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Sample records for airglow zodiacal light

  1. Ultraviolet spectroscopy of the zodiacal light

    NASA Technical Reports Server (NTRS)

    Cebula, R. P.; Feldman, P. D.

    1982-01-01

    The results of observations of the zodiacal light at 25 A resolution from two different viewing angles are reported. Airglow emission from both NO and O II were identified spectroscopically and according to altitude variation. The UV spectrometer was rocket-borne, and functioned in the wavelengths from 1700-3150 A. The solar spectrum was matched at wavelengths higher than 2600 A. Using the smaller elongation angle, an upper limit for the zodiacal light was determined to be 190 millionth erg/sq cm per sec per A/sr at 1800 A, i.e., four times the solar brightness at the same wavelength. It was found that the zodiacal light dependence on elongation was the same in the UV as in the visible. The color ratios for 2100-2400 A is discussed.

  2. Cosmic ultraviolet background radiation and zodiacal light

    NASA Technical Reports Server (NTRS)

    Tennyson, P. D.; Henry, R. C.; Feldman, P. D.; Hartig, G. F.

    1988-01-01

    Spectroscopic measurements of the diffuse cosmic UV background in the 1700-2850-A range are presented. In agreement with previous results, the data have resulted in the detection at high Galactic latitude of an intensity of 300 + or - 100 photons/sq cm s sr A at 1800 A without correction for starlight or airglow, a similar intensity over the 1900-2500-A range after correction for measured airglow, and a similar intensity over the 2500-2800-A range after correction for zodiacal light. It is suggested that this radiation may originate partly in line radiation from a Galactic halo and partly from extragalactic sources, perhaps the integrated light of distant galaxies.

  3. Experiment S001: Zodiacal Light Photography

    NASA Technical Reports Server (NTRS)

    Ney, E. P.; Huch, W. F.

    1971-01-01

    Observations made during the Gemini 5, 9, and 10 missions in the context of their relation to ground-based and balloon-based experiments on dim-light phenomena are reported. Zodiacal light is the visible manifestation of dust grains in orbit around the sun. The negatives that were exposed on the Gemini 9 mission were studied by the use of an isodensitracer to produce intensity isophotes. Data on the following factors were obtained: (1) intensity distribution of the zodiacal light, both morning and evening; (2) the height and intensity of the airglow at various geographic positions; and (3) intensity distribution of the Milky Way in the region of the sky near Cygnus. Also, a previously unreported phenomenon was discovered. This phenomenon appeared as an upward extension of the normal 90-kilometer airglow layer. The extension was in the form of wisps or plumes approximately 5 deg wide and extending upward approximately 5 deg. The results obtained from pictures exposed on the Gemini 10 mission were of qualitative or geometrical value only.

  4. Cosmic Infrared Background Fluctuations and Zodiacal Light

    NASA Astrophysics Data System (ADS)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

    2016-06-01

    We performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution or from IRAC observations of high-latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS field at low ecliptic latitude where the zodiacal light intensity varies by factors of ˜2 over the range of solar elongations at which the field can be observed. We find that the white-noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that are evident in the zodiacal light model. At large angular scales (≳100″) where excess power above the white noise is observed, we find no correlation of the power with the modeled intensity of the zodiacal light. This test clearly indicates that the large-scale power in the infrared background is not being caused by the zodiacal light.

  5. Ultraviolet spectroscopy of the zodiacal light at 20-deg elongation

    NASA Technical Reports Server (NTRS)

    Feldman, P. D.

    1977-01-01

    The zodiacal light at 20-deg elongation and 10-deg inclination was observed by rocket ultraviolet spectrometers at 10-15-A resolution in the spectral range 1200-3200 A during an experiment designed to observe comet Kohoutek (1973 XII). The data were obtained above 180 km when scattered horizon light in the startracker caused a loss of tracking on the comet. Airglow emission due to NO and O(+), identified spectroscopically and by its variation with altitude, is significant between 1900 and 2500 A. Longward of 2600 A, the spectrum matches that of the sun, and the derived value of the color ratio, relative to the visible, is 0.90 + or - 0.20. At 1600 A, an upper limit on the zodiacal-light emission of 0.07 R per A or 7 hundred-millionths erg/s per sq cm/sterad per A is obtained.

  6. A study of zodiacal light models

    NASA Technical Reports Server (NTRS)

    Gary, G. A.; Craven, P. D.

    1973-01-01

    A review is presented of the basic equations used in the analysis of photometric observations of zodiacal light. A survey of the methods used to model the zodiacal light in and out of the ecliptic is given. Results and comparison of various models are presented, as well as recent results by the authors.

  7. Light Phenomena over the ESO Observatories III: Zodiacal Light

    NASA Astrophysics Data System (ADS)

    Horálek, P.; Christensen, L. L.; Nesvorný, D.; Davies, R.

    2016-06-01

    The zodiacal light is often seen at the ESO observatories in the hours after sunset and before sunrise. The origin of the zodiacal light is described and recent research briefly summarised. Some fine images of the zodiacal light from Paranal and La Silla, including the full extent of the night sky are presented.

  8. Apollo 15 Zodiacal light views

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The four views of zodiacal light were photographed while the Apollo 15 command module was approaching sunrise while orbiting the moon. Although the sun is still behind the edge of the moon at lower right of each frame, its light is scattered by reflections from countless interplanetary dust grains which lie in or near to the orbital plane of the planets in our system. The view at upper left in this group is a 20 second exposure approximately centered on the ecliptic at 25 degrees elongation from the Sun. The view at upper right is in the same region but exposed for 60 seconds. The lower two views are at 15 degrees elongation with exposure times of ten seconds on the left and 30 seconds on the right. The streaking of the star fields occurs because the camera was rigidly mounted in the righ-hand rendezvous window while the spacecraft was making attitude changes to hold the line-of-sight approximately horizontal to the lunar surface and to the plane of orbit.

  9. Zodiacal Light Emission in Cosmological Missions

    NASA Astrophysics Data System (ADS)

    Maris, M.; Burigana, C.

    2015-01-01

    This contribution reviews the most difficult observational aspect of Zodiacal Light Emission (ZLE) in CMB missions below 1 THz: its separability from the background. We compare the background subtraction based on the use of priors and on differential methods exploiting signal time dependence. We illustrate the impact of systematics such as the straylight. Finally, we address the problem of differences in the ZLE geometrical properties possibly relevant at these frequencies.

  10. Zodiacal light photography. [from Apollo 17

    NASA Technical Reports Server (NTRS)

    Mercer, R. D.; Dunkelman, L.; Evans, R. E.

    1973-01-01

    Polarized and red- and blue-filter photographs of zodiacal light obtained by Apollo 17 are analyzed. Attempts were made to identify the cause of subtle change in the observed light and determine the dust composition of the light. A comparison of red and blue images indicates such changes may be caused by particle size distribution and range, number of particles along any given line of sight, particle surface characteristics including dielectric compared to metallic properties, and variations of the parameters as a function of distance from the sun.

  11. IRTS observation of zodiacal light and emission

    NASA Technical Reports Server (NTRS)

    Matsumoto, T.; Murakami, H.; Onaka, T.; Ootsubo, T.; Roellig, T. L.; Chan, K. -W.; Noda, M.

    1998-01-01

    We present the infrared spectrum of the zodiacal light and emission obtained by the Near-Infrared Spectrometer (NIRS) and Mid-Infrared Spectrometer (MIRS) onboard the Infrared Telescope in Space (IRTS). The wavelength coverages and spectral resolutions are 1.4-4.0 microns and 0.12 microns for the NIRS, and 4.5-11.7 microns and 0.23-0.36 microns for the MIRS respectively. Both instruments have the same beam size of 8 arcminutes square. The IRTS observations were made for 1995 March 29 - April 26. Here we present the data of two days, April 19 and April 20.

  12. Rutgers zodiacal light experiment on OSO-6

    NASA Technical Reports Server (NTRS)

    Carroll, B.

    1975-01-01

    A detector was placed in a slowly spinning wheel on OSO-6 whose axis was perpendicular to the line drawn to the sun, to measure the surface brightness and polarization at all elongations from the immediate neighborhood of the sun to the anti-solar point. Different wavelength settings and polarizations were calculated from the known order of magnitude brightness of the zodiacal light. The measuring sequence was arranged to give longer integration times for the regions of lower surface brightness. Three types of analysis to which the data on OSO-6 were subjected are outlined; (1) photometry, (2) colorimetry and (3) polarimetry.

  13. Colour dependence of zodiacal light models

    NASA Technical Reports Server (NTRS)

    Giese, R. H.; Hanner, M. S.; Leinert, C.

    1973-01-01

    Colour models of the zodiacal light in the ecliptic have been calculated for both dielectric and metallic particles in the sub-micron and micron size range. Two colour ratios were computed, a blue ratio and a red ratio. The models with a size distribution proportional to s to the -2.5 power ds (where s is the particle radius) generally show a colour close to the solar colour and almost independent of elongation. Especially in the blue colour ratio there is generally no significant dependence on the lower cutoff size (0.1-1 micron). The main feature of absorbing particles is a reddening at small elongations. The models for size distributions proportional to s to the -4 power ds show larger departures from solar colour and more variation with model parameters. Colour measurements, including red and near infra-red, therefore are useful to distinguish between flat and steep size spectra and to verify the presence of slightly absorbing particles.

  14. Research studies using OSO-6 zodiacal light experiment data

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The results of research studies on the OSO-6 zodiacal light experiment, conducted during the period from May 1976 to October 1977 are described. A discussion is included of the instrument performance and the empirical calibrations developed. Main areas of the research performed, i.e., (1) zodiacal light variation analysis; (2) integrated starlight and diffuse galactic light; and (3) earth/moon libration region counterglow, are covered. Considerable data processing was performed during these studies and it is summarized. Recommendations for future research to complete the interim results are given.

  15. Origin of Interplanetary Dust through Optical Properties of Zodiacal Light

    NASA Astrophysics Data System (ADS)

    Yang, Hongu; Ishiguro, Masateru

    2015-11-01

    This study investigates the origin of interplanetary dust particles (IDPs) through the optical properties, albedo and spectral gradient, of zodiacal light. The optical properties were compared with those of potential parent bodies in the solar system, which include D-type (as analogs of cometary nuclei), C-type, S-type, X-type, and B-type asteroids. We applied Bayesian inference to the mixture model composed of the distribution of these sources, and found that >90% of the IDPs originate from comets (or their spectral analogs, D-type asteroids). Although some classes of asteroids (C-type, X-type, and B-type) may make a moderate contribution, ordinary chondrite-like particles from S-type asteroids occupy a negligible fraction of the interplanetary dust cloud complex. The overall optical properties of the zodiacal light were similar to those of chondritic porous IDPs, supporting the dominance of cometary particles in the zodiacal cloud.

  16. High Efficiency Near Infrared Spectrometer for Zodiacal Light Spectral Study

    NASA Technical Reports Server (NTRS)

    Kutyrea, A. S.

    2008-01-01

    We are developing a near infrared spectrometer for measuring solar absorption lines in the zodiacal light in the near infrared region. R. Reynolds at el. (2004, ApJ 61 2, 1206) demonstrated that observing single Fraunhofer line can be a powerful tool for extracting zodiacal light parameters based on their measurements of the profile of the Mg I lneat 5 184 A. We are extending this technique to the near infrared with the primary goal of measuring the absolute intensity of the zodiacal light. This measurement will provide the crucial information needed to accurately subtract zodiacal emission from the DIRBE measurements to get a much higher quality measurement of the extragalactic IR background. The instrument design is based on a dual Fabry-Perot interferometer with a narrow band filter. Its double etalon design allows to achieve high spectral contrast to reject the bright out of band telluric OH emission. High spectral contrast is absolutely necessary to achieve detection limits needed to accurately measure the intensity of the absorption line. We present the design, estimated performance of the instrument with the expected results of the observing program.

  17. Pioneer 10 observations of zodiacal light brightness near the ecliptic - Changes with heliocentric distance

    NASA Technical Reports Server (NTRS)

    Hanner, M. S.; Weinberg, J. L.; Beeson, D. E.; Sparrow, J. G.

    1976-01-01

    Sky maps made by the Pioneer 10 Imaging Photopolarimeter (IPP) at sun-spacecraft distances from 1 to 3 AU have been analyzed to derive the brightness of the zodiacal light near the ecliptic at elongations greater than 90 degrees. The change in zodiacal light brightness with heliocentric distance is compared with models of the spatial distribution of the dust. Use of background starlight brightnesses derived from IPP measurements beyond the asteroid belt, where the zodiacal light is not detected, and, especially, use of a corrected calibration lead to considerably lower values for zodiacal light than those reported by us previously.

  18. A Near-Infrared Spectrometer to Measure Zodiacal Light Absorption Spectrum

    NASA Technical Reports Server (NTRS)

    Kutyrev, A. S.; Arendt, R.; Dwek, E.; Kimble, R.; Moseley, S. H.; Rapchun, D.; Silverberg, R. F.

    2010-01-01

    We have developed a high throughput infrared spectrometer for zodiacal light fraunhofer lines measurements. The instrument is based on a cryogenic dual silicon Fabry-Perot etalon which is designed to achieve high signal to noise Fraunhofer line profile measurements. Very large aperture silicon Fabry-Perot etalons and fast camera optics make these measurements possible. The results of the absorption line profile measurements will provide a model free measure of the zodiacal Light intensity in the near infrared. The knowledge of the zodiacal light brightness is crucial for accurate subtraction of zodiacal light foreground for accurate measure of the extragalactic background light after the subtraction of zodiacal light foreground. We present the final design of the instrument and the first results of its performance.

  19. On the photometric axis of the zodiacal light

    NASA Technical Reports Server (NTRS)

    Misconi, N. Y.

    1977-01-01

    A model of the zodiacal cloud is used to predict the position of the photometric axis (the locus of points of maximum brightness) of the zodiacal light at any elongation angle from the sun for any time of the year for various symmetry planes: the orbital planes of Venus, Mars, and Jupiter, the invariable plane, and the solar equatorial plane. Using a scattering function which combines isotropic scattering and Fresnel reflection, the geocentric distance of the dust that contributes most of the brightness at each elongation angle is determined by computing the brightness contribution along the line of sight. A comparison of the predicted and observed positions shows that at elongation angles of 15 to 60 deg, the axis of symmetry appears to be close to the orbital plane of Venus. At angles of less than 10 deg, it is difficult to distinguish among the proposed planes of symmetry. Observations of the photometric axis at angles of 60 to 180 deg are scarce and do not permit precise determination of the axis of symmetry in that region.

  20. Skylab experiment SO73: Gegenschein/zodiacal light. [electrophotometry of surface brightness and polarization

    NASA Technical Reports Server (NTRS)

    Weinberg, J. L.

    1976-01-01

    A 10 color photoelectric polarimeter was used to measure the surface brightness and polarization associated with zodiacal light, background starlight, and spacecraft corona during each of the Skylab missions. Fixed position and sky scanning observations were obtained during Skylab missions SL-2 and SL-3 at 10 wavelenghts between 4000A and 8200A. Initial results from the fixed-position data are presented on the spacecraft corona and on the polarized brightness of the zodiacal light. Included among the fixed position regions that were observed are the north celestial pole, south ecliptic pole, two regions near the north galactic pole, and 90 deg from the sun in the ecliptic. The polarized brightness of the zodiacal light was found to have the color of the sun at each of these positions. Because previous observations found the total brightness to have the color of the sun from the near ultraviolet out to 2.4 micrometers, the degree of polarization of the zodiacal light is independent of wavelength from 4000A to 8200A.

  1. The contribution of Venus to the brightness of the Zodiacal Light

    NASA Astrophysics Data System (ADS)

    Clarke, D.; Hendry, M. A.; McInnes, C. R.

    1989-09-01

    Hong's model (1985) for the brightness behavior of the Zodiacal Light has been applied to investigate the possibility of detecting an enhancement of intensity on the sunward side of Venus. It is shown that any detectable effect would not be observed beyond a few tenths of an arc minute from Venus, making it unlikely to be seen by the unaided eye.

  2. High Resolution Near Infrared Spectrometer to Study the Zodiacal Light Spectrum

    NASA Technical Reports Server (NTRS)

    Kutyrev, Alexander; Arendt, Richard G.; Dwek, Eli; Moseley, Samuel H.; Silverberg, Robert F.; Rapchun, David

    2008-01-01

    We are developing a near infrared spectrometer for measuring solar absorption lines in the zodiacal light in the near infrared region. R. Reynolds at el. (2004, ApJ 612, 1206) demonstrated that observing single Fraunhofer line can be a powerful tool for extracting zodiacal light parameters based on their measurements of the profile of the Mg I line at 5184 A. We are extending this technique to the near infrared with the primary goal of measuring the absolute intensity of the zodiacal light. This measurement will provide the crucial information needed to accurately subtract zodiacal emission from the DIRBE measurements to get a much higher quality measurement of the extragalactic IR background. The instrument design is based on a dual Fabry-Perot interferometer with a narrow band filter. Its double etalon design allows to achieve high spectral contrast to reject the bright out of band telluric OH emission. High spectral contrast is absolutely necessary to achieve detection limits needed to accurately measure the intensity of the absorption line. We present the design, estimated performance of the instrument with the expected results of the observing program.

  3. Far-ultraviolet studies. VIII - Apollo 17 search for zodiacal light

    NASA Technical Reports Server (NTRS)

    Henry, R. C.; Anderson, R. C.; Fastie, W. G.

    1980-01-01

    The analysis in a previous paper of a large quantity of far-ultraviolet spectrometer data from the Apollo 17 mission is reexamined with the intent of searching for zodiacal light. An upper limit at somewhat longer wavelengths than before is set. Spectrometer scannings were made from 1180 to 1680 A every 12 sec. Little evidence for a dependence of the residuals (calculated by subtracting the star catalog integration from the observed signal at 1558 to 1669 A for two portions of the sky) on an ecliptic parameter is shown. The present data do not show any detection of far ultraviolet zodiacal light or indeed of any light at all, but merely reflect the limitations of the star catalog integration.

  4. Zodiacal light dynamics experiment: A wideband imaging Fabry-Perot interferometer

    NASA Technical Reports Server (NTRS)

    Torr, D. G.; Young, E.; Torr, M. R.; Nagy, A. F.

    1978-01-01

    The Solar Probe will provide an ideal platform from which to study dynamics of dust particles near the sun by measuring the detailed character of the Fraunhofer structure of the zodiacal light. The suggested instrument is a wideband imaging Fabry-Perot interferometer with state of the art technology in both the optics and the detector. The instrument would function as a high-resolution imaging device providing wavelength resolution of 0.03 A over about a 20 A range. The wideband imaging capability would provide sky maps of the zodiacal light on a despun spacecraft without mechanical scanning. The Solar Probe mission would allow the velocity distribution of the dust to be mapped along most of the trajectory of the spacecraft.

  5. On the line profiles in the spectra of the zodiacal light.

    NASA Astrophysics Data System (ADS)

    Clarke, D.; Matthews, S. A.; Mundell, C. G.; Weir, A. S.

    1996-04-01

    The model proposed by Hong (1985) describing the surface brightness variation with elongation of the Zodiacal Light has been applied to predict the spectral line profiles produced by Doppler effects associated with scattering from interplanetary dust for the simple case of prograde Keplerian orbits. Over the greater elongation range, the predictions are substantially the same as for previous models but with shallower line depths and more pronounced asymmetries. At elongations ~30deg and less, however, Hong's mixture of phase angle scattering functions predicts bifurcation of the lines so providing an alternative explanation to the two dust stream model of Beavers et al. (1980) proposed as the interpretation of their spectra of the F corona. The work also highlights a general problem of using radial velocity correlation masks for investigations of Zodiacal Light spectra.

