain periods the lidar and Sun photometer measurements of AOT differed significantly, possibly because of variations in the aerosol physical characteristics (e.g., size, composition) which affect S(sub a). Estimates of PWV, derived from water vapor mixing ratio profiles measured by LASE, are within 5-10% of PWV derived from the airborne Sun photometer. Aerosol extinction profiles measured by both lidars show that aerosols were generally concentrated in the lowest 2-3 km.

Design and testing of a dual-band enhanced vision system

NASA Astrophysics Data System (ADS)

Way, Scott P.; Kerr, Richard; Imamura, Joseph J.; Arnoldy, Dan; Zeylmaker, Dick; Zuro, Greg

2003-09-01

An effective enhanced vision system must operate over a broad spectral range in order to offer a pilot an optimized scene that includes runway background as well as airport lighting and aircraft operations. The large dynamic range of intensities of these images is best handled with separate imaging sensors. The EVS 2000 is a patented dual-band Infrared Enhanced Vision System (EVS) utilizing image fusion concepts. It has the ability to provide a single image from uncooled infrared imagers combined with SWIR, NIR or LLLTV sensors. The system is designed to provide commercial and corporate airline pilots with improved situational awareness at night and in degraded weather conditions but can also be used in a variety of applications where the fusion of dual band or multiband imagery is required. A prototype of this system was recently fabricated and flown on the Boeing Advanced Technology Demonstrator 737-900 aircraft. This paper will discuss the current EVS 2000 concept, show results taken from the Boeing Advanced Technology Demonstrator program, and discuss future plans for the fusion system.

Rosette globulettes and shells in the infrared

NASA Astrophysics Data System (ADS)

Mäkelä, M. M.; Haikala, L. K.; Gahm, G. F.

2014-07-01

Context. Giant galactic H ii regions surrounding central young clusters show compressed molecular shells, which have broken up into clumps, filaments, and elephant trunks interacting with UV light from central OB stars. Tiny, dense clumps of subsolar mass, called globulettes, form in this environment. Aims: We observe and explore the nature and origin of the infrared emission and extinction in these cool, dusty shell features and globulettes in one H ii region, the Rosette nebula, and search for associated newborn stars. Methods: We imaged the northwestern quadrant of the Rosette nebula in the near-infrared (NIR) through wideband JHKs filters and narrowband H2 1-0 S(1) and Pβ plus continuum filters using the Son of Isaac (SOFI) instrument at the New Technology Telescope (NTT) at European Southern Observatory (ESO). We used the NIR images to study the surface brightness of the globulettes and associated bright rims. We used the NIR JHKs photometry to create a visual extinction map and to search for objects with NIR excess emission. In addition, archival images from Spitzer Infrared Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS) 24 μm and Herschel Photoconductor Array Camera and Spectrometer (PACS) observations, covering several bands in the mid-infrared and far-infrared, were used to further analyze the stellar population, to examine the structure of the trunks and other shell structures and to study this Rosette nebula photon-dominated region in more detail. Results: The globulettes and elephant trunks have bright rims in the Ks band, which are unresolved in our images, on the sides facing the central cluster. An analysis of 21 globulettes, where surface brightness in the H2 1-0 S(1) line at 2.12 μm is detected, shows that approximately a third of the surface brightness observed in the Ks filter is due to this line: the observed average of the H2/Ks surface brightness is 0.26 ± 0.02 in the globulettes' cores and 0.30 ± 0.01 in the rims. The estimated H2 1-0 S(1) surface brightness of the rims is ˜3-8 × 10-8 Wm-2 sr-1μm-1. The ratio of the surface brightnesses support fluorescence instead of shocks as the H2 excitation mechanism. The globulettes have number densities of n(H2) ˜ 10-4 cm-3 or higher. We estimated masses of individual globulettes and compared them to the results from previous optical and radio molecular line surveys. We confirm that the larger globulettes contain very dense cores, that the density is also high farther out from the core, and that their mass is subsolar. Two NIR protostellar objects were found in an elephant trunk and one was found in the most massive globulette in our study. Based on observations done at the European Southern Observatory, La Silla, Chile (ESO programmes 084.C-0299 and 088.C-0630).Appendix A is only available in electronic form at http://www.aanda.orgTables 5 and 6 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/567/A108

[Algorithms of multiband remote sensing for coastal red tide waters].

PubMed

Mao, Xianmou; Huang, Weigen

2003-07-01

The spectral characteristics of the coastal waters in East China Sea was studied using in situ measurements, and the multiband algorithms of remote sensing for bloom waters was discussed and developed. Examples of red tide detection using the algorithms in the East China Sea were presented. The results showed that the algorithms could provide information about the location and the area coverage of the red tide events.

Peculiarities of Forming a Multiband Transmission Function Based on Multifrequency Acousto-Optic Diffraction

NASA Astrophysics Data System (ADS)

Proklov, V. V.; Rezvov, Yu. G.

2018-01-01

An analytical solution for the transmission function of noncoherent wideband radiation is obtained under acousto-optic (AO) filtering using a discrete set of monochromatic AO waves with a small spectral overlap. We studied characteristics of the AO transformation of a continuous spectrum of noncoherent radiation into a given set of discrete narrow bands of spectral transmission by excitation of a discrete set of sound frequencies. We carried out the analysis of transmission functions of individual channels taking into account a partial overlap of their spectra and possible intermodulation distortions. It is shown that a stationary value of the root-mean-square light power is found at the electronic output due to the photoelectric transformation and detecting diffracted light. Based on this, a necessary stationary, multiband, and nearly equidistant transmission function of a device can be formed by using a relevant spectrum of acoustic excitation. Peculiarities of this way of forming the multiband transmission function are revealed: the limitation of diffraction efficiency for an individual channel, the possibility of decoupling side lobes of adjacent channels, etc. A multiband acousto-optic filter (MAOF) was simulated that was based on a paratellurite monocrystal (TeO2), which was previously used for experimental optical encoding. The theoretical and experimental results are in gratifying agreement.

RCSLenS: The Red Cluster Sequence Lensing Survey

NASA Astrophysics Data System (ADS)

Hildebrandt, H.; Choi, A.; Heymans, C.; Blake, C.; Erben, T.; Miller, L.; Nakajima, R.; van Waerbeke, L.; Viola, M.; Buddendiek, A.; Harnois-Déraps, J.; Hojjati, A.; Joachimi, B.; Joudaki, S.; Kitching, T. D.; Wolf, C.; Gwyn, S.; Johnson, N.; Kuijken, K.; Sheikhbahaee, Z.; Tudorica, A.; Yee, H. K. C.

2016-11-01

We present the Red Cluster Sequence Lensing Survey (RCSLenS), an application of the methods developed for the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) to the ˜785 deg2, multi-band imaging data of the Red-sequence Cluster Survey 2. This project represents the largest public, sub-arcsecond seeing, multi-band survey to date that is suited for weak gravitational lensing measurements. With a careful assessment of systematic errors in shape measurements and photometric redshifts, we extend the use of this data set to allow cross-correlation analyses between weak lensing observables and other data sets. We describe the imaging data, the data reduction, masking, multi-colour photometry, photometric redshifts, shape measurements, tests for systematic errors, and a blinding scheme to allow for more objective measurements. In total, we analyse 761 pointings with r-band coverage, which constitutes our lensing sample. Residual large-scale B-mode systematics prevent the use of this shear catalogue for cosmic shear science. The effective number density of lensing sources over an unmasked area of 571.7 deg2 and down to a magnitude limit of r ˜ 24.5 is 8.1 galaxies per arcmin2 (weighted: 5.5 arcmin-2) distributed over 14 patches on the sky. Photometric redshifts based on four-band griz data are available for 513 pointings covering an unmasked area of 383.5 deg2. We present weak lensing mass reconstructions of some example clusters as well as the full survey representing the largest areas that have been mapped in this way. All our data products are publicly available through Canadian Astronomy Data Centre at http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/community/rcslens/query.html in a format very similar to the CFHTLenS data release.

Building the Case for SNAP: Creation of Multi-Band, Simulated Images With Shapelets

NASA Technical Reports Server (NTRS)

Ferry, Matthew A.

2005-01-01

Dark energy has simultaneously been the most elusive and most important phenomenon in the shaping of the universe. A case for a proposed space-telescope called SNAP (SuperNova Acceleration Probe) is being built, a crucial component of which is image simulations. One method for this is "Shapelets," developed at Caltech. Shapelets form an orthonormal basis and are uniquely able to represent realistic space images and create new images based on real ones. Previously, simulations were created using the Hubble Deep Field (HDF) as a basis Set in one band. In this project, image simulations are created.using the 4 bands of the Hubble Ultra Deep Field (UDF) as a basis set. This provides a better basis for simulations because (1) the survey is deeper, (2) they have a higher resolution, and (3) this is a step closer to simulating the 9 bands of SNAP. Image simulations are achieved by detecting sources in the UDF, decomposing them into shapelets, tweaking their parameters in realistic ways, and recomposing them into new images. Morphological tests were also run to verify the realism of the simulations. They have a wide variety of uses, including the ability to create weak gravitational lensing simulations.

Skylab experiment performance evaluation manual. Appendix T: Experiment T027/S073 contamination measurement, photometer and Gegenschein/zodiacal light (MSFC)

NASA Technical Reports Server (NTRS)

Meyers, J. E.

1973-01-01

A series of analyses for Experiment T027/S073, contamination measurement, photometer and gegenschein/zodiacal light (MSFC), to be used for evaluating the performance of the Skylab corollary experiments under preflight, inflight, and post-flight conditons is presented. Experiment contingency plan workaround procedure and malfunction analyses are presented in order to assist in making the experiment operationally successful.

Measurements of the skylight scattering function.

PubMed

Volz, F E

1987-10-01

A small, handheld skylight photometer, incorporated into a sun photometer and capable of measuring sky radiation to within 2 degrees of the sun at lambda 0.50 and 0.93 microm is described. Calibration procedures are discussed; solar measurements in the wideband 0.93-microm channel show the expected influence of water vapor. Formulas to obtain the aerosol scattering function are presented. Samples of measured and theoretical aerosol scattering functions are discussed.

Development of Hazards Classification Data on Propellants and Explosives

DTIC Science & Technology

1978-11-01

scattering photometer. A near forward, dark field instrument called a Sinclair-Phoenix photometer is common- ly used for measuring a wide range of...hazardä classification pro- cedure for in-process materials, and 5) Experimental evaluation of selected small-scale tests for application in the hazards...responsible for the experimental por- tion of this work. In addition to the authors, other IITRI personnel who contributed to this program were R

Demonstrating Basic Properties of Spectroscopy Using a Self-Constructed Combined Fluorimeter and UV-Photometer

ERIC Educational Resources Information Center

Kvittingen, Eivind V.; Kvittingen, Lise; Melø, Thor Bernt; Sjursnes, Birte Johanne; Verley, Richard

2017-01-01

This article describes a combined UV-photometer and fluorimeter constructed from 3 LEDs and a few wires, all held in place with Lego bricks. The instrument has a flexible design. In its simplest version, two UV-LEDs (355 nm) are used as light source and to detect absorption, and a third LED, in the visible spectrum (e.g., 525 nm), is used to…

Hand-Held Photometer for Instant On-Spot Quantification of Nucleic Acids, Proteins, and Cells.

PubMed

Li, Shi-Hao; Jain, Abhinav; Tscharntke, Timo; Arnold, Tobias; Trau, Dieter W

2018-02-20

This paper presents a novel hand-held photometer, termed "Photopette", for on-spot absorbance measurements of biochemical analytes. The Photopette is a multicomponent, highly portable device with an overall weight of 160 g, which fits within 202 mm × 47 mm × 42 mm. Designed in the form factor of a micropipette, Photopette integrates a photodiode detector with light emitting diodes (LEDs) to form a highly customizable photometer which supports a wide variety of applications within the wavelengths between 260 and 1050 nm. A dual-purpose disposable reflective tip was designed to act as a sample holder and a light-reflecting system, which is in stark contrast to the operation of mainstream spectrophotometers and photometers. Small volume analytes may be measured with low sample loss using this proprietary CuveTip. A user-friendly software application running on smart devices was developed to control and read the values from Photopette via a low-energy Bluetooth link. This one-step strategy allows measurements on-spot without sample transfer, minimizing cross-contamination and human error. The results reported in this paper demonstrate Photopette's great potential to quantify DNA, direct protein, and cell density directly within the laminar flow hood. Results are compared with a Nanodrop 2000c spectrophotometer, a mainstream spectrophotometer for small-volume measurements.

Comparison of aerosol optical depth from satellite (MODIS), sun photometer and broadband pyrheliometer ground-based observations in Cuba

NASA Astrophysics Data System (ADS)

Antuña-Marrero, Juan Carlos; Cachorro Revilla, Victoria; García Parrado, Frank; de Frutos Baraja, Ángel; Rodríguez Vega, Albeth; Mateos, David; Estevan Arredondo, René; Toledano, Carlos

2018-04-01

In the present study, we report the first comparison between the aerosol optical depth (AOD) and Ångström exponent (AE) of the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Terra (AODt) and Aqua (AODa) satellites and those measured using a sun photometer (AODSP) at Camagüey, Cuba, for the period 2008 to 2014. The comparison of Terra and Aqua data includes AOD derived with both deep blue (DB) and dark target (DT) algorithms from MODIS Collection 6. Combined Terra and Aqua (AODta) data were also considered. Assuming an interval of ±30 min around the overpass time and an area of 25 km around the sun photometer site, two coincidence criteria were considered: individual pairs of observations and both spatial and temporal mean values, which we call collocated daily means. The usual statistics (root mean square error, RMSE; mean absolute error, MAE; median bias, BIAS), together with linear regression analysis, are used for this comparison. Results show very similar values for both coincidence criteria: the DT algorithm generally displays better statistics and higher homogeneity than the DB algorithm in the behaviour of AODt, AODa, AODta compared to AODSP. For collocated daily means, (a) RMSEs of 0.060 and 0.062 were obtained for Terra and Aqua with the DT algorithm and 0.084 and 0.065 for the DB algorithm, (b) MAE follows the same patterns, (c) BIAS for both Terra and Aqua presents positive and negative values but its absolute values are lower for the DT algorithm; (d) combined AODta data also give lower values of these three statistical indicators for the DT algorithm; (e) both algorithms present good correlations for comparing AODt, AODa, AODta vs. AODSP, with a slight overestimation of satellite data compared to AODSP, (f). The DT algorithm yields better figures with slopes of 0.96 (Terra), 0.96 (Aqua) and 0.96 (Terra + Aqua) compared to the DB algorithm (1.07, 0.90, 0.99), which displays greater variability. Multi-annual monthly means of AODta establish a first climatology that is more comparable to that given by the sun photometer and their statistical evaluation reveals better agreement with AODSP for the DT algorithm. Results of the AE comparison showed similar results to those reported in the literature concerning the two algorithms' capacity for retrieval. A comparison between broadband aerosol optical depth (BAOD), derived from broadband pyrheliometer observations at the Camagüey site and three other meteorological stations in Cuba, and AOD observations from MODIS on board Terra and Aqua show a poor correlation with slopes below 0.4 for both algorithms. Aqua (Terra) showed RMSE values of 0.073 (0.080) and 0.088 (0.087) for the DB and DT algorithms. As expected, RMSE values are higher than those from the MODIS-sun photometer comparison, but within the same order of magnitude. Results from the BAOD derived from solar radiation measurements demonstrate its reliability in describing climatological AOD series estimates.

Chromoendoscopy and Advanced Imaging Technologies for Surveillance of Patients with IBD

PubMed Central

Barkin, Jodie A.; Abreu, Maria T.

2012-01-01

Inflammatory bowel disease patients with long-standing colitis have an increased risk of colorectal cancer. The high rate of interval colitis-associated cancers among patients who adhere to a nontargeted, random biopsy surveillance strategy underlies the need for improved methods of early dysplasia detection. Compelling evidence supports the efficacy of chromoendoscopy for increasing the detection rate of dysplasia; however, this technology is currently underutilized in the clinical setting. Other contrast-based technologies—including confocal laser endomicroscopy (Pentax), endocytoscopy, multiband imaging, i-scan (Pentax), and molecular-targeted techniques—show promise in the detection of dysplasia in patients with inflammatory bowel disease. The strategies currently available for identifying patients with dysplasia or colitis-associated cancers remain inadequate and need to demonstrate both cost and time efficiency before they can be adopted in community-based practices. PMID:24693269

A multi-band environment-adaptive approach to noise suppression for cochlear implants.

PubMed

Saki, Fatemeh; Mirzahasanloo, Taher; Kehtarnavaz, Nasser

2014-01-01

This paper presents an improved environment-adaptive noise suppression solution for the cochlear implants speech processing pipeline. This improvement is achieved by using a multi-band data-driven approach in place of a previously developed single-band data-driven approach. Seven commonly encountered noisy environments of street, car, restaurant, mall, bus, pub and train are considered to quantify the improvement. The results obtained indicate about 10% improvement in speech quality measures.

Momentum dependence of the superconducting gap and in-gap states in MgB 2 multiband superconductor

DOE PAGES

Mou, Daixiang; Jiang, Rui; Taufour, Valentin; ...

2015-06-29

We use tunable laser-based angle-resolved photoemission spectroscopy to study the electronic structure of the multiband superconductor MgB 2. These results form the baseline for detailed studies of superconductivity in multiband systems. We find that the magnitude of the superconducting gap on both σ bands follows a BCS-like variation with temperature with Δ 0 ~ 7meV. Furthermore, the value of the gap is isotropic within experimental uncertainty and in agreement with a pure s-wave pairing symmetry. We observe in-gap states confined to k F of the σ band that occur at some locations of the sample surface. As a result, themore » energy of this excitation, ~ 3 meV, was found to be somewhat larger than the previously reported gap on π Fermi sheet and therefore we cannot exclude the possibility of interband scattering as its origin.« less

Performance evaluation and optimization of multiband phase-modulated radio over IsOWC link with balanced coherent homodyne detection

NASA Astrophysics Data System (ADS)

Zong, Kang; Zhu, Jiang

2018-04-01

In this paper, we present a multiband phase-modulated (PM) radio over intersatellite optical wireless communication (IsOWC) link with balanced coherent homodyne detection. The proposed system can provide the transparent transport of multiband radio frequency (RF) signals with higher linearity and better receiver sensitivity than intensity modulated with direct detection (IM/DD) system. The expressions of RF gain, noise figure (NF) and third-order spurious-free dynamic range (SFDR) are derived considering the third-order intermodulation product and amplifier spontaneous emission (ASE) noise. The optimal power of local oscillator (LO) optical signal is also derived theoretically. Numerical results for RF gain, NF and third-order SFDR are given for demonstration. Results indicate that the gain of the optical preamplifier and the power of LO optical signal should be optimized to obtain the satisfactory performance.

Multiband DSB-SC modulated radio over IsOWC link with coherent homodyne detection

NASA Astrophysics Data System (ADS)

Kang, Zong; Zhu, Jiang

2018-02-01

In this paper, we present a multiband double sideband-suppressed carrier (DSB-SC) modulated radio over intersatellite optical wireless communication (IsOWC) link with coherent homodyne detection. The proposed system can provide the transparent transport of multiband radio frequency (RF) signals with higher linearity and better receiver sensitivity than the intensity modulated with direct detection (IM/DD) scheme. The full system model and the exactly analytical expression of signal to noise and distortion ratio (SNDR) are derived considering the third-order intermodulation product and amplifier spontaneous emission (ASE) noise. The finite extinction ratio (ER) of Mach-Zehnder Modulator (MZM) and the saturation property of erbium doped fiber amplifier (EDFA) are also considered. Numerical results of SNDR with various numbers of subchannels and ERs are given. Results indicate that the optimal modulation index exists to maximize the SNDR and the power of local oscillator (LO) carrier should be within an appropriate range.

Multiband product rule and consonant identification.

PubMed

Li, Feipeng; Allen, Jont B

2009-07-01

The multiband product rule, also known as band-independence, is a basic assumption of articulation index and its extension, the speech intelligibility index. Previously Fletcher showed its validity for a balanced mix of 20% consonant-vowel (CV), 20% vowel-consonant (VC), and 60% consonant-vowel-consonant (CVC) sounds. This study repeats Miller and Nicely's version of the hi-/lo-pass experiment with minor changes to study band-independence for the 16 Miller-Nicely consonants. The cut-off frequencies are chosen such that the basilar membrane is evenly divided into 12 segments from 250 to 8000 Hz with the high-pass and low-pass filters sharing the same six cut-off frequencies in the middle. Results show that the multiband product rule is statistically valid for consonants on average. It also applies to subgroups of consonants, such as stops and fricatives, which are characterized by a flat distribution of speech cues along the frequency. It fails for individual consonants.

Interband interference effects at the edge of a multiband chiral p -wave superconductor

NASA Astrophysics Data System (ADS)

Zhang, Jia-Long; Huang, Wen; Sigrist, Manfred; Yao, Dao-Xin

2017-12-01

Chiral superconductors support chiral edge modes and potentially spontaneous edge currents at their boundaries. Motivated by the putative multiband chiral p -wave superconductor Sr2RuO4 , we study the influence of the interference between different bands at the edges, which may appear in the presence of moderate edge disorder or in edge tunneling measurements. We show that interband interference can strongly modify the measurable quantities at the edges when the order parameter exhibits phase difference between the bands. This is illustrated by investigating the edge dispersion and the edge current distribution in the presence of interband mixing, as well as the conductance at a tunneling junction. The results are discussed in connection with the putative chiral p -wave superconductor Sr2RuO4 . In passing, we also discuss similar interference effects in multiband models with other pairing symmetries.

The use of LANDSAT-1 imagery for water quality studies in southern Scandinavia

NASA Technical Reports Server (NTRS)

Hellden, U.

1975-01-01

The possibilities of using LANDSAT-1 images for environmental studies, with special references to water quality studies, were investigated by selecting test areas in southern Scandinavia. The MSS images of different bands are compared under the magnification of an Interpretoscope and densitometric analyses are performed in a Schnell-photometer. The possibility of tracing pollution plumes is studied in the Oresund outside Copenhagen. The effect of different sewers and the circulation of the polluted water is analyzed in various situations. The variation in reflectivity of a great number of lakes in South and Middle Sweden is studied by means of densitometric analyses and significant regional differences are found. The correlation with in situ measurements of water quality (turbidity and secchi disc transparency) of the sampled lakes (made by the National Swedish Environment Protection Board) is fairly good.