  6. Airglow Intensities and the Solar Cycle

    NASA Astrophysics Data System (ADS)

    Garstang, R. H.

    1997-05-01

    Some time ago we reported (Bull AAS 27,1213,1995) on an analysis of a series of measurements of night sky brightness published by Walker (1988). Those measures were made at San Benito Mountain in California over a period of about 12 years. We have made minor improvements to our analysis and present our final results. We took each observed brightness measurement, and subtracted from it in turn our estimated contributions of light pollution, zodiacal light and faint star background. Allowances were made for nightly extinction coefficients. The remainder is the contribution of the airglow to the sky brightness. The airglow intensities, which are integrals over the B and V photometric bands, show good correlations with the Ottawa 10.7 cm solar flux intensities. We are performing a similar analysis on night sky brightnesses measured at Kitt Peak by Pilachowski and colleagues (PASP 101,707,1989) to strengthen our deduced correlations.

  7. The mid-infrared spectrum of the zodiacal and exozodiacal light

    NASA Astrophysics Data System (ADS)

    Reach, William T.; Morris, Patrick; Boulanger, François; Okumura, Koryo

    2003-08-01

    The zodiacal light is the dominant source of the mid-infrared sky brightness seen from Earth, and exozodiacal light is the dominant emission from planetary and debris systems around other stars. We observed the zodiacal light spectrum with the mid-infrared camera ISOCAM over the wavelength range 5-16 μm and a wide range of orientations relative to the Sun (solar elongations 68°-113°) and the ecliptic (plane to pole). The temperature in the ecliptic ranged from 269 K at solar elongation 68° to 244 K at 113°, and the polar temperature, characteristic of dust 1 AU from the Sun, is 274 K. The observed temperature is exactly as expected for large (>10 μm radius), low-albedo (<0.08), rapidly-rotating, gray particles 1 AU from the Sun. Smaller particles (<10 μm radius) radiate inefficiently in the infrared and are warmer than observed. We present theoretical models for a wide range of particle size distributions and compositions; it is evident that the zodiacal light is produced by particles in the 10-100 μm radius range. In addition to the continuum, we detect a weak excess in the 9-11 μm range, with an amplitude of 6% of the continuum. The shape of the feature can be matched by a mixture of silicates: amorphous forsterite/olivine provides most of the continuum and some of the 9-11 μm silicate feature, dirty crystalline olivine provides the red wing of the silicate feature (and a bump at 11.35 μm), and a hydrous silicate (montmorillonite) provides the blue wing of the silicate feature. The presence of hydrous silicate suggests the parent bodies of those particles were formed in the inner solar nebula. Large particles dominate the size distribution, but at least some small particles (radii ˜1 μm) are required to produce the silicate emission feature. The strength of the feature may vary spatially, with the strongest features being at the lowest solar elongations as well as at high ecliptic latitudes; if confirmed, this would imply that the dust properties

  8. Clementine Observations of the Zodiacal Light and the Dust Content of the Inner Solar System

    NASA Technical Reports Server (NTRS)

    Hahn, Joseph M.; Zook, Herbert A.; Cooper, Bonnie; Sunkara, Bhaskar

    2002-01-01

    Using the Moon to occult the Sun, the Clementine spacecraft used its navigation cameras to map the inner zodiacal light at optical wavelengths over elongations of 3 approx. less than epsilon approx. less than 30 deg from the Sun. This surface brightness map is then used to infer the spatial distribution of interplanetary dust over heliocentric distances of about 10 solar radii to the orbit of Venus. The averaged ecliptic surface brightness of the zodiacal light falls off as Z(epsilon) is a member of epsilon(sup -2.45 +/- 0.05), which suggests that the dust cross-sectional density nominally falls off as sigma(r) is a member of r(sup - 1.45 +/- 0.05). The interplanetary dust also has an albedo of alpha approx. = 0.1 that is uncertain by a factor of approx. 2. Asymmetries of approx. 10% are seen in directions east-west and north-south of the Sun, and these may be due the giant planets' secular gravitational perturbations. We apply a simple model that attributes the zodiacal light as due to three dust populations having distinct inclination distributions, namely, dust from asteroids and Jupiter-family comets (JFCs) having characteristic inclinations of i approx. 7 deg, dust from Halley-type comets having i approx. 33 deg, and an isotropic cloud of dust from Oort Cloud comets. The best-fitting scenario indicates that asteroids + JFCs are the source of about 45% of the optical dust cross section seen in the ecliptic at 1 AU but that at least 89% of the dust cross section enclosed by a 1-AU-radius sphere is of a cometary origin. Each population's radial density variations can also deviate somewhat from the nominal sigma(r) is a member of r(sup -1.45). When these results are extrapolated out to the asteroid belt, we find an upper limit on the mass of the light-reflecting asteroidal dust that is equivalent to a 12-km asteroid, and a similar extrapolation of the isotropic dust cloud out to Oort Cloud distances yields a mass equivalent to a 30-km comet, although the latter

  9. Calibration of imaging parameters for space-borne airglow photography using city light positions

    NASA Astrophysics Data System (ADS)

    Hozumi, Yuta; Saito, Akinori; Ejiri, Mitsumu K.

    2016-09-01

    A new method for calibrating imaging parameters of photographs taken from the International Space Station (ISS) is presented in this report. Airglow in the mesosphere and the F-region ionosphere was captured on the limb of the Earth with a digital single-lens reflex camera from the ISS by astronauts. To utilize the photographs as scientific data, imaging parameters, such as the angle of view, exact position, and orientation of the camera, should be determined because they are not measured at the time of imaging. A new calibration method using city light positions shown in the photographs was developed to determine these imaging parameters with high accuracy suitable for airglow study. Applying the pinhole camera model, the apparent city light positions on the photograph are matched with the actual city light locations on Earth, which are derived from the global nighttime stable light map data obtained by the Defense Meteorological Satellite Program satellite. The correct imaging parameters are determined in an iterative process by matching the apparent positions on the image with the actual city light locations. We applied this calibration method to photographs taken on August 26, 2014, and confirmed that the result is correct. The precision of the calibration was evaluated by comparing the results from six different photographs with the same imaging parameters. The precisions in determining the camera position and orientation are estimated to be ±2.2 km and ±0.08°, respectively. The 0.08° difference in the orientation yields a 2.9-km difference at a tangential point of 90 km in altitude. The airglow structures in the photographs were mapped to geographical points using the calibrated imaging parameters and compared with a simultaneous observation by the Visible and near-Infrared Spectral Imager of the Ionosphere, Mesosphere, Upper Atmosphere, and Plasmasphere mapping mission installed on the ISS. The comparison shows good agreements and supports the validity

  10. Mid-infrared spectrum of the zodiacal light observed with ISOPHOT

    NASA Astrophysics Data System (ADS)

    Leinert, Ch.; Ábrahám, P.; Acosta-Pulido, J.; Lemke, D.; Siebenmorgen, R.

    2002-10-01

    We present 29 mid-infrared spectra of the zodiacal light distributed over the sky. The observed 5.9-11.7 mu m spectral shapes are well represented by blackbody radiation with colour temperatures in the range of 255<= T<= 300 K. The spectra are smooth and featureless. The variation of the temperature can be explained by the geometrical distribution of dust in the inner solar system. This result indicates that although the interplanetary dust particles originate from discrete sources (comets, asteroids) the interplanetary cloud of today seems to be well mixed in terms of grain composition and size distribution. Based on observations with ISO, an ESA project with instruments funded by ESA member states (especially the PI countries France, Germany, The Netherlands and the UK) with participation of ISAS and NASA.

  11. Measurements of Zodiacal-light brightness from the Solar Mass Ejection Imager (SMEI)

    NASA Astrophysics Data System (ADS)

    Buffington, A.; Bisi, M. M.; Clover, J. M.; Hick, P. P.; Jackson, B.

    2009-12-01

    Observations from the Solar Mass Ejection Imager (SMEI), now spanning over 6 years, provide unprecedented near-full-sky photometric maps each 102-minute orbit, using data from 3 unfiltered CCD cameras. SMEI’s 0.1% photometric precision enables observation of heliospheric structures with surface brightness down to several S10’s (an S10 is the equivalent brightness of a 10th magnitude star spread over one square degree). When individual bright stars and an empirical residual sidereal background are removed from the maps, the residue is dominated by the zodiacal light (ZL). The present work combines individual SMEI sky maps to produce daily average maps, and uses the sequence of these for both an empirical characterization of the ZL and an investigation of its variation over time scales from several days to several years.

  12. Four years of zodiacal light observations from the Helios space probes - Evidence for a smooth distribution of interplanetary dust

    NASA Technical Reports Server (NTRS)

    Leinert, C.; Richter, I.; Pitz, E.; Hanner, M.

    1980-01-01

    Zodiacal light experiments on Helios 2 that has been operating continually since January 1976 are discussed, with the purpose of elucidating the distribution of interplanetary dust. Results for the observed gradient of zodiacal light intensity between 1 A.U. and perihelion at 0.3 A.U. show that for all elongations, from 17.5 deg to 135 deg from the sun, the exponent of intensity increase is -2.3 plus or minus 0.1. Color investigations show no systematic variation with heliocentric distance, but a slight reddening is present, increasing towards small elongations. The degree of polarization is found to be higher at 1 A.U. than given previously and decreases towards the sun, even if no correction for electron scattering is made. All results thus fit the hypothesized power law for radial distribution of dust. It is concluded from the stability of zodiacal intensity that the distribution of interplanetary dust is rather simple in space and quite constant in time.

  13. A CMB foreground study in WMAP data: Extragalactic point sources and zodiacal light emission

    NASA Astrophysics Data System (ADS)

    Chen, Xi

    The Cosmic Microwave Background (CMB) radiation is the remnant heat from the Big Bang. It serves as a primary tool to understand the global properties, content and evolution of the universe. Since 2001, NASA's Wilkinson Microwave Anisotropy Probe (WMAP) satellite has been napping the full sky anisotropy with unprecedented accuracy, precision and reliability. The CMB angular power spectrum calculated from the WMAP full sky maps not only enables accurate testing of cosmological models, but also places significant constraints on model parameters. The CMB signal in the WMAP sky maps is contaminated by microwave emission from the Milky Way and from extragalactic sources. Therefore, in order to use the maps reliably for cosmological studies, the foreground signals must be well understood and removed from the maps. This thesis focuses on the separation of two foreground contaminants from the WMAP maps: extragalactic point sources and zodiacal light emission. Extragalactic point sources constitute the most important foreground on small angular scales. Various methods have been applied to the WMAP single frequency maps to extract sources. However, due to the limited angular resolution of WMAP, it is possible to confuse positive CMB excursions with point sources or miss sources that are embedded in negative CMB fluctuations. We present a novel CMB-free source finding technique that utilizes the spectrum difference of point sources and CMB to form internal linear combinations of multifrequency maps to suppress the CMB and better reveal sources. When applied to the WMAP 41, 64 and 94 GHz maps, this technique has not only enabled detection of sources that are previously cataloged by independent methods, but also allowed disclosure of new sources. Without the noise contribution from the CMB, this method responds rapidly with the integration time. The number of detections varies as 0( t 0.72 in the two-band search and 0( t 0.70 in the three-band search from one year to five years

  14. Partially light-controlled imager based on liquid crystal plate and image intensifier for aurora and airglow measurement.

    PubMed

    Tang, Yuanhe; Cao, Xiangang; Liu, Hanchen; Shepherd, G G; Liu, Shulin; Gao, Haiyang; Yang, Xusan; Wu, Yong; Wang, Shuiwei

    2012-04-20

    In order to obtain information both of aurora and airglow in one image by the same detector, a PLCI based on liquid crystal plate LCP and super second-generation image intensifier SSGII is proposed in this research. The detection thresholds of the CCD for aurora and airglow are calculated. For the detectable illumination range of 10(4)-10(-2) lx, the corresponding electron count is 1.57×10(5) - 0.2 for every pixel of CCD. The structure and work principle of the PLCI are described. An LC is introduced in the front of CCD to decrease the intensities of aurora in overexposure areas by means of controlling transmittances pixel by pixel, while an image intensifier is set between the LC and CCD to increase the intensity of the weak airglow. The modulation transfer function MTF of this system is calculated as 0.391 at a Nyquist frequency of 15 lp/mm. The curve of transmittance with regard to gray level for the LC is obtained by calibration experiment. Based on the design principle, the prototype is made and used to take photos of objects under strong light greater than 2×10(5) lx. The clear details of [symbols: see text] presented in the image indicate that the PLCI can greatly improve the imaging quality. The theoretical calculations and experiment results prove that this device can extend the dynamic range and it provides a more effective method for upper atmospheric wind measurement.

  15. Astronomical photography. Part A: Gum nebula, galactic cluster, and zodiacal light photography

    NASA Technical Reports Server (NTRS)

    Mercer, R. D.; Dunkelman, L.; Mattingly, T. K.

    1972-01-01

    It is reported that the Apollo 16 command module astronomical photography was performed with the specific objective of capitalizing on the uniqueness of the double umbra as a vantage point to collect astronomical data that are obtainable only near our Moon. For this reason, these data will be compared directly to analogous photography performed from Earth orbit during Project Mercury and the Gemini Program as well as to the Apollo-duplicated photography taken from sites on the Earth surface. Comparison with Earth-based photography should yield direct information on the Earth airglow layer and on atmospheric scattering and extinction.

  16. 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.

  17. The Origin of the Excess Near-Infrared Diffuse Sky Brightness: Population III Stars or Zodiacal Light?

    NASA Technical Reports Server (NTRS)

    Dwek, Eli

    2006-01-01

    The intensity of the diffuse 1 to 5 micron sky emission from which solar system and Galactic foregrounds have been subtracted is in excess of that expected from energy released by galaxies and stars that formed during the z < 5 redshift interval. The spectral signature of this excess near-infrared background light (NIRBL) component is almost identical to that of reflected sunlight from the interplanetary dust cloud, and could therefore be the result of the incomplete subtraction of this foreground emission component from the diffuse sky maps. Alternatively, this emission component could be extragalactic. Its spectral signature is consistent with that of redshifted continuum and recombination line emission from H-II regions formed by the first generation of very massive stars. In this talk I will present the implications of this excess emission for our understanding of the zodiacal dust cloud, the formation rate of Pop III stars, and the TeV gamma-ray opacity to nearby blazars.

  18. Zodiac II: Debris Disk Imaging Potential

    NASA Technical Reports Server (NTRS)

    Traub Wesley; Bryden, Geoff; Stapelfeldt, Karl; Chen, Pin; Trauger, John

    2011-01-01

    Zodiac II is a proposed coronagraph on a balloon-borne platform, for the purpose of observing debris disks around nearby stars. Zodiac II will have a 1.2-m diameter telescope mounted in a balloon-borne gondola capable of arcsecond quality pointing, and with the capability to make long-duration (several week) flights. Zodiac II will have a coronagraph able to make images of debris disks, meaning that its scattered light speckles will be at or below an average contrast level of about 10(exp -7) in three narrow (7 percent) bands centered on the V band, and one broad (20%) one at I band. We will discuss the potential science to be done with Zodiac II.

  19. Functional characteristics of the OGO main body airglow photometer

    NASA Technical Reports Server (NTRS)

    Reed, E. I.; Fowler, W. B.; Blamont, J. E.

    1972-01-01

    The OGO-4 main body airglow photometer used a trialkali cathode photomultiplier to sense light at selected wavelengths between 2500 and 6300A corresponding to important emissions in the aurora and night airglow at emission rates ranging from a few rayleighs to about 200 kilorayleighs. The optical, electronic, and mechanical systems are described in terms of their functional characteristics.

  20. Enhanced airglow at Titan

    NASA Astrophysics Data System (ADS)

    Royer, Emilie; Esposito, Larry; Wahlund, Jan-Erik

    2016-06-01

    The Cassini Ultraviolet Imaging Spectrograph (UVIS) instrument made thousand of observations of Titan since its arrival in the Saturnian system in 2004, but only few of them have been analyzed yet. Using the imaging capability of UVIS combined to a big data analytics approach, we have been able to uncover an unexpected pattern in this observations: on several occasions the Titan airglow exhibits an enhanced brightness by approximately a factor of 2, generally combined with a lower altitude of the airglow emission peak. These events typically last from 10 to 30 minutes and are followed and preceded by an airglow of regular and expected level of brightness and altitude. Observations made by the Cassini Plasma Spectrometer (CAPS) instrument onboard Cassini allowed us to correlate the enhanced airglow observed on T-32 with an electron burst. The timing of the burst and the level of energetic electrons (1 keV) observed by CAPS correspond to a brighter and lower than typical airglow displayed on the UVIS data. Furthermore, during T-32 Titan was inside the Saturn's magnetosheath and thus more subject to bombardment by energetic particles. However, our analysis demonstrates that the presence of Titan inside the magnetosheath is not a necessary condition for the production of an enhanced airglow, as we detected other similar events while Titan was within Saturn's magnetosphere. The study presented here aims to a better understanding of the interactions of Titan's upper atmosphere with its direct environment.

  1. A Chinese Zodiac Mathematical Structure.

    ERIC Educational Resources Information Center

    Lamb, John F., Jr.

    2000-01-01

    Helps students identify the animal that corresponds to the year of their birth according to the Chinese zodiac. Defines the structure of the Chinese zodiac so that the subsets of compatibles and opposites form closed substructures with interesting mathematical properties. (ASK)

  2. Thermospheric aurora and airglow

    SciTech Connect

    Meier, R.R.

    1987-04-01

    New information added in the years between 1983 and 1986 to the understanding of the physics and chemistry responsible for the production of aurora and airglow emissions is presented. On auroras, the bulk of new information comes from the information obtained from satellite-based imaging (by DE1) and spectroscopy, rocket-based observations of bremsstrahlung from electrons precipitating in the auroral zone, and measurements of metastable ion species. On airglow, the DE1 photometric experiment has provided the opportunity of studying the geocorona on a global scale. A geotail was detected in the antisolar direction, confirming earlier observations. 123 references.

  3. Inferring Sources in the Interplanetary Dust Cloud, from Observations and Simulations of Zodiacal Light and Thermal Emission

    NASA Technical Reports Server (NTRS)

    Levasseur-Regourd, A. C.; Lasue, J.

    2011-01-01

    Interplanetary dust particles physical properties may be approached through observations of the solar light they scatter, specially its polarization, and of their thermal emission. Results, at least near the ecliptic plane, on polarization phase curves and on the heliocentric dependence of the local spatial density, albedo, polarization and temperature are summarized. As far as interpretations through simulations are concerned, a very good fit of the polarization phase curve near 1.5 AU is obtained for a mixture of silicates and more absorbing organics material, with a significant amount of fluffy aggregates. In the 1.5-0.5 AU solar distance range, the temperature variation suggests the presence of a large amount of absorbing organic compounds, while the decrease of the polarization with decreasing solar distance is indeed compatible with a decrease of the organics towards the Sun. Such results are in favor of the predominance of dust of cometary origin in the interplanetary dust cloud, at least below 1.5 AU. The implication of these results on the delivery of complex organic molecules on Earth during the LHB epoch, when the spatial density of the interplanetary dust cloud was orders of magnitude greater than today, is discussed.