SELECTION OF BURST-LIKE TRANSIENTS AND STOCHASTIC VARIABLES USING MULTI-BAND IMAGE DIFFERENCING IN THE PAN-STARRS1 MEDIUM-DEEP SURVEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, S.; Gezari, S.; Heinis, S.

2015-03-20

We present a novel method for the light-curve characterization of Pan-STARRS1 Medium Deep Survey (PS1 MDS) extragalactic sources into stochastic variables (SVs) and burst-like (BL) transients, using multi-band image-differencing time-series data. We select detections in difference images associated with galaxy hosts using a star/galaxy catalog extracted from the deep PS1 MDS stacked images, and adopt a maximum a posteriori formulation to model their difference-flux time-series in four Pan-STARRS1 photometric bands g {sub P1}, r {sub P1}, i {sub P1}, and z {sub P1}. We use three deterministic light-curve models to fit BL transients; a Gaussian, a Gamma distribution, and anmore » analytic supernova (SN) model, and one stochastic light-curve model, the Ornstein-Uhlenbeck process, in order to fit variability that is characteristic of active galactic nuclei (AGNs). We assess the quality of fit of the models band-wise and source-wise, using their estimated leave-out-one cross-validation likelihoods and corrected Akaike information criteria. We then apply a K-means clustering algorithm on these statistics, to determine the source classification in each band. The final source classification is derived as a combination of the individual filter classifications, resulting in two measures of classification quality, from the averages across the photometric filters of (1) the classifications determined from the closest K-means cluster centers, and (2) the square distances from the clustering centers in the K-means clustering spaces. For a verification set of AGNs and SNe, we show that SV and BL occupy distinct regions in the plane constituted by these measures. We use our clustering method to characterize 4361 extragalactic image difference detected sources, in the first 2.5 yr of the PS1 MDS, into 1529 BL, and 2262 SV, with a purity of 95.00% for AGNs, and 90.97% for SN based on our verification sets. We combine our light-curve classifications with their nuclear or off-nuclear host galaxy offsets, to define a robust photometric sample of 1233 AGNs and 812 SNe. With these two samples, we characterize their variability and host galaxy properties, and identify simple photometric priors that would enable their real-time identification in future wide-field synoptic surveys.« less

Black carbon aerosol properties measured by a single particle soot photometer in emissions from biomass burning in the laboratory and field

Treesearch

G. R. McMeeking; J. W. Taylor; A. P. Sullivan; M. J. Flynn; S. K. Akagi; C. M. Carrico; J. L. Collett; E. Fortner; T. B. Onasch; S. M. Kreidenweis; R. J. Yokelson; C. Hennigan; A. L. Robinson; H. Coe

2010-01-01

We present SP2 observations of BC mass, size distributions and mixing state in emissions from laboratory and field biomass fires in California, USA. Biomass burning is the primary global black carbon (BC) source, but understanding of the amount emitted and its physical properties at and following emission are limited. The single particle soot photometer (SP2) uses a...

A fibre optic, four channel comparative photometer

NASA Technical Reports Server (NTRS)

Walker, E. N.

1988-01-01

Development of a four channel comparative photometer is described. Tests have shown that it is stable from night to night and is capable of working in very poor sky conditions. Even when the sky conditions are so poor that stars are barely visible, light curves can still be obtained with an r.m.s. value of 0.0016 mag., provided that integration times that are long compared with the transparancy changes are possible.

A solar infrared photometer for space flight application

NASA Technical Reports Server (NTRS)

Kostiuk, Theodor; Deming, Drake

1991-01-01

A photometer concept which is capable of nearly simultaneous measurements of solar radiation from 1.6 to 200 microns in seven wavelength bands is described. This range of wavelengths can probe the solar photosphere from below the level of unit optical depth in the visible to the temperature minimum, about 500 km above it. An instrument package including a 20-cm Gregorian telescope and a filter wheel photometer utilizing noncryogenic pyroelectric infrared detectors is described. Approaches to the rejection of the visible solar spectrum in the instrument, the availability of optical and mechanical components, and the expected instrumental sensitivity are discussed. For wavelengths below 35 microns, the projected instrumental sensitivity is found to be adequate to detect the intensity signature of solar p-mode oscillations during 5 min of integration. For longer wavelengths, clear detection is expected through Fourier analysis of modest data sets.

Validating Phasing and Geometry of Large Focal Plane Arrays

NASA Technical Reports Server (NTRS)

Standley, Shaun P.; Gautier, Thomas N.; Caldwell, Douglas A.; Rabbette, Maura

2011-01-01

The Kepler Mission is designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-sized and smaller planets in or near the habitable zone. The Kepler photometer is an array of 42 CCDs (charge-coupled devices) in the focal plane of a 95-cm Schmidt camera onboard the Kepler spacecraft. Each 50x25-mm CCD has 2,200 x 1,024 pixels. The CCDs accumulate photons and are read out every six seconds to prevent saturation. The data is integrated for 30 minutes, and then the pixel data is transferred to onboard storage. The data is subsequently encoded and transmitted to the ground. During End-to-End Information System (EEIS) testing of the Kepler Mission System (KMS), there was a need to verify that the pixels requested by the science team operationally were correctly collected, encoded, compressed, stored, and transmitted by the FS, and subsequently received, decoded, uncompressed, and displayed by the Ground Segment (GS) without the outputs of any CCD modules being flipped, mirrored, or otherwise corrupted during the extensive FS and GS processing. This would normally be done by projecting an image on the focal plane array (FPA), collecting the data in a flight-like way, and making a comparison between the original data and the data reconstructed by the science data system. Projecting a focused image onto the FPA through the telescope would normally involve using a collimator suspended over the telescope opening. There were several problems with this approach: the collimation equipment is elaborate and expensive; as conceived, it could only illuminate a limited section of the FPA (.25 percent) during a given test; the telescope cover would have to be deployed during testing to allow the image to be projected into the telescope; the equipment was bulky and difficult to situate in temperature-controlled environments; and given all the above, test setup, execution, and repeatability were significant concerns. Instead of using this complicated approach of projecting an optical image on the FPA, the Kepler project developed a method using known defect features in the CCDs to verify proper collection and reassembly of the pixels, thereby avoiding the costs and risks of the optical projection approach. The CCDs composing the Kepler FPA, as all CCDs, had minor defects. At ambient temperature, some pixels look far brighter than they should. These ghot h pixels have a higher rate of charge leakage than the others due to manufacturing variations. They are usually stable over time, and appear at temperatures above 5 oC. The hot pixels on the Kepler FPA were mapped before photometer assembly during module testing. Selected hot pixels were used as target gstars h for the purposes of EEIS testing. gDead h pixels are permanently off, producing a permanently black pixel. These can also be used if there is some illumination of the FPA. During EEIS testing, Dark Current Full Frame Images (FFIs) taken at room temperature were used to create the hot pixel maps for all 84 Kepler photometer CCD channels. Data from two separate nights were used to create two hot pixel maps per channel, which were cross-correlated to remove cosmic ray events which appear to be hot pixels. These hot pixel maps obtained during EEIS testing were compared to the maps made during module testing to verify that the end-to-end data flow was correct.

[Application of single-band brightness variance ratio to the interference dissociation of cloud for satellite data].

PubMed

Qu, Wei-ping; Liu, Wen-qing; Liu, Jian-guo; Lu, Yi-huai; Zhu, Jun; Qin, Min; Liu, Cheng

2006-11-01

In satellite remote-sensing detection, cloud as an interference plays a negative role in data retrieval. How to discern the cloud fields with high fidelity thus comes as a need to the following research. A new method rooting in atmospheric radiation characteristics of cloud layer, in the present paper, presents a sort of solution where single-band brightness variance ratio is used to detect the relative intensity of cloud clutter so as to delineate cloud field rapidly and exactly, and the formulae of brightness variance ratio of satellite image, image reflectance variance ratio, and brightness temperature variance ratio of thermal infrared image are also given to enable cloud elimination to produce data free from cloud interference. According to the variance of the penetrating capability for different spectra bands, an objective evaluation is done on cloud penetration of them with the factors that influence penetration effect. Finally, a multi-band data fusion task is completed using the image data of infrared penetration from cirrus nothus. Image data reconstruction is of good quality and exactitude to show the real data of visible band covered by cloud fields. Statistics indicates the consistency of waveband relativity with image data after the data fusion.

Land use mapping and modelling for the Phoenix Quadrangle

NASA Technical Reports Server (NTRS)

Place, J. L. (Principal Investigator)

1973-01-01

The author has identified the following significant results. The land use of the Phoenix Quadrangle in Arizona had been mapped previously from aerial photographs and recorded in a computer data bank. During the ERTS experiment, changes in land use were detected, first with the ERTS-simulation photographs, then with the ERTS-1 images when they became available. In each case, the I2S color additive viewer was used as the primary image enhancement tool, operated in a multispectral mode. A search was made for a method of creating hard copy color composite images of the best combinations of multiband composites from ERTS-1, mostly by photographic and diazo processes. The I2S viewer was also used to enhance changes between successive images by quick flip techniques or by registering with different color filters. Improved interpretation of land use change resulted, and a map of changes in the Phoenix Quadrangle was compiled using magnified ERTS-1 images alone. The first level of a standard land use classification system was successfully used. Between the ERTS-1 images for August and November, some differences were detected that could be caused by seasonal characteristics of vegetation or by change in use.

Land use mapping and modelling for the Phoenix Quadrangle

NASA Technical Reports Server (NTRS)

Place, J. L. (Principal Investigator)

1973-01-01

The author has identified the following significant results. The land use of the Phoenix Quadrangle in Arizona had been mapped previously from aerial photographs and recorded in a computer data bank. During the ERTS-1 experiment, changes in land use were detected using only the ERTS-1 images. The I2S color additive viewer was used as the principal image enhancement tool, operated in a multispectral mode. Hard copy color composite images of the best multiband combinations from ERTS-1 were made by photographic and diazo processes. The I2S viewer was also used to enhance changes between successive images by quick flip techniques or by registering with different color filters. More recently, a Bausch and Lomb zoom transferscope has been used for the same purpose. Improved interpretation of land use change resulted, and a map of changes within the Phoenix Quadrangle was compiled. The first level of a proposed standard land use classification system was sucessfully used. ERTS-1 underflight photography was used to check the accuracy of the ERTS-1 image interpretation. It was found that the total areas of change detected in the photos were comparable with the total areas of change detected in the ERTS-1 images.

General review of multispectral cooled IR development at CEA-Leti, France

NASA Astrophysics Data System (ADS)

Boulard, F.; Marmonier, F.; Grangier, C.; Adelmini, L.; Gravrand, O.; Ballet, P.; Baudry, X.; Baylet, J.; Badano, G.; Espiau de Lamaestre, R.; Bisotto, S.

2017-02-01

Multicolor detection capabilities, which bring information on the thermal and chemical composition of the scene, are desirable for advanced infrared (IR) imaging systems. This communication reviews intra and multiband solutions developed at CEA-Leti, from dual-band molecular beam epitaxy grown Mercury Cadmium Telluride (MCT) photodiodes to plasmon-enhanced multicolor IR detectors and backside pixelated filters. Spectral responses, quantum efficiency and detector noise performances, pros and cons regarding global system are discussed in regards to technology maturity, pixel pitch reduction, and affordability. From MWIR-LWIR large band to intra MWIR or LWIR bands peaked detection, results underline the full possibility developed at CEA-Leti.

Remote sensing of atmospheric aerosol and ocean color for the COMS/GOCI

NASA Astrophysics Data System (ADS)

Lee, Kwon-Ho; Kim, Young J.; Kim, Gwan C.; Wong, Man S.; Ahn, Yu H.

2010-10-01

The Geostationary Ocean Color Imager (GOCI) on board the Communication Ocean Meteorological Satellite (COMS) requires accurate atmospheric correction for the purpose of qualified ocean remote sensing. Since its eight bands are affected by atmospheric constituents such as gases, molecules and atmospheric aerosols, understanding of aerosolradiation interactions is needed. Aerosol optical properties based on sun-photometer measurements are used to analysis aerosol optical thickness (AOT) under various aerosol type and loadings. It is found that the choice of aerosol type makes little different in AOT retrieval for AOT<0.2. These results will be useful for aerosol retrieval of COMS/GOCI data processing.

NGC 5523: An isolated product of soft galaxy mergers?

NASA Astrophysics Data System (ADS)

Fulmer, Leah M.; Gallagher, John S.; Kotulla, Ralf

2017-02-01

Multi-band images of the very isolated spiral galaxy NGC 5523 show a number of unusual features consistent with NGC 5523 having experienced a significant merger. (1) Near-infrared images from the Spitzer Space Telescope (SST) and the WIYN 3.5-m telescope reveal a nucleated bulge-like structure embedded in a spiral disk; (2) the bulge is offset by 1.8 kpc from a brightness minimum at the center of the optically bright inner disk; (3) a tidal stream, possibly associated with an ongoing satellite interaction, extends from the nucleated bulge along the disk. We interpret these properties as the results of one or more non-disruptive mergers between NGC 5523 and companion galaxies or satellites, raising the possibility that some galaxies become isolated because they have merged with former companions. The reduced images (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A119

Selective coherent perfect absorption in metamaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nie, Guangyu; Shi, Quanchao; Zhu, Zheng

2014-11-17

We show multi-band coherent perfect absorption (CPA) in simple bilayered asymmetrically split ring metamaterials. The selectivity of absorption can be accomplished by separately excited electric and magnetic modes in a standing wave formed by two coherent counterpropagating beams. In particular, each CPA can be completely switched on/off by the phase of a second coherent wave. We propose a practical scheme for realizing multi-band coherent perfect absorption of 100% that is allowed to work from microwave to optical frequency.

Multiband Spectral-Spatial RF Excitation for Hyperpolarized [2-13C]Dihydroxyacetone 13C-MR Metabolism Studies

PubMed Central

Marco-Rius, Irene; Cao, Peng; von Morze, Cornelius; Merrit, Matthew; Moreno, Karlos X; Chang, Gene-Yuan; Ohliger, Michael A.; Pearce, David; Kurhanewicz, John; Larson, Peder E. Z.; Vigneron, Daniel B.

2016-01-01

Purpose To develop a specialized multislice, single-acquisition approach to detect the metabolites of hyperpolarized [2-13C]dihydroxyacetone (DHAc) to probe gluconeogenesis in vivo, which have a broad 144 ppm spectral range (~4.6 KHz at 3T). A novel multiband RF excitation pulse was designed for independent flip angle control over 5-6 spectral-spatial (SPSP) excitation bands, each corrected for chemical shift misregistration effects. Methods Specialized multi-band SPSP RF pulses were designed, tested and applied to investigate hyperpolarized [2-13C]DHAc metabolism in kidney and liver of fasted rats with dynamic 13C-MRS and an optimal flip angle scheme. For comparison, experiments were also performed with narrow-band slice-selective RF pulses and a sequential change of the frequency offset to cover the five frequency bands of interest. Results The SPSP pulses provided a controllable spectral profile free of baseline distortion with improved signal to noise of the metabolite peaks, allowing for quantification of the metabolic products. We observed organ-specific differences in DHAc metabolism. There was 2-5 times more [2-13C]phosphoenolpyruvate and about 19 times more [2-13C]glycerol 3-phosphate in the liver than in the kidney. Conclusion A multiband SPSP RF pulse covering a spectral range over 144 ppm enabled in vivo characterization of HP [2-13C]dihydroxyacetone metabolism in rat liver and kidney. PMID:27017966

Vitamin D synthesis measured with a multiband filter radiometer in Río Gallegos, Argentina

NASA Astrophysics Data System (ADS)

Orte, Facundo; Wolfram, Elian; Salvador, Jacobo; D'Elia, Raúl; Bulnes, Daniela; Leme, N. Paes; Quel, Eduardo

2013-05-01

Vitamin D plays an important role in human health. Vitamin D production from the sun is affected by UVB solar radiation. This paper presents a simple method for retrieving vitamin D-weighted UV by using a multiband filter radiometer GUV-541 installed at the Atmospheric Observatory of Southern Patagonia (OAPA) (51 ° 33' S, 69° 19' W), Río Gallegos. The methodology used combines irradiance measurements from a multiband filter radiometer with spectral irradiance modeled by the SOS radiative transfer code (developed by Lille University of Science and Technology (USTL)). The spectrum modeled is weighted with vitamin D action spectra published by the International Commission on Illumination (CIE), which describes the relative effectiveness of different wavelengths in the generation of this particular biological response. This method is validated using the vitamin D-weighted UV derived from a Brewer MKIII spectrophotometer (SN 124) belonging to the National Institute for Spatial Research (INPE), Brazil, which is able to measure solar spectra between 290 and 325nm. The method presents a good correlation between the two independent instruments. This procedure increases the instrumental capabilities of the multiband filter radiometer. Moreover, it evaluates the annual variation of vitamin D-weighted UV doses from exposure to ultraviolet radiation. These values are likely to be lower than suitable levels of vitamin D during winter and part of spring and autumn at these latitudes.

VizieR Online Data Catalog: NGC 4038/4039 broad and /narrow band photometry (Mengel+, 2005)

NASA Astrophysics Data System (ADS)

Mengel, S.; Lehnert, M. D.; Thatte, N.; Genzel, R.

2005-06-01

The Ks-band image which was used for the 3{sigma}-detection was obtained with ISAAC on VLT-ANTU as part of programme 65.N-0577, and has a FWHM of ~0.38". 1072 point-like objects were detected. For the multi-band photometry, we also used the HST archival images obtained by Whitmore et al. (see Whitmore et al., 1999AJ....118.1551W), which we rebinned to the same pixel size as the ISAAC image (0.1484"/pix). The CO narrow band image was also obtained with ISAAC, while the Br{gamma} image was obtained with SOFI at the NTT (programme number 63.N-0528). The Br{gamma} image had a lower image quality than the other two images (FWHM=0.7"). The photometry data were used to simultaneously fit age and extinction for each individual cluster in comparison to an evolutionary synthesis model. Where possible, the visual extinction was determined from an average of the extinction from the broadband fit and from the Hydrogen recombination line ratios (in comparison to the expected Case B line ratio). The age estimate from the fit was, where possible, averaged with the aged determined from equivalent widths and CO index. (1 data file).

Coordinated ionospheric and magnetospheric observations from the ISIS 2 satellite by the ISIS 2 experimenters. Volume 3: High-latitude charged particle, magnetic field and ionospheric plasma observations during northern summer

NASA Technical Reports Server (NTRS)

1980-01-01

A list of ISIS 2 experiments and a description of the satellite are presented. Instrumentation of the satellite included an auroral scanning photometer, a red line photometer, a swept frequency sounder, an ion mass spectrometer, and triaxial fluxgate magnetometer. Data format descriptions are provided. Included with the geophysical data set is a list of all passes.

Super-resolved Parallel MRI by Spatiotemporal Encoding

PubMed Central

Schmidt, Rita; Baishya, Bikash; Ben-Eliezer, Noam; Seginer, Amir; Frydman, Lucio

2016-01-01

Recent studies described an alternative “ultrafast” scanning method based on spatiotemporal (SPEN) principles. SPEN demonstrates numerous potential advantages over EPI-based alternatives, at no additional expense in experimental complexity. An important aspect that SPEN still needs to achieve for providing a competitive acquisition alternative entails exploiting parallel imaging algorithms, without compromising its proven capabilities. The present work introduces a combination of multi-band frequency-swept pulses simultaneously encoding multiple, partial fields-of-view; together with a new algorithm merging a Super-Resolved SPEN image reconstruction and SENSE multiple-receiving methods. The ensuing approach enables one to reduce both the excitation and acquisition times of ultrafast SPEN acquisitions by the customary acceleration factor R, without compromises in either the ensuing spatial resolution, SAR deposition, or the capability to operate in multi-slice mode. The performance of these new single-shot imaging sequences and their ancillary algorithms were explored on phantoms and human volunteers at 3T. The gains of the parallelized approach were particularly evident when dealing with heterogeneous systems subject to major T2/T2* effects, as is the case upon single-scan imaging near tissue/air interfaces. PMID:24120293

Hi-fidelity multi-scale local processing for visually optimized far-infrared Herschel images

NASA Astrophysics Data System (ADS)

Li Causi, G.; Schisano, E.; Liu, S. J.; Molinari, S.; Di Giorgio, A.

2016-07-01

In the context of the "Hi-Gal" multi-band full-plane mapping program for the Galactic Plane, as imaged by the Herschel far-infrared satellite, we have developed a semi-automatic tool which produces high definition, high quality color maps optimized for visual perception of extended features, like bubbles and filaments, against the high background variations. We project the map tiles of three selected bands onto a 3-channel panorama, which spans the central 130 degrees of galactic longitude times 2.8 degrees of galactic latitude, at the pixel scale of 3.2", in cartesian galactic coordinates. Then we process this image piecewise, applying a custom multi-scale local stretching algorithm, enforced by a local multi-scale color balance. Finally, we apply an edge-preserving contrast enhancement to perform an artifact-free details sharpening. Thanks to this tool, we have thus produced a stunning giga-pixel color image of the far-infrared Galactic Plane that we made publicly available with the recent release of the Hi-Gal mosaics and compact source catalog.

(abstract) Topographic Signatures in Geology

NASA Technical Reports Server (NTRS)

Farr, Tom G.; Evans, Diane L.

1996-01-01

Topographic information is required for many Earth Science investigations. For example, topography is an important element in regional and global geomorphic studies because it reflects the interplay between the climate-driven processes of erosion and the tectonic processes of uplift. A number of techniques have been developed to analyze digital topographic data, including Fourier texture analysis. A Fourier transform of the topography of an area allows the spatial frequency content of the topography to be analyzed. Band-pass filtering of the transform produces images representing the amplitude of different spatial wavelengths. These are then used in a multi-band classification to map units based on their spatial frequency content. The results using a radar image instead of digital topography showed good correspondence to a geologic map, however brightness variations in the image unrelated to topography caused errors. An additional benefit to the use of Fourier band-pass images for the classification is that the textural signatures of the units are quantative measures of the spatial characteristics of the units that may be used to map similar units in similar environments.