  4. Suomi satellite brings to light a unique frontier of nighttime environmental sensing capabilities.

    PubMed

    Miller, Steven D; Mills, Stephen P; Elvidge, Christopher D; Lindsey, Daniel T; Lee, Thomas F; Hawkins, Jeffrey D

    2012-09-25

    Most environmental satellite radiometers use solar reflectance information when it is available during the day but must resort at night to emission signals from infrared bands, which offer poor sensitivity to low-level clouds and surface features. A few sensors can take advantage of moonlight, but the inconsistent availability of the lunar source limits measurement utility. Here we show that the Day/Night Band (DNB) low-light visible sensor on the recently launched Suomi National Polar-orbiting Partnership (NPP) satellite has the unique ability to image cloud and surface features by way of reflected airglow, starlight, and zodiacal light illumination. Examples collected during new moon reveal not only meteorological and surface features, but also the direct emission of airglow structures in the mesosphere, including expansive regions of diffuse glow and wave patterns forced by tropospheric convection. The ability to leverage diffuse illumination sources for nocturnal environmental sensing applications extends the advantages of visible-light information to moonless nights.

  5. Structure of the Zodiacal Emission by Spitzer Archive Data

    NASA Astrophysics Data System (ADS)

    Verebélyi, Erika

    2015-08-01

    Dust in the Interplanetary Dust Cloud not just reflects the sunlight (known as zodiacal light) but also has its own thermal emission. At the heliocentric distance of Earth the peak of this emission (with particle size 100 μm) is close to 20 μm. In this study we used the data of four programs completed with the MIPS camera of the Spitzer Space Telescope at 24 μm to probe the large scale brightness distribution as well as the small-scale (subarcmin) structure of the Zodiacal Could. The four programs were:1. The Production of Zodiacal Dust by Asteroids and Comets (ID: 2317)2. High Latitude Dust Bands in the Main Asteroid Belt: Fingerprints of Recent Breakup Events (ID: 20539)3. A New Source of Interplanetary Dust: Type II Dust Trails (ID: 30545)4. First Look Survey - Ecliptic Plane Component (ID: 98)We take into account that while the Spitzer Space Telescope carried out the measurements it was orbiting the Sun at an Earth-trailing orbit and looked at different parts of the Zodiacal Cloud, in many cases looking through the same parts of the cloud from different locations. This gives us the chance to investigate the 3D distribution of zodiacal dust in addition to its large and small scale structure.

  6. Structure of the zodiacal emission by Spitzer archive data

    NASA Astrophysics Data System (ADS)

    Verebelyi, E.; Kiss, C.; Balog, Z.; Stansberry, J.

    2014-07-01

    Dust in the interplanetary dust cloud not just reflects the sunlight (known as zodiacal light) but also has its own thermal emission. At the heliocentric distance of the Earth, the peak of this emission (with particle size ˜ 100 μ m) is close to 20 μ m. In this study, we used the data of four programs completed with the MIPS camera of the Spitzer Space Telescope at 24 μ m to probe the large-scale brightness distribution as well as the small-scale (sub-arcmin) structure of the zodiacal cloud. The four programs were: - The Production of Zodiacal Dust by Asteroids and Comets (ID: 2317) - High Latitude Dust Bands in the Main Asteroid Belt: Fingerprints of Recent Breakup Events (ID: 20539) - A New Source of Interplanetary Dust: Type II Dust Trails (ID: 30545) - First Look Survey - Ecliptic Plane Component (ID: 98) We take into account that, when the Spitzer Space Telescope carried out the measurements, it was orbiting the Sun at an Earth-trailing orbit and looking at different parts of the zodiacal cloud, in many cases looking through the same parts of the cloud from different locations. This gives us the chance to investigate the 3D distribution of zodiacal dust in addition to large- and small-scale structure of the cloud.

  7. The symmetry surface of the zodiacal cloud outside the earth's orbit

    NASA Technical Reports Server (NTRS)

    Misconi, Nebil Y.; Rusk, Edwin T.; Weinberg, J. L.

    1990-01-01

    The location in space of the symmetry surface of the zodiacal cloud at elongation angles 110-140 deg from the sun is determined from observations of the zodiacal light taken from the Pioneer 10 space probe, and from the zodiacal light experiment on Skylab. The inclination and ascending node of the symmetry surface from the ecliptic plane are shown to be about 1.2 and 23 deg, respectively, closest to those of the orbital plane of Mars. These results are consistent with those obtained from IRAS at elongation angle of 90 deg from the sun.

  8. Unambiguous evidence of HF pump-enhanced airglow at auroral latitudes

    NASA Astrophysics Data System (ADS)

    Brändström, B. U. E.; Leyser, T. B.; Steen, Å.; Rietveld, M. T.; Gustavsson, B.; Aso, T.; Ejiri, M.

    1999-12-01

    Simultaneous observations by up to three low-light imaging stations belonging to the Auroral Large Imaging System (ALIS) have provided the first strong evidence of high-frequency (HF) pump-enhanced airglow at auroral latitudes. The airglow was enhanced by an ordinary mode 4.04 MHz electromagnetic wave with an effective radiated power (ERP) of about 210 MW that was transmitted from the EISCAT-Heating facility near Tromsø, Norway. While often observed at low or mid-latitudes, and despite numerous earlier experiments, no unambiguous observations of pump-enhanced airglow have been reported at auroral latitudes. On February 16, 1999, the first successful results were obtained, and this paper concentrates on discussing optical data from this event. Triangulated estimations of the altitude and position of the enhanced airglow are also presented. Auroral-latitude observations of HF pump-enhanced airglow are important in order to better understand the underlying excitation mechanisms.

  9. Artificial airglow excited by high-power radio waves.

    PubMed

    Bernhardt, P A; Duncan, L M; Tepley, C A

    1988-11-18

    High-power electromagnetic waves beamed into the ionosphere from ground-based transmitters illuminate the night sky with enhanced airglow. The recent development of a new intensified, charge coupled-device imager made it possible to record optical emissions during ionospheric heating. Clouds of enhanced airglow are associated with large-scale plasma density cavities that are generated by the heater beam. Trapping and focusing of electromagnetic waves in these cavities produces accelerated electrons that collisionally excite oxygen atoms, which emit light at visible wavelengths. Convection of plasma across magnetic field lines is the primary source for horizontal motion of the cavities and the airglow enhancements. During ionospheric heating experiments, quasi-cyclic formation, convection, dissipation and reappearance of the cavites comprise a major source of long-term variability in plasma densities during ionospheric heating experiments.

  10. The exo-zodiacal disk mapper

    NASA Technical Reports Server (NTRS)

    Petro, Larry; Bely, P.; Burg, R.; Wade, L.; Beichman, C.; Gay, J.; Baudoz, P.; Rabbia, Y.; Perrin, J. M.

    1998-01-01

    Zodiacal dust around neighboring stars could obscure the signal of terrestrial planets observed with the Terrestrial Planet Finder (TPF) if that dust is similar to that in the Solar System. Unfortunately, little is known about the presence, or frequency of occurrence of zodiacal dust around stars and so the relevance of zodiacal dust to the design of the TPF, or to the TPF mission, is unknown. It is likely that direct observation of zodiacal dust disks will be necessary to confidently determine the characteristics of individual systems. A survey of a large number of stars in the solar neighborhood that could be candidates for observation with TPF should be undertaken. We present a concept for a space mission to undertake a sensitive, large-scale survey capable of characterizing solar-system-like zodiacal dust around 400 stars within 20 pc of the Sun.

  11. Atmospheric airglow imaging with CCDs

    SciTech Connect

    Swenson, G.; Mende, S.

    1994-12-31

    Airglow imaging instrumentation has been developed to provide quality imagery of airglow in the visible and near IR wavelengths. The lower thermosphere airglow layers emit between 85 and 102 km altitude. The layers are structured with nonuniformity in the horizontal dimension as a result of Atmospheric Gravity Waves (AGWs) passing through the layer and disturbing the nominal recombination processes producing intensity and temperature modulations. Imagers have been developed to measure the AGW-produced airglow non-uniformities. The instrumentation combines large format, low noise CCDs with large aperture optics for improved S/N images. In particular, the large dynamic range of the detectors provides information from the low intensity zenith sky and the bright, van Rhijn enhanced horizon simultaneously in all-sky fields. The imagers have been used effectively to identify AGW structure from a number of ground based facilities as well as a recent NSF sponsored aircraft campaign. Imagery from the OH Meinel bands and OI 5577 {angstrom} are presented. Discussions are also presented regarding Na 5896 {angstrom}, and O{sub 2} Atmospheric (0,1) band at 8650 {angstrom} emissions.

  12. WINDII atmospheric wave airglow imaging

    SciTech Connect

    Armstrong, W.T.; Hoppe, U.-P.; Solheim, B.H.; Shepherd, G.G.

    1996-12-31

    Preliminary WINDII nighttime airglow wave-imaging data in the UARS rolldown attitude has been analyzed with the goal to survey gravity waves near the upper boundary of the middle atmosphere. Wave analysis is performed on O[sub 2](0,0) emissions from a selected 1[sup 0] x 1[sup 0] oblique view of the airglow layer at approximately 95 km altitude, which has no direct earth background and only an atmospheric background which is optically thick for the 0[sub 2](0,0) emission. From a small data set, orbital imaging of atmospheric wave structures is demonstrated, with indication of large variations in wave activity across land and sea. Comparison ground-based imagery is discussed with respect to similarity of wave variations across land/sea boundaries and future orbital mosaic image construction.

  13. Airglow measurement looking downward from orbit at selected darker fields of view

    NASA Astrophysics Data System (ADS)

    Croft, T. A.

    1982-03-01

    It is pointed out that many sources of airglow are below the more desirable satellite attitudes. However, the conventional airglow sensors must look either upward or toward the limb. The feasibility to measure airglow when looking downward from a satellite is considered, taking into account an approach involving the collection and analysis of the light which emanates from the most dark regions near nadir. An investigation is conducted regarding the possibility to implement the considered approach by making use of two satellite systems, each of which measures radiance in the nadir region at midnight. The two systems include the Atmospheric Explorer (AE) and satellites of the Defense Meteorological Satellite Program (DMSP). The results of the investigation are evaluated and details for a suitable procedure of airglow measurements are discussed.

  14. Airglow on Titan During Eclipse

    NASA Astrophysics Data System (ADS)

    West, R. A.; Ajello, J. M.; Stevens, M. H.; Strobel, D. F.; Gladstone, R.; Evans, J. S.; Bradley, E. T.

    2012-12-01

    Magnetospheric or cosmic ray charged particle precipitation into Titan's atmosphere is a potential energy source for driving chemistry and may contribute to airglow and energy balance. Estimates of the significance of these processes vary widely and thus far have been only poorly constrained because of the dominance of XUV radiation in stimulating UV airglow. To address these issues we observed Titan when it was deeply embedded in Saturn's shadow in 2009. We obtained EUV and FUV spectra with the Cassini Ultraviolet Imaging Spectrograph (UVIS) and images with the Cassini Imaging Science Subsystem (ISS) at visible wavelengths. For the first time, nitrogen emissions were seen in the spectra in the absence of XUV stimulation, although with insufficient spatial resolution to do limb profiling. The emissions are about a factor of ten smaller than peak dayside emissions observed with UVIS at closer range (from Stevens et al., , J. Geophys. Res., 116, A05304, doi10.1029/2010ja016284). Hydrogen emissions are also observed, consistent with the idea that precipitating protons and oxygen ions are responsible for part of the emission. The visible images from ISS contribute because they resolve the disk well. No auroral structures are seen. Rather, there is a very faint airglow seen on the limb between about 300 and 1000 km and a stronger intensity coming from the region of the haze at 300 km altitude. Although the limb glow is near the noise limit, the radial profile appears to be inconsistent with ionization profiles expected for precipitating electrons, protons, or oxygen ions which are expected to produce strong limb brightening. The stronger glow from the haze region was unexpected. Its origin is not understood but deeply-penetrating cosmic ray ionization and chemiluminescence are candidates that deserve additional scrutiny. . Part of this work was performed by the Jet Propulsion Lab, Cal. Inst. of Tech. under contract with the National Aeronautics and Space Administration.

  15. The origin and evolution of the zodiacal dust cloud

    NASA Astrophysics Data System (ADS)

    Dermott, Stanley F.; Durda, Daniel D.; Gustafson, Bo A. S.; Jayaraman, S.; Xu, Y. L.; Gomes, R. S.; Nicholson, P. D.

    1992-12-01

    We have now analyzed a substantial fraction of the IRAS observations of the zodiacal cloud, particularly in the 25 micron waveband. We have developed a gravitational perturbation theory that incorporates the effects of Poynting-Robertson light drag (Gomes and Dermott, 1992). We have also developed a numerical model, the SIMUL mode, that reproduces the exact viewing geometry of the IRAS telescope and calculates the distribution of thermal flux produced by any particular distribution of dust particle orbits (Dermott and Nicholson, 1989). With these tools, and using a distribution of orbits based on those of asteroidal particles with 3.4 micron radii whose orbits decay due to Poynting-Robertson light drag and are perturbed by the planets, we have been able to: (1) account for the inclination and node of the background zodiacal cloud observed by IRAS in the 25 micron waveband; (2) relate the distribution of orbits in the Hirayama asteroid families to the observed shapes of the IRAS solar system dustbands; and (3) show that there is observational evidence in the IRAS data for the transport of asteroidal particles from the main belt to the Earth by Poynting-Robertson light drag.

  16. The origin and evolution of the zodiacal dust cloud

    NASA Technical Reports Server (NTRS)

    Dermott, Stanley F.; Durda, Daniel D.; Gustafson, Bo A. S.; Jayaraman, S.; Xu, Y. L.; Gomes, R. S.; Nicholson, P. D.

    1992-01-01

    We have now analyzed a substantial fraction of the IRAS observations of the zodiacal cloud, particularly in the 25 micron waveband. We have developed a gravitational perturbation theory that incorporates the effects of Poynting-Robertson light drag (Gomes and Dermott, 1992). We have also developed a numerical model, the SIMUL mode, that reproduces the exact viewing geometry of the IRAS telescope and calculates the distribution of thermal flux produced by any particular distribution of dust particle orbits (Dermott and Nicholson, 1989). With these tools, and using a distribution of orbits based on those of asteroidal particles with 3.4 micron radii whose orbits decay due to Poynting-Robertson light drag and are perturbed by the planets, we have been able to: (1) account for the inclination and node of the background zodiacal cloud observed by IRAS in the 25 micron waveband; (2) relate the distribution of orbits in the Hirayama asteroid families to the observed shapes of the IRAS solar system dustbands; and (3) show that there is observational evidence in the IRAS data for the transport of asteroidal particles from the main belt to the Earth by Poynting-Robertson light drag.

  17. Comparison of Airglow from excited O2- and OH-molecules in the global model EMAC compared to observations

    NASA Astrophysics Data System (ADS)

    Versick, Stefan; Sinnhuber, Miriam; von Savigny, Christian; Teiser, Georg; Vlasov, Alexey

    2015-04-01

    Airglow is a luminous effect mainly in the upper atmosphere (mesosphere and thermosphere). It is caused by various processes. Airglow can be used to derive minor species abundances, to diagnose dynamical phenomena or to derive chemical heating rates. There are many molecules which produce airglow, here we concentrate on Airglow from excited O2- and OH-molecules. For the presented study we use the newly developed extended EMAC version which now includes the thermosphere and reaches up to 3.5E-05 Pa. Vibrationally excited OH-molecules are mainly produced by the reaction of atomic hydrogen with ozone. We include this production in the global model EMAC, as well as other important processes for excited OH (e.g. quenching by other molecules, spontaneous emission of photons). As a result we get the airglow for different transitions of the excited OH-molecules. Our model results are compared to airglow derived from observations by SCIAMACHY onboard ENVISAT. The airglow from O2 is produced by light emission from two excited O2 states, O2(1Δ) at 1.27μm and O2(1Σ) at 762nm. O2(1Δ) is mainly produced by photolysis of ozone in the Hartley-Band and O2(1Σ) is mainly produced by the chemical reaction of O(1D) with molecular oxygen. We show first model results and compare them to values from literature.

  18. [Signs of the zodiac and personality].

    PubMed

    Angst, J; Scheidegger, P

    1976-01-01

    3074 young men resident in the canton of Zurich, representing 50% of the 19 year old male population, form the fully representative sample of our large scale investigation. We investigated whether personality traits measured by means of the differentiated "Freiburger personality inventory" (FPI) could in any way be correlated to the signs of the zodiac under which the young men were born. The statistical analysis did not reveal any correlation between signs of the zodiac and personality. The claim made by astrologers that people can be characterized according to their sign of the zodiac (sagitarius, taurus, cancer, scorpion) must be refuted. Of course the astrologically founded description of human personality does not base itself on the position of the sun only, however the latter does form a very essential part of the astrological evaluation of people. This, at any rate has been shown to be without any scientific basis. The fact that astrological evaluation of human personality is so popular nowadays can be explained by the fact that even modern people are inclined towards magical thinking.

  19. Suomi satellite brings to light a unique frontier of nighttime environmental sensing capabilities

    PubMed Central

    Miller, Steven D.; Mills, Stephen P.; Elvidge, Christopher D.; Lindsey, Daniel T.; Lee, Thomas F.; Hawkins, Jeffrey D.

    2012-01-01

    Most environmental satellite radiometers use solar reflectance information when it is available during the day but must resort at night to emission signals from infrared bands, which offer poor sensitivity to low-level clouds and surface features. A few sensors can take advantage of moonlight, but the inconsistent availability of the lunar source limits measurement utility. Here we show that the Day/Night Band (DNB) low-light visible sensor on the recently launched Suomi National Polar-orbiting Partnership (NPP) satellite has the unique ability to image cloud and surface features by way of reflected airglow, starlight, and zodiacal light illumination. Examples collected during new moon reveal not only meteorological and surface features, but also the direct emission of airglow structures in the mesosphere, including expansive regions of diffuse glow and wave patterns forced by tropospheric convection. The ability to leverage diffuse illumination sources for nocturnal environmental sensing applications extends the advantages of visible-light information to moonless nights. PMID:22984179

  20. Measurements and an empirical model of the Zodiacal brightness as observed by the Solar Mass Ejection Imager (SMEI)

    NASA Astrophysics Data System (ADS)

    Buffington, Andrew; Bisi, Mario M.; Clover, John M.; Hick, P. Paul; Jackson, Bernard V.; Kuchar, Thomas A.; Price, Stephan D.

    2016-07-01

    The Solar Mass Ejection Imager (SMEI) provided near-full-sky broadband visible-light photometric maps for 8.5 years from 2003 to 2011. At a cadence of typically 14 maps per day, these each have an angular resolution of about 0.5º and differential photometric stability of about 1% throughout this time. When individual bright stars are removed from the maps and an empirical sidereal background subtracted, the residue is dominated by the zodiacal light. This sky coverage enables the formation of an empirical zodiacal-light model for observations at 1 AU which summarizes the SMEI data. When this is subtracted, analysis of the ensemble of residual sky maps sets upper limits of typically 1% for potential secular change of the zodiacal light for each of nine chosen ecliptic sky locations. An overall long-term photometric stability of 0.25% is certified by analysis of three stable sidereal objects. Averaging the nine ecliptic results together yields a 1-σ upper limit of 0.3% for zodiacal light change over this 8.5 year period.

  1. Measurements and an Empirical Model of the Zodiacal Brightness as Observed by the Solar Mass Ejection Imager (SMEI)

    NASA Astrophysics Data System (ADS)

    Buffington, A.; Bisi, M. M.; Clover, J. M.; Hick, P. P.; Jackson, B. V.; Kuchar, T. A.; Price, S. D.

    2015-12-01

    The Solar Mass Ejection Imager (SMEI) has provided near-full-sky broadband visible-light photometric maps for 8.5 years from 2003 to 2011. These have an angular resolution of about 0.5º and differential photometric stability of about 1% per map throughout this time. When individual bright stars are removed from the maps and an empirical sidereal background subtracted, the residue is dominated by the zodiacal light. This sky coverage enables the formation of an empirical zodiacal-light model for observations at 1 AU which summarizes the SMEI data. When this is subtracted, analysis of the ensemble of residual sky maps sets upper limits of typically 1% for potential secular change of the zodiacal light for each of nine chosen ecliptic sky locations. An overall long-term photometric stability of 0.25% is certified by analysis of three stable sidereal objects. Averaging the nine ecliptic results together yields a 1-σ upper limit of 0.3% for zodiacal light change over this 8.5 year period.

  2. [[On the change of sex ratio by the Japanese zodiac

    PubMed

    Sakai, H

    1989-04-01

    Changes in the sex ratio in Japan from 1899 to 1986 are analyzed using data from official sources. The emphasis is on differences in the sex ratio according to the signs of the Japanese zodiac. The author notes that although the significance of the zodiac on the sex ratio has been decreasing since the early 1970s, it still has a measurable impact.

  3. Equatorial airglow and the ionospheric geomagnetic anomaly.

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Reed, E. I.; Troy, B. E., Jr.; Blamont, J. E.

    1973-01-01

    Ogo 4 observations of the O I (6300-A) emissions have revealed a global pattern hitherto undetected from the ground-based observations. It is seen that the postsunset emission of O I (6300 A) in October 1967 is very asymmetrical with respect to the geomagnetic equator in certain longitude regions and shows poor correlation with the electron density measured simultaneously from the same spacecraft. This asymmetry is less marked in the UV airglow, O I (1356 A), which appears to vary as the square of the maximum electron density in the F region. The horizon scan data of the 6300-A airglow reveal that the latitudinal asymmetry is associated with asymmetry in the height of the O I (6300-A) emission and hence with the altitude of the F2 peak. From the correlative studies of the airglow and the ionospheric measurements the mechanisms of the UV and the 6300 A emissions are discussed in terms of the processes involving radiative and dissociative recombination. Theoretical expressions are developed which relate the airglow data to the ionospheric parameters.

  4. The Saptarishis Calendar: 'The Indian tropical Zodiac'!

    NASA Astrophysics Data System (ADS)

    Indrasena, Buddhike S. H.

    2015-07-01

    The Saptarishis Calendar of ancient India is based on precession of the equinoxes. It employs the tropical zodiac of the Greeks and the precessional rate of Hipparchus. The Saptarishis era has to be determined by naked eye observation of the sky. Currently, the line of reference goes through the stars Dubhe and Merak in the constellation of Ursa Major, touching both of them, and crosses the ecliptic in the sidereal Purvaphalguni Nakshatra of Simha Rashi at a point close to the star 59 Leonis. The angular difference between this 'Saptarishis pointer' and the vernal equinox gives the tropical lunar mansion in which Saptarishis resides at a given point in time.

  5. The Extra-Zodiacal Explorer (EZE)

    NASA Astrophysics Data System (ADS)

    Greenhouse, Matthew A.; Benson, S. W.; Fixsen, D. J.; Gardner, J. P.; Kruk, J. W.; Thronson, H. A.

    2012-01-01

    We describe a mission architecture study designed to substantially increase the potential science performance of the NASA SMD Astrophysics Explorer Program for all AO offerors working within the near-UV to far-infrared spectrum. We have demonstrated that augmentation of Falcon 9 Explorer launch services with a Solar Electric Propulsion (SEP) stage can deliver a 700 kg science observatory payload to an extra-Zodiacal orbit. This new capability enables up to 10X increased photometric sensitivity and 150X increased observing speed relative to a Sun-Earth L2 or Earth-trailing orbit with no increase in telescope aperture. All enabling SEP stage technologies for this launch service augmentation have reached sufficient readiness (TRL-6) for Explorer Program application in conjunction with the Falcon 9. We demonstrate that enabling Astrophysics Explorers to reach extra-zodiacal orbit will allow this small payload program to rival the science performance of much larger long development time systems; thus, providing a means to realize major science objectives while increasing the SMD Astrophysics portfolio diversity and resiliency to external budget pressure. The SEP technology employed in this study has applicability to SMD Planetary competed missions and aligns with NASA in-space propulsion technology road map objectives and associated flight demonstration planning.

  6. Microwave thermal emission from the zodiacal dust cloud predicted with contemporary meteoroid models

    NASA Astrophysics Data System (ADS)

    Dikarev, Valery V.; Schwarz, Dominik J.

    2015-12-01

    Predictions of the microwave thermal emission from the zodiacal dust cloud are made using several contemporary meteoroid models to construct the distributions of the cross-section area of dust in space, and by applying the Mie light-scattering theory to estimate the temperatures and emissivities of dust particles in a wide range of sizes and heliocentric distances. In particular, the Kelsall model of the zodiacal light emission based on COBE infrared observations is extrapolated to the microwaves with assistance from fits to selected IRAS and Planck data. Furthermore, the five populations of interplanetary meteoroids by Divine and the Interplanetary Meteoroid Engineering Model (IMEM) based on a variety of remote and in situ observations of dust are used in combination with the optical properties of olivine, carbonaceous, and iron spherical particles. The Kelsall model has been accepted by the cosmic microwave background (CMB) community for subtraction of the zodiacal cloud's foreground emission. We show, however, that the Kelsall model predicts microwave emission from interplanetary dust that is remarkably different from the results obtained by applying the meteoroid engineering models. We make maps and spectra of the microwave emission predicted by all three models assuming different compositions of dust particles. The predictions can be used to look for the emission from interplanetary dust in CMB experiments and to plan new observations.

  7. Signatures of planets: Observations and modeling of structure in the zodiacal cloud and Kuiper disk

    NASA Astrophysics Data System (ADS)

    Holmes, Elizabeth Katherine

    2002-12-01

    There is a possible connection between structure in evolved circumstellar disks and the presence of planets, our own zodiacal cloud being a proven example. Asymmetries in such a disk could be diagnostic of planets which would be otherwise undetectable. Using COBE DIRBE observations, we link structure in the zodiacal cloud, namely the warp and offset of the cloud, to the presence of planets using secular perturbation theory. In addition, we obtain supplementary ISO observations and determine a scale factor for the data which we apply to calibrate the data to the observed COBE brightness. A Kuiper dust disk will have a resonant structure, with two concentrations in brightness along the ecliptic longitude arising because 10 15% of the Kuiper belt objects are in the 3:2 mean motion resonance with Neptune. We run numerical integrations of particles originating from source bodies trapped in the 3:2 resonance and we determine what percentage of particles remain in the resonance for a variety of particle and source body sizes. The dynamical evolution of the particles is followed from source to sink with Poynting- Robertson light drag, solar wind drag, radiation pressure, the Lorentz force, neutral interstellar gas drag, and the effects of planetary gravitational perturbations included. We then conduct an observational search in the 60 μm COBE data for the Kuiper disk, which is predicted to be, at most, a few percent of the brightness of the zodiacal cloud. By removing emission due to the background zodiacal cloud and the dust bands, we expect to see the trailing/leading signature of Earth's resonant ring. However, when subtracted from the data, we find that none of the empirical background zodiacal cloud models give the residuals predicted by theory. We conclude that a dynamical two-component (both inner and outer) zodiacal cloud model must be created to complete the search. Lastly, we extend our work outside the solar system and obtain upper limits on the flux around ten

  8. Heater-induced ionization inferred from spectrometric airglow measurements

    NASA Astrophysics Data System (ADS)

    Hysell, D. L.; Miceli, R. J.; Varney, R. H.; Schlatter, N.; Huba, J. D.

    2013-12-01

    Spectrographic airglow measurements were made during an ionospheric modification experiment at HAARP on March 12, 2013. Artificial airglow enhancements at 427.8, 557.7, 630.0, 777.4, and 844.6 nm were observed. On the basis of these emissions and using a methodology based on the method of Backus and Gilbert [1968, 1970], we estimate the suprathermal electron population and the subsequent equilibrium electron density profile, including contributions from electron impact ionization. We find that the airglow is consistent with significant induced ionization in view of the spatial intermittency of the airglow.

  9. Apollo 16 far ultraviolet imagery of the polar auroras, tropical airglow belts, and general airglow

    NASA Technical Reports Server (NTRS)

    Carruthers, G. R.; Page, T.

    1976-01-01

    Far-ultraviolet imagery of the earth in the wavelength ranges from 1050 to 1600 A and from 1250 to 1600 A was obtained from the lunar surface during the Apollo 16 mission on Apr. 21, 1972. The images have an angular resolution of about 2 arcmin (230-km linear resolution) and have been quantitatively analyzed to obtain absolute intensities and spatial distributions of the polar auroras (both wavelength ranges), the day and night airglow, and tropical airglow belts (1250-A to 1600-A wavelength range). The observations are consistent with previous results obtained from the OGO-4 spacecraft, but they have also provided details on the spatial distributions of the various emissions over an entire hemisphere at a single time. A general night airglow, at least in the Northern Hemisphere, is indicated.

  10. 72. 451 MADISON AVENUE, GRAND STAIR, ZODIAC CLOCK WITH DECORATIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    72. 451 MADISON AVENUE, GRAND STAIR, ZODIAC CLOCK WITH DECORATIVE CARVING BY STANFORD WHITE AND AUGUSTUS SAINT-GAUDENS - Villard Houses, 451-457 Madison Avenue & 24 East Fifty-first Street, New York County, NY

  11. The Primeval Zodiac: Its Social, Religious, and Mythological Background

    NASA Astrophysics Data System (ADS)

    Verderame, L.

    2009-08-01

    In this brief paper we try to draw the lines of the possible development of the originary iconographic and symbolic repertoire of the Mesopotamian zodiac, which through the Greeks was adopted in the Western world.

  12. Zodiac II: Debris Disk Science from a Balloon

    NASA Technical Reports Server (NTRS)

    Bryden, Geoffrey; Traub, Wesley; Roberts, Lewis C., Jr.; Bruno, Robin; Unwin, Stephen; Backovsky, Stan; Brugarolas, Paul; Chakrabarti, Supriya; Chen, Pin; Hillenbrand, Lynne; Krist, John; Lillie, Charles; Macintosh, Bruce; Mawet, Dimitri; Mennesson, Bertrand; Moody, Dwight; Rey, Justin; Stapelfeldt, Karl; Stuchlik, David; Trauger, John; Vasisht, Gautam

    2011-01-01

    Zodiac II is a proposed balloon-borne science investigation of debris disks around nearby stars. Debris disks are analogs of the Asteroid Belt (mainly rocky) and Kuiper Belt (mainly icy) in our Solar System. Zodiac II will measure the size, shape, brightness, and color of a statistically significant sample of disks. These measurements will enable us to probe these fundamental questions: what do debris disks tell us about the evolution of planetary systems; how are debris disks produced; how are debris disks shaped by planets; what materials are debris disks made of; how much dust do debris disks make as they grind down; and how long do debris disks live? In addition, Zodiac II will observe hot, young exoplanets as targets of opportunity. The Zodiac II instrument is a 1.1-m diameter SiC (Silicone carbide) telescope and an imaging coronagraph on a gondola carried by a stratospheric balloon. Its data product is a set of images of each targeted debris disk in four broad visible-wavelength bands. Zodiac II will address its science questions by taking high-resolution, multi-wavelength images of the debris disks around tens of nearby stars. Mid-latitude flights are considered: overnight test flights in the US followed by half-global flights in the Southern Hemisphere. These longer flights are required to fully explore the set of known debris disks accessible only to Zodiac II. On these targets, it will be 100 times more sensitive than the Hubble Space Telescope's Advanced Camera for Surveys (HST/ACS); no existing telescope can match the Zodiac II contrast and resolution performance. A second objective of Zodiac II is to use the near-space environment to raise the Technology Readiness Level (TRL) of SiC mirrors, internal coronagraphs, deformable mirrors, and wavefront sensing and control, all potentially needed for a future space-based telescope for high-contrast exoplanet imaging.

  13. Zodiac II: Debris Disk Science from a Balloon

    NASA Technical Reports Server (NTRS)

    Bryden, Geoffrey; Traub, Wesley; Roberts, Lewis C., Jr.; Bruno, Robin; Unwin, Stephen; Backovsky, Stan; Brugarolas, Paul; Chakrabarti, Supriya; Chen, Pin; Hillenbrand, Lynne; Krist, John; Lillie, Charles; Macintosh, Bruce; Mawet, Dimitri; Mennesson, Bertrand; Moody, Dwight; Rahman, Zahidul; Rey, Justin; Stapelfeldt, Karl; Stuchlik, David; Trauger, John; Vasisht, Gautam

    2011-01-01

    Zodiac II is a proposed balloon-borne science investigation of debris disks around nearby stars. Debris disks are analogs of the Asteroid Belt (mainly rocky) and Kuiper Belt (mainly icy) in our Solar System. Zodiac II will measure the size, shape, brightness, and color of a statistically significant sample of disks. These measurements will enable us to probe these fundamental questions: what do debris disks tell us about the evolution of planetary systems; how are debris disks produced; how are debris disks shaped by planets; what materials are debris disks made of; how much dust do debris disks make sa they grind down; and how long do debris disks live? In addition, Zodiac II will observe hot, young exoplanets as targets of opportunity. The Zodiac II instrument is a 1.1-m diameter SiC telescope and an imaging coronagraph on a gondola carried by a stratospheric balloon. Its data product is a set of images of each targeted debris disk in four broad visible wavelength bands. Zodiac II will address its science questions by taking high-resolution, multi-wavelength images of the debris disks around tens of nearby stars. Mid-latitude flights are considered: overnight test flights within the United States followed by half-global flights in the Southern Hemisphere. These longer flights are required to fully explore the set of known debris disks accessible only to Zodiac II. On these targets, it will be 100 times more sensitive than the Hubble Space Telescope's Advanced Camera for Surveys (HST/ACS); no existing telescope can match the Zodiac II contrast and resolution performance. A second objective of Zodiac II is to use the near-space environment to raise the Technology Readiness Level (TRL) of SiC mirrors, internal coronagraphs, deformable mirrors, and wavefront sensing and control, all potentially needed for a future space-based telescope for high-contrast exoplanet imaging.

  14. Berkeley extreme-ultraviolet airglow rocket spectrometer - BEARS

    NASA Technical Reports Server (NTRS)

    Cotton, D. M.; Chakrabarti, S.

    1992-01-01

    The Berkeley EUV airglow rocket spectrometer (BEARS) instrument is described. The instrument was designed in particular to measure the dominant lines of atomic oxygen in the FUV and EUV dayglow at 1356, 1304, 1027, and 989 A, which is the ultimate source of airglow emissions. The optical and mechanical design of the instrument, the detector, electronics, calibration, flight operations, and results are examined.

  15. Astronomical spectra as powerful source for airglow studies

    NASA Astrophysics Data System (ADS)

    Kausch, W.; Noll, S.; Unterguggenberger, S.; Proxauf, B.; Kimeswenger, S.

    2015-03-01

    Light from astronomical objects has to pass the Earth's atmosphere before it reaches ground-based telescopes. Thus, any observation taken with such facilities contains information on the chemical composition and the physical state of the atmosphere. In particular, optical and near-infrared spectra taken with such telescopes are well suited to study various airglow emissions arising in the upper atmosphere thanks to the small field-of-view of the telescopes, large mirror sizes, and the frequent usage of medium to high resolution spectrographs. We study data taken by two frequently used echelle spectrographs from the Very Large Telescope (VLT) of the European Southern Observatory at Cerro Paranal (Chile): UVES, operative since 1999, is a high-resolution (20000 R 110000) instrument covering the wavelength range from 300 to 1100 nm. Hence, several O2 band systems (Herzberg I+II, Chamberlain, atmospheric), the green and red OI lines ( 557 nm; 630 nm), the recently discovered FeO bands ( 550 to 720 nm), NaID ( 589 nm), and all hydroxyl bands up to OH(3-0) can be investigated. The high temporal coverage allows investigations for more than one solar cycle. The X-Shooter instrument is an echelle spectrograph which is able to take medium-resolution (3000 R 18000) spectra from 300 to 2480 nm within one shot. Therefore, it is well suited for a comprehensive study of OH, as it covers all bands with a vibrational level difference 2 (up to OH(9-7)) simultaneously, apart from the previously mentioned other lines and bands. X-Shooter was put into operation in 2009. In this presentation, we will give a review on the available spectra, their quality and time coverage. Moreover, we will illustrate the potential of the data for airglow studies by showing results

  16. Lightning induced brightening in the airglow layer

    SciTech Connect

    Boeck, W.L. ); Vaughan, O.H. Jr.; Blakeslee, R. ); Vonnegut, B. ); Brook, M. )

    1992-01-24

    This report describes a transient luminosity observed at the altitude of the airglow layer (about 95 km) in coincidence with a lightning flash in a tropical oceanic thunderstorm directly beneath it. This event provides new evidence of direct coupling between lightning and ionospheric events. This luminous event in the ionosphere was the only one of its kind observed during an examination of several thousand images of lightning recorded under suitable viewing conditions with Space Shuttle cameras. Several possible mechanisms and interpretations are discussed briefly.

  17. Tether-Induced Airglow: Collisionless Effects

    NASA Technical Reports Server (NTRS)

    Mishin, E. V.; Khazanov, G. V.

    2006-01-01

    Martinez-Sanchez and Sanmartin [1997] showed that a bare conducting tether can be used as a source of an energetic electron beam. Interacting with the E region atmosphere, the beam should produce airglow thus making possible to deduce the neutral density on a continuous basis. Fujii et al. [2005] suggested that this idea be tested in a specially-designed sounding rocket experiment. We show that collisionless beam-plasma interactions (BPI) complement direct impact, leading to appreciable green-line (557.7 nm) emissions in the F region. In the E region, BPI develops near the entry in the valley, resulting in a narrow layer of strongly-elevated and airglow. Besides, neutralizing electric currents carried by ionospheric electrons in the valley can become unstable or even insufficient to compensate the beam current. Developing plasma waves inhibit neutralizing currents. In the extreme case, the beam might be locked in the valley (the 'virtual cathode'). In addition to optical observations, these effects can also be observed by radiophysical means.

  18. Mesopause region wind, temperature and airglow irradiance above Eureka, Nunavut

    NASA Astrophysics Data System (ADS)

    Kristoffersen, Samuel; Ward, William E.; Vail, Christopher; Shepherd, Marianna

    2016-07-01

    The PEARL All Sky Imager (PASI, airglow images), the Spectral Airglow Temperature Imager (SATI, airglow irradiance and temperature) and the E-Region Wind Interferometer II (ERWIN2, wind, airglow irradiance and temperature) are co-located at the Polar Environment Atmospheric Research Laboratory (PEARL)in Eureka, Nunavut (80 N, 86 W). These instruments view the wind, temperature and airglow irradiance of hydroxyl (all three) O2 (ERWIN2 and SATI), sodium (PASI), and oxygen green line (PASI and ERWIN2). The viewing locations and specific emissions of the various instruments differ. Nevertheless, the co-location of these instruments provides an excellent opportunity for case studies of specific events and for intercomparison between the different techniques. In this paper we discuss the approach we are using to combine observations from the different instruments. Case studies show that at times the various instruments are in good agreement but at other times they differ. Of particular interest are situations where gravity wave signatures are evident for an extended period of time and one such situation is presented. The discussion includes consideration of the filtering effect of viewing through airglow layers and the extent to which wind, airglow and temperature variations can be associated with the same gravity wave.