Multiple Waveband Temperature Sensor (MWTS)

NASA Technical Reports Server (NTRS)

Bandara, Sumith V.; Gunapala, Sarath; Wilson, Daniel; Stirbl, Robert; Blea, Anthony; Harding, Gilbert

2006-01-01

This slide presentation reviews the development of Multiple Waveband Temperature Sensor (MWTS). The MWTS project will result in a highly stable, monolithically integrated, high resolution infrared detector array sensor that records registered thermal imagery in four infrared wavebands to infer dynamic temperature profiles on a laser-irradiated ground target. An accurate surface temperature measurement of a target in extreme environments in a non-intrusive manner is required. The development challenge is to: determine optimum wavebands (suitable for target temperatures, nature of the targets and environments) to measure accurate target surface temperature independent of the emissivity, integrate simultaneously readable multiband Quantum Well Infrared Photodetectors (QWIPs) in a single monolithic focal plane array (FPA) sensor and to integrate the hardware/software and system calibration for remote temperature measurements. The charge was therefore to develop and demonstrate a multiband infrared imaging camera with the detectors simultaneously sensitive to multiple distinct color bands for front surface temperature measurements Wavelength ( m) measurements. Amongst the requirements are: that the measurement system will not affect target dynamics or response to the laser irradiation and that the simplest criterion for spectral band selection is to choose those practically feasible spectral bands that create the most contrast between the objects or scenes of interest in the expected environmental conditions. There is in the presentation a review of the modeling and simulation of multi-wave infrared temperature measurement and also a review of the detector development and QWIP capacities.

Observations of Exoplanets with the Stratospheric Observatory for Infrared Astronomy (SOFIA)

NASA Astrophysics Data System (ADS)

Gehrz, R.; Becklin, E.

2010-10-01

The joint U.S. and German Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5-meter infrared airborne telescope in a Boeing 747-SP that will begin science flights in 2010. Flying in the stratosphere at altitudes as high as 45,000 feet, SOFIA will be used to conduct photometric, spectroscopic, and imaging observations at wavelengths from 0.3 microns to 1.9 millimeters with an average transmission of greater than 80 percent. SOFIA's first-generation instrument complement includes high speed photometers, broadband imagers, moderate resolution spectrographs capable of resolving broad features due to dust and large molecules, and high resolution spectrometers suitable for kinematic studies of molecular and atomic gas lines at km/s resolution. These and future instruments will give SOFIA the potential to make unique contributions to the characterization of the atmospheres of exoplanets that transit their parent stars. First-light images obtained on May 26, 2010 with the FORCAST imager will be shown. We will discuss several types of experiments that are being contemplated with respect to observations of exoplanets .

Multiband rectenna for microwave applications

NASA Astrophysics Data System (ADS)

Okba, Abderrahim; Takacs, Alexandru; Aubert, Hervé; Charlot, Samuel; Calmon, Pierre-François

2017-02-01

This paper reports a multiband rectenna (rectifier + antenna) suitable for the electromagnetic energy harvesting of the spill-over loss of microwave antennas placed on board of geostationary satellites. Such rectenna is used for powering autonomous wireless sensors for satellite health monitoring. The topology of the rectenna is presented. The experimental results demonstrate that the proposed compact rectenna can harvest efficiently the incident electromagnetic energy at three different frequencies that are close to the resonant frequencies of the cross-dipoles implemented in the antenna array. xml:lang="fr"

The Design and Evaluation of Transmit and Receive Antennas for an Ionospheric Communications Probe System: A. Multiband Dipole Antenna

DTIC Science & Technology

1992-12-01

RECEIVE ANTENNAS FOR AN IONOSPHERIC COMMUNICATIONS PROBE SYSTEM: A. MULTIBAND DIPOLE ANTENNA by Sotirios Georgios Perros December, 1992 Thesis Advisor...PROBE SYSTEM: A. MULTIBANDDIPOLE ANTENNA 12 PERSONAL AUTHOR(S) PERROS , Sotirios Georgios 13a TYPE OF REPORT 13b TIME COVERED 14 DATE OF REPORT (Year...Sotirios Georgios Perros By Lieutenant, Hellenic Navy Dist! ibution I B.S., Hellenic Naval Academy, 1984 Availabiity des Avail i•,(lior Submitted in

The Ivory Coral Program on Ionospheric Modification

DTIC Science & Technology

1974-09-01

k . and \\..1-- y - Transmitterlooosonde rl IDENVER I /240 km WESTCLIFFE Photometer 8727-65-396 FIGURE 5 LOCATION OF PHOTOMETERS TO MEASURE 6300-A...Nebraska 4ro ns Trc nsmitter 400J DEUVER Co Io ado Co’orodo Springs 38° Westcliffe 080 0I1020 8727-65-397 UGURE 6 TYPICAL AIRGLOW REGION AT ABOUT...FIGURE 7 AIRGLQW OF 18 SEPTEMBER 1972 AT 2130 MST 4-4- - ~ ml <~,ele ero sko Craig 400 Erie ~ ATrasmiter DENVERI Colorado Springs 380 Westcliffe 1080

Preliminary results of an intercomparison of total ozone spectrophotometers

NASA Technical Reports Server (NTRS)

Parsons, C. L.; Gerlach, J. C.; Williams, M. E.; Kerr, J. B.

1981-01-01

Preliminary results from an intercomparison of five total ozone spectrophotometers are presented. These are the Dobson spectrophotometer, the USSR M-83 ozonometer, the Canterbury filter photometer, the SenTran Company filter photometer, and the Brewer grating spectrophotometer. The pertinent characteristics of each are described, and conclusions are drawn about the agreement of each instrument's measurements with the Dobson's values over a time period of nearly one year. A discussion of the importance of calibration and long-term stability and reliability is included.

Method of Reproduction of the Luminous Flux of the LED Light Sources by a Spherical Photometer

NASA Astrophysics Data System (ADS)

Huriev, M.; Neyezhmakov, P.

2018-02-01

In connection with transition to energy-efficient temporally stable light-emitting diodes (LEDs) lighting, a problem of ensuring the traceability of results of measurement of characteristics of light sources arises. The problem is related to existing measurement standards of luminous flux based on spherical photometers optimized for the reference incandescent lamps with a relative spectral characteristic different from the spectrum of the LEDs. We propose a method for reproduction of the luminous flux, which solves this problem.

VizieR Online Data Catalog: From optical to infrared photometry of SN 2013dy (Pan+, 2015)

NASA Astrophysics Data System (ADS)

Pan, Y.-C.; Foley, R. J.; Kromer, M.; Fox, O. D.; Zheng, W.; Challis, P.; Clubb, K. I.; Filippenko, A. V.; Folatelli, G.; Graham, M. L.; Hillebrandt, W.; Kirshner, R. P.; Lee, W. H.; Pakmor, R.; Patat, F.; Phillips, M. M.; Pignata, G.; Ropke, F.; Seitenzahl, I.; Silverman, J. M.; Simon, J. D.; Sternberg, A.; Stritzinger, M. D.; Taubenberger, S.; Vinko, J.; Wheeler, J. C.

2017-11-01

We obtained broad-band BVRI photometry of SN 2013dy with the 0.76m Katzman Automatic Imaging Telescope (KAIT; Filippenko et al. 2001ASPC..246..121F). The multiband images were observed with the KAIT4 filter set from -16d to +337d relative to B-band maximum (MJD=56501.105). We also obtained riZYJH photometry of SN 2013dy with the multichannel Reionization And Transients InfraRed camera (RATIR; Butler et al. 2012SPIE.8446E..10B) mounted on the 1.5m Johnson telescope at the Mexican Observatorio Astronomico Nacional on Sierra San Pedro Martir in Baja California, Mexico (Watson et al. 2012SPIE.8444E..5LW). Typical observations include a series of 80s exposures in the ri bands and 60s exposures in the ZYJH bands, with dithering between exposures. (2 data files).

Archeological treasures protection based on early forest wildfire multi-band imaging detection system

NASA Astrophysics Data System (ADS)

Gouverneur, B.; Verstockt, S.; Pauwels, E.; Han, J.; de Zeeuw, P. M.; Vermeiren, J.

2012-10-01

Various visible and infrared cameras have been tested for the early detection of wildfires to protect archeological treasures. This analysis was possible thanks to the EU Firesense project (FP7-244088). Although visible cameras are low cost and give good results during daytime for smoke detection, they fall short under bad visibility conditions. In order to improve the fire detection probability and reduce the false alarms, several infrared bands are tested ranging from the NIR to the LWIR. The SWIR and the LWIR band are helpful to locate the fire through smoke if there is a direct Line Of Sight. The Emphasis is also put on the physical and the electro-optical system modeling for forest fire detection at short and longer ranges. The fusion in three bands (Visible, SWIR, LWIR) is discussed at the pixel level for image enhancement and for fire detection.

ConvPhot: A profile-matching algorithm for precision photometry

NASA Astrophysics Data System (ADS)

De Santis, C.; Grazian, A.; Fontana, A.; Santini, P.

2007-02-01

We describe in this paper a new, public software for accurate "PSF-matched" multiband photometry for images of different resolution and depth, that we have named ConvPhot, of which we analyse performances and limitations. It is designed to work when a high resolution image is available to identify and extract the objects, and colours or variations in luminosity are to be measured in another image of lower resolution but comparable depth. To maximise the usability of this software, we explicitly use the outputs of the popular SExtractor code that is used to extract all objects from the high resolution "detection" image. The technique adopted by the code is essentially to convolve each object to the PSF of the lower resolution "measure" image, and to obtain the flux of each object by a global χ2 minimisation on such measure image. We remark that no a priori assumption is done on the shape of the objects. In this paper we provide a full description of the algorithm, a discussion of the possible systematic effects involved and the results of a set of simulations and validation tests that we have performed on real as well as simulated images. The source code of ConvPhot, written in C language under the GNU Public License, is released worldwide.

ASTER VNIR 15 years growth to the standard imaging radiometer in remote sensing

NASA Astrophysics Data System (ADS)

Hiramatsu, Masaru; Inada, Hitomi; Kikuchi, Masakuni; Sakuma, Fumihiro

2015-10-01

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Visible and Near Infrared Radiometer (VNIR) is the remote sensing equipment which has 3 spectral bands and one along-track stereoscopic band radiometer. ASTER VNIR's planned long life design (more than 5 years) is successfully achieved. ASTER VNIR has been imaging the World-wide Earth surface multiband images and the Global Digital Elevation Model (GDEM). VNIR data create detailed world-wide maps and change-detection of the earth surface as utilization transitions and topographical changes. ASTER VNIR's geometric resolution is 15 meters; it is the highest spatial resolution instrument on NASA's Terra spacecraft. Then, ASTER VNIR was planned for the geometrical basis map makers in Terra instruments. After 15-years VNIR growth to the standard map-maker for space remote-sensing. This paper presents VNIR's feature items during 15-year operation as change-detection images , DEM and calibration result. VNIR observed the World-wide Earth images for biological, climatological, geological, and hydrological study, those successful work shows a way on space remote sensing instruments. Still more, VNIR 15 years observation data trend and onboard calibration trend data show several guide or support to follow-on instruments.

Daylight coloring for monochrome infrared imagery

NASA Astrophysics Data System (ADS)

Gabura, James

2015-05-01

The effectiveness of infrared imagery in poor visibility situations is well established and the range of applications is expanding as we enter a new era of inexpensive thermal imagers for mobile phones. However there is a problem in that the counterintuitive reflectance characteristics of various common scene elements can cause slowed reaction times and impaired situational awareness-consequences that can be especially detrimental in emergency situations. While multiband infrared sensors can be used, they are inherently more costly. Here we propose a technique for adding a daylight color appearance to single band infrared images, using the normally overlooked property of local image texture. The simple method described here is illustrated with colorized images from the visible red and long wave infrared bands. Our colorizing process not only imparts a natural daylight appearance to infrared images but also enhances the contrast and visibility of otherwise obscure detail. We anticipate that this colorizing method will lead to a better user experience, faster reaction times and improved situational awareness for a growing community of infrared camera users. A natural extension of our process could expand upon its texture discerning feature by adding specialized filters for discriminating specific targets.

High Dynamic Imaging for Photometry and Graphic Arts Evaluation

NASA Astrophysics Data System (ADS)

T. S., Sudheer Kumar; Kurian, Ciji Pearl; Shama, Kumara; K. R., Shailesh

2018-05-01

High Dynamic Range Imaging (HDRI) techniques for luminance measurement is gaining importance in recent years. This paper presents the application of the HDRI system for obtaining the photometric characteristics of lighting fixtures as well to assess the quality of lighting in colour viewing booth of a printing press. The process of quality control of prints in a printing press is known as graphic arts evaluation. This light booth plays a major role in the quality control of prints. In this work, Nikon D5100 camera was used to obtain the photometric characteristics of narrow beam spotlight. The results of this experiment are in agreement with photometric characteristics obtained from a standard industry grade Gonio-photometer. Similarly, Canon 60D camera was used to assess the quality of spatial luminance distribution of light in the colour viewing booth. This work demonstrates the usefulness of HDRI technology for photometric measurements and luminance distributions of illuminated interiors.

RTS2: a powerful robotic observatory manager

NASA Astrophysics Data System (ADS)

Kubánek, Petr; Jelínek, Martin; Vítek, Stanislav; de Ugarte Postigo, Antonio; Nekola, Martin; French, John

2006-06-01

RTS2, or Remote Telescope System, 2nd Version, is an integrated package for remote telescope control under the Linux operating system. It is designed to run in fully autonomous mode, picking targets from a database table, storing image meta data to the database, processing images and storing their WCS coordinates in the database and offering Virtual-Observatory enabled access to them. It is currently running on various telescope setups world-wide. For control of devices from various manufacturers we developed an abstract device layer, enabling control of all possible combinations of mounts, CCDs, photometers, roof and cupola controllers. We describe the evolution of RTS2 from Python-based RTS to C and later C++ based RTS2, focusing on the problems we faced during development. The internal structure of RTS2, focusing on object layering, which is used to uniformly control various devices and provides uniform reporting layer, is also discussed.

Diseño, Construcción Y Desarrollo De Un Sistema Limitado Por Difracción Para Telescopios Terrestres: Fastcam

NASA Astrophysics Data System (ADS)

Lopez Lopez, Roberto

2013-02-01

This work describes the concept, design, development, evolution and application of the FastCam instrument. FastCam is an image photometer for astronomy with image capture in a high-frequency range and diraction limited, in order to apply the Lucky Imaging technique to medium- and large-sized ( 1.5 to 4 m) telescopes. The Lucky Imaging technique allows, for ground-based telescopes, to achieve the resolution limit for astronomical images under suitable conditions. This work describes the atmospheric problems and the active and adaptive optics techniques to solve them, as well as the Lucky Imaging fundamentals. A description of the considerations to the project development and design parameters is performed. Then, the optical design and dierent adaptations to several telescopes will be revised. In a next step, some of the scientic results obtained thanks to this project are shown, both in position astronomy and complex structures in globular cluster and binary systems. Dierent designs arising from the basic idea and the instruments now in development that are expanding the system's capabilities and the technique are explained. Some other possible applications to other elds in which the image sharpness is necessary despite uctuations or instabilities of the observing system will be also pointed out: ophthalmology, video-control, etc.

Monitoring lightning from space with TARANIS

NASA Astrophysics Data System (ADS)

Farges, T.; Blanc, E.; Pinçon, J.

2010-12-01

Some recent space experiments, e.g. OTD, LIS, show the large interest of lightning monitoring from space and the efficiency of optical measurement. Future instrumentations are now defined for the next generation of geostationary meteorology satellites. Calibration of these instruments requires ground truth events provided by lightning location networks, as NLDN in US, and EUCLID or LINET in Europe, using electromagnetic observations at a regional scale. One of the most challenging objectives is the continuous monitoring of the lightning activity over the tropical zone (Africa, America, and Indonesia). However, one difficulty is the lack of lightning location networks at regional scale in these areas to validate the data quality. TARANIS (Tool for the Analysis of Radiations from lightNings and Sprites) is a CNES micro satellite project. It is dedicated to the study of impulsive transfers of energy, between the Earth atmosphere and the space environment, from nadir observations of Transient Luminous Events (TLEs), Terrestrial Gamma ray Flashes (TGFs) and other possible associated emissions. Its orbit will be sun-synchronous at 10:30 local time; its altitude will be 700 km. Its lifetime will be nominally 2 years. Its payload is composed of several electromagnetic instruments in different wavelengths: X and gamma-ray detectors, optical cameras and photometers, electromagnetic wave sensors from DC to 30 MHz completed by high energy electron detectors. The optical instrument includes 2 cameras and 4 photometers. All sensors are equipped with filters for sprite and lightning differentiation. The filters of cameras are designed for sprite and lightning observations at 762 nm and 777 nm respectively. However, differently from OTD or LIS instruments, the filter bandwidth and the exposure time (respectively 10 nm and 91 ms) prevent lightning optical observations during daytime. The camera field of view is a square of 500 km at ground level with a spatial sampling frequency of about 1 km. One of the photometers will measure precisely the lightning radiance in a wide spectral range from 600 to 900 nm with a sampling frequency of 20 kHz. We suggest using the Event and mainly Survey mode of MCP instrument to monitor lightning activity and compare it to the geostationary satellite lightning mapper data. In the Event mode, data are recorded with their highest resolution. In the camera survey mode, every image is archived using a specific compression algorithm. The photometer Survey mode consists in decimating the data by a factor of 10 and to reduce the data dynamic. However, it remains well adapted to provide a good continuous characterization of lightning activity. The use of other instruments for example 0+ whistler detector will complete the lightning characterization.

Multi-Band Received Signal Strength Fingerprinting Based Indoor Location System

NASA Astrophysics Data System (ADS)

Sertthin, Chinnapat; Fujii, Takeo; Ohtsuki, Tomoaki; Nakagawa, Masao

This paper proposes a new multi-band received signal strength (MRSS) fingerprinting based indoor location system, which employs the frequency diversity on the conventional single-band received signal strength (RSS) fingerprinting based indoor location system. In the proposed system, the impacts of frequency diversity on the enhancements of positioning accuracy are analyzed. Effectiveness of the proposed system is proved by experimental approach, which was conducted in non line-of-sight (NLOS) environment under the area of 103m2 at Yagami Campus, Keio University. WLAN access points, which simultaneously transmit dual-band signal of 2.4 and 5.2GHz, are utilized as transmitters. Likewise, a dual-band WLAN receiver is utilized as a receiver. Signal distances calculated by both Manhattan and Euclidean were classified by K-Nearest Neighbor (KNN) classifier to illustrate the performance of the proposed system. The results confirmed that Frequency diversity attributions of multi-band signal provide accuracy improvement over 50% of the conventional single-band.

Sampling Frequency Optimisation and Nonlinear Distortion Mitigation in Subsampling Receiver

NASA Astrophysics Data System (ADS)

Castanheira, Pedro Xavier Melo Fernandes

Subsampling receivers utilise the subsampling method to down convert signals from radio frequency (RF) to a lower frequency location. Multiple signals can also be down converted using the subsampling receiver, but using the incorrect subsampling frequency could result in signals aliasing one another after down conversion. The existing method for subsampling multiband signals focused on down converting all the signals without any aliasing between the signals. The case considered initially was a dual band signal, and then it was further extended to a more general multiband case. In this thesis, a new method is proposed with the assumption that only one signal is needed to not overlap the other multiband signals that are down converted at the same time. The proposed method will introduce unique formulas using the said assumption to calculate the valid subsampling frequencies, ensuring that the target signal is not aliased by the other signals. Simulation results show that the proposed method will provide lower valid subsampling frequencies for down conversion compared to the existing methods.

Generation of Multi-band Chorus by Lower Band Cascade in the Earth's Magnetosphere

NASA Astrophysics Data System (ADS)

Gao, X.; Lu, Q.; Chen, L.; Bortnik, J.; Li, W.; Wang, S.

2016-12-01

Chorus waves are intense electromagnetic whistler-mode emissions in the magnetosphere, typically falling into two distinct frequency bands: a lower band (0.1-0.5fce) and an upper band (0.5-0.8fce) with a power gap at about 0.5fce. In this letter, with the THEMIS satellite, we observed two special chorus events, which are called as multi-band chorus because upper band chorus is located at harmonics of lower band chorus. We propose a new potential generation mechanism for multi-band chorus, which is called as lower band cascade. In this scenario, a density mode with a frequency equal to that of lower band chorus is caused by the ponderomotive effect (inhomogeneity of the electric amplitude) along the wave vector, and then upper band chorus with the frequency twice that of lower band chorus is generated through wave-wave couplings between lower band chorus and the density mode. The mechanism provides a new insight into the evolution of whistler-mode chorus in the Earth's magnetosphere.

The Whipple Mission: Design and development of the focal plane

NASA Astrophysics Data System (ADS)

Kenter, A.; Kraft, R.; Murray, S. S.; Gauron, T.; Alcock, C.; Vrtilek, J.

2014-12-01

Whipple is a proposed space borne mission intended to detect and characterize thesize and spatial distribution of Trans Neptunian Objects (TNOs) using the ``blind'' occultation technique. This technique measures the size of, and distance to, a TNO by discerning features of the Fresnel diffraction pattern that is produced when a TNO intercepts the light path between a distant star and the observatory. As the observatory transects the diffraction pattern, it resolves that pattern as a light curve using a differential photometer. The light curve decrement is relatively large (few percent) and the temporal duration is short. For a TNO in the Kuiper Belt the duration is a fraction of a second. For objects in the Oort cloud the duration is ~ a few seconds. Since a blind occultation event is rare, tens of thousands of stars need to be observed simultaneously over several years to accumulate sufficient statistics. Stars need to be observed at cadences up to 40 Hz with a read noise <20e rms (post CDS)Though this is beyond the capability of CCDs, such a high speed, low noise, multi-object differential photometer instrument can be implemented with CMOS imaging technology. The proposed focal plane for the Whipple photometer consists of nine Teledyne HyVISI Silicon hybrid CMOS detectors behind a 77cm F1.34 optic. The detectors consist of 1k by 1k 36 micron pitch pixels and each detector is connected to its own SIDECAR ASIC. Due to the high cadence required, the detectors are operatedin window readout mode. Approximately 700 stars per detector, each in a 2x2 pixel window, will be read out at 40Hz. Progressively more stars can be observed as the cadence decreases, until the limit of the SIDECAR memory is reached at about 4,000 windows The lack of atmospheric turbulence combined with the large field of view and high, speed low noise performance of the focal plane will provide the Whipple mission with unprecedented capability in exploring our Solar System.

The New Sun-Sky-Lunar Cimel CE318-T Multiband Photometer - A Comprehensive Performance Evaluation

NASA Technical Reports Server (NTRS)

Barreto, Africa; Cuevas, Emilio; Granados-Munoz, Maria-Jose; Alados-Arboledas, Lucas; Romero, Pedro M.; Grobner, Julian; Kouremeti, Natalia; Almansa, Antonio F.; Stone, Tom; Toledano, Carlos;

One-Meter Telescope in Kolonica Saddle - 4 Years of Operation

NASA Astrophysics Data System (ADS)

Kudzej, I.; Dubovsky, P. A.