  19. Origin and evolution of the zodiacal dust cloud

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.; Durda, D.; Gustafson, B.; Jayaraman, S.; Xu, Y.-L.; Nicholson, P. D.; Gomes, R. S.

    1991-01-01

    The astrophysical importance of the zodiacal cloud became more apparent. The most useful source of information on the structure of the zodiacal cloud is the Infrared Astronomical Satellite (IRAS) observations. A substantial fraction of the extensive IRAS data set was analyzed. Also, a numerical model was developed (SIMUL) that allows to calculate the distribution of night-sky brightness that would be produced by any particular distribution of dust particle orbits. This model includes the effects of orbital perturbations by both the planets and solar radiation, it reproduces the exact viewing geometry of the IRAS telescope, and allows for the eccentricity of the Earth's orbit. SIMUL now is used to model not just the solar system dust bands discovered by IRAS but the whole zodiacal cloud.

  20. Teeth and numerology from zodiac signs. A correlative study.

    PubMed

    Kudva, S; Bhat, A P

    2000-01-01

    Comparative anatomical descriptions have been time and again mentioned in the literature. Based on these aspects, an attempt is made to correlate the morphological features of the human teeth, the zodiac sun signs and numerology. This unique study (first ever of its kind) is also done with a purpose as to whether a particular 'Zodiac Sunsign' or numerology can predict about an individual dental health, the same way the future predictions are being made. It was quite interesting to note that there are few definite attributable dental morphological traits and health to the specific sun signs and numerology.

  1. Teeth and numerology from zodiac signs. A correlative study.

    PubMed

    Kudva, S; Bhat, A P

    2000-01-01

    Comparative anatomical descriptions have been time and again mentioned in the literature. Based on these aspects, an attempt is made to correlate the morphological features of the human teeth, the zodiac sun signs and numerology. This unique study (first ever of its kind) is also done with a purpose as to whether a particular 'Zodiac Sunsign' or numerology can predict about an individual dental health, the same way the future predictions are being made. It was quite interesting to note that there are few definite attributable dental morphological traits and health to the specific sun signs and numerology. PMID:11307432

  2. Airglow events visible to the naked eye

    NASA Technical Reports Server (NTRS)

    Peterson, A. W.

    1979-01-01

    During IR photographic airglow observations covering several years, three naked-eye events have been recorded. Two of these are moving luminous acoustic-gravity-wave groups of some 10-15-km wavelength, which occur near high lunar tide in the atmosphere. The events appear quickly, endure 0.5-1 h, then fade. Visible photos of two events appear enhanced, while little enhancement is present in the IR photos, although the structures are well correlated. If these events are due to OH, it is suggested that some unrecognized mechanism, perhaps a gravity wave interaction, enhances the visible transitions of the OH over the IR transitions. If the events are due to an unrecognized continuum emitter, perhaps NO, its emission must occur at the same height as the OH. Spectra seem to be the only reasonable approach to solving this problem.

  3. Equatorial Enhancement of the Nighttime OH Mesospheric Infrared Airglow

    NASA Technical Reports Server (NTRS)

    Baker, D. J.; Mlynczak, M. G.; Russell, J. M.

    2007-01-01

    Global measurements of the hydroxyl mesospheric airglow over an extended period of time have been made possible by the NASA SABER infrared sensor aboard the TIMED satellite which has been functioning since December of 2001. The orbital mission has continued over a significant portion of a solar cycle. Experimental data from SABER for several years have exhibited equatorial enhancements of the nighttime mesospheric OH (delta v = 2) airglow layer consistent with the high average diurnal solar flux. The brightening of the OH airglow typically means more H + O3 is being reacted. At both the spring and autumn seasonal equinoxes when the equatorial solar UV irradiance mean is greatest, the peak volume emission rate (VER) of the nighttime Meinel infrared airglow typically appears to be both significantly brighter plus lower in altitude by several kilometres at low latitudes compared with midlatitude findings.

  4. Removing Milky Way from airglow images using principal component analysis

    NASA Astrophysics Data System (ADS)

    Li, Zhenhua; Liu, Alan; Sivjee, Gulamabas G.

    2014-04-01

    Airglow imaging is an effective way to obtain atmospheric gravity wave information in the airglow layers in the upper mesosphere and the lower thermosphere. Airglow images are often contaminated by the Milky Way emission. To extract gravity wave parameters correctly, the Milky Way must be removed. The paper demonstrates that principal component analysis (PCA) can effectively represent the dominant variation patterns of the intensity of airglow images that are associated with the slow moving Milky Way features. Subtracting this PCA reconstructed field reveals gravity waves that are otherwise overwhelmed by the strong spurious waves associated with the Milky Way. Numerical experiments show that nonstationary gravity waves with typical wave amplitudes and persistences are not affected by the PCA removal because the variances contributed by each wave event are much smaller than the ones in the principal components.

  5. Venus Night Airglow Distibutions and Variability: NCAR VTGCM Simulations

    NASA Astrophysics Data System (ADS)

    Brecht, Amanda; Bougher, S.; Gerard, J.; Rafkin, S.; Foster, B.

    2008-09-01

    The National Center for Atmospheric Research (NCAR) thermospheric general circulation model for Venus (VTGCM) is producing results that are comparative to Pioneer Venus and Venus Express data. The model is a three dimensional model that can calculate temperatures, zonal winds, meridional winds, vertical winds, and concentration of specific species. The VTGCM can also compute the O2-IR and NO-UV night airglow intensity distributions. With a lower boundary set at 70 Km and a range of sensitivity tests, the VTGCM is able to show consistent set of results with the nightside temperature and the night airglows. These results can show possible controlling parameters of the O2-IR, NO-UV night airglow layers, and the nightside hot spot. Being able to understand the night airglow distribution and variability provides valuable insight into the changing circulation of Venus’ upper atmosphere and leads to an overall planetary perception of the atmospheric dynamics.

  6. Two-dimensional inversion technique for satellite airglow data

    NASA Technical Reports Server (NTRS)

    Fesen, C. G.; Hays, P. B.

    1982-01-01

    A technique is described which inverts satellite airglow data producing volume emission rates as functions of altitude and position. The inversion is applied to data obtained when the spacecraft spins in the orbital plane. The altitude and height resolutions are constrained by the geometry chosen to simplify the inversion. The limitations of the method and its implementation on data from the Visual Airglow Experiment onboard the Atmosphere Explorer satellite are discussed. Sample maps of brightness and volume emission rates are shown.

  7. Two-dimensional inversion technique for satellite airglow data.

    PubMed

    Fesen, C G; Hays, P B

    1982-10-15

    A technique is described which inverts satellite airglow data producing volume emission rates as functions of altitude and position. The inversion is applied to data obtained when the spacecraft spins in the orbital plane. The altitude and height resolutions are constrained by the geometry chosen to simplify the inversion. The limitations of the method and its implementation on data from the Visual Airglow Experiment onboard the Atmosphere Explorer satellite are discussed. Sample maps of brightness and volume emission rates are shown.

  8. Signatures of Planets: Observations and Modeling of Structure in the Zodiacal Cloud and Kuiper Disk

    NASA Astrophysics Data System (ADS)

    Holmes, E. K.; Dermott, S. F.

    2001-12-01

    There is a possible connection between structure in evolved circumstellar disks and the presence of planets. Asymmetries in such a disk (such as the zodiacal cloud in the inner solar system or the Kuiper disk in the outer solar system) could be diagnostic of planets that would be otherwise undetectable. At least three different types of asymmetries can serve to indicate bodies orbiting a star in a disk: (1) a warp in the plane of symmetry of the disk, (2) an offset in the center of symmetry of the disk with respect to the central star, and (3) density anomalies in the plane of the disk such as dust bands or resonant rings. Structure in the zodiacal cloud, namely the warp and offset of the cloud, are linked to the presence of planets using secular perturbation theory. A Kuiper disk would most likely have a resonant structure, with two concentrations in brightness along the ecliptic longitude. This structure arises because 10-15% of the Kuiper belt objects, the Plutinos, are in the 3:2 mean motion resonance with Neptune (Jewitt 1999, Malhotra 1995). A size-frequency distribution of particles in the Plutino disk based on the percentage of particles that are trapped in the 3:2 resonance is determined by running numerical integrations of particles in Pluto-like orbits. The dynamical evolution of the particles is followed from source to sink with Poynting-Robertson light drag, solar wind drag, radiation pressure, the Lorentz force, neutral interstellar gas drag, and the effects of planetary gravitational perturbations included. In addition, a search is conducted in COBE DIRBE data for far-infrared emission from the Kuiper disk, which is predicted to be, at most, a few percent of the brightness of the zodiacal cloud from COBE upper limits (Dermott et al. 1999, Backman et al. 1995, Teplitz et al. 1999).

  9. AKARI far-infrared maps of the zodiacal dust bands

    NASA Astrophysics Data System (ADS)

    Ootsubo, Takafumi; Doi, Yasuo; Takita, Satoshi; Nakagawa, Takao; Kawada, Mitsunobu; Kitamura, Yoshimi; Matsuura, Shuji; Usui, Fumihiko; Arimatsu, Ko

    2016-06-01

    Zodiacal emission is thermal emission from interplanetary dust. Its contribution to the sky brightness is non-negligible in the region near the ecliptic plane, even in the far-infrared (far-IR) wavelength regime. We analyze zodiacal emission observed by the AKARI far-IR all-sky survey, which covers 97% of the entire sky at arcminute-scale resolution in four photometric bands, with central wavelengths of 65, 90, 140, and 160 μm. AKARI detected small-scale structures in the zodiacal dust cloud, including the asteroidal dust bands and the circumsolar ring, at far-IR wavelengths. Although the smooth component of the zodiacal emission structure in the far-IR sky can be reproduced well by models based on existing far-IR observations, previous zodiacal emission models have discrepancies in the small-scale structures compared with observations. We investigate the geometry of the small-scale dust-band structures in the AKARI far-IR all-sky maps and construct template maps of the asteroidal dust bands and the circumsolar ring components based on the AKARI far-IR maps. In the maps, ± 1.4°, ± 2.1°, and ± 10° asteroidal dust-band structures are detected in the 65 μm and 90 μm bands. A possible ± 17° band may also have been detected. No evident dust-band structures are identified in either the 140 μm or the 160 μm bands. By subtracting the dust-band templates constructed in this paper, we can achieve a similar level of flux calibration of the AKARI far-IR all-sky maps in the |β| < 40° region to that in the region for |β| > 40°.

  10. Synthetic spectra for the Arizona Airglow Experiment

    SciTech Connect

    Johnston, J.E.; Hatfield, D.B.; Broadfoot, A.L.

    1994-12-31

    The Arizona Airglow Experiment (GLO) is a panchromatic Intensified CCD (ICCD) spectrograph, bore sighted with 12 monochromatic imagers. The spectrograph provides continuous spectral coverage from 1150 {angstrom} to 11,000 {angstrom} with a resolution of 5 {angstrom} to 20 {angstrom}. The spectrograph was designed to record simultaneously as much information as possible from a single column of gas. The resolution was selected to allow the determination of molecular emission vibrational and rotational structure. Molecular band emissions contain much more information than atomic lines, although interpretation of band emissions is more complicated. This complexity is due to the distribution of their energies over broad spectral ranges that overlap. The most productive method of interpreting molecular spectra is by modeling. The nature of the molecular transitions is well known, and synthetic spectra can be calculated to match the recorded spectrum accurately. Their knowledge of the transition probabilities allows accurate estimates of the intensity and shape of blended bands. It is the goal to synthesize all of the emissions recorded by the GLO as a tool to aid in detailed analysis of spectra. This work describes the approach used in calculating the synthetic spectra and references the source of parameters used for 14 band systems. This software utility will become a part of the GLO facility.

  11. Spectrophotometric measurement of the Extragalacic Background Light

    NASA Astrophysics Data System (ADS)

    Mattila, Kalevi; Lehtinen, Kimmo; Väisänen, Petri; von Appen-Schnur, Gerhard; Leinert, Christoph

    2012-08-01

    The Extragalactic Background Light (EBL) at UV, optical and NIR wavelengths consists of the integrated light of all unresolved galaxies along the line of sight plus any contributions by intergalactic matter including hypothetical decaying relic particles. The measurement of the EBL has turned out to be a tedious problem. This is because of the foreground components of the night sky brightness, much larger than the EBL itself: the Zodiacal Light (ZL), Integrated Starlight (ISL), Diffuse Galactic Light (DGL) and, for ground-based observations, the Airglow (AGL) and the tropospheric scattered light. We have been developing a method for the EBL measurement which utilises the screening effect of a dark nebula on the EBL. A differential measurement in the direction of a high-latitude dark nebula and its surrounding area provides a signal that is due to two components only, i.e. the EBL and the diffusely scattered ISL from the cloud. We present a progress report of this method where we are now utilising intermediate resolution spectroscopy with ESO's VLT telescope. We detect and remove the scattered ISL component by using its characteristic Fraunhofer line spectral signature. In contrast to the ISL, in the EBL spectrum all spectral lines are washed out. We present a high quality spectrum representing the difference between an opaque position within our target cloud and several clear OFF positions around the cloud. We derive a preliminary EBL value at 400 nm and an upper limit to the EBL at 520 nm. These values are in the same range as the EBL lower limits derived from galaxy counts. Unit: We will use in this paper the abbreviation 1 cgs = 10-9erg s-1cm-2sr-1Å-1

  12. The Chevroches zodiacal cap and its Burgundy relations

    NASA Astrophysics Data System (ADS)

    Devevey, Frédéric; Vernou, Christian; Rousseau, Aurélie

    2011-06-01

    The excavation of an unexplored secondary agglomeration in Chevroches (France), from 2001 to 2002 has led to the discovery of a bronze dome of a type unknown in the Ancient world. It is inscribed with three lines in Greek transcribing Egyptian and Roman months, and the twelve signs of the Zodiac. This paper presents the first observations and some other finds from similar objects in Burgundy.

  13. Correlated measurements of mesospheric density and near infrared airglow

    NASA Astrophysics Data System (ADS)

    Moreels, G.; Pautet, D.; Faivre, M.; Keckhut, P.; Hauchecorne, A.

    A program aimed at simultaneously measuring the mesospheric density and the evolution with time of the near IR emission at the mesopause level was initiated in July 2000 and July 2001. The atmospheric density is measured along a vertical line using the Rayleigh scattering lidar located at Observatoire de Haute Provence (OHP). The near IR emission, mainly due to OH, is measured along a slant path from the Pic de Château-Renard (Hautes-Alpes, altitude 2989 m). The field of view of the CCD camera encompasses an area located vertically above OHP. Rayleigh scattering by air molecules is much less efficient than fluorescence by alkaline atoms. Therefore, the lidar data could only be retrieved with a one-hour time resolution at altitudes of 65, 70, 72.5 and 75 km. The time resolution for the airglow intensity measurement was equal to three minutes. The temporal evolution over the 5-hour duration of the night appears as opposite in the density up to 75 km and in the near IR airglow. The airglow shows around 23h30 a minimum intensity about 28% lower than its maximum value. During the first part of the night the intensity decreases. During the second part, it increases. The increase during the second part cannot be explained by the evolution of the atmospheric chemical system. Given the variation in opposite phases of the air density and of the emission, it is suggested that the near IR airglow is a semi-direct tracer of the density variations at the mesopause level, the air molecules being effective quenchers of the excited OH radicals. The excitation and quenching rates will therefore be discussed. Two short movie films showing the airglow waves coming across the observation field of view will be presented.

  14. Prehistory of Zodiac Dating: Three Strata of Upper Paleolithic Constellations

    NASA Astrophysics Data System (ADS)

    Gurshtein, Alex A.

    A pattern of archaic proto-constellations is extracted from Aratus' "The Phaenomena" didactic poem list according to a size criterion elaborated earlier, and their symbolism is analyzed. As a result of this approach three celestial symbolical strata are discovered to be probably a reflection of the symbols for the Lower, the Middle and the Upper Worlds; the Under-World creatures have a water character, the Middle World ones are mostly anthropomorphic and flying beings are for the Upper World. The strata excerpted from Aratus' sky seems to be in agreement with the well-known Babylonian division into three god pathways for Ea (Enki), Anu and Enlil. There is a possibility of dating the pattern discovered because of precession's strong influence as far back as 16 thousand years, the result being supported by the comparison of different star group mean sizes. The archaic constellation pattern under consideration is a reasonable background of symbolical meanings for the first Zodiacal generation quartet (7.5 thousand years old) examined by the author previously. The enormous size of the Argo constellation (Ship of Argo and his Argonauts) as well as the large sizes of other southern constellations are explained as due to the existence of an accumulation zone near the South celestial pole. Some extra correlations between the reconstruction proposed and cultural data available are discussed. The paper is the second part of the investigation "On the Origin of the Zodiacal constellations" published in Vistas in Astronomy, vol.36, pp.171-190, 1993.

  15. A Global, Multi-Waveband Model for the Zodiacal Cloud

    NASA Technical Reports Server (NTRS)

    Grogan, Keith; Dermott, Stanley F.; Kehoe, Thomas J. J.

    2003-01-01

    This recently completed three-year project was undertaken by the PI at the University of Florida, NASA Goddard and JPL, and by the Co-I and Collaborator at the University of Florida. The funding was used to support a continuation of research conducted at the University of Florida over the last decade which focuses on the dynamics of dust particles in the interplanetary environment. The main objectives of this proposal were: To produce improved dynamical models of the zodiacal cloud by performing numerical simulations of the orbital evolution of asteroidal and cometary dust particles. To provide visualizations of the results using our visualization software package, SIMUL, simulating the viewing geometries of IRAS and COBE and comparing the model results with archived data. To use the results to provide a more accurate model of the brightness distribution of the zodiacal cloud than existing empirical models. In addition, our dynamical approach can provide insight into fundamental properties of the cloud, including but not limited to the total mass and surface area of dust, the size-frequency distribution of dust, and the relative contributions of asteroidal and cometary material. The model can also be used to provide constraints on trace signals from other sources, such as dust associated with the "Plutinos" , objects captured in the 2:3 resonance with Neptune.

  16. Zodiac: A Comprehensive Depiction of Genetic Interactions in Cancer by Integrating TCGA Data

    PubMed Central

    Zhu, Yitan; Xu, Yanxun; Helseth, Donald L.; Gulukota, Kamalakar; Yang, Shengjie; Pesce, Lorenzo L.; Mitra, Riten; Müller, Peter; Sengupta, Subhajit; Guo, Wentian; Silverstein, Jonathan C.; Foster, Ian; Parsad, Nigel; White, Kevin P.

    2015-01-01

    Background: Genetic interactions play a critical role in cancer development. Existing knowledge about cancer genetic interactions is incomplete, especially lacking evidences derived from large-scale cancer genomics data. The Cancer Genome Atlas (TCGA) produces multimodal measurements across genomics and features of thousands of tumors, which provide an unprecedented opportunity to investigate the interplays of genes in cancer. Methods: We introduce Zodiac, a computational tool and resource to integrate existing knowledge about cancer genetic interactions with new information contained in TCGA data. It is an evolution of existing knowledge by treating it as a prior graph, integrating it with a likelihood model derived by Bayesian graphical model based on TCGA data, and producing a posterior graph as updated and data-enhanced knowledge. In short, Zodiac realizes “Prior interaction map + TCGA data → Posterior interaction map.” Results: Zodiac provides molecular interactions for about 200 million pairs of genes. All the results are generated from a big-data analysis and organized into a comprehensive database allowing customized search. In addition, Zodiac provides data processing and analysis tools that allow users to customize the prior networks and update the genetic pathways of their interest. Zodiac is publicly available at www.compgenome.org/ZODIAC. Conclusions: Zodiac recapitulates and extends existing knowledge of molecular interactions in cancer. It can be used to explore novel gene-gene interactions, transcriptional regulation, and other types of molecular interplays in cancer. PMID:25956356

  17. Zodiac: A Comprehensive Depiction of Genetic Interactions in Cancer by Integrating TCGA Data

    SciTech Connect

    Zhu, Yitan; Xu, Yanxun; Helseth, Donald L.; Gulukota, Kamalakar; Yang, Shengjie; Pesce, Lorenzo L.; Mitra, Riten; Muller, Peter; Sengupta, Subhajit; Guo, Wentian; Foster, Ian; Bullock, JaQuel A.

    2015-08-01

    Background: Genetic interactions play a critical role in cancer development. Existing knowledge about cancer genetic interactions is incomplete, especially lacking evidences derived from large-scale cancer genomics data. The Cancer Genome Atlas (TCGA) produces multimodal measurements across genomics and features of thousands of tumors, which provide an unprecedented opportunity to investigate the interplays of genes in cancer. Methods: We introduce Zodiac, a computational tool and resource to integrate existing knowledge about cancer genetic interactions with new information contained in TCGA data. It is an evolution of existing knowledge by treating it as a prior graph, integrating it with a likelihood model derived by Bayesian graphical model based on TCGA data, and producing a posterior graph as updated and data-enhanced knowledge. In short, Zodiac realizes “Prior interaction map + TCGA data → Posterior interaction map.” Results: Zodiac provides molecular interactions for about 200 million pairs of genes. All the results are generated from a big-data analysis and organized into a comprehensive database allowing customized search. In addition, Zodiac provides data processing and analysis tools that allow users to customize the prior networks and update the genetic pathways of their interest. Zodiac is publicly available at www.compgenome.org/ZODIAC. Conclusions: Zodiac recapitulates and extends existing knowledge of molecular interactions in cancer. It can be used to explore novel gene-gene interactions, transcriptional regulation, and other types of molecular interplays in cancer.

  18. Ionospheric imaging using merged ultraviolet airglow and radio occultation data

    NASA Astrophysics Data System (ADS)

    Stephan, Andrew W.; Budzien, Scott A.; Finn, Susanna C.; Cook, Timothy A.; Chakrabarti, Supriya; Powell, Steven P.; Psiaki, Mark L.

    2014-09-01

    The Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) and GPS Radio Occultation and Ultraviolet Photometry-Colocated (GROUP-C) experiments are being considered for flight aboard the Space Test Program Houston 5 (STP-H5) experiment pallet to the International Space Station (ISS). LITES is a compact imaging spectrograph that makes one-dimensional images of atmospheric and ionospheric ultraviolet (60-140 nm) airglow above the limb of the Earth. The LITES optical design is advantageous in that it uses a toroidal grating as its lone optical surface to create these high-sensitivity images without the need for any moving parts. GROUP-C consists of two instruments: a nadir-viewing ultraviolet photometer that measures nighttime ionospheric airglow at 135.6 nm with unprecedented sensitivity, and a GPS receiver that measures ionospheric electron content and scintillation with the assistance of a novel antenna array designed for multipath mitigation. By flying together, these two experiments form an ionospheric observatory aboard the ISS that will provide new capability to study low- and mid-latitude ionospheric structures on a global scale. This paper presents the design and implementation of the LITES and GROUP-C experiments on the STP-H5 payload that will combine for the first time high-sensitivity in-track photometry with vertical spectrographic imagery of ionospheric airglow to create high-fidelity images of ionospheric structures. The addition of the GPS radio occultation measurement provides the unique opportunity to constrain, as well as cross-validate, the merged airglow measurements.

  19. Near-infrared oxygen airglow from the Venus nightside

    NASA Technical Reports Server (NTRS)

    Crisp, D.; Meadows, V. S.; Allen, D. A.; Bezard, B.; Debergh, C.; Maillard, J.-P.

    1992-01-01

    Groundbased imaging and spectroscopic observations of Venus reveal intense near-infrared oxygen airglow emission from the upper atmosphere and provide new constraints on the oxygen photochemistry and dynamics near the mesopause (approximately 100 km). Atomic oxygen is produced by the Photolysis of CO2 on the dayside of Venus. These atoms are transported by the general circulation, and eventually recombine to form molecular oxygen. Because this recombination reaction is exothermic, many of these molecules are created in an excited state known as O2(delta-1). The airglow is produced as these molecules emit a photon and return to their ground state. New imaging and spectroscopic observations acquired during the summer and fall of 1991 show unexpected spatial and temporal variations in the O2(delta-1) airglow. The implications of these observations for the composition and general circulation of the upper venusian atmosphere are not yet understood but they provide important new constraints on comprehensive dynamical and chemical models of the upper mesosphere and lower thermosphere of Venus.

  20. The contribution of cometary dust to the zodiacal cloud

    NASA Astrophysics Data System (ADS)

    Liou, J. C.; Dermott, S. F.; Xu, Y. L.

    1995-06-01

    Any theory of the origin of the particles that supply the zodiacal cloud must account for two key, well-established observations. These are: (1) the observed plane of symmetry of the cloud; and (2) the observed shape of the cloud, that is, the observed variation of the flux in a given waveband with ecliptic latitude for a given elongation angle. The dynamics of small asteroidal particles appears to account for the first observation (Dermott et al., Chaos, Resonance and Collective Phenomena in the Solar System, pp. 333-347. Kluwer, Dordrecht, 1992). However, asteroidal particles that spiral towards the Sun under the action of drag forces without significant disintegration due to dust-dust collisions do not, on their own, provide an explanation for the observed shape of the cloud, because asteroidal dust models provide insufficient flux at the Earth's ecliptic poles (Dermott et al., Chaos, Resonance and Collective Phenomena in the Solar System, pp. 333-347. Kluwer, Dordrecht, 1992). In an attempt to account for this major diserepancy, the dynamics of cometary particles is investigated. The orbital evolution of 9 μm diameter dust particles that originate from Comet Encke is described. The orbits of 5000 particles are integrated numerically in order to determine their spatial distribution in 1983. All planetary perturbations (except those due to Mercury and Pluto), radiation pressure, Poynting-Robertson drag, and solar wind drag are included in the calculation. The SIMUL code (Dermott et al., Comets to Cosmology, pp. 3-18. Springer, Berlin, 1988) is used to calculate the shapes of several model zodiacal clouds consisting of a range of combinations of cometary and asteroidal particles. By comparing the model results with IRAS observations in the 25 μm waveband, it is shown that the observed shape of the zodiacal cloud can be accounted for by a combination of about 1/4 to 1/3 asteroidal dust and about 3/4 to 2/3 cometary dust. This result is consistent with other work

  1. Measurements of near- and far-infrared zodiacal dust emission

    SciTech Connect

    Salama, A.; Andreani, P.; Debernardis, P.; Masi, S.; Dalloglio, G.

    1987-02-01

    Results concerning zodiacal dust emission are reported from an IR sky survey experiment performed during a balloon flight on July 30, 1984 which explored five wavelength bands centered at 11, 19, 50, 108, and 225 microns. The dust density n decreases at a rate slower than r exp -1.3 with increasing heliocentric distance. The trend of n depends critically on the radial variation of the temperature which, in turn, depends on the chemical composition of the grains. The spatial distribution of the dust is in good agreement with that previously inferred from IR measurements. A comparison between IR and optical observations points out the uncertainties affecting the estimates of the dust density obtained with both methods. The emission spectrum of the dust is used to discriminate among the different species of grains, showing that the observations can be accounted for by an appropriate mixture of graphite and silicates. 18 references.

  2. Global temperature distributions from OGO-6 6300 A airglow measurements

    NASA Technical Reports Server (NTRS)

    Blamont, J. E.; Luton, J. M.; Nisbet, J. S.

    1974-01-01

    The OGO-6 6300 A airglow temperature measurements have been used to develop models of the global temperature distributions under solstice and equinox conditions for the altitude region from 240 to 300 km and for times ranging from dawn in this altitude region to shortly after sunset. The distributions are compared with models derived from satellite orbital decay and incoherent scatter sounding. The seasonal variation of the temperature as a function of latitude is shown to be very different from that derived from static diffusion models with constant boundary conditions.

  3. Measurements of the earth's airglow in the vacuum ultraviolet

    NASA Technical Reports Server (NTRS)

    Waters, C. R.; Fishburne, E. S.

    1972-01-01

    A valuable by-product of the OAO-2 astronomy mission has been the first extensive set of measurements of the earth's airglow between 1000 and 3000 A. These measurements, made with the Wisconsin experiment package, provide clues to the structure and chemistry of the upper atmosphere. The most significant results from these observations are: (1) the detailed altitude profile of the emissions from the dark and sunlit earth limb; and (2) the confirmation of recent theories concerning the source of the dayglow radiation between 1350 and 1700 A.

  4. Near Infrared Characterization of Hot Exo-Zodiacal Disks around Nearby Stars

    NASA Astrophysics Data System (ADS)

    Mennesson, Bertrand

    Debris disks found around main sequence stars are the remnants of planetary formation. The outer colder parts of these disks, analogous to our solar system Kuiper belt, were first detected via their mid/far infrared excess emission, and then abundantly imaged at visible to sub-millimeter wavelengths. Structures and asymmetries in spatially resolved debris disks have been used to infer the presence of yet unseen planets. The power of this technique was recently demonstrated with the direct imaging of massive planets at the inner edge of warped extended dust disks previously detected around Fomalhaut and beta Pic. Conversely, very little is known about the warmer dust component of debris disks, similar to the zodiacal dust of the inner solar system. A few hot disks have been found by Spitzer around mature stars via excess emission at 24 microns. But surprisingly, the majority of hot debris disk detections has come from the ground, where near infrared interferometric observations have recently revealed small (~1%) resolved excesses around a dozen nearby main sequence stars. The dust grains forming in these bright "exozodi disks" or dust belts are located within a few AU of their parent star. They are thought to be produced by the evaporation of comets or by collisions between larger rocky bodies, as in the solar zodiacal disk. Many of the detected disks are however much hotter (1000-1500K) and more massive than the zodiacal cloud. Their grain populations should be rapidly expelled from the inner planetary system by radiation pressure, which indicates inordinate replenishment rates. In practice, the steady state collisional grinding of a massive asteroid belt cannot be at the origin of these dust populations. They are most likely produced by isolated catastrophic events (e.g., major asteroid collision, break-up of a massive comet), or by major dynamical perturbations such as the Falling Evaporating Bodies (FEB) phenomenon in the beta Pic inner disk or the Late Heavy

  5. Extra-Zodiacal-Cloud Astronomy via Solar Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Benson, Scott W.; Falck, Robert D.; Oleson, Steven R.; Greenhouse, Matthew A.; Kruk, Jeffrey W.; Gardner, Jonathan P.; Thronson, Harley A.; Vaughn, Frank J.; Fixsen, Dale J.

    2011-01-01

    Solar electric propulsion (SEP) is often considered as primary propulsion for robotic planetary missions, providing the opportunity to deliver more payload mass to difficult, high-delta-velocity destinations. However, SEP application to astrophysics has not been well studied. This research identifies and assesses a new application of SEP as primary propulsion for low-cost high-performance robotic astrophysics missions. The performance of an optical/infrared space observatory in Earth orbit or at the Sun-Earth L2 point (SEL2) is limited by background emission from the Zodiacal dust cloud that has a disk morphology along the ecliptic plane. By delivering an observatory to a inclined heliocentric orbit, most of this background emission can be avoided, resulting in a very substantial increase in science performance. This advantage enabled by SEP allows a small-aperture telescope to rival the performance of much larger telescopes located at SEL2. In this paper, we describe a novel mission architecture in which SEP technology is used to enable unprecedented telescope sensitivity performance per unit collecting area. This extra-zodiacal mission architecture will enable a new class of high-performance, short-development time, Explorer missions whose sensitivity and survey speed can rival flagship-class SEL2 facilities, thus providing new programmatic flexibility for NASA's astronomy mission portfolio. A mission concept study was conducted to evaluate this application of SEP. Trajectory analyses determined that a 700 kg-class science payload could be delivered in just over 2 years to a 2 AU mission orbit inclined 15 to the ecliptic using a 13 kW-class NASA's Evolutionary Xenon Thruster (NEXT) SEP system. A mission architecture trade resulted in a SEP stage architecture, in which the science spacecraft separates from the stage after delivery to the mission orbit. The SEP stage and science spacecraft concepts were defined in collaborative engineering environment studies. The

  6. Direct Measurements of Upper Limits for Transient Density Fluctuations in the Zodiacal Cloud

    NASA Astrophysics Data System (ADS)

    Olsson, B.

    1997-12-01

    Questions regarding the density of the local zodiacal clouds have recently become important in many areas. Several planned searches for extrasolar system planets require a better knowledge of the behavior of zodiacal clouds, the solar system zodiacal cloud has been suggested as a driving force for glaciations, and it is becoming clear that discussions regarding prebiotic chemistry must include the flux of interplanetary particles onto Earth. No certain upper limits can today be set for transient density variations in the local zodiacal cloud, nor for fluctuations in the particle-flux onto Earth. Some new results have, however, created a possibility to measure this in the geological record. An interdisciplinary project is described. The goal for the project is to set upper limits for the zodiacal dust-flux onto Earth during passages through IRAS dust-bands during the last 2.5 million years, and use these limits to calculate the maximum density of the bands. We estimate the predicted flux of zodiacal particles onto Earth through orbital modeling., where it is assumed that the source for the IRAS dust-bands are a few Hirayama asteroid families. The orbits of the asteroids and the produced dust are integrated to find the times when Earth revolved within a dust-band. This forms the basis for a geochemical analysis of oceanic sediments, lake sediments, ice-cores and loess-deposits, with the goal to find the signal from a passage through a dust-band. Apart from providing an excellent stratigraphic dating tool, the identification and characterization of such a signal would give important information about the behavior of the zodiacal cloud over shorter times (1-2 My). Some astronomical results are presented and compared with sedimentological observations.

  7. Single vs multi-level quenching of the hydroxyl airglow

    NASA Astrophysics Data System (ADS)

    Franzen, Christoph; Espy, Patrick J.; Hibbins, Robert; Djupvik, Anlaug Amanda

    2016-04-01

    The reaction in the upper mesosphere between atomic hydrogen and ozone results in hydroxyl (OH) that is produced in excited vibrational levels 6 through 9. The vibrationally excited OH radiates in a thin (~8 km thick) layer near 87 km, giving rise to the strong near infrared airglow emission that has been used for remote sensing of the mesopause region. The interpretation of the emission relies on accurate knowledge of the population and quenching of the upper states, and open questions remain as to whether the quenching takes place through single- or multi-quantum deactivation. Here we will demonstrate how high quality spectral observations of OH (9,7) and (8,6) airglow emissions are available as background measurements during standard K-band astronomical observations from the Nordic Optical Telescope (18°W, 29°N). These emissions have been analysed to ascertain the quenching of the upper vibrational populations. Together with a steady-state model of these emissions, an estimate of the ratio of single to multi-quantum quenching efficiency and the impact on the populations of the lower vibrational levels will be presented.

  8. Voyages of the Zodiac, an Impenitent Traveller across Lands and Ages

    NASA Astrophysics Data System (ADS)

    Belmonte, Juan Antonio

    2015-05-01

    The zodiac is one of humankind's oldest astronomical heritages. Indeed, it has a long history and had an impressive cultural influence in the past that could be traced from the steppes of Mesopotamia to the wilderness of the Roman frontiers in Great Britain. In the present essay, we will discuss the origin of the zodiacal constellations in ancient Mesopotamia from their possible prehistoric ancestors in the pre-ceramic context of the 10,000-year-old site of Göbleki Tepe. Later on, we will discuss the role that the zodiac played in the development of the new cult established by King Antiochos I of Commagene in his hierothesion at Nemrud Dag, where a planetary conjunction in Leo has played a role in the clues to understand the enigmas of such an impressive monument. This will be followed by the analysis of its southwards travel to the Valley of the Nile, where we will study the famous Zodiac of Dendera. Then we will travel westwards to discuss the astronomical aspects of a new religion where astronomical eras and the zodiac ought to play a most relevant role, Mithraism. Finally, new ideas for future research in this most interesting topic will briefly be sketched.

  9. Vacuum ultraviolet instrumentation for solar irradiance and thermospheric airglow

    NASA Technical Reports Server (NTRS)

    Woods, Thomas N.; Rottman, Gary J.; Bailey, Scott M.; Solomon, Stanley C.

    1993-01-01

    A NASA sounding rocket experiment was developed to study the solar extreme ultraviolet (EUV) spectral irradiance and its effect on the upper atmosphere. Both the solar flux and the terrestrial molecular nitrogen via the Lyman-Birge-Hopfield bands in the far ultraviolet (FUV) were measured remotely from a sounding rocket on October 27, 1992. The rocket experiment also includes EUV instruments from Boston University (Supriya Chakrabarti), but only the National Center for Atmospheric Research (NCAR)/University of Colorado (CU) four solar instruments and one airglow instrument are discussed here. The primary solar EUV instrument is a 1/4 meter Rowland circle EUV spectrograph which has flown on three rockets since 1988 measuring the solar spectral irradiance from 30 to 110 nm with 0.2 nm resolution. Another solar irradiance instrument is an array of six silicon XUV photodiodes, each having different metallic filters coated directly on the photodiodes. This photodiode system provides a spectral coverage from 0.1 to 80 nm with about 15 nm resolution. The other solar irradiance instrument is a silicon avalanche photodiode coupled with pulse height analyzer electronics. This avalanche photodiode package measures the XUV photon energy providing a solar spectrum from 50 to 12,400 eV (25 to 0.1 nm) with an energy resolution of about 50 eV. The fourth solar instrument is an XUV imager that images the sun at 17.5 nm with a spatial resolution of 20 arc-seconds. The airglow spectrograph measures the terrestrial FUV airglow emissions along the horizon from 125 to 160 nm with 0.2 nm spectral resolution. The photon-counting CODACON detectors are used for three of these instruments and consist of coded arrays of anodes behind microchannel plates. The one-dimensional and two-dimensional CODACON detectors were developed at CU by Dr. George Lawrence. The pre-flight and post-flight photometric calibrations were performed at our calibration laboratory and at the Synchrotron Ultraviolet

  10. Calibration of the Berkeley EUV Airglow Rocket Spectrometer

    NASA Technical Reports Server (NTRS)

    Cotton, Daniel M.; Chakrabarti, Supriya; Siegmund, Oswald

    1989-01-01

    The Berkeley Extreme-ultraviolet Airglow Rocket Spectrometer (BEARS), a multiinstrument sounding rocket payload, made comprehensive measurements of the earth's dayglow. The primary instruments consisted of two near-normal Rowland mount spectrometers: one channel to measure several atomic oxygen features at high spectral resolution (about 1.5 A) in the band passes 980-1040 and 1300-1360 A, and the other to measure EUV dayglow and the solar EUV simultaneously in a much broader bandpass (250-1150 A) at moderate resolution (about 10 A). The payload also included a hydrogen Lyman-alpha photometer to monitor the solar irradiance and goecoronal emissions. The instrument was calibrated at the EUV calibration facility at the University of California at Berkeley, and was subsequently launched successfully on September 30, 1988 aboard a four-stage experimental sounding rocket, Black Brant XII flight 12.041 WT. The calibration procedure and resulting data are presented.