2010-12-01

The actual technical status of 1 meter Vihorlat National Telescope (VNT) at Astronomical Observatory at Kolonica Saddle is presented. Cassegrain and Nasmyth focus, autoguiding system, computer controlled focusing and fine movements and other improvements achieved recently. For two channel photoelectric photometer the system of channels calibration based on artificial light source is described. For CCD camera FLI PL1001E actually installed in Cassegrain focus we presents transformation coefficients from our instrumental to international photometric BVRI system. The measurements were done during regular observations when good photometry of the constant field stars was available. Before FLI camera acquisition we used SBIG ST9 camera. Transformation coefficients for this instrument are presented as well. In the second part of the paper we presents results of variable stars observations with 1 meter telescope in recent four years. The first experimental electronic measurements were done in 2006. Both with CCD cameras and with two channel photoelectric photometer. Starting in 2007 the regular observing program is in operation. There are only few stars suitable for two channel photoelectric photometer observation. Generally the photometer is better when fast brightness changes (time scale of seconds) must be recorded. Thus the majority of observations is done with CCD detectors. We presents an brief overview of most important observing programs: long term monitoring of selected intermediate polars, eclipse observations of SW Sex stars. Occasional observing campaigns were performed on several interesting objects: OT J071126.0+440405, V603 Aql, V471 Tau eclipse timings, Z And in outburst.

Separation of parallel encoded complex-valued slices (SPECS) from a single complex-valued aliased coil image.

PubMed

Rowe, Daniel B; Bruce, Iain P; Nencka, Andrew S; Hyde, James S; Kociuba, Mary C

2016-04-01

Achieving a reduction in scan time with minimal inter-slice signal leakage is one of the significant obstacles in parallel MR imaging. In fMRI, multiband-imaging techniques accelerate data acquisition by simultaneously magnetizing the spatial frequency spectrum of multiple slices. The SPECS model eliminates the consequential inter-slice signal leakage from the slice unaliasing, while maintaining an optimal reduction in scan time and activation statistics in fMRI studies. When the combined k-space array is inverse Fourier reconstructed, the resulting aliased image is separated into the un-aliased slices through a least squares estimator. Without the additional spatial information from a phased array of receiver coils, slice separation in SPECS is accomplished with acquired aliased images in shifted FOV aliasing pattern, and a bootstrapping approach of incorporating reference calibration images in an orthogonal Hadamard pattern. The aliased slices are effectively separated with minimal expense to the spatial and temporal resolution. Functional activation is observed in the motor cortex, as the number of aliased slices is increased, in a bilateral finger tapping fMRI experiment. The SPECS model incorporates calibration reference images together with coefficients of orthogonal polynomials into an un-aliasing estimator to achieve separated images, with virtually no residual artifacts and functional activation detection in separated images. Copyright © 2015 Elsevier Inc. All rights reserved.

The design of atmosphere polarimetry sensing with multi-bands

NASA Astrophysics Data System (ADS)

Dou, Chenhao; Wang, Shurong; Zhang, Zihui; Huang, Yu; Yang, Xiaohu; Li, Bo

2018-03-01

A new aerosol and cloud polarimetry sensing (ACPS) has been presented to measure four polarization components of eight specific wavelengths selected from 400 ∼ 2400 nm simultaneously. The ACPS system can provide high accurate polarized intensity components of atmospheric radiance with a simple and compact structure. The ACPS structure can be regarded as a 4- f Fourier optics system. It takes Wollaston prisms as polarimeters, uses filters and slits to select the appropriate wavelength, and locates the monochromatic polarized light images on different places of focal plane. In our approach, the visible Part 1 is designed as an example and all fields MTFs of Part 1 are larger than 0.5 at detectors' Nyquist frequency 20 lp/mm.

Observation of Possible Lava Tube Skylights by SELENE cameras

NASA Astrophysics Data System (ADS)

Haruyama, Junichi; Hiesinger, Harald; van der Bogert, Carolyn

We have discovered three deep hole-structures on the Moon in the Terrain Camera and Multi-band Imager on the SELENE. These holes are large depth to diameter ratios: Marius Hills Hole (MHH) is 65 m in diameter and 88-90 m in depth, Mare Tranquillitatis Hole (MTH) is 120 x 110 m in diameter and 180 m in depth, and Mare Ingenii Hole (MIH) is 140 x 110 m in diameter and deeper than 90 m. No volcanic material from the holes nor dike-relating pit craters is seen around the holes. They are possible lava tube skylights. These holes and possibly connected tubes have a lot of scientific interests and high potentialities as lunar bases.

Photometric Follow-up of Eclipsing Binary Candidates from KELT and Kepler

NASA Astrophysics Data System (ADS)

Garcia Soto, Aylin; Rodriguez, Joseph E.; Bieryla, Allyson; KELT survey

2018-01-01

Eclipsing binaries (EBs) are incredibly valuable, as they provide the opportunity to precisely measure fundamental stellar parameters without the need for stellar models. Therefore, we can use EBs to directly test stellar evolution models. Constraining the stellar properties of stars is important since they directly influence our understanding of any planets orbiting them. Using the Harvard University's Clay 0.4m telescope and Fred Lawrence Whipple Observatory’s 1.2m telescope on Mount Hopkins, Arizona, we conducted follow-up multi-band photometric observations of EB candidates from the Kilodegree Extremely Little Telescope (KELT) survey and the Kepler mission. We will present our follow-up observations and AstroImageJ analysis on these 5 EB systems.

Folded tubular photometer for atmospheric measurements of NO2 and NO

NASA Astrophysics Data System (ADS)

Birks, John W.; Andersen, Peter C.; Williford, Craig J.; Turnipseed, Andrew A.; Strunk, Stanley E.; Ennis, Christine A.; Mattson, Erick

2018-05-01

We describe and characterize a modular folded tubular photometer for making direct measurements of the concentrations of nitrogen dioxide (NO2) and specify how this method could be extended to measure other pollutants such as sulfur dioxide (SO2), ozone (O3), and black carbon particulate matter. Direct absorbance measurements using this photometer can be made across the spectral range from the ultraviolet (UV) to the near infrared. The absorbance cell makes use of modular components (tubular detection cells and mirror cubes) that allow construction of path lengths of up to 2 m or more while maintaining low cell volumes. The long path lengths and low cell volumes enable sensitive detection of ambient air pollutants down to low part-per-billion levels for gas species and aerosol extinctions down to 1 Mm-1, corresponding to ˜ 0.1 µg m-3 for black carbon particulates. Pressure equalization throughout the stages of the absorbance measurement is shown to be critical to accurate measurements of analyte concentrations. The present paper describes the application of this photometer to direct measurements of nitrogen dioxide (NO2) and the incorporation of design features that also enable measurement of nitric oxide (NO) in the same instrument. Excellent agreement for ambient measurements along an urban roadside was found for both NO2 and NO measured by the folded tubular photometer compared to existing standard techniques. Compared to commonly used methods for measurements of NOx species, the advantages of this approach include (1) an absolute quantification for NO2 based on the Beer-Lambert law, thereby greatly reducing the frequency at which calibrations are required; (2) the direct measurement of NO2 concentration without prior conversion to NO as is required for the commonly used chemiluminescence method; (3) the use of modular components that allow construction of absorbance detection cells of varying lengths for extending the dynamic range of concentrations that can be measured; (4) a more economical instrument than other currently available direct measurement techniques for NO2; and (5) the potential for simultaneous detection of additional species such as SO2, O3, and black carbon in the same instrument. In contrast to other commercially available direct NO2 measurements, such as cavity-attenuated phase-shift spectroscopy (CAPS), the folded tubular photometer also measures NO simultaneously in the same apparatus by quantitatively converting NO to NO2 with ozone, which is then detected by direct absorbance.

Optical signature of an ionospheric hole

NASA Technical Reports Server (NTRS)

Mendillo, M.; Baumgardner, J.

1982-01-01

Simultaneous radio and optical diagnostics of a large, artificially-induced ionospheric modification were conducted during the June 1981 launch of a weather satellite. Intensified imaging and photometer observations at 6300 A, along the same ray path as VHF polarimeter measurements of the ionosphere's total electron content (TEC), were made while the rocket plume caused disturbances. A rapid TEC chemical depletion, on the order of -16.8 x 10 to the 12th el/sq cm, caused a burst of 6300 A radiation which expanded over 60 deg of the sky, with a peak intensity of almost 9 k R. Atmospheric diffusion and O(1D) quenching rate theoretical estimates were then tested, using the event as an active space plasma experiment.

NIMBUS: A Near-Infrared Multi-Band Ultraprecise Spectroimager for SOFIA

NASA Technical Reports Server (NTRS)

McElwain, Michael W.; Mandell, Avi; Woodgate, Bruce E.; Spiegel, David S.; Madhusudhan, Nikku; Amatucci, Edward; Blake, Cullen; Budinoff, Jason; Burgasser, Adam; Burrows, Adam;

SOFIA Science Instruments: Commissioning, Upgrades and Future Opportunities

NASA Technical Reports Server (NTRS)

Smith, Erin C.

2014-01-01

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is the world's largest airborne observatory, featuring a 2.5 meter telescope housed in the aft section of a Boeing 747sp aircraft. SOFIA's current instrument suite includes: FORCAST (Faint Object InfraRed CAmera for the SOFIA Telescope), a 5-40 µm dual band imager/grism spectrometer developed at Cornell University; HIPO (High-speed Imaging Photometer for Occultations), a 0.3-1.1 micron imager built by Lowell Observatory; FLITECAM (First Light Infrared Test Experiment CAMera), a 1-5 micron wide-field imager/grism spectrometer developed at UCLA; FIFI-LS (Far-Infrared Field-Imaging Line Spectrometer), a 42-210 micron IFU grating spectrograph completed by University Stuttgart; and EXES (Echelon-Cross- Echelle Spectrograph), a 5-28 micron high-resolution spectrometer being completed by UC Davis and NASA Ames. A second generation instrument, HAWC+ (Highresolution Airborne Wideband Camera), is a 50-240 micron imager being upgraded at JPL to add polarimetry and new detectors developed at GSFC. SOFIA will continually update its instrument suite with new instrumentation, technology demonstration experiments and upgrades to the existing instrument suite. This paper details instrument capabilities and status as well as plans for future instrumentation, including the call for proposals for 3rd generation SOFIA science instruments.

Sky type discrimination using a ground-based sun photometer

USGS Publications Warehouse

DeFelice, Thomas P.; Wylie, Bruce K.

2001-01-01

A 2-year feasibility study was conducted at the USGS EROS Data Center, South Dakota (43.733°N, 96.6167°W) to assess whether a four-band, ground-based, sun photometer could be used to discriminate sky types. The results indicate that unique spectral signatures do exist between sunny skies (including clear and hazy skies) and cirrus, and cirrostratus, altocumulus or fair-weather cumulus, and thin stratocumulus or altostratus, and fog/fractostratus skies. There were insufficient data points to represent other cloud types at a statistically significant level.

Hubble Space Telescope high speed photometer orbital verification

NASA Technical Reports Server (NTRS)

Richards, Evan E.

1991-01-01

The purpose of this report is to provide a summary of the results of the HSP (High Speed Photometer) Orbital Verification (OV) tests and to report conclusions and lessons learned from the initial operations of the HSP. The HSP OV plan covered the activities through fine (phase 3) alignment. This report covers all activities (OV, SV, and SAO) from launch to the completion of phase 3 alignment. Those activities in this period that are not OV tests are described to the extent that they relate to OV activities.

Optimal monochromatic color combinations for fusion imaging of FDG-PET and diffusion-weighted MR images.

PubMed

Kamei, Ryotaro; Watanabe, Yuji; Sagiyama, Koji; Isoda, Takuro; Togao, Osamu; Honda, Hiroshi

2018-05-23

To investigate the optimal monochromatic color combination for fusion imaging of FDG-PET and diffusion-weighted MR images (DW) regarding lesion conspicuity of each image. Six linear monochromatic color-maps of red, blue, green, cyan, magenta, and yellow were assigned to each of the FDG-PET and DW images. Total perceptual color differences of the lesions were calculated based on the lightness and chromaticity measured with the photometer. Visual lesion conspicuity was also compared among the PET-only, DW-only and PET-DW-double positive portions with mean conspicuity scores. Statistical analysis was performed with a one-way analysis of variance and Spearman's rank correlation coefficient. Among all the 12 possible monochromatic color-map combinations, the 3 combinations of red/cyan, magenta/green, and red/green produced the highest conspicuity scores. Total color differences between PET-positive and double-positive portions correlated with conspicuity scores (ρ = 0.2933, p < 0.005). Lightness differences showed a significant negative correlation with conspicuity scores between the PET-only and DWI-only positive portions. Chromaticity differences showed a marginally significant correlation with conspicuity scores between DWI-positive and double-positive portions. Monochromatic color combinations can facilitate the visual evaluation of FDG-uptake and diffusivity as well as registration accuracy on the FDG-PET/DW fusion images, when red- and green-colored elements are assigned to FDG-PET and DW images, respectively.

Exploring the multiband emission of TXS 0536+145: the most distant -γray flaring blazar

DOE PAGES

Orienti, M.; D'Ammando, F.; Giroletti, M.; ...

2014-09-15

We report results of a multi-band monitoring campaign of the flat spectrum radio quasar TXS 0536+145 at redshift 2.69. This source was detected during a very high γ-ray activity state in 2012 March by the Large Area Telescope on board Fermi, becoming the γ-ray flaring blazar at the highest redshift detected so far. At the peak of the flare the source reached an apparent isotropic γ-ray luminosity of 6.6×1049 erg s-1 which is comparable to the values achieved by the most luminous blazars. This activity triggered radio-to-X-rays monitoring observations by Swift, Very Long Baseline Array, European VLBI Network, and Medicinamore » single-dish telescope. Significant variability was observed from radio to X-rays supporting the identification of the γ-ray source with TXS 0536+145. Both the radio and γ-ray light curves show a similar behaviour, with the γ-rays leading the radio variability with a time lag of about 4-6 months. The luminosity increase is associated with a flattening of the radio spectrum. No new superluminal component associated with the flare was detected in high resolution parsec-scale radio images. During the flare the γ-ray spectrum seems to deviate from a power law, showing a curvature that was not present during the average activity state. The γ-ray properties of TXS 0536+145 are consistent with those shown by the high-redshift γ-ray blazar population.« less

Exploring the multiband emission of TXS 0536+145: the most distant γ-ray flaring blazar

NASA Astrophysics Data System (ADS)

Orienti, M.; D'Ammando, F.; Giroletti, M.; Finke, J.; Ajello, M.; Dallacasa, D.; Venturi, T.

2014-11-01

We report results of a multiband monitoring campaign of the flat spectrum radio quasar TXS 0536+145 at redshift 2.69. This source was detected during a very high γ-ray activity state in 2012 March by the Large Area Telescope on board Fermi, becoming the γ-ray flaring blazar at the highest redshift detected so far. At the peak of the flare the source reached an apparent isotropic γ-ray luminosity of 6.6 × 1049 erg s-1 which is comparable to the values achieved by the most luminous blazars. This activity triggered radio-to-X-rays monitoring observations by Swift, Very Long Baseline Array, European VLBI Network, and Medicina single-dish telescope. Significant variability was observed from radio to X-rays supporting the identification of the γ-ray source with TXS 0536+145. Both the radio and γ-ray light curves show a similar behaviour, with the γ-rays leading the radio variability with a time lag of about 4-6 months. The luminosity increase is associated with a flattening of the radio spectrum. No new superluminal component associated with the flare was detected in high-resolution parsec-scale radio images. During the flare the γ-ray spectrum seems to deviate from a power law, showing a curvature that was not present during the average activity state. The γ-ray properties of TXS 0536+145 are consistent with those shown by the high-redshift γ-ray blazar population.

Non-London electrodynamics in a multiband London model: Anisotropy-induced nonlocalities and multiple magnetic field penetration lengths

NASA Astrophysics Data System (ADS)

Silaev, Mihail; Winyard, Thomas; Babaev, Egor

2018-05-01

The London model describes strongly type-2 superconductors as massive vector field theories, where the magnetic field decays exponentially at the length scale of the London penetration length. This also holds for isotropic multiband extensions, where the presence of multiple bands merely renormalizes the London penetration length. We show that, by contrast, the magnetic properties of anisotropic multiband London models are not this simple, and the anisotropy leads to the interband phase differences becoming coupled to the magnetic field. This results in the magnetic field in such systems having N +1 penetration lengths, where N is the number of field components or bands. That is, in a given direction, the magnetic field decay is described by N +1 modes with different amplitudes and different decay length scales. For certain anisotropies we obtain magnetic modes with complex masses. That means that magnetic field decay is not described by a monotonic exponential increment set by a real penetration length but instead is oscillating. Some of the penetration lengths are shown to diverge away from the superconducting phase transition when the mass of the phase-difference mode vanishes. Finally the anisotropy-driven hybridization of the London mode with the Leggett modes can provide an effectively nonlocal magnetic response in the nominally local London model. Focusing on the two-component model, we discuss the magnetic field inversion that results from the effective nonlocality, both near the surface of the superconductor and around vortices. In the regime where the magnetic field decay becomes nonmonotonic, the multiband London superconductor is shown to form weakly-bound states of vortices.

Comparison of an objective method of measuring bulbar redness to the use of traditional grading scales.

PubMed

Sorbara, Luigina; Simpson, Trefford; Duench, Stephanie; Schulze, Marc; Fonn, Desmond

2007-03-01

The primary objective was to compare measures of bulbar redness objectively using a photometric method with standard grading methods. Measures of redness were made on 24 participants wearing a silicone hydrogel contact lens in one eye for overnight wear. This report compares hyperaemia after 1 week of daily wear (baseline) with redness measured after 6 months of overnight wear. A new method of objectively measuring bulbar conjunctival redness was performed using the Spectrascan650 Photometer by Photo Research under fixed illumination. Photometric measures in CIEu(*) chromaticity values involve the measurement of chromaticity, a physical analogue of redness, greenness and blueness in the image. This method was validated in Part 1 of the study using repeated measurements on the photographic CCLRU scale. In Part 2 of the study, the photographic grading scale (CCLRU) from 0 (none) to 100 (extreme) was used to make the comparison. Part 1 indicated that the photometer provides a repeatable and reliable measure of bulbar redness (CCC=0.989). A moderately strong and significant correlation was found between the CIEu(*) chromaticity values and the analogue data (R=0.795, p=0.000) at each measurement session (from baseline to 1 day, 1 week, and 1, 3 and 6 months of overnight wear). This new standardized and objective method of measuring bulbar redness has great potential to replace subjective grading scales, especially with multi-centre studies, where variability between investigators occurs. This method may also detect smaller changes between visits or between eyes.

VizieR Online Data Catalog: YSOVAR: infrared photometry in NGC 1333 (Rebull+, 2015)

NASA Astrophysics Data System (ADS)

Rebull, L. M.; Stauffer, J. R.; Cody, A. M.; Gunther, H. M.; Hillenbrand, L. A.; Poppenhaeger, K.; Wolk, S. J.; Hora, J.; Hernandez, J.; Bayo, A.; Covey, K.; Forbrich, J.; Gutermuth, R.; Morales-Calderon, M.; Plavchan, P.; Song, I.; Bouy, H.; Terebey, S.; Cuillandre, J. C.; Allen, L. E.

2016-06-01

We present the Young Stellar Object VARiability (YSOVAR) data for NGC1333. There are 701 objects (see Table1) with mid-infrared light curves in one or both warm Spitzer bands. All YSOVAR Spitzer light curve tabular data are available via the YSOVAR data delivery to the Infrared Science Archive (IRSA; http://irsa.ipac.caltech.edu/frontpage/). The sky observed by the two IRAC channels (3.6 and 4.5μm, or IRAC-1 and -2) fields of view is slightly offset with the central ~10'*10' region, centered on 03:29:06+31:19:30, covered by both channels. The observations were obtained under program ID61026, between 2011 October 10 and November 14 (~35 days). Near-infrared observations were obtained using the Peters Automated Infrared Imaging Telescope (PAIRITEL), which is an automated 1.3m telescope. PAIRITEL was located at the Whipple Observatory at Mt. Hopkins, Arizona; the same telescope and camera used for the northern part of 2MASS, PAIRITEL acquired simultaneous J, H, and Ks images. The observations of NGC1333 were obtained over 24 epochs from 2010 October 7 to 2012 November 19. We compiled additional photometry from several different sources. Early in the Spitzer mission, NGC1333 was observed by both the guaranteed time observations (GTOs) and the Cores-to-Disks (c2d) Legacy program (Evans et al. 2009, cat. J/ApJS/181/321), with both IRAC and the Multiband Imaging Photometer for Spitzer (MIPS). NGC1333 was covered in the Two-Micron All Sky Survey (2MASS; see cat II/246) and was also located in a field targeted by the long exposure 6X 2MASS program (see cat II/281). As described in Rebull 2015 (cat. J/AJ/150/17), we included these main 2MASS catalog and deeper 6X catalog near-infrared JHKs data into our database. We also include the ~30 deep JH space-based measurements from Greissl et al. (2007AJ....133.1321G). Chandra X-ray Observatory Advanced CCD Imaging Spectrometer for wide-field imaging (ACIS-I) observations of NGC1333 were first reported in Getman et al. 2002 (cat. J/ApJ/575/354) and then Winston et al. 2010 (cat. J/AJ/140/266). There are three pointings in NGC1333, with obsids 642, 6436, and 6437, with a total exposure time of 119.3ks. NGC1333 was observed in several optical bands from Subaru and the Canada-France-Hawaii Telescope (CFHT), and we obtained these data from the public archives. Optical data from both telescopes cover the full extent of the region monitored for YSOVAR. NGC1333 was observed in the i' and z' bands with the Suprime-Cam wide-field camera on Subaru on 2006 November 18. A total of 1 short exposure (10s) and 60 dithered long exposures (60s) were obtained in each filter as part of the SONYC project (Scholz et al. 2012, cat. J/ApJ/744/6). NGC1333 was observed in the ugri filters at several epochs (2005 Sep 27 with g filter; 2008 Dec 21, 2009 Mar 24, 2009 Mar 26, and 2009 Sep 21 with i filter; 2005 Sep 27 with r filter; 2005 Sep 27, 2005 Dec 23, and 2006 Feb 28 with u filter) with the MegaCam wide-field camera mounted on the CFHT as part of the DANCE survey (Bouy et al. 2013A&A...554A.101B). The individual CFHT images were retrieved from the public archives maintained at the Canadian Astronomy Data Centre. Single-valued measurements (such as the single-epoch optical photometry) or metrics (such as the SED slope and class, or mean from the light curve, etc.) for all of the objects with light curves are collected in Table1. (4 data files).

Plan for the uniform mapping of earth resources and environmental complexes from Skylab imagery. Assessment of natural vegetation, environmental, and crop analogs. [Sierra-Lahontan, Colorado Plateau, Louisiana coastal plain, and Northern Great Valley, California

NASA Technical Reports Server (NTRS)

Poulton, C. E. (Principal Investigator); Welch, R. I.

1975-01-01

The author has identified the following significant results. For interpreting a wide range of natural vegetation analogs, S-190A color infrared and the ERTS-1 color composite were consistently more useful than were conventional color or black and white photos. Color infrared was superior for five vegetation analogs while color was superior for only three. The errors in identification appeared to associate more with black and white single band images than with multiband color. For rice crop analogs, spectral and spatial discriminations both contribute to the usefulness of images for data collection. Tests and subjective analyses conducted in this study indicated that the spectral bands exploited in color infrared film were the most useful for agricultural crop analysis. Accuracy of crop identification on any single date of Skylab images was less than that of multidate analysis due to differences in crop calendar, cultural practices used, rice variety, planting date, planting method, water use, fertilization, disease, or mechanical problems.

Substructures in DAFT/FADA survey clusters based on XMM and optical data

NASA Astrophysics Data System (ADS)

Durret, F.; DAFT/FADA Team

2014-07-01

The DAFT/FADA survey was initiated to perform weak lensing tomography on a sample of 90 massive clusters in the redshift range [0.4,0.9] with HST imaging available. The complementary deep multiband imaging constitutes a high quality imaging data base for these clusters. In X-rays, we have analysed the XMM-Newton and/or Chandra data available for 32 clusters, and for 23 clusters we fit the X-ray emissivity with a beta-model and subtract it to search for substructures in the X-ray gas. This study was coupled with a dynamical analysis for the 18 clusters with at least 15 spectroscopic galaxy redshifts in the cluster range, based on a Serna & Gerbal (SG) analysis. We detected ten substructures in eight clusters by both methods (X-rays and SG). The percentage of mass included in substructures is found to be roughly constant with redshift, with values of 5-15%. Most of the substructures detected both in X-rays and with the SG method are found to be relatively recent infalls, probably at their first cluster pericenter approach.

DISCOVERY OF A DISK GAP CANDIDATE AT 20 AU IN TW HYDRAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akiyama, E.; Kusakabe, N.; Kandori, R.

We present a new Subaru/HiCIAO high-contrast H-band polarized intensity (PI) image of a nearby transitional disk associated with TW Hydrae. The scattered light from the disk was detected from 0.″ 2 to 1.″ 5 (11–81 AU) and the PI image shows a clear axisymmetric depression in PI at ∼0.″ 4 (∼20 AU) from the central star, similar to the ∼80 AU gap previously reported from Hubble Space Telescope images. The azimuthal PI profile also shows that the disk beyond 0.″ 2 is almost axisymmetric. We discuss two possible scenarios explaining the origin of the PI depression: (1) a gap structuremore » may exist at ∼20 AU from the central star because of a shallow slope seen in the PI profile, and (2) grain growth may be occurring in the inner region of the disk. Multi-band observations at near-infrared and millimeter/submillimeter wavelengths play a complementary role in investigating dust opacity and may help reveal the origin of the gap more precisely.« less

Interband coding extension of the new lossless JPEG standard

NASA Astrophysics Data System (ADS)

Memon, Nasir D.; Wu, Xiaolin; Sippy, V.; Miller, G.

1997-01-01

Due to the perceived inadequacy of current standards for lossless image compression, the JPEG committee of the International Standards Organization (ISO) has been developing a new standard. A baseline algorithm, called JPEG-LS, has already been completed and is awaiting approval by national bodies. The JPEG-LS baseline algorithm despite being simple is surprisingly efficient, and provides compression performance that is within a few percent of the best and more sophisticated techniques reported in the literature. Extensive experimentations performed by the authors seem to indicate that an overall improvement by more than 10 percent in compression performance will be difficult to obtain even at the cost of great complexity; at least not with traditional approaches to lossless image compression. However, if we allow inter-band decorrelation and modeling in the baseline algorithm, nearly 30 percent improvement in compression gains for specific images in the test set become possible with a modest computational cost. In this paper we propose and investigate a few techniques for exploiting inter-band correlations in multi-band images. These techniques have been designed within the framework of the baseline algorithm, and require minimal changes to the basic architecture of the baseline, retaining its essential simplicity.

Non-Intrusive Techniques of Inspections During the Pre-Launch Phase of Space Vehicle

NASA Technical Reports Server (NTRS)

Thirumalainambi, Rejkumar; Bardina, Jorge E.

2005-01-01

This paper addresses a method of non-intrusive local inspection of surface and sub-surface conditions, interfaces, laminations and seals in both space vehicle and ground operations with an integrated suite of imaging sensors during pre-launch operations. It employs an advanced Raman spectrophotometer with additional spectrophotometers and lidar mounted on a flying robot to constantly monitor the space hardware as well as inner surface of the vehicle and ground operations hardware. This paper addresses a team of micro flying robots with necessary sensors and photometers to monitor the entire space vehicle internally and externally. The micro flying robots can reach altitude with least amount of energy, where astronauts have difficulty in reaching and monitoring the materials and subsurface faults. The micro flying robot has an embedded fault detection system which acts as an advisory system and in many cases micro flying robots act as a Supervisor to fix the problems. As missions expand to a sustainable presence in the Moon, and extend for durations longer than one year in lunar outpost, the effectiveness of the instrumentation and hardware has to be revolutionized if NASA is to meet high levels of mission safety, reliability, and overall success. The micro flying robot uses contra-rotating propellers powered by an ultra-thin, ultrasonic motor with currently the world's highest power weight ratio, and is balanced in mid-air by means of the world's first stabilizing mechanism using a linear actuator. The essence of micromechatronics has been brought together in high-density mounting technology to minimize the size and weight. The robot can take suitable payloads of photometers, embedded chips for image analysis and micro pumps for sealing cracks or fixing other material problems. This paper also highlights advantages that this type of non-intrusive techniques offer over costly and monolithic traditional techniques.

Advanced Ionospheric Sensing using GROUP-C and LITES aboard the ISS

NASA Astrophysics Data System (ADS)

Budzien, S. A.; Stephan, A. W.; Chakrabarti, S.; Finn, S. C.; Cook, T.; Powell, S. P.; O'Hanlon, B.; Bishop, R. L.

2015-12-01

The GPS Radio Occultation and Ultraviolet Photometer Co-located (GROUP-C) and Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) experiments are manifested for flight aboard the International Space Station (ISS) in 2016 as part of the Space Test Program Houston #5 payload. The two experiments provide technical development and risk-reduction for future DoD space weather sensors suitable for ionospheric specification, space situational awareness, and data products for global ionosphere assimilative models. In addition, the combined instrument complement of these two experiments offers a unique opportunity to study structures of the nighttime ionosphere. GROUP-C includes an advanced GPS receiver providing ionospheric electron density profiles and scintillation measurements and a high-sensitivity far-ultraviolet photometer measuring horizontal ionospheric gradients. LITES is an imaging spectrograph that spans 60-140 nm and will obtain high-cadence limb profiles of the ionosphere and thermosphere from 150-350 km altitude. In the nighttime ionosphere, recombination of O+ and electrons produces optically thin emissions at 91.1 and 135.6 nm that can be used to tomographically reconstruct the two-dimensional plasma distribution in the orbital plane below ISS altitudes. Ionospheric irregularities, such as plasma bubbles and blobs, are transient features of the low and middle latitude ionosphere with important implications for operational systems. Irregularity structures have been studied primarily using ground-based systems, though some spaced-based remote and in-situ sensing has been performed. An ionospheric observatory aboard the ISS would provide new capability to study low- and mid-latitude ionospheric structures on a global scale. By combining for the first time high-sensitivity in-track photometry, vertical ionospheric airglow spectrographic imagery, and recent advancements in UV tomography, high-fidelity tomographic reconstruction of nighttime structures can be performed from the ISS. We discuss the tomographic approach, simulated reconstructions, and value added by including complementary ground-based observations. Acknowledgements: This work is supported by NRL Work Unit 76-1C09-05.

Nonintrusive techniques of inspections during the pre-launch phase of space vehicle

NASA Astrophysics Data System (ADS)

Thirumalainambi, Rajkumar; Bardina, Jorge E.; Miyazawa, Osamu

2005-05-01

As missions expand to a sustainable presence in the Moon, and extend for durations longer than one year in lunar outpost, the effectiveness of the instrumentation and hardware has to be revolutionized if NASA is to meet high levels of mission safety, reliability, and overall success. This paper addresses a method of non-intrusive local inspection of surface and sub-surface conditions, interfaces, laminations and seals in both space vehicle and ground operations with an integrated suite of imaging sensors during pre-launch operations. It employs an advanced Raman spectrometer with additional spectrometers and lidar mounted on a flying robot to constantly monitor the space hardware as well as inner surface of the vehicle and ground operations hardware. A team of micro flying robots with necessary sensors and photometers is required to internally and externally monitor the entire space vehicle. The micro flying robots should reach an altitude with least amount of energy, where astronauts have difficulty in reaching and monitoring the materials and subsurface faults. The micro flying robots have an embedded fault detection system which acts as an advisory system and in many cases micro flying robots act as a `Supervisor' to fix the problems. The micro flying robot uses contra-rotating propellers powered by an ultra-thin, ultrasonic motor with currently the world's highest power weight ratio, and is balanced in mid-air by means of the world's first stabilizing mechanism using a linear actuator. The essence of micromechatronics has been brought together in high-density mounting technology to minimize the size and weight. Each robot can take suitable payloads of photometers, embedded chips for image analysis and micro pumps for sealing cracks or fixing other material problems. This paper also highlights advantages that this type of non-intrusive techniques offer over costly and monolithic traditional techniques.

ROSAS: a robotic station for atmosphere and surface characterization dedicated to on-orbit calibration

NASA Astrophysics Data System (ADS)

Meygret, Aimé; Santer, Richard P.; Berthelot, Béatrice

2011-10-01

La Crau test site is used by CNES since 1987 for vicarious calibration of SPOT cameras. The former calibration activities were conducted during field campaigns devoted to the characterization of the atmosphere and the site reflectances. Since 1997, au automatic photometric station (ROSAS) was set up on the site on a 10m height pole. This station measures at different wavelengths, the solar extinction and the sky radiances to fully characterize the optical properties of the atmosphere. It also measures the upwelling radiance over the ground to fully characterize the surface reflectance properties. The photometer samples the spectrum from 380nm to 1600nm with 9 narrow bands. Every non cloudy days the photometer automatically and sequentially performs its measurements. Data are transmitted by GSM (Global System for Mobile communications) to CNES and processed. The photometer is calibrated in situ over the sun for irradiance and cross-band calibration, and over the Rayleigh scattering for the short wavelengths radiance calibration. The data are processed by an operational software which calibrates the photometer, estimates the atmosphere properties, computes the bidirectional reflectance distribution function of the site, then simulates the top of atmosphere radiance seen by any sensor over-passing the site and calibrates it. This paper describes the instrument, its measurement protocol and its calibration principle. Calibration results are discussed and compared to laboratory calibration. It details the surface reflectance characterization and presents SPOT4 calibration results deduced from the estimated TOA radiance. The results are compared to the official calibration.

Circular Microstrip Antenna with Fractal Slots for Multiband Applications

NASA Astrophysics Data System (ADS)

Singh, Sivia Jagtar; Singh, Gurpreet; Bharti, Gurpreet

2017-10-01

In this paper, a multiband, fractal, slotted, Circular Microstrip Patch Antenna for GSM, WiMAX, C and X bands (satellite communication applications) is presented. A cantor set theory is used to make fractal slots for obtaining the desired multiband. The projected antenna is simulated using Ansys HFSS v13.0 software. Simulation test of this antenna has been carried out for a frequency range of 1 GHz-10 GHz and a peak gain of 9.19 dB at a resonance frequency of 1.9 GHz is obtained. The antenna also resonates at 3.7 GHz, 6.06 GHz and 7.9 GHz with gains of 3.04 dB, 5.19 dB and 5.39 dB respectively. Parameters like voltage standing wave ratio, return loss, and gain are used to compare the results of the projected antenna with conventional CMPA's of same dimensions with full and defective grounds. The projected antenna is fabricated on a glass epoxy material and is tested using Vector Network Analyzer. The performance parameters of the antenna are found to in good agreement with each both using simulated and measured data.

Quasiparticle interference in multiband superconductors with strong coupling

NASA Astrophysics Data System (ADS)

Dutt, A.; Golubov, A. A.; Dolgov, O. V.; Efremov, D. V.

2017-08-01

We develop a theory of the quasiparticle interference (QPI) in multiband superconductors based on the strong-coupling Eliashberg approach within the Born approximation. In the framework of this theory, we study dependencies of the QPI response function in the multiband superconductors with the nodeless s -wave superconductive order parameter. We pay special attention to the difference in the quasiparticle scattering between the bands having the same and opposite signs of the order parameter. We show that at the momentum values close to the momentum transfer between two bands, the energy dependence of the quasiparticle interference response function has three singularities. Two of these correspond to the values of the gap functions and the third one depends on both the gaps and the transfer momentum. We argue that only the singularity near the smallest band gap may be used as a universal tool to distinguish between the s++ and s± order parameters. The robustness of the sign of the response function peak near the smaller gap value, irrespective of the change in parameters, in both the symmetry cases is a promising feature that can be harnessed experimentally.

Generation of multiband chorus by lower band cascade in the Earth's magnetosphere

NASA Astrophysics Data System (ADS)

Gao, Xinliang; Lu, Quanming; Bortnik, Jacob; Li, Wen; Chen, Lunjin; Wang, Shui

2016-03-01

Chorus waves are intense electromagnetic whistler mode emissions in the magnetosphere, typically falling into two distinct frequency bands: a lower band (0.1-0.5fce) and an upper band (0.5-0.8fce) with a power gap at about 0.5fce. In this letter, with the Time History of Events and Macroscale Interactions during Substorms satellite, we observed two special chorus events, which are called as multiband chorus because upper band chorus is located at harmonics of lower band chorus. We propose a new potential generation mechanism for multiband chorus, which is called as lower band cascade. In this scenario, a density mode with a frequency equal to that of lower band chorus is generated by the ponderomotive effect (inhomogeneity of the electric amplitude) along the wave vector, and then upper band chorus with the frequency twice that of lower band chorus is generated through wave-wave couplings between lower band chorus and the density mode. The mechanism provides a new insight into the evolution of whistler mode chorus in the Earth's magnetosphere.

Analysis on the electromagnetic scattering properties of crops at multi-band

NASA Astrophysics Data System (ADS)

Wu, Tao; Wu, Zhensen; Liu, Xiaoyi

2014-12-01

The vector radiative transfer (VRT) theory for active microwave remote sensing and Rayleigh-Gans approximation (GRG) are applied in the study, and an iterative algorithm is used to solve the RT equations, thus we obtain the zeroorder and first-order equation for numerical results. The Michigan Microwave Canopy Scattering (MIMICS) model is simplified to adapt to the crop model, by analyzing body-surface bistatic scattering and backscattering properties between a layer of soybean or wheat consisting of stems and leaves and different underlying soil surface at multi-band (i.e. P, L, S, X, Ku-band), we obtain microwave scattering mechanisms of crop components and the effect of underlying ground on total crop scattering. Stem and leaf are regard as a needle and a circular disk, respectively. The final results are compared with some literature data to verify our calculating method, numerical results show multi-band crop microwave scattering properties differ from scattering angle, azimuth angle and moisture of vegetation and soil, which offer the part needed information for the design of future bistatic radar systems for crop sensing applications.

Rapid brain MRI acquisition techniques at ultra-high fields

PubMed Central

Setsompop, Kawin; Feinberg, David A.; Polimeni, Jonathan R.

2017-01-01

Ultra-high-field MRI provides large increases in signal-to-noise ratio as well as enhancement of several contrast mechanisms in both structural and functional imaging. Combined, these gains result in a substantial boost in contrast-to-noise ratio that can be exploited for higher spatial resolution imaging to extract finer-scale information about the brain. With increased spatial resolution, however, is a concurrent increased image encoding burden that can cause unacceptably long scan times for structural imaging and slow temporal sampling of the hemodynamic response in functional MRI—particularly when whole-brain imaging is desired. To address this issue, new directions of imaging technology development—such as the move from conventional 2D slice-by-slice imaging to more efficient Simultaneous MultiSlice (SMS) or MultiBand imaging (which can be viewed as “pseudo-3D” encoding) as well as full 3D imaging—have provided dramatic improvements in acquisition speed. Such imaging paradigms provide higher SNR efficiency as well as improved encoding efficiency. Moreover, SMS and 3D imaging can make better use of coil sensitivity information in multi-channel receiver arrays used for parallel imaging acquisitions through controlled aliasing in multiple spatial directions. This has enabled unprecedented acceleration factors of an order of magnitude or higher in these imaging acquisition schemes, with low image artifact levels and high SNR. Here we review the latest developments of SMS and 3D imaging methods and related technologies at ultra-high field for rapid high-resolution functional and structural imaging of the brain. PMID:26835884

Nighttime Aerosol Optical Depth Measurements Using a Ground-based Lunar Photometer

NASA Technical Reports Server (NTRS)

Berkoff, Tim; Omar, Ali; Haggard, Charles; Pippin, Margaret; Tasaddaq, Aasam; Stone, Tom; Rodriguez, Jon; Slutsker, Ilya; Eck, Tom; Holben, Brent;

High aerosol load over the Pearl River Delta, China, observed with Raman lidar and Sun photometer

NASA Astrophysics Data System (ADS)

Ansmann, Albert; Engelmann, Ronny; Althausen, Dietrich; Wandinger, Ulla; Hu, Min; Zhang, Yuanghang; He, Qianshan

2005-07-01

Height-resolved data of the particle optical properties, the vertical extend of the haze layer, aerosol stratification, and the diurnal cycle of vertical mixing over the Pearl River Delta in southern China are presented. The observations were performed with Raman lidar and Sun photometer at Xinken (22.6°N, 113.6°E) near the south coast of China throughout October 2004. The lidar run almost full time on 21 days. Sun photometer data were taken on 23 days, from about 0800 to 1700 local time. The particle optical depth (at about 533-nm wavelength) ranged from 0.3-1.7 and was, on average, 0.92. Ångström exponents varied from 0.65-1.35 (for wavelengths 380 to 502 nm) and from 0.75-1.6 (for 502 to 1044 nm), mean values were 0.97 and 1.22. The haze-layer mean extinction-to-backscatter ratio ranged from 35-59 sr, and was, on average, 46.7 sr. The top of the haze layer reached to heights of 1.5-3 km in most cases.

Psychophysical contrast calibration

PubMed Central

To, Long; Woods, Russell L; Goldstein, Robert B; Peli, Eli

2013-01-01

Electronic displays and computer systems offer numerous advantages for clinical vision testing. Laboratory and clinical measurements of various functions and in particular of (letter) contrast sensitivity require accurately calibrated display contrast. In the laboratory this is achieved using expensive light meters. We developed and evaluated a novel method that uses only psychophysical responses of a person with normal vision to calibrate the luminance contrast of displays for experimental and clinical applications. Our method combines psychophysical techniques (1) for detection (and thus elimination or reduction) of display saturating nonlinearities; (2) for luminance (gamma function) estimation and linearization without use of a photometer; and (3) to measure without a photometer the luminance ratios of the display’s three color channels that are used in a bit-stealing procedure to expand the luminance resolution of the display. Using a photometer we verified that the calibration achieved with this procedure is accurate for both LCD and CRT displays enabling testing of letter contrast sensitivity to 0.5%. Our visual calibration procedure enables clinical, internet and home implementation and calibration verification of electronic contrast testing. PMID:23643843

Network based sky Brightness Monitor

NASA Astrophysics Data System (ADS)

McKenna, Dan; Pulvermacher, R.; Davis, D. R.

2009-01-01

We have developed and are currently testing an autonomous 2 channel photometer designed to measure the night sky brightness in the visual wavelengths over a multi-year campaign. The photometer uses a robust silicon sensor filtered with Hoya CM500 glass. The Sky brightness is measured every minute at two elevation angles typically zenith and 20 degrees to monitor brightness and transparency. The Sky Brightness monitor consists of two units, the remote photometer and a network interface. Currently these devices use 2.4 Ghz transceivers with a free space range of 100 meters. The remote unit is battery powered with day time recharging using a solar panel. Data received by the network interface transmits data via standard POP Email protocol. A second version is under development for radio sensitive areas using an optical fiber for data transmission. We will present the current comparison with the National Park Service sky monitoring camera. We will also discuss the calibration methods used for standardization and temperature compensation. This system is expected to be deployed in the next year and be operated by the International Dark Sky Association SKYMONITOR project.

First photometric properties of Dome C, Antarctica

NASA Astrophysics Data System (ADS)

Chadid, M.; Vernin, J.; Jeanneaux, F.; Mekarnia, D.; Trinquet, H.

2008-07-01

Here we present the first photometric extinction measurements in the visible range performed at Dome C in Antarctica, using PAIX photometer (Photometer AntarctIca eXtinction). It is made with "off the shelf" components, Audine camera at the focus of Blazhko telescope, a Meade M16 diaphragmed down to 15 cm. For an exposure time of 60 s without filter, a 10th V-magnitude star is measured with a precision of 1/100 mag. A first statistics over 16 nights in August 2007 leads to a 0.5 magnitude per air mass extinction, may be due to high altitude cirrus. This rather simple experiment shows that continuous observations can be performed at Dome C, allowing high frequency resolution on pulsation and asteroseismology studies. Light curves of one of RR Lyrae stars: SAra were established. They show the typical trend of a RRLyrae star. A recent sophisticated photometer, PAIX II, has been installed recently at Dome C during polar summer 2008, with a ST10 XME camera, automatic guiding, auto focusing and Johnson/Bessel UBVRI filter wheels.

Multi-band description of the specific heat and thermodynamic critical field in MgB2 superconductor

NASA Astrophysics Data System (ADS)

Szcześniak, R.; Jarosik, M. W.; Tarasewicz, P.; Durajski, A. P.