  11. Balloon-borne spectroscopic observation of the infrared hydroxyl airglow.

    PubMed

    Lowe, R P; Lytle, E A

    1973-03-01

    A balloon-borne grating spectrometer has been used to study the spectrum of the airglow between 1.8 microm and 3.6 microm and its diurnal variation. The principal features identified are the bands of the Deltaupsilon = 2 and Deltaupsilon = 1 sequences of the vibration-rotation spectrum of OH. The brightness of the 1-0 band at night was measured to be in the range 270-400 kR on two flights. A sudden decrease in the intensity of the hydroxyl bands occurred in morning twilight at a solar depression of 4 degrees and is ascribed to the photodissociation of ozone. The temperature, as indicated by the Q/R branch ratio, rose from 170 K at night to 255 K at noon indicating a reduction in the height of the emitting layer during the day.

  12. Dynamical Model for the Zodiacal Cloud and Sporadic Meteors

    NASA Astrophysics Data System (ADS)

    Nesvorný, David; Janches, Diego; Vokrouhlický, David; Pokorný, Petr; Bottke, William F.; Jenniskens, Peter

    2011-12-01

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving at the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer (gsim 105 yr at 1 AU) than postulated in the standard collisional models (~104 yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) × 1011 km2 and ~4 × 1019 g, respectively, in a good agreement with previous studies. The mass input required to keep the zodiacal cloud in a steady state is estimated to be ~104-105 kg s-1. The input is up to ~10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 μm and 1 cm is found to be ~15,000 tons yr-1 (factor of two uncertainty), which is a large share of the accretion flux measured by the Long Term Duration

  13. Dynamical Model for the Zodiacal Cloud and Sporadic Meteors

    NASA Technical Reports Server (NTRS)

    Nesvorny, David; Janches, Diego; Vokrouhlicky, David; Pokorny, Petr; Bottke, William F.; Jenniskens, Peter

    2011-01-01

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving to the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer (approx. > 10(exp 5) yr at 1 AU) than postulated in the standard collisional models (approx 10(exp 4) yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite (IRAS) to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) 10(exp 11) sq km and approx. 4 10(exp 19) g, respectively, in a good agreement with previous studies. The mass input required to keep the Zodiacal Cloud (ZC) in a steady state is estimated to be approx. 10(exp 4)-10(exp 5) kg/s. The input is up to approx 10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes, and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 micron and 1 cm is found to be approx 15,000 tons/yr (factor of 2 uncertainty), which is

  14. The influence of the Chinese zodiac on fertility in Hong Kong SAR.

    PubMed

    Yip, Paul S F; Lee, Joseph; Cheung, Y B

    2002-11-01

    The annual total of births in Hong Kong SAR fell substantially in the past 20 years; hence the total fertility rate (TFR) followed the downward trend and dropped to a low of 0.9 below replacement level in 2000. Despite the long-term downward trend, short-run increases in the annual total of births and the TFR were exhibited. Such temporary fertility increases are identified in the Dragon Years of 1988 and 2000. The phenomenon of fertility changes associated with zodiacal animal years is examined in this paper with a view to gaining some insight into whether Chinese cultural preferences and folklore beliefs might have influenced prospective parents' reproductive behaviour. The paper explains the underlying philosophy of the Chinese astrological tradition and discusses how zodiacal preferences affect fertility between 1976 and 2000. The paper also explores why zodiacal influences on Chinese fertility before 1976 did not exist. It is unquestionable that the Dragon Year preference exerts an influence on fertility of modern Chinese populations through zodiacal birth-timing motivations. Birth rate rise in the Dragon Year is due to changes in timing of births that will have little effect on cumulative fertility.

  15. The influence of the Chinese zodiac on fertility in Hong Kong SAR.

    PubMed

    Yip, Paul S F; Lee, Joseph; Cheung, Y B

    2002-11-01

    The annual total of births in Hong Kong SAR fell substantially in the past 20 years; hence the total fertility rate (TFR) followed the downward trend and dropped to a low of 0.9 below replacement level in 2000. Despite the long-term downward trend, short-run increases in the annual total of births and the TFR were exhibited. Such temporary fertility increases are identified in the Dragon Years of 1988 and 2000. The phenomenon of fertility changes associated with zodiacal animal years is examined in this paper with a view to gaining some insight into whether Chinese cultural preferences and folklore beliefs might have influenced prospective parents' reproductive behaviour. The paper explains the underlying philosophy of the Chinese astrological tradition and discusses how zodiacal preferences affect fertility between 1976 and 2000. The paper also explores why zodiacal influences on Chinese fertility before 1976 did not exist. It is unquestionable that the Dragon Year preference exerts an influence on fertility of modern Chinese populations through zodiacal birth-timing motivations. Birth rate rise in the Dragon Year is due to changes in timing of births that will have little effect on cumulative fertility. PMID:12383464

  16. Laboratory studies on the excitation and collisional deactivation of metastable atoms and molecules in the aurora and airglow

    NASA Technical Reports Server (NTRS)

    Zipf, E. C.

    1974-01-01

    The aeronomy group at the University of Pittsburgh is actively engaged in a series of coordinated satellite, sounding rocket, and laboratory studies designed to expand and clarify knowledge of the physics and chemistry of planetary atmospheres. Three major discoveries have been made that will lead ultimately to a complete and dramatic revision of our ideas on the ionospheres of Mars, Venus, and the Earth and on the origin of their vacuum ultraviolet airglows. The results have already suggested a new generation of ionosphere studies which probably can be carried out best by laser heterodyning techniques. Laboratory studies have also identified, for the first time, the physical mechanism responsible for the remarkable nitric oxide buildup observed in some auroral arcs. This development is an important break-through in auroral physics, and has military ramifications of considerable interest to the Department of Defense. This work may also shed some light on related NO and atomic nitrogen problems in the mesosphere.

  17. Spectroscopy of the Cameron bands in the Mars airglow

    NASA Technical Reports Server (NTRS)

    Conway, R. R.

    1981-01-01

    Mars airglow spectra obtained by the ultraviolet spectrometer on board the Mariner 9 spacecraft were analyzed by using a high-resolution synthesis of the observed emissions. Bright limb observations were made of altitudes between 88 and 180 km of which the brightest features are the carbon monoxide Cameron bands in the wavelength region 1800-2600 A. The shape of these bands cannot be characterized by a single rotational temperature, but is best described by temperatures of 1600 K for lower J values and 10,000 K for higher J values. The observed zenith intensity of 16.7 kR is in good agreement with an excitation theory in which electron-impact dissociation is the most important mechanism. The observations suggest the value of the cross section for this process should be 7 x 10 to the -17th/sq cm. The first negative bands of CO(+) are not identified in the Mariner 9 spectra. This is consistent with the excitation theory for these bands.

  18. Airglow continuum emission in the visible wavelength regime

    NASA Astrophysics Data System (ADS)

    Unterguggenberger, S.; Noll, S.; Kausch, W.; Proxauf, B.; Kimeswenger, S.

    2015-03-01

    To probe dynamics and chemistry of the atmosphere at high altitudes ( 80-100 km), we need to understand airglow line and continuum emission. Accounting for the continuum emission is harder than for the emission lines. Gaining knowledge of the upper atmospheric continuum emission needs e.g. a proper subtraction of the other continuum components, and a very good subtraction of the other emission lines which requires a high spectral resolution. In this study, we want to focus on FeO continuum emission. FeO emits in the wavelength range from 0.5 to 0.72 m and probes an altitude of about 89 km. The altitude of the emission peak lies between those of OH (87 km) and NaD (92 km). Fe and Na are linked by their source, meteors, and their common reactant O3, which holds also for OH emission. Lidar and limb sounding studies provide measurements about the continuum contribution of the FeO and Fe density in the upper atmosphere, but for a more detailed analysis in terms of emission structure and variability a ground-based high resolution and high signal-to-noise spectrum would be preferable.

  19. DYNAMICAL MODEL FOR THE ZODIACAL CLOUD AND SPORADIC METEORS

    SciTech Connect

    Nesvorny, David; Vokrouhlicky, David; Pokorny, Petr; Bottke, William F.; Janches, Diego

    2011-12-20

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving at the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer ({approx}> 10{sup 5} yr at 1 AU) than postulated in the standard collisional models ({approx}10{sup 4} yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) Multiplication-Sign 10{sup 11} km{sup 2} and {approx}4 Multiplication-Sign 10{sup 19} g, respectively, in a good agreement with previous studies. The mass input required to keep the zodiacal cloud in a steady state is estimated to be {approx}10{sup 4}-10{sup 5} kg s{sup -1}. The input is up to {approx}10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 {mu}m and 1 cm is found to be {approx}15

  20. Simulations of airglow variations induced by the CO2 increase and solar cycle variation from 1980 to 1991

    NASA Astrophysics Data System (ADS)

    Huang, Tai-Yin

    2016-09-01

    Airglow intensity and Volume Emission Rate (VER) variations induced by the increase of CO2 gas concentration and F10.7 variation (used as a proxy for the 11-year solar cycle variation) were investigated for the period from 1980 to 1991, encompassing a full solar cycle. Two airglow models are used to simulate the induced variations of O(1S) greenline, O2(0,1) atmospheric band , and OH(8,3) airglow for this study. The results show that both the airglow intensities and peak VERs correlate positively with the F10.7 solar cycle variation and display a small linear trend due to the increase of CO2 gas concentration. The solar-cycle induced airglow intensity variations show that O(1S) greenline has the largest variation (~26%) followed by the O2(0,1) atmospheric band (~23%) and then OH(8,3) airglow (~8%) over the 11 year timespan. The magnitudes of the induced airglow intensity variations by the increase of CO2 gas concentration are about an order of magnitude smaller than those by the F10.7 solar cycle variation. In general, the F10.7 solar cycle variation and CO2 increase do not seem to systematically alter the VER peak altitude of the airglow emissions, though the OH(8,3) VER peak altitude moves up slightly during the years when the F10.7 value falls under 100 SFU.

  1. Dynamical-chemical model of fluctuations in the OH airglow driven by migrating tides, stationary tides, and planetary waves

    SciTech Connect

    Walterscheid, R.L.; Schubert, G.

    1995-09-01

    The theory of tidally driven fluctuations in the OH airglow, generalized to account for emission from an extended layer, is applied to airglow fluctuations due to both migrating and zonally symmetric tides and free traveling planetary (Rossby) waves. Krassovsky`s ratio {eta}{sub E} (the ratio of normalized airglow fluctuation intensity to normalized temperature fluctuation) is evaluated for a suite of tidal modes and for the traveling planetary waves. Values of {eta}{sub E} are distinct enough to allow for identification of a variety of tidal modes and planetary waves in airglow observations. The theory predicts that airglow observations at very high latitude should contain prominent signatures of zonally symmetric tidal modes with periods of 6,8, and 12 hours. 32 refs., 4 figs., 3 tabs.

  2. Modeling of the Zodiacal Emission for the AKARI/IRC Mid-infrared All-sky Diffuse Maps

    NASA Astrophysics Data System (ADS)

    Kondo, Toru; Ishihara, Daisuke; Kaneda, Hidehiro; Nakamichi, Keichiro; Takaba, Sachi; Kobayashi, Hiroshi; Ootsubo, Takafumi; Pyo, Jeonghyun; Onaka, Takashi

    2016-03-01

    The zodiacal emission, which is the thermal infrared (IR) emission from the interplanetary dust (IPD) in our solar system, has been studied for a long time. Nevertheless, accurate modeling of the zodiacal emission has not been successful to reproduce the all-sky spatial distribution of the zodiacal emission, especially in the mid-IR where the zodiacal emission peaks. Therefore, we aim to improve the IPD cloud model based on Kelsall et al., using the AKARI 9 and 18 μm all-sky diffuse maps. By adopting a new fitting method based on the total brightness, we have succeeded in reducing the residual levels after subtraction of the zodiacal emission from the AKARI data and thus in improving the modeling of the zodiacal emission. Comparing the AKARI and the COBE data, we confirm that the changes from the previous model to our new model are mostly due to model improvements, but not temporal variations between the AKARI and the COBE epoch, except for the position of the Earth-trailing blob. Our results suggest that the size of the smooth cloud, a dominant component in the model, is about 10% more compact than previously thought, and that the dust sizes are not large enough to emit blackbody radiation in the mid-IR. Furthermore, we detect a significant isotropically distributed IPD component, owing to an accurate baseline measurement with AKARI.

  3. Airglow observation by VISI on ISS-IMAP: current status of development and simulation of measurement

    NASA Astrophysics Data System (ADS)

    Sakanoi, Takeshi; Yamazaki, Atsushi; Akiya, Yusuke; Saito, Akinori; Otsuka, Yuichi; Abe, Takumi; Taguchi, Makoto; Kubota, Minoru; Takeyama, Norihide; Obuchi, Yasuyuki; Yamamoto, Mamoru; Yoshikawa, Ichiro; Suzuki, Makoto

    The ISS-IMAP mission is one of the constituents of the Japanese Experiment Module (JEM) 2nd stage plan which will be launched in 2011 or 2012 onto the International Space Station (ISS). The main scientific subject of this mission is to clarify the energy and physical transfer processes in the boundary region between earth's atmosphere and space with the visible spectrometer and extra ultraviolet imagers. We have been developing the visible imaging spectrometer instrument (VISI) on ISS-IMAP. VISI will measure three nightglow emissions; O (630 nm, altitude 250 km), OH Meinel band (730 nm, altitude 87km), and O2 (0-0) atmospheric band (762 nm, altitude 95 km). We designed a bright (F/0.9), wide-angle (field-of-view 90 degrees) objective lens. To subtract background contaminations from clouds and ground structures, VISI will perform a stereoscopic measurement by taking two line-scans of the airglow spectra in 45 deg. forward and 45 deg. backward directions. Each field-of-view is faced perpendicular to the orbital plane, and its width is about 550 km mapping to an altitude of 100 km. The phase velocity of airglow wave structure is also estimated from the difference between forward and backward data. We will obtain a continuous line-scanning image for all emissions line from +51 deg to -51 deg. in geographic latitude by the successive exposure cycle with a time interval of 1 -several sec. From the simulation of airglow observation with a simple sinecurve airglow pattern including noises, we found that the wave structure in airglow can be identified for the three emissions. In this presentation, the current status of instrumental development, system design, operation plan, and simulation of airglow observations will be reported.

  4. Nonlinear airglow signatures of ducted gravity waves in the mesosphere and lower thermosphere

    NASA Astrophysics Data System (ADS)

    Snively, J. B.; Hickey, M. P.; Taylor, M. J.

    2010-12-01

    Signatures of short-period gravity waves are detected frequently in airglow data, revealing typical horizontal wavelengths of ˜15-35 km and periods of ˜4-8 minutes [e.g., Simkhada et al., Ann. Geophys., 27, 3213, 2009]. Many of such waves are ducted within the mesosphere and lower thermosphere (MLT) region [e.g., Walterscheid and Hickey, 114, D19109, 2009], and typical airglow intensity perturbations suggest amplitudes on the order of a few to tens of Kelvin within the airglow layers. At these amplitudes, trapped small-scale waves may be intermittently subject to nonlinear dissipation, potentially contributing to the local small-scale dynamics and variability of the lower thermosphere. For exceptionally strong small-scale waves, nonlinear behavior may become detectable in airglow data, including examples of wave breakdown [e.g., Yamada et al., GRL, 28(11), 2153, 2001], or apparent bore formation [e.g., Smith et al., JGR, 108(A2), 1083, 2003]. For moderately strong gravity waves with principally-linear propagation characteristics, however, airglow signatures may also exhibit nonlinearity in the form of harmonics, due to strong perturbations of reacting minor species at steep gradients of density [Huang et al., JGR, 108(A5), 1173, 2003; Snively et al., JGR, In Press, 2010]. Two scenarios are investigated numerically, using a nonlinear photochemical-dynamical model to simulate ducted gravity wave perturbations to the hydroxyl airglow layer. First, signatures of ducted waves are considered that exhibit nonlinearity associated with the wave perturbations to minor species participating in the emission processes. In this case, the nonlinear signatures are not indicative of changes in the wave packet spectrum. Second, we consider signatures of ducted waves at sufficient amplitudes to exhibit nonlinear propagation as they approach dissipation. In this second case, observable nonlinearity in the airglow signatures arise simultaneously from the overall wave perturbation and

  5. The Hunt for Observable Signatures of Terrestrial Planetary Systems (HOSTS): LBTI's Zodiacal Dust Survey

    NASA Astrophysics Data System (ADS)

    Hinz, Philip

    2013-01-01

    The Large Binocular Telescope Interferometer (LBTI) is a NASA funded instrument, designed to carry out a survey of nearby stars for the existence of faint zodiacal dust disks. The survey is named the Hunt for Observable Signatures of Terrestrial planetary Systems (HOSTS). These observations will constrain the prevalence and brightness of dust in the habitable zone to reduce risk for future NASA exoplanet imaging missions. The instrument uses nulling interferometry at 10 microns wavelength to precisely measure the small amount of thermal radiation a zodiacal dust disk emits, and isolate it from the much brighter stellar signal. The LBTI is completing commissioning, and will begin initial observations in the upcoming year. The instrument status, early results, and survey plans will be summarized.

  6. The Zodiacal Emission Spectrum as Determined by COBE and its Implications

    NASA Technical Reports Server (NTRS)

    Fixsen, D. J.; Dwek, Eli; Oliversen, R. (Technical Monitor)

    2002-01-01

    We combine observations from the DIRBE and FIRAS instruments on the COBE satellite to derive an annually-averaged spectrum of the zodiacal cloud in the 10 to 1000 micron wavelength region. The spectrum exhibits a break at approx. 150 microns which indicates a sharp break in the dust size distribution at a radius of about 30 microns The spectrum can be fit with a single blackbody with a lambda(exp -2) emissivity law beyond 150 microns and a temperature of 240 K. We also used a more realistic characterization of the cloud to fit the spectrum, including a distribution of dust temperatures, representing different dust compositions and distances from the sun, as well as a realistic representation of the spatial distribution of the dust. We show that amorphous carbon and silicate dust with respective temperatures of 280 and 274 K at 1 AU, and size distributions with a break at grain radii of 14 and 32 microns, can provide a good fit to the average zodiacal dust spectrum. The total mass of the zodiacal cloud is 2 to 11 Eg (Eg=10(exp 18) g), depending on the grain composition. The lifetime of the cloud, against particle loss by Poynting- Robertson drag and the effects of solar wind, is about 10(exp 5) yr. The required replenishment rate is approx. 10(exp 14) g/yr. If this is provided by asteroid belt alone, the asteroids lifetime would be approx. 3 x 10(exp 10) yr. But comets and Kuiper belt objects may also contribute to the zodiacal cloud.

  7. Wave breaking signatures in OH airglow and sodium densities and temperatures 1. Airglow imaging, Na lidar, and MF radar observations

    NASA Astrophysics Data System (ADS)

    Hecht, J. H.; Walterscheid, R. L.; Fritts, D. C.; Isler, J. R.; Senft, D. C.; Gardner, C. S.; Franke, S. J.