2018-05-01

The thermodynamic properties of MgB2 superconductor can be explained using the multi-band models. In the present paper we have examined the experimental data available in literature and we have found out that it is possible to reproduce the measured values of the superconducting energy gaps, the thermodynamic critical magnetic field and specific heat jump within the framework of two-band Eliashberg formalism and appropriate defined free energy difference between superconducting and normal state. Moreover, we found that the obtained results differ significantly from the predictions of the conventional Bardeen-Cooper-Schrieffer theory.

Comparison of two laboratory-based systems for evaluation of halos in intraocular lenses

PubMed Central

Alexander, Elsinore; Wei, Xin; Lee, Shinwook

2018-01-01

Purpose Multifocal intraocular lenses (IOLs) can be associated with unwanted visual phenomena, including halos. Predicting potential for halos is desirable when designing new multifocal IOLs. Halo images from 6 IOL models were compared using the Optikos modulation transfer function bench system and a new high dynamic range (HDR) system. Materials and methods One monofocal, 1 extended depth of focus, and 4 multifocal IOLs were evaluated. An off-the-shelf optical bench was used to simulate a distant (>50 m) car headlight and record images. A custom HDR system was constructed using an imaging photometer to simulate headlight images and to measure quantitative halo luminance data. A metric was developed to characterize halo luminance properties. Clinical relevance was investigated by correlating halo measurements to visual outcomes questionnaire data. Results The Optikos system produced halo images useful for visual comparisons; however, measurements were relative and not quantitative. The HDR halo system provided objective and quantitative measurements used to create a metric from the area under the curve (AUC) of the logarithmic normalized halo profile. This proposed metric differentiated between IOL models, and linear regression analysis found strong correlations between AUC and subjective clinical ratings of halos. Conclusion The HDR system produced quantitative, preclinical metrics that correlated to patients’ subjective perception of halos. PMID:29503526

SiFAP: a Simple Sub-Millisecond Astronomical Photometer

NASA Astrophysics Data System (ADS)

Ambrosino, F.; Meddi, F.; Nesci, R.; Rossi, C.; Sclavi, S.; Bruni, I.

2013-09-01

A new fast photometer based on SiPM technology was developed at the University of Rome "La Sapienza" starting from 2009. A first prototype was successfully tested observing the Crab pulsar at the Loiano telescope of the Bologna Observatory. In this paper we illustrate the improvements we applied to our instrument, concerning new cooled commercial sensors, a new version of our custom dedicated electronics and an upgraded control timing software. Finally we report the results obtained with this instrument on December 2012 on the Crab pulsar at the Loiano telescope to show its goodness and capabilities.

Multiband observations of Cygnus A: A study of pressure balance in the core of a powerful radio galaxy

NASA Technical Reports Server (NTRS)

Carilli, Chris; Conner, Sam; Dreher, John; Perley, Rick

1990-01-01

Cygnus A is a powerful double radio source associated with a giant elliptical galaxy at the center of a poor cluster of galaxies. The radio source also sits within the core radius of a dense, cooling flow, x ray emitting cluster gas. Optical spectroscopy and narrow band imaging have revealed copious amounts of narrow line emission from the inner 20 kpc of the associated galaxy. Researchers assume H sub o = 75 km sec (-1) Mpc(-1). Discussed here are the pressures in the three components of the Interstellar Medium (ISM) (i.e., the radio, x ray, and line emitting fluids) within a radius of about 15 kpc of the active nucleus of the Cygnus A galaxy.

Integrated focal plane arrays for millimeter-wave astronomy

NASA Astrophysics Data System (ADS)

Bock, James J.; Goldin, Alexey; Hunt, Cynthia; Lange, Andrew E.; Leduc, Henry G.; Day, Peter K.; Vayonakis, Anastasios; Zmuidzinas, Jonas

2002-02-01

We are developing focal plane arrays of bolometric detectors for sub-millimeter and millimeter-wave astrophysics. We propose a flexible array architecture using arrays of slot antennae coupled via low-loss superconducting Nb transmission line to microstrip filters and antenna-coupled bolometers. By combining imaging and filtering functions with transmission line, we are able to realize unique structures such as a multi-band polarimeter and a planar, dispersive spectrometer. Micro-strip bolometers have significantly smaller active volume than standard detectors with extended absorbers, and can realize higher sensitivity and speed of response. The integrated array has natural immunity to stray radiation or spectral leaks, and minimizes the suspended mass operating at 0.1-0.3 K. We also discuss future space-borne spectroscopy and polarimetry applications. .

The XMM Large Scale Structure Survey

NASA Astrophysics Data System (ADS)

Pierre, Marguerite

2005-10-01

We propose to complete, by an additional 5 deg2, the XMM-LSS Survey region overlying the Spitzer/SWIRE field. This field already has CFHTLS and Integral coverage, and will encompass about 10 deg2. The resulting multi-wavelength medium-depth survey, which complements XMM and Chandra deep surveys, will provide a unique view of large-scale structure over a wide range of redshift, and will show active galaxies in the full range of environments. The complete coverage by optical and IR surveys provides high-quality photometric redshifts, so that cosmological results can quickly be extracted. In the spirit of a Legacy survey, we will make the raw X-ray data immediately public. Multi-band catalogues and images will also be made available on short time scales.

Ocean Observations with EOS/MODIS: Algorithm Development and Post Launch Studies

NASA Technical Reports Server (NTRS)

Gordon, Howard R.; Conboy, B. (Technical Monitor)

1999-01-01

Significant accomplishments made during the present reporting period include: 1) Installed spectral optimization algorithm in the SeaDas image processing environment and successfully processed SeaWiFS imagery. The results were superior to the standard SeaWiFS algorithm (the MODIS prototype) in a turbid atmosphere off the US East Coast, but similar in a clear (typical) oceanic atmosphere; 2) Inverted ACE-2 LIDAR measurements coupled with sun photometer-derived aerosol optical thickness to obtain the vertical profile of aerosol optical thickness. The profile was validated with simultaneous aircraft measurements; and 3) Obtained LIDAR and CIMEL measurements of typical maritime and mineral dust-dominated marine atmosphere in the U.S. Virgin Islands. Contemporaneous SeaWiFS imagery were also acquired.

Modeling of multi-band drift in nanowires using a full band Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Hathwar, Raghuraj; Saraniti, Marco; Goodnick, Stephen M.

2016-07-01

We report on a new numerical approach for multi-band drift within the context of full band Monte Carlo (FBMC) simulation and apply this to Si and InAs nanowires. The approach is based on the solution of the Krieger and Iafrate (KI) equations [J. B. Krieger and G. J. Iafrate, Phys. Rev. B 33, 5494 (1986)], which gives the probability of carriers undergoing interband transitions subject to an applied electric field. The KI equations are based on the solution of the time-dependent Schrödinger equation, and previous solutions of these equations have used Runge-Kutta (RK) methods to numerically solve the KI equations. This approach made the solution of the KI equations numerically expensive and was therefore only applied to a small part of the Brillouin zone (BZ). Here we discuss an alternate approach to the solution of the KI equations using the Magnus expansion (also known as "exponential perturbation theory"). This method is more accurate than the RK method as the solution lies on the exponential map and shares important qualitative properties with the exact solution such as the preservation of the unitary character of the time evolution operator. The solution of the KI equations is then incorporated through a modified FBMC free-flight drift routine and applied throughout the nanowire BZ. The importance of the multi-band drift model is then demonstrated for the case of Si and InAs nanowires by simulating a uniform field FBMC and analyzing the average carrier energies and carrier populations under high electric fields. Numerical simulations show that the average energy of the carriers under high electric field is significantly higher when multi-band drift is taken into consideration, due to the interband transitions allowing carriers to achieve higher energies.

Isotope and multiband effects in layered superconductors.

PubMed

Bussmann-Holder, Annette; Keller, Hugo

2012-06-13

In this review we consider three classes of superconductors, namely cuprate superconductors, MgB(2) and the new Fe based superconductors. All of these three systems are layered materials and multiband compounds. Their pairing mechanisms are under discussion with the exception of MgB(2), which is widely accepted to be a 'conventional' electron-phonon interaction mediated superconductor, but extending the Bardeen-Cooper-Schrieffer (BCS) theory to account for multiband effects. Cuprates and Fe based superconductors have higher superconducting transition temperatures and more complex structures. Superconductivity is doping dependent in these material classes unlike in MgB(2) which, as a pure compound, has the highest values of T(c) and a rapid suppression of superconductivity with doping takes place. In all three material classes isotope effects have been observed, including exotic ones in the cuprates, and controversial ones in the Fe based materials. Before the area of high-temperature superconductivity, isotope effects on T(c) were the signature for phonon mediated superconductivity-even when deviations from the BCS value to smaller values were observed. Since the discovery of high T(c) materials this is no longer evident since competing mechanisms might exist and other mediating pairing interactions are discussed which are of purely electronic origin. In this work we will compare the three different material classes and especially discuss the experimentally observed isotope effects of all three systems and present a rather general analysis of them. Furthermore, we will concentrate on multiband signatures which are not generally accepted in cuprates even though they are manifest in various experiments, the evidence for those in MgB(2), and indications for them in the Fe based compounds. Mostly we will consider experimental data, but when possible also discuss theoretical models which are suited to explain the data.

AMICA: The First camera for Near- and Mid-Infrared Astronomical Imaging at Dome C

NASA Astrophysics Data System (ADS)

Straniero, O.; Dolci, M.; Valentini, A.; Valentini, G.; di Rico, G.; Ragni, M.; Giuliani, C.; di Cianno, A.; di Varano, I.; Corcione, L.; Bortoletto, F.; D'Alessandro, M.; Magrin, D.; Bonoli, C.; Giro, E.; Fantinel, D.; Zerbi, F. M.; Riva, A.; de Caprio, V.; Molinari, E.; Conconi, P.; Busso, M.; Tosti, G.; Abia, C. A.

AMICA (Antarctic Multiband Infrared CAmera) is an instrument designed to perform astronomical imaging in the near- (1{-}5 μm) and mid- (5 27 μm) infrared wavelength regions. Equipped with two detectors, an InSb 2562 and a Si:As 1282 IBC, cooled at 35 and 7 K respectively, it will be the first instrument to investigate the potential of the Italian-French base Concordia for IR astronomy. The main technical challenge is represented by the extreme conditions of Dome C (T ˜ -90 °C, p ˜640 mbar). An environmental control system ensures the correct start-up, shut-down and housekeeping of the various components of the camera. AMICA will be mounted on the IRAIT telescope and will perform survey-mode observations in the Southern sky. The first task is to provide important site-quality data. Substantial contributions to the solution of fundamental astrophysical quests, such as those related to late phases of stellar evolution and to star formation processes, are also expected.

The Kaguya Mission: Science Achievements and Data Release

NASA Astrophysics Data System (ADS)

Kato, Manabu; Sasaki, Susumu; Takizawa, Yoshisada

2010-05-01

Lunar orbiter Kaguya (SELENE) has impacted the Moon on July 10, 2009. The Kaguya mission has completed to observe the whole Moon for total twenty months; checkout term of three months, nominal one of ten months, and the extension of seven months. In the extended mission before the impact the measurements of magnetic field and gamma-ray from lower orbits have been perrformed successfully in addition to low altitude observation by Terraine Camera, Multiband Imager, and HDTV Camera. New data of intense magnetic anomaly and GRS data with higher spacial resolution has been acquired to study elemental distribution and magnetism of the Moon. New information and insights have been brought to lunar sciences in topography, gra-vimetry, geology, mineralogy, lithology, plasma physics. On November 1, 2009 the Kaguya team has released science data to the public as an international promise. The archive data can be accessed through Kaguya homepage of JAXA. Image gallary and 3D GIS system have been also put on view from the same homepage.

Switched integration amplifier-based photocurrent meter for accurate spectral responsivity measurement of photometers.

PubMed

Park, Seongchong; Hong, Kee-Suk; Kim, Wan-Seop

2016-03-20

This work introduces a switched integration amplifier (SIA)-based photocurrent meter for femtoampere (fA)-level current measurement, which enables us to measure a 10⁷ dynamic range of spectral responsivity of photometers even with a common lamp-based monochromatic light source. We described design considerations and practices about operational amplifiers (op-amps), switches, readout methods, etc., to compose a stable SIA of low offset current in terms of leakage current and gain peaking in detail. According to the design, we made six SIAs of different integration capacitance and different op-amps and evaluated their offset currents. They showed an offset current of (1.5-85) fA with a slow variation of (0.5-10) fA for an hour under opened input. Applying a detector to the SIA input, the offset current and its variation were increased and the SIA readout became noisier due to finite shunt resistance and nonzero shunt capacitance of the detector. One of the SIAs with 10 pF nominal capacitance was calibrated using a calibrated current source at the current level of 10 nA to 1 fA and at the integration time of 2 to 65,536 ms. As a result, we obtained a calibration formula for integration capacitance as a function of integration time rather than a single capacitance value because the SIA readout showed a distinct dependence on integration time at a given current level. Finally, we applied it to spectral responsivity measurement of a photometer. It is demonstrated that the home-made SIA of 10 pF was capable of measuring a 10⁷ dynamic range of spectral responsivity of a photometer.

The Kepler Project: Mission Update

NASA Technical Reports Server (NTRS)

Borucki, William J.; Koch, David G.

2009-01-01

Kepler is a Discovery-class mission designed to determine the frequency of Earth-size planets in and near the habitable zone of solar-like stars. The instrument consists of a 0.95 m aperture photometer designed to obtain high precision photometric measurement of > 100,000 stars to search for patterns of transits. The focal plane of the Schmidt-telescope contains 42 CCDs with at total of 95 mega pixels that cover 116 square degrees of sky. The photometer was launched into an Earth-trailing heliocentric orbit on March 6, 2009, finished its commissioning on May 12, and is now in the science operations mode. During the commissioning of the Kepler photometer, data were obtained at a 30 minute cadence for 53,000 stars for 9.7 days. Although the data have not yet been corrected for the presence of systematic errors and artifacts, the data show the presence of hundreds of eclipsing binary stars and variable stars of amazing variety. To provide some estimate of the capability of the photometer, a quick analysis of the photometric precision was made. Analysis of the commissioning data also show transits, occultations and light emitted from the known exoplanet HAT-P7b. The data show a smooth rise and fall of light: from the planet as it orbits its star, punctuated by a drop of 130 +/- 11 ppm in flux when the planet passes behind its star. We interpret this as the phase variation of the dayside thermal emission plus reflected light from the planet as it orbits its star and is occulted. The depth of the occultation is similar in amplitude to that expected from a transiting Earth-size planet and demonstrates that the Mission has the precision necessary to detect such planets.

Kepler Mission: Current Status

NASA Astrophysics Data System (ADS)

Borucki, William J.; Koch, D. G.; Lissauer, J. J.; Bryson, S.; Natalie, B.; Caldwell, D. A.; DeVore, E.; Jenkins, J. M.; Christensen-Dalsgaard, J.; Cochran, W. D.; Dunham, E. W.; Gautier, T. N.; Geary, J. C.; Latham, D. W.; Sasselov, D.; Gilliland, R. L.; Gould, A.; Howell, S. B.; Monet, D. G.

2007-12-01

Kepler is a Discovery-class mission designed to determine the frequency of Earth-size planets in and near the habitable zone of solar-like stars. The instrument consists of a high precision photometer with Schmidt-type optics and a focal plane containing 95 million pixels to monitor over 100,000 stars to search for patterns of transits generated by planets as small as Mars. The recent reduction in the mission duration is discussed with regard to the impact on the expected science product and null statistics. Both terrestrial and giant planets discoveries will be followed up with ground-based Doppler-velocity observations to determine mass and density. The first meeting of Kepler Asteroseismic Science Consortium was held in Paris to organize an international team to analyze the Kepler data to determine the characteristics of the brighter target stars including their size and age. Stellar size determinations accurate to a few percent are expected. These will allow very accurate planet sizes to be determined from the depth of the transit signals. NASA HQ received thirty six proposals for the Participating Scientist Program and chose several new members to join the Science Team. Both the 0.95 m Schmidt corrector and 1.4 m aperture primary mirror have been completed and delivered for integration into the photometer. The focal plane with forty-two science CCD detectors and their processing electronics has been assembled and tested. The spacecraft assembly has begun with the mounting of the reaction control system, reaction wheels, attitude determination & control system, and power systems. Both the photometer and spacecraft are nearing final assembly with all subsystems having passed their environmental and performance testing. The photometer to spacecraft integration will begin this spring. The Mission is on schedule for a launch in February 2009. The Kepler Mission is funded by the NASA Astrophysics Division, Science Mission Directorate.

Sunlight Transmission through Desert Dust and Marine Aerosols: Diffuse Light Corrections to Sun Photometry and Pyrheliometry

NASA Technical Reports Server (NTRS)

Russell, P. B.; Livingston, J. M.; Dubovik, O.; Ramirez, S. A.; Wang, J.; Redemann, J.; Schmid, B.; Box, M.; Holben, B. N.

2003-01-01

Desert dust and marine aerosols are receiving increased scientific attention because of their prevalence on intercontinental scales and their potentially large effects on Earth radiation and climate, as well as on other aerosols, clouds, and precipitation. The relatively large size of desert dust and marine aerosols produces scattering phase functions that are strongly forward- peaked. Hence, Sun photometry and pyrheliometry of these aerosols are more subject to diffuse-light errors than is the case for smaller aerosols. Here we quantify these diffuse-light effects for common Sun photometer and pyrheliometer fields of view (FOV), using a data base on dust and marine aerosols derived from (1) AERONET measurements of sky radiance and solar beam transmission and (2) in situ measurements of aerosol layer size distribution and chemical composition. Accounting for particle non-sphericity is important when deriving dust size distribution from both AERONET and in situ aerodynamic measurements. We express our results in terms of correction factors that can be applied to Sun photometer and pyrheliometer measurements of aerosol optical depth (AOD). We find that the corrections are negligible (less than approximately 1% of AOD) for Sun photometers with narrow FOV (half-angle eta less than degree), but that they can be as large as 10% of AOD at 354 nm wavelength for Sun photometers with eta = 1.85 degrees. For pyrheliometers (which can have eta up to approximately 2.8 degrees), corrections can be as large as 16% at 354 nm. We find that AOD correction factors are well correlated with AOD wavelength dependence (hence Angstrom exponent). We provide best-fit equations for determining correction factors from Angstrom exponents of uncorrected AOD spectra, and we demonstrate their application to vertical profiles of multiwavelength AOD.

Application LANDSAT imagery to geologic mapping in the ice-free valleys of Antarctica

NASA Technical Reports Server (NTRS)

Houston, R. S. (Principal Investigator); Marrs, R. W.; Smithson, S. B.

1976-01-01

The author has identified the following significant results. Studies in the Ice-Free Valleys are resulted in the compilation of a sizeable library of maps and publications. Rock reflectance measurements were taken during the Antarctic summer of 1973. Spectral reflectance of rocks (mostly mafic lava flows) in the McMurdo and Ice-Free Valleys areas were measured using a filter wheel photometer equipped to measure reflectances in the four Landsat bands. A series of samples were collected at regular intervals across a large differentiated, mafic sill near Lake Vida. Chemical analyses of the sample suggest that the tonal variations in this sill are controlled by changes in the iron content of the rock. False color images were prepared for a number of areas by the diazo method and with an optical multispectral biviewer. These images were useful in defining boundaries of sea ice, snow cover, and in the study of ablating glaciers, but were not very useful for rock discrimination.

A Herschel-Resolved Debris Disk Around the Nearby G Star HIP 32480

NASA Technical Reports Server (NTRS)

Stapelfeldt, K.

2011-01-01

The Herschel Space Observatory is providing unprecedented sensitivity and angular resolution in the far-infrared. The DUNES Key Project (DUst around NEarby Stars, PI Carlos Eiroa) has finished its survey of 133 FGK stars within 25 pc of the Sun using the PACS photometer at 100 and 160 microns. We report the detection of a resolved debris ring around HIP 32480, a G0 star 16.5 parsecs distant. The ring is almost 300 AU in diameter and inclined 30 degrees from edge-on. We present a thermal emission model for the system that fits the Spitzer spectroscopy and Herschel images of the system. We find a minimum grainsize of approximately 4 microns in the main ring and a distinct warm dust population interior to it. Faint detached emission features just outside the ring may trace a separate, more distant ring in the system. The non-detection of the ring in archival HST/ACS coronagraphic images limits the dust grain albedo in the ring to be no more than 10%.

A Resolved Debris Disk Around the Nearby G Star HIP 32480

NASA Technical Reports Server (NTRS)

Stapelfeldt, K. R.; Bryden, G. C.; Marshall, J.; Eiroa, C.; Absil, O.; Mora, A.; Krist, J. E.; Su, K. Y. L.

2012-01-01

The Herschel Space Observatory is providing unprecedented sensitivity and angular resolution in the far-infrared. The DUNES Key Project (DUst around NEarby Stars, PI Carlos Eiroa) has finished its survey of 133 FGK stars within 25 pc of the Sun using the PACS photometer at 100 and 160 microns. We report the detection of a resolved debris ring around HIP 32480, a GO star 16.5 parsecs distant. The ring is almost 300 AU in diameter and inclined 30 degrees from edge-on. We present a thermal emission model for the system that fits the Spitzer spectroscopy and Herschel images of the system. We find a minimum grain-size of 4 microns in the main ring and a distinct warm dust population interior to it. Faint detached emission features just outside the ring may trace a separate, more distant ring in the system. The non-detection of the ring in archival HST/ACS coronagraphic images limits the dust grain albedo in the ring to be no more than 10%.

Ultraviolet Views of Enceladus, Tethys, and Dione

NASA Technical Reports Server (NTRS)

Hansen, C. J.; Hendrix, A. R.

2005-01-01

The Cassini Ultraviolet Imaging Spectrograph (UVIS) has collected ultraviolet observations of many of Saturn's icy moons since Cassini's insertion into orbit around Saturn. We will report on results from Enceladus, Tethys and Dione, orbiting in the Saturn system at distances of 3.95, 4.88 and 6.26 Saturn radii, respectively. Icy satellite science objectives of the UVIS include investigations of surface age and evolution, surface composition and chemistry, and tenuous exospheres. We address these objectives by producing albedo maps, and reflection and emission spectra, and observing stellar occultations. UVIS has four channels: EUV: Extreme Ultraviolet (55 nm to 110 nm), FUV: Far Ultraviolet (110 to 190 nm), HSP: High Speed Photometer, and HDAC: Hydrogen-Deuterium Absorption Cell. The EUV and FUV spectrographs image onto a 2-dimensional detector, with 64 spatial rows by 1024 spectral columns. To-date we have focused primarily on the far ultraviolet data acquired with the low resolution slit width (4.8 angstrom spectral resolution). Additional information is included in the original extended abstract.

Dual-view inverted selective plane illumination microscopy (diSPIM) with improved background rejection for accurate 3D digital pathology

NASA Astrophysics Data System (ADS)

Hu, Bihe; Bolus, Daniel; Brown, J. Quincy

2018-02-01

Current gold-standard histopathology for cancerous biopsies is destructive, time consuming, and limited to 2D slices, which do not faithfully represent true 3D tumor micro-morphology. Light sheet microscopy has emerged as a powerful tool for 3D imaging of cancer biospecimens. Here, we utilize the versatile dual-view inverted selective plane illumination microscopy (diSPIM) to render digital histological images of cancer biopsies. Dual-view architecture enabled more isotropic resolution in X, Y, and Z; and different imaging modes, such as adding electronic confocal slit detection (eCSD) or structured illumination (SI), can be used to improve degraded image quality caused by background signal of large, scattering samples. To obtain traditional H&E-like images, we used DRAQ5 and eosin (D&E) staining, with 488nm and 647nm laser illumination, and multi-band filter sets. Here, phantom beads and a D&E stained buccal cell sample have been used to verify our dual-view method. We also show that via dual view imaging and deconvolution, more isotropic resolution has been achieved for optical cleared human prostate sample, providing more accurate quantitation of 3D tumor architecture than was possible with single-view SPIM methods. We demonstrate that the optimized diSPIM delivers more precise analysis of 3D cancer microarchitecture in human prostate biopsy than simpler light sheet microscopy arrangements.

unWISE: Unblurred Coadds of the WISE Imaging

NASA Astrophysics Data System (ADS)

Lang, Dustin

2014-05-01

The Wide-field Infrared Survey Explorer (WISE) satellite observed the full sky in four mid-infrared bands in the 2.8-28 μm range. The primary mission was completed in 2010. The WISE team has done a superb job of producing a series of high-quality, well-documented, complete data releases in a timely manner. However, the "Atlas Image" coadds that are part of the recent AllWISE and previous data releases were intentionally blurred. Convolving the images by the point-spread function while coadding results in "matched-filtered" images that are close to optimal for detecting isolated point sources. But these matched-filtered images are sub-optimal or inappropriate for other purposes. For example, we are photometering the WISE images at the locations of sources detected in the Sloan Digital Sky Survey through forward modeling, and this blurring decreases the available signal-to-noise by effectively broadening the point-spread function. This paper presents a new set of coadds of the WISE images that have not been blurred. These images retain the intrinsic resolution of the data and are appropriate for photometry preserving the available signal-to-noise. Users should be cautioned, however, that the W3- and W4-band coadds contain artifacts around large, bright structures (large galaxies, dusty nebulae, etc.); eliminating these artifacts is the subject of ongoing work. These new coadds, and the code used to produce them, are publicly available at http://unwise.me.

Development Status of Optical and Electromagnetic Instruments onboard JEM-GLIMS

NASA Astrophysics Data System (ADS)

Sato, Mitsuteru; Ushio, Tomoo; Morimoto, Takeshi; Suzuki, Makoto; Yamazaki, Atsushi; Ishida, Ryohei; Takahashi, Yukihiro; Hobara, Yasuhide; Sakamoto, Yuji; Yoshita, Kengo

In order to study the generation mechanism of Transient Luminous Events (TLEs), global oc-currence rates and distributions of lightning and TLEs, and the relationship between lightning, TLEs and Terrestrial Gamma-ray Flashes (TGFs), we will carry out the lightning and TLE observation at Exposed Facility of Japanese Experiment Module (JEM-EF) of International Space Station (ISS). In this mission named JEM-GLIMS (Global Lightning and sprIte Mea-surementS on JEM-EF) two kinds of optical instruments and two sets of radio receivers will be integrated into the Multi mission Consolidated Equipment (MCE) which is the bus system and will be installed at JEM-EF. The optical instruments consist of two wide FOV CMOS cameras and six wide FOV photometers, and all these optical instruments are pointed to the nadir direction. CMOS cameras named LSI (Lightning and Sprite Imager) use the STAR-250 device as a detector, which has 512x512 pixels and 25x25 µm pixel size, and have 28.3x28.3 deg. FOV. One CMOS camera with a wide band filter (730-830 nm) mainly measures lightning emission, while another camera with a narrowband filter (766+/-6 nm) mainly measures TLE emission. Five of six photometers named as PH have 42.7 deg. FOV and use photomultiplier tube (PMT) as a photon detector. They equip band-pass filters (150-280 nm, 316+/-5 nm, 337+/-5 nm, 392+/-5 nm, and 762+/-5 nm) for the absolute intensity measurement of the TLE emission. One of six photometers equips a wide-band filter (600-900 nm) to detect light-ning occurring within 86.8 deg. FOV. These output signals will be recorded with the sampling frequency of 20 kHz with a 12-bit resolution. One of two electromagnetic instruments is a VLF receiver (VLFR), which measures electromagnetic waves in the frequency range of 1-40 kHz with 16-bit resolution. Another instrument is VHF interferometer (VITF), which measures VHF pulses generated lightning discharge in the frequency range of 70-100 MHz. JEM-GIMS will be launched in 2011. We have passed the critical design review (CDR) on January and February and have started the fabrication of the proto-flight model. We will present the devel-opment status of the JEM-GLISM optical instruments and discuss the scientific outputs derived from this mission more in detail.

Tunable multiband polarization conversion and manipulation in vanadium dioxide-based asymmetric chiral metamaterial

NASA Astrophysics Data System (ADS)

Song, Shichao; Ma, Xiaoliang; Pu, Mingbo; Li, Xiong; Zhang, Zuojun; Gao, Ping; Luo, Xiangang

2018-04-01

Tunable multiband polarization conversion and manipulation are achieved by introducing vanadium dioxide (VO2) into a planar spiral asymmetric chiral metamaterial. Numerical simulations demonstrate that when VO2 is in the insulating state, circularly polarized electromagnetic waves are emitted at two distinct resonant frequencies. When VO2 is in the metallic state, the number of resonant frequencies changes from two to four. In addition, the initial left-handed and right-handed circularly polarized transmitted waves correspondingly transform into right and left ones. Moreover, the surface current distributions are studied in order to investigate the transformation behaviors of both the insulating and metallic states.

Microsatellite markers isolated from a polyploid saltbush, Atriplex nummularia Lindl. (Chenopodiaceae).

PubMed

Byrne, Margaret; Hankinson, Margaret; Sampson, Jane F; Stankowski, Sean

2008-11-01

Atriplex nummularia is a polyploid Australian saltbush which has been identified as a suitable species for use in the rehabilitation of agricultural land affected by salinity. We isolated 12 polymorphic loci for a preliminary assessment of genetic variability and structure within the species as a basis for a breeding programme. Preliminary screening of loci in 40 individuals from two populations revealed multibanded genotypes consisting of up to seven alleles in a single individual, with up to 29 alleles observed at a single locus. The multibanded patterns are consistent with the polyploid status of this species. © 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd.

Multi-wavelength and multiband RE-doped optical fiber source array for WDM-GPON applications

NASA Astrophysics Data System (ADS)

Perez-Sanchez, G. G.; Bertoldi-Martins, I.; Gallion, P.; Gosset, C.; Álvarez-Chávez, J. A.

2013-12-01

In this paper, a multiband, multi-wavelength, all-fibre source array consisting of an 810nm pump laser diode, thretwo fiber splitters and three segments of Er-, Tm- and Nd-doped fiber is proposed for PON applications. In the set-up, cascaded pairs of standard fiber gratings are used for extracting the required multiple wavelengths within their corresponding bands. A thorough design parameter description, optical array details and full simulation results, such as: full multi-wavelength spectrum, peak and average powers for each generated wavelength, linewidth at FWHM for each generated signal, and individual and overall conversion efficiency, will be included in the manuscript.

Isotope effect on electron-phonon interaction in the multiband superconductor MgB 2

DOE PAGES

Mou, Daixiang; Manni, Soham; Taufour, Valentin; ...

2016-04-07

We investigate the effect of isotope substitution on the electron-phonon interaction in the multiband superconductor MgB 2 using tunable laser-based angle-resolved photoemission spectroscopy. The kink structure around 70 meV in the σ band, which is caused by electron coupling to the E 2g phonon mode, is shifted to higher binding energy by ~3.5 meV in Mg 10B 2 and the shift is not affected by superconducting transition. Furthermore, these results serve as the benchmark for investigations of isotope effects in known, unconventional superconductors and newly discovered superconductors where the origin of pairing is unknown.

Geometric optics-based multiband cloaking of large objects with the wave phase and amplitude preservation.

PubMed

Duan, Ran; Semouchkina, Elena; Pandey, Ravi

2014-11-03

The geometric optics principles are used to develop a unidirectional transmission cloak for hiding objects with dimensions substantially exceeding the incident radiation wavelengths. Invisibility of both the object and the cloak is achieved without metamaterials, so that significant widths of the cloaking bands are provided. For the preservation of wave phases, the λ-multiple delays of waves passing through the cloak are realized. Suppression of reflection losses is achieved by using half-λ multiple thicknesses of optical elements. Due to periodicity of phase delay and reflection suppression conditions, the cloak demonstrates efficient multiband performance confirmed by full-wave simulations.

Multiband guided-mode resonance filter in bilayer asymmetric metallic gratings

NASA Astrophysics Data System (ADS)

Wang, Yanhui; Li, Xiangjun; Lang, Tingting; Jing, Xufeng; Hong, Zhi

2018-07-01

In this paper, a guided-mode resonances (GMRs) based multiband filter in bilayer asymmetric metallic gratings is presented. Four sharp dips are generated in the frequency range of 1.4-2.0 THz, which are induced by the split of two GMR modes (TE0 and TM0) due to the break of the structure's symmetry. This symmetry of the structure depends on the relative position between the upper layer and lower layer gratings. Therefore, by choosing proper lateral displacement, the split of TE0 or/and TM0 modes can be eliminated. Two-, three-, and four- GMRs based polarization insensitive or sensitive filters are demonstrated numerically.

Evaluation of multiband photography for rock discrimination

NASA Technical Reports Server (NTRS)

Raines, G. L.

1974-01-01

An evaluation is presented of the multiband photography concept that tonal differences between rock formations on aerial photography can be improved through the selection of the appropriate bands. The concept involves: (1) acquiring band reference data for the rocks being considered; (2) selecting the best combination of bands to discriminate the rocks using these reference data; (3) acquiring aerial photography using these selected bands; and (4) extracting the desired geologic information in an optimum manner. The test site geology and rock reflectance are discussed in detail. The evaluation found that the differences in contrast ratios are not statistically significant, and the spectral information in different bands is not advantageous.

High-precision multiband spectroscopy of ultracold fermions in a nonseparable optical lattice

NASA Astrophysics Data System (ADS)

Fläschner, Nick; Tarnowski, Matthias; Rem, Benno S.; Vogel, Dominik; Sengstock, Klaus; Weitenberg, Christof

2018-05-01

Spectroscopic tools are fundamental for the understanding of complex quantum systems. Here, we demonstrate high-precision multiband spectroscopy in a graphenelike lattice using ultracold fermionic atoms. From the measured band structure, we characterize the underlying lattice potential with a relative error of 1.2 ×10-3 . Such a precise characterization of complex lattice potentials is an important step towards precision measurements of quantum many-body systems. Furthermore, we explain the excitation strengths into different bands with a model and experimentally study their dependency on the symmetry of the perturbation operator. This insight suggests the excitation strengths as a suitable observable for interaction effects on the eigenstates.

Optical frequency comb based multi-band microwave frequency conversion for satellite applications.

PubMed

Yang, Xinwu; Xu, Kun; Yin, Jie; Dai, Yitang; Yin, Feifei; Li, Jianqiang; Lu, Hua; Liu, Tao; Ji, Yuefeng

2014-01-13

Based on optical frequency combs (OFC), we propose an efficient and flexible multi-band frequency conversion scheme for satellite repeater applications. The underlying principle is to mix dual coherent OFCs with one of which carrying the input signal. By optically channelizing the mixed OFCs, the converted signal in different bands can be obtained in different channels. Alternatively, the scheme can be configured to generate multi-band local oscillators (LO) for widely distribution. Moreover, the scheme realizes simultaneous inter- and intra-band frequency conversion just in a single structure and needs only three frequency-fixed microwave sources. We carry out a proof of concept experiment in which multiple LOs with 2 GHz, 10 GHz, 18 GHz, and 26 GHz are generated. A C-band signal of 6.1 GHz input to the proposed scheme is successfully converted to 4.1 GHz (C band), 3.9 GHz (C band) and 11.9 GHz (X band), etc. Compared with the back-to-back (B2B) case measured at 0 dBm input power, the proposed scheme shows a 9.3% error vector magnitude (EVM) degradation at each output channel. Furthermore, all channels satisfy the EVM limit in a very wide input power range.

Generalized multiband typical medium dynamical cluster approximation: Application to (Ga,Mn)N

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yi; Nelson, R.; Siddiqui, Elisha

We generalize the multiband typical medium dynamical cluster approximation and the formalism introduced by Blackman, Esterling, and Berk so that it can deal with localization in multiband disordered systems with both diagonal and off-diagonal disorder with complicated potentials. We also introduce an ansatz for the momentum-resolved typical density of states that greatly improves the numerical stability of the method while preserving the independence of scattering events at different frequencies. Starting from the first-principles effective Hamiltonian, we apply this method to the diluted magnetic semiconductor Ga 1 - x Mn x N , and find the impurity band is completely localizedmore » for Mn concentrations x < 0.03 , while for 0.03 < x < 0.10 the impurity band has delocalized states but the chemical potential resides at or above the mobility edge. So, the system is always insulating within the experimental compositional limit ( x ≈ 0.10 ) due to Anderson localization. But, for 0.03 < x < 0.10 hole doping could make the system metallic, allowing double-exchange mediated, or enhanced, ferromagnetism. Finally, this developed method is expected to have a large impact on first-principles studies of Anderson localization.« less

Multiband and Broadband Absorption Enhancement of Monolayer Graphene at Optical Frequencies from Multiple Magnetic Dipole Resonances in Metamaterials

NASA Astrophysics Data System (ADS)

Liu, Bo; Tang, Chaojun; Chen, Jing; Xie, Ningyan; Tang, Huang; Zhu, Xiaoqin; Park, Gun-sik

2018-05-01

It is well known that a suspended monolayer graphene has a weak light absorption efficiency of about 2.3% at normal incidence, which is disadvantageous to some applications in optoelectronic devices. In this work, we will numerically study multiband and broadband absorption enhancement of monolayer graphene over the whole visible spectrum, due to multiple magnetic dipole resonances in metamaterials. The unit cell of the metamaterials is composed of a graphene monolayer sandwiched between four Ag nanodisks with different diameters and a SiO2 spacer on an Ag substrate. The near-field plasmon hybridizations between individual Ag nanodisks and the Ag substrate form four independent magnetic dipole modes, which result into multiband absorption enhancement of monolayer graphene at optical frequencies. When the resonance wavelengths of the magnetic dipole modes are tuned to approach one another by changing the diameters of the Ag nanodisks, a broadband absorption enhancement can be achieved. The position of the absorption band in monolayer graphene can be also controlled by varying the thickness of the SiO2 spacer or the distance between the Ag nanodisks. Our designed graphene light absorber may find some potential applications in optoelectronic devices, such as photodetectors.

RRI-GBT MULTI-BAND RECEIVER: MOTIVATION, DESIGN, AND DEVELOPMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maan, Yogesh; Deshpande, Avinash A.; Chandrashekar, Vinutha

2013-01-15

We report the design and development of a self-contained multi-band receiver (MBR) system, intended for use with a single large aperture to facilitate sensitive and high time-resolution observations simultaneously in 10 discrete frequency bands sampling a wide spectral span (100-1500 MHz) in a nearly log-periodic fashion. The development of this system was primarily motivated by need for tomographic studies of pulsar polar emission regions. Although the system design is optimized for the primary goal, it is also suited for several other interesting astronomical investigations. The system consists of a dual-polarization multi-band feed (with discrete responses corresponding to the 10 bandsmore » pre-selected as relatively radio frequency interference free), a common wide-band radio frequency front-end, and independent back-end receiver chains for the 10 individual sub-bands. The raw voltage time sequences corresponding to 16 MHz bandwidth each for the two linear polarization channels and the 10 bands are recorded at the Nyquist rate simultaneously. We present the preliminary results from the tests and pulsar observations carried out with the Robert C. Byrd Green Bank Telescope using this receiver. The system performance implied by these results and possible improvements are also briefly discussed.« less

High-order modes of spoof surface plasmonic wave transmission on thin metal film structure.

PubMed

Liu, Xiaoyong; Feng, Yijun; Zhu, Bo; Zhao, Junming; Jiang, Tian

2013-12-16

Recently, conformal surface plasmon (CSP) structure has been successfully proposed that could support spoof surface plasmon polaritons (SPPs) on corrugated metallic strip with ultrathin thickness [Proc. Natl. Acad. Sci. U.S.A. 110, 40-45 (2013)]. Such concept provides a flexible, conformal, and ultrathin wave-guiding element, very promising for application of plasmonic devices, and circuits in the frequency ranging from microwave to mid-infrared. In this work, we investigated the dispersions and field patterns of high-order modes of spoof SPPs along CSP structure of thin metal film with corrugated edge of periodic array of grooves, and carried out direct measurement on the transmission spectrum of multi-band of surface wave propagation at microwave frequency. It is found that the mode number and mode bands are mainly determined by the depth of the grooves, providing a way to control the multi-band transmission spectrum. We have also experimentally verified the high-order mode spoof SPPs propagation on curved CSP structure with acceptable bending loss. The multi-band propagation of spoof surface wave is believed to be applicable for further design of novel planar devices such as filters, resonators, and couplers, and the concept can be extended to terahertz frequency range.

Generalized multiband typical medium dynamical cluster approximation: Application to (Ga,Mn)N

DOE PAGES

Zhang, Yi; Nelson, R.; Siddiqui, Elisha; ...

2016-12-29

We generalize the multiband typical medium dynamical cluster approximation and the formalism introduced by Blackman, Esterling, and Berk so that it can deal with localization in multiband disordered systems with both diagonal and off-diagonal disorder with complicated potentials. We also introduce an ansatz for the momentum-resolved typical density of states that greatly improves the numerical stability of the method while preserving the independence of scattering events at different frequencies. Starting from the first-principles effective Hamiltonian, we apply this method to the diluted magnetic semiconductor Ga 1 - x Mn x N , and find the impurity band is completely localizedmore » for Mn concentrations x < 0.03 , while for 0.03 < x < 0.10 the impurity band has delocalized states but the chemical potential resides at or above the mobility edge. So, the system is always insulating within the experimental compositional limit ( x ≈ 0.10 ) due to Anderson localization. But, for 0.03 < x < 0.10 hole doping could make the system metallic, allowing double-exchange mediated, or enhanced, ferromagnetism. Finally, this developed method is expected to have a large impact on first-principles studies of Anderson localization.« less

The phase transition in VO 2 probed using x-ray, visible and infrared radiations

DOE PAGES

Kumar, Suhas; Strachan, John Paul; Kilcoyne, A. L. David; ...

2016-02-15

Vanadium dioxide (VO 2) is a model system that has been used to understand closely occurring multiband electronic (Mott) and structural (Peierls) transitions for over half a century due to continued scientific and technological interests. Among the many techniques used to study VO 2, the most frequently used involve electromagnetic radiation as a probe. Understanding of the distinct physical information provided by different probing radiations is incomplete, mostly owing to the complicated nature of the phase transitions. Here, we use transmission of spatially averaged infrared (λ = 1.5 μm) and visible (λ = 500 nm) radiations followed by spectroscopy andmore » nanoscale imaging using x-rays (λ = 2.25–2.38 nm) to probe the same VO 2 sample while controlling the ambient temperature across its hysteretic phase transitions and monitoring its electrical resistance. We directly observed nanoscale puddles of distinct electronic and structural compositions during the transition. The two main results are that, during both heating and cooling, the transition of infrared and visible transmission occurs at significantly lower temperatures than the Mott transition, and the electronic (Mott) transition occurs before the structural (Peierls) transition in temperature. We use our data to provide insights into possible microphysical origins of the different transition characteristics. We highlight that it is important to understand these effects because small changes in the nature of the probe can yield quantitatively, and even qualitatively, different results when applied to a non-trivial multiband phase transition. Our results guide more judicious use of probe type and interpretation of the resulting data.« less

A Multi-Band Analytical Algorithm for Deriving Absorption and Backscattering Coefficients from Remote-Sensing Reflectance of Optically Deep Waters

NASA Technical Reports Server (NTRS)

Lee, Zhong-Ping; Carder, Kendall L.

2001-01-01

A multi-band analytical (MBA) algorithm is developed to retrieve absorption and backscattering coefficients for optically deep waters, which can be applied to data from past and current satellite sensors, as well as data from hyperspectral sensors. This MBA algorithm applies a remote-sensing reflectance model derived from the Radiative Transfer Equation, and values of absorption and backscattering coefficients are analytically calculated from values of remote-sensing reflectance. There are only limited empirical relationships involved in the algorithm, which implies that this MBA algorithm could be applied to a wide dynamic range of waters. Applying the algorithm to a simulated non-"Case 1" data set, which has no relation to the development of the algorithm, the percentage error for the total absorption coefficient at 440 nm a (sub 440) is approximately 12% for a range of 0.012 - 2.1 per meter (approximately 6% for a (sub 440) less than approximately 0.3 per meter), while a traditional band-ratio approach returns a percentage error of approximately 30%. Applying it to a field data set ranging from 0.025 to 2.0 per meter, the result for a (sub 440) is very close to that using a full spectrum optimization technique (9.6% difference). Compared to the optimization approach, the MBA algorithm cuts the computation time dramatically with only a small sacrifice in accuracy, making it suitable for processing large data sets such as satellite images. Significant improvements over empirical algorithms have also been achieved in retrieving the optical properties of optically deep waters.

Compact full-motion video hyperspectral cameras: development, image processing, and applications

NASA Astrophysics Data System (ADS)

Kanaev, A. V.

2015-10-01

Emergence of spectral pixel-level color filters has enabled development of hyper-spectral Full Motion Video (FMV) sensors operating in visible (EO) and infrared (IR) wavelengths. The new class of hyper-spectral cameras opens broad possibilities of its utilization for military and industry purposes. Indeed, such cameras are able to classify materials as well as detect and track spectral signatures continuously in real time while simultaneously providing an operator the benefit of enhanced-discrimination-color video. Supporting these extensive capabilities requires significant computational processing of the collected spectral data. In general, two processing streams are envisioned for mosaic array cameras. The first is spectral computation that provides essential spectral content analysis e.g. detection or classification. The second is presentation of the video to an operator that can offer the best display of the content depending on the performed task e.g. providing spatial resolution enhancement or color coding of the spectral analysis. These processing streams can be executed in parallel or they can utilize each other's results. The spectral analysis algorithms have been developed extensively, however demosaicking of more than three equally-sampled spectral bands has been explored scarcely. We present unique approach to demosaicking based on multi-band super-resolution and show the trade-off between spatial resolution and spectral content. Using imagery collected with developed 9-band SWIR camera we demonstrate several of its concepts of operation including detection and tracking. We also compare the demosaicking results to the results of multi-frame super-resolution as well as to the combined multi-frame and multiband processing.

High resolution multispectral photogrammetric imagery: enhancement, interpretation and evaluations

NASA Astrophysics Data System (ADS)

Roberts, Arthur; Haefele, Martin; Bostater, Charles; Becker, Thomas

2007-10-01

A variety of aerial mapping cameras were adapted and developed into simulated multiband digital photogrammetric mapping systems. Direct digital multispectral, two multiband cameras (IIS 4 band and Itek 9 band) and paired mapping and reconnaissance cameras were evaluated for digital spectral performance and photogrammetric mapping accuracy in an aquatic environment. Aerial films (24cm X 24cm format) tested were: Agfa color negative and extended red (visible and near infrared) panchromatic, and; Kodak color infrared and B&W (visible and near infrared) infrared. All films were negative processed to published standards and digitally converted at either 16 (color) or 10 (B&W) microns. Excellent precision in the digital conversions was obtained with scanning errors of less than one micron. Radiometric data conversion was undertaken using linear density conversion and centered 8 bit histogram exposure. This resulted in multiple 8 bit spectral image bands that were unaltered (not radiometrically enhanced) "optical count" conversions of film density. This provided the best film density conversion to a digital product while retaining the original film density characteristics. Data covering water depth, water quality, surface roughness, and bottom substrate were acquired using different measurement techniques as well as different techniques to locate sampling points on the imagery. Despite extensive efforts to obtain accurate ground truth data location errors, measurement errors, and variations in the correlation between water depth and remotely sensed signal persisted. These errors must be considered endemic and may not be removed through even the most elaborate sampling set up. Results indicate that multispectral photogrammetric systems offer improved feature mapping capability.

AMICA (Antarctic Multiband Infrared CAmera) project

NASA Astrophysics Data System (ADS)

Dolci, Mauro; Straniero, Oscar; Valentini, Gaetano; Di Rico, Gianluca; Ragni, Maurizio; Pelusi, Danilo; Di Varano, Igor; Giuliani, Croce; Di Cianno, Amico; Valentini, Angelo; Corcione, Leonardo; Bortoletto, Favio; D'Alessandro, Maurizio; Bonoli, Carlotta; Giro, Enrico; Fantinel, Daniela; Magrin, Demetrio; Zerbi, Filippo M.; Riva, Alberto; Molinari, Emilio; Conconi, Paolo; De Caprio, Vincenzo; Busso, Maurizio; Tosti, Gino; Nucciarelli, Giuliano; Roncella, Fabio; Abia, Carlos

2006-06-01

The Antarctic Plateau offers unique opportunities for ground-based Infrared Astronomy. AMICA (Antarctic Multiband Infrared CAmera) is an instrument designed to perform astronomical imaging from Dome-C in the near- (1 - 5 μm) and mid- (5 - 27 μm) infrared wavelength regions. The camera consists of two channels, equipped with a Raytheon InSb 256 array detector and a DRS MF-128 Si:As IBC array detector, cryocooled at 35 and 7 K respectively. Cryogenic devices will move a filter wheel and a sliding mirror, used to feed alternatively the two detectors. Fast control and readout, synchronized with the chopping secondary mirror of the telescope, will be required because of the large background expected at these wavelengths, especially beyond 10 μm. An environmental control system is needed to ensure the correct start-up, shut-down and housekeeping of the camera. The main technical challenge is represented by the extreme environmental conditions of Dome C (T about -90 °C, p around 640 mbar) and the need for a complete automatization of the overall system. AMICA will be mounted at the Nasmyth focus of the 80 cm IRAIT telescope and will perform survey-mode automatic observations of selected regions of the Southern sky. The first goal will be a direct estimate of the observational quality of this new highly promising site for Infrared Astronomy. In addition, IRAIT, equipped with AMICA, is expected to provide a significant improvement in the knowledge of fundamental astrophysical processes, such as the late stages of stellar evolution (especially AGB and post-AGB stars) and the star formation.

Hubble Space Telescope: High speed photometer instrument handbook. Version 2.0

NASA Technical Reports Server (NTRS)

White, Richard L. (Editor)

1990-01-01

This manual is a guide for astronomers who intend to use the High Speed Photometer (HSP), one of the scientific instruments onboard the Hubble Space Telescope (HST). All the information needed for ordinary uses of the HSP is presented, including: (1) an overview of the instrument; (2) a detailed description of some details of the HSP-ST system that may be important for some observations; (3) tables and figures describing the sensitivity and limitations of the HSP; (4) how to go about planning an observation with the HSP; and (5) a description of the standard calibration to be applied to HSP data and the resulting data products.

MAXIMA-1: A Measurement of the Cosmic Microwave Background Anisotropy on Angular Scales of 10' to 5 degrees

DOE R&D Accomplishments Database

Ade, P.; Balbi, A.; Bock, J.; Borrill, J.; Boscaleri, A.; de Bernardis, P.; Ferreira, P. G.; Hanany, S.; Hristov, V. V.; Jaffe, A. H.; Lange, A. E.; Lee, A. T.; Mauskopf, P. D.; Netterfield, C. B.; Oh, S.; Pascale, E.; Rabii, B.; Richards, P. L.; Smoot, G. F.; Stompor, R.; Winant,C. D.; Wu, J. H. P.

2005-06-04

We present a map and an angular power spectrum of the anisotropy of the cosmic microwave background (CMB) from the first flight of MAXIMA. MAXIMA is a balloon-borne experiment with an array of 16 bolometric photometers operated at 100 mK. MAXIMA observed a 124 deg{sup 2} region of the sky with 10' resolution at frequencies of 150, 240 and 410 GHz. The data were calibrated using in-flight measurements of the CMB dipole anisotropy. A map of the CMB anisotropy was produced from three 150 and one 240 GHz photometer without need for foreground subtractions.

Results from the Balloon Ozone Intercomparison Campaign (BOIC)

NASA Technical Reports Server (NTRS)

Hilsenrath, E.; Hagemeyer, R.; Mentall, J.; Torres, A.; Attmannspacher, W.; Bass, A.; Evans, W.; Barnes, R. A.; Komhyr, W.; Robbins, D.

1986-01-01

Data from the BOIC which consisted of three balloon missions conducted in Palestine, Texas from June 1983 to March 1984 are presented. The BOIC was to assess the ability to perform ozone measurements from balloon platforms. The accuracy and precision of the various ozone measurement systems, which were composed of a photometer, a mass spectrometer, and solar UV absorption sensors, are evaluated. The ozone observations obtained with the instruments on the three flight missions are analyzed and intercompared. The flight in situ data are also compared to the National Bureau of Standards reference photometer, satellite measurements, and under simulated stratospheric pressure and ozone concentrations.

Nocturnal aerosol optical depth measurements with a small-aperture automated photometer using the moon as a light source

USGS Publications Warehouse

Berkoff, T.A.; Sorokin, M.; Stone, T.; Eck, T.F.; Hoff, R.; Welton, E.; Holben, B.

2011-01-01

A method is described that enables the use of lunar irradiance to obtain nighttime aerosol optical depth (AOD) measurements using a small-aperture photometer. In this approach, the U.S. Geological Survey lunar calibration system was utilized to provide high-precision lunar exoatmospheric spectral irradiance predictions for a ground-based sensor location, and when combined with ground measurement viewing geometry, provided the column optical transmittance for retrievals of AOD. Automated multiwavelength lunar measurements were obtained using an unmodified Cimel-318 sunphotometer sensor to assess existing capabilities and enhancements needed for day/night operation in NASA's Aerosol Robotic Network (AERONET). Results show that even existing photometers can provide the ability for retrievals of aerosol optical depths at night near full moon. With an additional photodetector signal-to-noise improvement of 10-100, routine use over the bright half of the lunar phase and a much wider range of wavelengths and conditions can be achieved. Although the lunar cycle is expected to limit the frequency of observations to 30%-40% compared to solar measurements, nevertheless this is an attractive extension of AERONET capabilities. ?? 2011 American Meteorological Society.

Calibration of Raman lidar water vapor profiles by means of AERONET photometer observations and GDAS meteorological data

NASA Astrophysics Data System (ADS)

Dai, Guangyao; Althausen, Dietrich; Hofer, Julian; Engelmann, Ronny; Seifert, Patric; Bühl, Johannes; Mamouri, Rodanthi-Elisavet; Wu, Songhua; Ansmann, Albert

2018-05-01

We present a practical method to continuously calibrate Raman lidar observations of water vapor mixing ratio profiles. The water vapor profile measured with the multiwavelength polarization Raman lidar PollyXT is calibrated by means of co-located AErosol RObotic NETwork (AERONET) sun photometer observations and Global Data Assimilation System (GDAS) temperature and pressure profiles. This method is applied to lidar observations conducted during the Cyprus Cloud Aerosol and Rain Experiment (CyCARE) in Limassol, Cyprus. We use the GDAS temperature and pressure profiles to retrieve the water vapor density. In the next step, the precipitable water vapor from the lidar observations is used for the calibration of the lidar measurements with the sun photometer measurements. The retrieved calibrated water vapor mixing ratio from the lidar measurements has a relative uncertainty of 11 % in which the error is mainly caused by the error of the sun photometer measurements. During CyCARE, nine measurement cases with cloud-free and stable meteorological conditions are selected to calculate the precipitable water vapor from the lidar and the sun photometer observations. The ratio of these two precipitable water vapor values yields the water vapor calibration constant. The calibration constant for the PollyXT Raman lidar is 6.56 g kg-1 ± 0.72 g kg-1 (with a statistical uncertainty of 0.08 g kg-1 and an instrumental uncertainty of 0.72 g kg-1). To check the quality of the water vapor calibration, the water vapor mixing ratio profiles from the simultaneous nighttime observations with Raman lidar and Vaisala radiosonde sounding are compared. The correlation of the water vapor mixing ratios from these two instruments is determined by using all of the 19 simultaneous nighttime measurements during CyCARE. Excellent agreement with the slope of 1.01 and the R2 of 0.99 is found. One example is presented to demonstrate the full potential of a well-calibrated Raman lidar. The relative humidity profiles from lidar, GDAS (simulation) and radiosonde are compared, too. It is found that the combination of water vapor mixing ratio and GDAS temperature profiles allow us to derive relative humidity profiles with the relative uncertainty of 10-20 %.

Analysis of the Performance Characteristics of the Five-Channel Microtops II Sun Photometer for Measuring Aerosol Optical Thickness and Precipitable Water Vapor

NASA Technical Reports Server (NTRS)

Ichoku, Charles; Levy, Robert; Kaufman, Yoram; Remer, Lorraine A.; Li, Rong-Rong; Martins, Vanderlei J.; Holben, Brent N.; Abuhassan, Nader; Slutsker, Ilya; Eck, Thomas F.;

Direct-reading inhalable dust monitoring--an assessment of current measurement methods.

PubMed

Thorpe, Andrew; Walsh, Peter T

2013-08-01

Direct-reading dust monitors designed specifically to measure the inhalable fraction of airborne dust are not widely available. Current practice therefore often involves comparing the response of photometer-type dust monitors with the concentration measured with a reference gravimetric inhalable sampler, which is used to adjust the dust monitor measurement. However, changes in airborne particle size can result in significant errors in the estimation of inhalable concentration by this method. The main aim of this study was to assess how these dust monitors behave when challenged with airborne dust containing particles in the inhalable size range and also to investigate alternative dust monitors whose response might not be as prone to variations in particle size or that could be adapted to measure inhalable dust concentration. Several photometer-type dust monitors and a Respicon TM, tapered element oscillating microbalance (TEOM) personal dust monitor (PDM) 3600, TEOM 1400, and Dustrak DRX were assessed for the measurement of airborne inhalable dust during laboratory and field trials. The PDM was modified to allow it to sample and measure larger particles in the inhalable size range. During the laboratory tests, the dust monitors and reference gravimetric samplers were challenged inside a large dust tunnel with aerosols of industrial dusts known to present an inhalable hazard and aluminium oxide powders with a range of discrete particle sizes. A constant concentration of each dust type was generated and peak concentrations of larger particles were periodically introduced to investigate the effects of sudden changes in particle size on monitor calibration. The PDM, Respicon, and DataRam photometer were also assessed during field trials at a bakery, joinery, and a grain mill. Laboratory results showed that the Respicon, modified PDM, and TEOM 1400 observed good linearity for all types of dust when compared with measurements made with a reference IOM sampler; the photometer-type dust monitors on the other hand showed little correlation. The Respicon also accurately measured the inhalable concentration, whereas the modified PDM underestimated it by ~27%. Photometer responses varied considerably with changing particle size, which resulted in appreciable errors in airborne inhalable dust concentration measurements. Similar trends were also observed during field trials. Despite having limitations, both the modified PDM and Respicon showed promise as real-time inhalable dust monitors.

Automatic optical inspection of regular grid patterns with an inspection camera used below the Shannon-Nyquist criterion for optical resolution

NASA Astrophysics Data System (ADS)

Ferreira, Flávio P.; Forte, Paulo M. F.; Felgueiras, Paulo E. R.; Bret, Boris P. J.; Belsley, Michael S.; Nunes-Pereira, Eduardo J.

2017-02-01

An Automatic Optical Inspection (AOI) system for optical inspection of imaging devices used in automotive industry using an inspecting optics of lower spatial resolution than the device under inspection is described. This system is robust and with no moving parts. The cycle time is small. Its main advantage is that it is capable of detecting and quantifying defects in regular patterns, working below the Shannon-Nyquist criterion for optical resolution, using a single low resolution image sensor. It is easily scalable, which is an important advantage in industrial applications, since the same inspecting sensor can be reused for increasingly higher spatial resolutions of the devices to be inspected. The optical inspection is implemented with a notch multi-band Fourier filter, making the procedure especially fitted for regular patterns, like the ones that can be produced in image displays and Head Up Displays (HUDs). The regular patterns are used in production line only, for inspection purposes. For image displays, functional defects are detected at the level of a sub-image display grid element unit. Functional defects are the ones impairing the function of the display, and are preferred in AOI to the direct geometric imaging, since those are the ones directly related with the end-user experience. The shift in emphasis from geometric imaging to functional imaging is critical, since it is this that allows quantitative inspection, below Shannon-Nyquist. For HUDs, the functional detect detection addresses defects resulting from the combined effect of the image display and the image forming optics.

Small maritime target detection through false color fusion

NASA Astrophysics Data System (ADS)

Toet, Alexander; Wu, Tirui

2008-04-01

We present an algorithm that produces a fused false color representation of a combined multiband IR and visual imaging system for maritime applications. Multispectral IR imaging techniques are increasingly deployed in maritime operations, to detect floating mines or to find small dinghies and swimmers during search and rescue operations. However, maritime backgrounds usually contain a large amount of clutter that severely hampers the detection of small targets. Our new algorithm deploys the correlation between the target signatures in two different IR frequency bands (3-5 and 8-12 μm) to construct a fused IR image with a reduced amount of clutter. The fused IR image is then combined with a visual image in a false color RGB representation for display to a human operator. The algorithm works as follows. First, both individual IR bands are filtered with a morphological opening top-hat transform to extract small details. Second, a common image is extracted from the two filtered IR bands, and assigned to the red channel of an RGB image. Regions of interest that appear in both IR bands remain in this common image, while most uncorrelated noise details are filtered out. Third, the visual band is assigned to the green channel and, after multiplication with a constant (typically 1.6) also to the blue channel. Fourth, the brightness and colors of this intermediate false color image are renormalized by adjusting its first order statistics to those of a representative reference scene. The result of these four steps is a fused color image, with naturalistic colors (bluish sky and grayish water), in which small targets are clearly visible.

Demosaicking for full motion video 9-band SWIR sensor

NASA Astrophysics Data System (ADS)

Kanaev, Andrey V.; Rawhouser, Marjorie; Kutteruf, Mary R.; Yetzbacher, Michael K.; DePrenger, Michael J.; Novak, Kyle M.; Miller, Corey A.; Miller, Christopher W.

2014-05-01

Short wave infrared (SWIR) spectral imaging systems are vital for Intelligence, Surveillance, and Reconnaissance (ISR) applications because of their abilities to autonomously detect targets and classify materials. Typically the spectral imagers are incapable of providing Full Motion Video (FMV) because of their reliance on line scanning. We enable FMV capability for a SWIR multi-spectral camera by creating a repeating pattern of 3x3 spectral filters on a staring focal plane array (FPA). In this paper we present the imagery from an FMV SWIR camera with nine discrete bands and discuss image processing algorithms necessary for its operation. The main task of image processing in this case is demosaicking of the spectral bands i.e. reconstructing full spectral images with original FPA resolution from spatially subsampled and incomplete spectral data acquired with the choice of filter array pattern. To the best of author's knowledge, the demosaicking algorithms for nine or more equally sampled bands have not been reported before. Moreover all existing algorithms developed for demosaicking visible color filter arrays with less than nine colors assume either certain relationship between the visible colors, which are not valid for SWIR imaging, or presence of one color band with higher sampling rate compared to the rest of the bands, which does not conform to our spectral filter pattern. We will discuss and present results for two novel approaches to demosaicking: interpolation using multi-band edge information and application of multi-frame super-resolution to a single frame resolution enhancement of multi-spectral spatially multiplexed images.

High Resolution Airborne Digital Imagery for Precision Agriculture

NASA Technical Reports Server (NTRS)

Herwitz, Stanley R.

1998-01-01

The Environmental Research Aircraft and Sensor Technology (ERAST) program is a NASA initiative that seeks to demonstrate the application of cost-effective aircraft and sensor technology to private commercial ventures. In 1997-98, a series of flight-demonstrations and image acquisition efforts were conducted over the Hawaiian Islands using a remotely-piloted solar- powered platform (Pathfinder) and a fixed-wing piloted aircraft (Navajo) equipped with a Kodak DCS450 CIR (color infrared) digital camera. As an ERAST Science Team Member, I defined a set of flight lines over the largest coffee plantation in Hawaii: the Kauai Coffee Company's 4,000 acre Koloa Estate. Past studies have demonstrated the applications of airborne digital imaging to agricultural management. Few studies have examined the usefulness of high resolution airborne multispectral imagery with 10 cm pixel sizes. The Kodak digital camera integrated with ERAST's Airborne Real Time Imaging System (ARTIS) which generated multiband CCD images consisting of 6 x 106 pixel elements. At the designated flight altitude of 1,000 feet over the coffee plantation, pixel size was 10 cm. The study involved the analysis of imagery acquired on 5 March 1998 for the detection of anomalous reflectance values and for the definition of spectral signatures as indicators of tree vigor and treatment effectiveness (e.g., drip irrigation; fertilizer application).

Revisiting Stephan's Quintet with deep optical images

NASA Astrophysics Data System (ADS)

Duc, Pierre-Alain; Cuillandre, Jean-Charles; Renaud, Florent

2018-03-01

Stephan's Quintet, a compact group of galaxies, is often used as a laboratory to study a number of phenomena, including physical processes in the interstellar medium, star formation, galaxy evolution, and the formation of fossil groups. As such, it has been subject to intensive multiwavelength observation campaigns. Yet, models lack constrains to pin down the role of each galaxy in the assembly of the group. We revisit here this system with multiband deep optical images obtained with MegaCam on the Canada-France-Hawaii Telescope (CFHT), focusing on the detection of low surface brightness (LSB) structures. They reveal a number of extended LSB features, some new, and some already visible in published images but not discussed before. An extended diffuse, reddish, lopsided, halo is detected towards the early-type galaxy NGC 7317, the role of which had so far been ignored in models. The presence of this halo made of old stars may indicate that the group formed earlier than previously thought. Finally, a number of additional diffuse filaments are visible, some close to the foreground galaxy NGC 7331 located in the same field. Their structure and association with mid-infrared emission suggest contamination by emission from Galactic cirrus.

Exploring the relative boundaries of the patchy pulsating aurora

NASA Astrophysics Data System (ADS)

Carlisle, E.; Donovan, E.; Jackel, B. J.

2017-12-01

Pulsating aurora is a common auroral feature that occurs most frequently on the nightside, in the equatorward part of the auroral oval. It is caused by pitch angle scattering of electrons due to wave-particle interactions near the equatorial plane. As such, observations of pulsating aurora provide information about the distribution of the plasma waves in the magnetosphere. Anecdotal evidence suggests that pulsating aurora occur equatorward of the proton aurora, and hence in the largely dipolar region at or inside the inner edge of the plasma sheet. Here we present results of a statistical survey of photometer observations of proton aurora and simultaneous all-sky imager observations of electron aurora. Our objective is to provide a definitive statement regarding the location of pulsating aurora relative to the proton aurora.

Space telescope scientific instruments

NASA Technical Reports Server (NTRS)

Leckrone, D. S.

1979-01-01

The paper describes the Space Telescope (ST) observatory, the design concepts of the five scientific instruments which will conduct the initial observatory observations, and summarizes their astronomical capabilities. The instruments are the wide-field and planetary camera (WFPC) which will receive the highest quality images, the faint-object camera (FOC) which will penetrate to the faintest limiting magnitudes and achieve the finest angular resolution possible, and the faint-object spectrograph (FOS), which will perform photon noise-limited spectroscopy and spectropolarimetry on objects substantially fainter than those accessible to ground-based spectrographs. In addition, the high resolution spectrograph (HRS) will provide higher spectral resolution with greater photometric accuracy than previously possible in ultraviolet astronomical spectroscopy, and the high-speed photometer will achieve precise time-resolved photometric observations of rapidly varying astronomical sources on short time scales.