    The Collaborative Observations Regarding the Nightglow (CORN) campaign took place at the Urbana Atmospheric Observatory during September 1992. The instrumentation included, among others, the Aerospace Corporation narrowband nightglow CCD camera, which observes the OH Meinel (6-2) band (hereafter designated OH) and the O2 atmospheric (0-1) band (hereafter designated O2) nightglow emissions; the University of Illinois Na density/temperature lidar; and the University of Illinois MF radar. Here we report on observations of small-scale (below 10-km horizontal wavelength) structures in the OH airglow images obtained with the CCD camera. These small-scale structures were aligned perpendicular to the motion of 30- to 50-km horizontal wavelength waves, which had observed periods of about 10-20 min. The small-scale structures were present for about 20 min and appear to be associated with an overturned or breaking atmospheric gravity wave as observed by the lidar. The breaking wave had a horizontal wavelength of between 500 and 1500 km, a vertical wavelength of about 6 km, and an observed period of between 4 and 6 hours. The motion of this larger-scale wave was in the same direction as the ~30- to 50-km waves. While such small-scale structures have been observed before, and have been previously described as ripple-type wave structures [Taylor and Hapgood, 1990], these observations are the first which can associate their occurrence with independent evidence of wave breaking. The characteristics of the observed small-scale structures are similar to the vortices generated during wave breakdown in three dimensions in simulations described in Part 2 of this study [Fritts et al., this issue]. The results of this study support the idea that ripple type wave structures we observe are these vortices generated by convective instabilities rather than structures generated by dynamical instabilities.

  8. The dynamics of asteroidal dust and structure of the zodiacal cloud

    NASA Astrophysics Data System (ADS)

    Espy, Ashley Jeanne

    The zodiacal cloud, the debris disk of our solar system, has been studied for many years, yet we still do not know the origin of the background cloud particles. We know the cloud has asteroidal and cometary components, but in what proportions? The zodiacal dust bands, discovered by the Infrared Astronomical Satellite (IRAS; Low et al., 1984), are known to be asteroidal and thus hold the key to determining the asteroidal contribution of dust to the cloud. When an asteroid is disrupted, a wave of dust is injected into the zodiacal cloud. Through an investigation of the dynamical evolution of this dust from its source region to the resonant inner edge of the main belt, dynamical models and line-of-sight thermal emission profiles of the dust are created and compared directly with observations. The comparison of the models to the dust band observations constrains the parameters of the dust in the bands, including the cross-sectional area, and the particle-size, orbital-element, and heliocentric distributions of the dust. Using these constraints on the dust, we estimate the magnitude of the asteroidal component of the zodiacal cloud. Then, through a method of coadding the IRAS data, we reveal an additional, very young dust band. An analytical model of the dynamical evolution of the dust of this young still-forming band is created. The comparison of the thermal emission dust torus of the model dust distribution with that of the coadded observations of this young structure constrains the node and age, in addition to the inclination, and allows us, for the first time, to determine a unique source for a dust band. Because the dust in this band is so young, it has not yet been altered by collisions, thus modeling of this band allows us a first ever look at the original size-distribution and magnitude of dust produced in the catastrophic disruption of an asteroid. This knowledge of the dust produced immediately following a disruption then allows us to estimate the magnitude of

  9. Mesospheric sodium airglow emission: Modeling and first results over a mid-latitude

    NASA Astrophysics Data System (ADS)

    Bag, Tikemani; Krishna, M. V. Sunil; Singh, Vir

    2016-07-01

    Atmospheric sodium plays a very important role in the mesospheric chemistry and dynamics. We have developed a comprehensive model for mesospheric/thermospheric sodium airglow emission by incorporating all the known reaction mechanisms. The latest reaction rate coefficients and the related cross sections are obtained from the theoretical studies and experimental observations. The continuity equations are explicitly solved for the major species. Similarly, the steady-state approximation has been used for the intermediate and short lived minor species. The number densities from in-situ observations, NRLMSISE-00, and IRI-2012 have been successfully implemented to calculate the vertical volume emission rate. The modeled results compared to a good agreement with the measured profiles of Na airglow emission. The mesospheric sodium density shows a large day-to-day variability. The observed variations in the mesospheric sodium layer have been incorporated to obtain the variations in the sodium airglow intensities. The nocturnal variation of sodium airglow emissions are presented over a mid latitude location using this model.

  10. HF-induced airglow structure as a proxy for ionospheric irregularity detection

    NASA Astrophysics Data System (ADS)

    Kendall, E. A.

    2013-12-01

    The High Frequency Active Auroral Research Program (HAARP) heating facility allows scientists to test current theories of plasma physics to gain a better understanding of the underlying mechanisms at work in the lower ionosphere. One powerful technique for diagnosing radio frequency interactions in the ionosphere is to use ground-based optical instrumentation. High-frequency (HF), heater-induced artificial airglow observations can be used to diagnose electron energies and distributions in the heated region, illuminate natural and/or artificially induced ionospheric irregularities, determine ExB plasma drifts, and measure quenching rates by neutral species. Artificial airglow is caused by HF-accelerated electrons colliding with various atmospheric constituents, which in turn emit a photon. The most common emissions are 630.0 nm O(1D), 557.7 nm O(1S), and 427.8 nm N2+(1NG). Because more photons will be emitted in regions of higher electron energization, it may be possible to use airglow imaging to map artificial field-aligned irregularities at a particular altitude range in the ionosphere. Since fairly wide field-of-view imagers are typically deployed in airglow campaigns, it is not well-known what meter-scale features exist in the artificial airglow emissions. Rocket data show that heater-induced electron density variations, or irregularities, consist of bundles of ~10-m-wide magnetic field-aligned filaments with a mean depletion depth of 6% [Kelley et al., 1995]. These bundles themselves constitute small-scale structures with widths of 1.5 to 6 km. Telescopic imaging provides high resolution spatial coverage of ionospheric irregularities and goes hand in hand with other observing techniques such as GPS scintillation, radar, and ionosonde. Since airglow observations can presumably image ionospheric irregularities (electron density variations), they can be used to determine the spatial scale variation, the fill factor, and the lifetime characteristics of

  11. Nature's Late-Night Light Shows

    NASA Astrophysics Data System (ADS)

    Peterson, Carolyn Collins

    2002-09-01

    In addition to stars and planets, there are other interesting lights to be seen in the night sky. The northern and southern lights, called the aurora borealis and aurora australis, are created by charged particles from the Sun reacting in Earth's magnetic field. Night-shining clouds or noctilucent clouds appear at evening twilight as a result of water vapor in the polar mesosphere. Zodiacal light can be seen stretching up from the horizon after sunset or before sunrise.

  12. HF-enhanced 4278-Å airglow: evidence of accelerated ionosphere electrons?

    NASA Astrophysics Data System (ADS)

    Fallen, C. T.; Watkins, B. J.

    2013-12-01

    We report calculations from a one-dimensional physics-based self-consistent ionosphere model (SCIM) demonstrating that HF-heating of F-region electrons can produce 4278-Å airglow enhancements comparable in magnitude to those reported during ionosphere HF modification experiments at the High-frequency Active Auroral Research Program (HAARP) observatory in Alaska. These artificial 'blue-line' emissions, also observed at the EISCAT ionosphere heating facility in Norway, have been attributed to arise solely from additional production of N2+ ions through impact ionization of N2 molecules by HF-accelerated electrons. Each N2+ ion produced by impact ionization or photoionization has a probability of being created in the N2+(1N) excited state, resulting in a blue-line emission from the allowed transition to its ground state. The ionization potential of N2 exceeds 18 eV, so enhanced impact ionization of N2 implies that significant electron acceleration processes occur in the HF-modified ionosphere. Further, because of the fast N2+ emission time, measurements of 4278-Å intensity during ionosphere HF modification experiments at HAARP have also been used to estimate artificial ionization rates. To the best of our knowledge, all observations of HF-enhanced blue-line emissions have been made during twilight conditions when resonant scattering of sunlight by N2+ ions is a significant source of 4278-Å airglow. Our model calculations show that F-region electron heating by powerful O-mode HF waves transmitted from HAARP is sufficient to increase N2+ ion densities above the shadow height through temperature-enhanced ambipolar diffusion and temperature-suppressed ion recombination. Resonant scattering from the modified sunlit region can cause a 10-20 R increase in 4278-Å airglow intensity, comparable in magnitude to artificial emissions measured during ionosphere HF-modification experiments. This thermally-induced artificial 4278-Å aurora occurs independently of any artificial

  13. A technique for the analysis of two-dimensional data Application to OI 5577 A airglow

    NASA Astrophysics Data System (ADS)

    Elphinstone, R.; Murphree, J. S.; Cogger, L. L.

    1986-03-01

    A method to determine whether a two-dimensional data set can be represented by two independent separable functions is demonstrated using both synthetic data and satellite observations of OI 5577 A airglow. For such cases when the functions are separable it is possible to identify the function in the presence of noise using an iterative procedure based on the properties of an equitable matrix. In the specific case of the airglow, the latitudinal and temporal variations are separable for the data set studied. The spatial structure shows a minimum near the equator, with maxima at 35 deg in the winter hemisphere and 25 deg in the summer hemisphere. The long-term temporal function shows maxima after the equinoxes, with minima near the solstice. A 12 month component has a maximum near day 300.

  14. Measurement of atomic oxygen and related airglows in the lower thermosphere

    NASA Technical Reports Server (NTRS)

    Thomas, R. J.; Young, R. A.

    1981-01-01

    Instruments on board a sounding rocket were used to make simultaneous observations of atomic oxygen density and airglow emissions between 80 and 120 km. Atomic oxygen was measured with a resonance lamp and was found to have a peak density of 6 x 10 to the 11th at 94 km. Similar structure is seen in the oxygen density profile on both uplegs and downlegs. The following airglow emissions were measured by using vertical-viewing photometers: Herzberg I bands near 300 nm; O(1S) green line at 557.7 nm; background at 566 nm; O2(1 Delta g) bands at 1.27 microns; and OH (X 2 pi) Meinel bands near 1.7 microns.

  15. Similarities Between RF- and Lightning-Induced Airglow in the Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Sentman, D. D.; Wescott, E. M.; Stenbaek-Nielsen, H. C.; Moudry, D. R.; Sao Sabbas, F. T.

    2002-12-01

    Recent experiments in Alaska using the HAARP and HIPAS high power RF transmitters have succeeded in artificially generating oxygen neutral and molecular nitrogen ion emissions, or artificial airglow, in the ionosphere. An apparently different type of transient airglow generated by lightning, in the form of sprites and elves in the mesosphere and lower ionosphere, has been extensively studied in recent years. Despite occurring in vastly different atmospheric regimes, these seemingly disparate forms of optical emissions, one derived from artificial modification of the ionosphere and the other from natural thunderstorm processes, share a common underlying microphysical description based on electron heating by RF and quasi-DC electric fields, respectively, accompanied by impact excitation of ambient neutrals and subsequent optical relaxation and quenching of excited species. The theoretical description of these processes has its roots in work described by Zel'dovich and Raizer on the microphysics of shock waves and high temperature gasses. This work was subsequently adapted by Gurevich, Papadopoulis and coworkers to describe high power microwave interactions with the stratosphere. Extended to include nonlinear plasma interactions, it is the basis for understanding the effects of intense RF waves on the ionosphere, including creation of airglow, from high power transmitters currently operating in Alaska, Sweden and Russia. Pasko and coworkers have successfully adapted these theories to conditions appropriate to lightning impulse interactions with the upper atmosphere to describe the basic breakdown and streamer processes associated with sprite production. Thus, sprites and RF-induced airglow theories share a common set of concepts at the microphysical level and a common theoretical language. This talk outlines areas of especially strong overlap, and describes some possible high power RF ionospheric interaction experiments that could be performed to help study

  16. Mars dayside temperature from airglow limb profiles : comparison with in situ measurements and models

    NASA Astrophysics Data System (ADS)

    Gérard, Jean-Claude; Bougher, Stephen; Montmessin, Franck; Bertaux, Jean-Loup; Stiepen, A.

    The thermal structure of the Mars upper atmosphere is the result of the thermal balance between heating by EUV solar radiation, infrared heating and cooling, conduction and dynamic influences such as gravity waves, planetary waves, and tides. It has been derived from observations performed from different spacecraft. These include in situ measurements of orbital drag whose strength depends on the local gas density. Atmospheric temperatures were determined from the altitude variation of the density measured in situ by the Viking landers and orbital drag measurements. Another method is based on remote sensing measurements of ultraviolet airglow limb profiles obtained over 40 years ago with spectrometers during the Mariner 6 and 7 flybys and from the Mariner 9 orbiter. Comparisons with model calculations indicate that they both reflect the CO_2 scale height from which atmospheric temperatures have been deduced. Upper atmospheric temperatures varying over the wide range 270-445 K, with a mean value of 325 K were deduced from the topside scale height of the airglow vertical profile. We present an analysis of limb profiles of the CO Cameron (a(3) Pi-X(1) Sigma(+) ) and CO_2(+) doublet (B(2) Sigma_u(+) - X(2) PiΠ_g) airglows observed with the SPICAM instrument on board Mars Express. We show that the temperature in the Mars thermosphere is very variable with a mean value of 270 K, but values ranging between 150 and 400 K have been observed. These values are compared to earlier determinations and model predictions. No clear dependence on solar zenith angle, latitude or season is apparent. Similarly, exospheric variations with F10.7 in the SPICAM airglow dataset are small over the solar minimum to moderate conditions sampled by Mars Express since 2005. We conclude that an unidentified process is the cause of the large observed temperature variability, which dominates the other sources of temperature variations.

  17. Investigating Titan Airglow's Sources, Using the Imaging Capability of the Cassini-UVIS Instrument

    NASA Astrophysics Data System (ADS)

    Royer, E. M.; Esposito, L. W.; Holsclaw, G.; Lavvas, P.; Larsen, K. W.; Stevens, M. H.; West, R. A.

    2015-12-01

    The Ultraviolet Imaging Spectrograph (UVIS) instrument includes two spectrographic channels that provide both images and spectra covering the wavelength ranges from 56 to 118 nm (EUV) and 110 to 190 nm (far-UV). While previous studies focused on analyzing spectra, very few have used the capability of UVIS to produce images. This approach allows for the investigation of a much wider set of observations (currently about 10,000 over 10 years of data). A big data analytics approach narrows the number of observations for more specific applications and detailed spectral analysis. Previous studies on a reduced set of UVIS observations have demonstrated that dayglow emissions are at least a factor of ten brighter than the nightglow and are predominantly excited by solar photoelectrons. On the other hand, energetic Saturnian magnetosphere-plasma interactions with Titan's ambient neutral species are a significant source of UV nightglow emissions. Magnetosphere particle interactions, particularly the particles H+ and O+, along with secondary electrons, produce a nightglow spectrum. Our preliminary results from the UVIS images show that the airglow is highly variable in intensity and nightglow emissions are sporadic. We investigate here the various sources of nightglow to relate the nightglow spatial distribution and occurrence to the orbital position. We also present a case study where UVIS observed an airglow brightening, with an enhanced intensity over a short period of time (15 minutes). Further investigation demonstrates that other particles instruments onboard Cassini detected an electron burst correlated with this airglow. Modeling of this event brings information on the aerosols distribution in the Titan's upper atmosphere, on the airglow characteristics and the possible energy sources.

  18. Forward modeling of tsunami-driven gravity waves observed in airglow emission

    NASA Astrophysics Data System (ADS)

    Coisson, P.; Makela, J. J.; Vadas, S.; Sladen, A.

    2013-12-01

    Tsunamis propagating through the ocean excite gravity waves in the overlying atmosphere that propagate vertically, reaching ionospheric heights. Due to the exponential decay of the atmosphere density, waves with amplitudes as low as 10 cm at ocean level are highly amplified in the upper atmosphere, where they can have an appreciable effect on both the neutral an plasma environment. In the last decade, tsunami-generated gravity waves have been detected in the upper atmosphere for all major tsunami using ground-based GPS networks, satellite altimeters and/or airglow imagers. Airglow oscillations following tsunami propagation have been observed from an observatory on the Haleakala volcano in Hawaii for two recent large events: the Mw 9.0, 11 March 2011, Tohoku-Oki, Japan, earthquake and the Mw 7.8, 28 October 2012, Haida Gwaii, Canada, earthquake. The signature of gravity waves traveling at tsunami speed in the same direction of its propagation has been observed in the images of an all-sky imaging system for the first tsunami and in the images of a narrow-field imaging system for the second one. In order to investigate the physics of the coupling between the ocean, the neutral and charged atmosphere and understand the exact origin of the atmospheric imprint recorded by airglow imagers, we present modeling results of gravity waves excited by a realistic tsunami propagation model coupled to the atmosphere and ionosphere, during these two events. The model has been developed to include the propagation of the gravity waves in the atmosphere, the coupling between neutral and charged particles in the ionosphere and the production of the airglow emission at 630.0 nm. The results of the model are compared to the 630.0 nm emission measured by the imaging systems.

  19. Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles: II. A Study of Three Radars with Different Sensitivity

    NASA Astrophysics Data System (ADS)

    Janches, D.; Swarnalingam, N.; Plane, J. M. C.; Nesvorný, D.; Feng, W.; Vokrouhlický, D.; Nicolls, M. J.

    2015-07-01

    The sensitivity of radar systems to detect different velocity populations of the incoming micrometeoroid flux is often the first argument considered to explain disagreements between models of the Near-Earth dust environment and observations. Recently, this was argued by Nesvorný et al. to support the main conclusions of a Zodiacal Dust Cloud (ZDC) model which predicts a flux of meteoric material into the Earth’s upper atmosphere mostly composed of small and very slow particles. In this paper, we expand on a new methodology developed by Janches et al. to test the ability of powerful radars to detect the meteoroid populations in question. In our previous work, we focused on Arecibo 430 MHz observations since it is the most sensitive radar that has been used for this type of observation to date. In this paper, we apply our methodology to two other systems, the 440 MHz Poker Flat Incoherent Scatter Radar and the 46.5 Middle and Upper Atmosphere radar. We show that even with the less sensitive radars, the current ZDC model over-predicts radar observations. We discuss our results in light of new measurements by the Planck satellite which suggest that the ZDC particle population may be characterized by smaller sizes than previously believed. We conclude that the solution to finding agreement between the ZDC model and sensitive high power and large aperture meteor observations must be a combination of a re-examination not only of our knowledge of radar detection biases, but also the physical assumptions of the ZDC model itself.

  20. Seasonal and interannual variability of gravity waves from airglow imaging at Adelaide and Alice Springs

    NASA Astrophysics Data System (ADS)

    Gelinas, L. J.; Hecht, J. H.; Reid, I. M.; Vincent, R. A.; Walterscheid, R. L.; Woithe, J. M.

    2009-12-01

    The mesosphere and lower thermosphere (MALT) is a region largely controlled by tides and gravity waves. In this paper, we explore the seasonal and interannual variability of the MALT and its relationship to gravity wave fluxes using long-term airglow measurements at two Australian sites. The data presented here are the result of more than seven years of airglow imager observations at Adelaide 34°55’S, 138°36’ E) and Alice Springs (23°42’ S, 133°53’ E). The imagers measure rotational temperature and intensity of two atmospheric emissions, OH Meinel (6, 2) and O2 atmospheric (0, 1). Here we present analysis of the seasonal and interannual variation of gravity waves at both Australian sites. Automated analysis is used to determine individual gravity wave wavelength and orientation in each airglow image. Gravity wave statistics are then compiled and correlated with tropospheric disturbances, as characterized by Australian rainfall statistics and low pressure systems. By these methods, both seasonal variations in gravity wave occurrence and directionality and storm-related wave events can be identified.

  1. Airglow-imaging observation of plasma bubble disappearance at geomagnetically conjugate points

    NASA Astrophysics Data System (ADS)

    Shiokawa, Kazuo; Otsuka, Yuichi; Lynn, Kenneth JW; Wilkinson, Philip; Tsugawa, Takuya

    2015-03-01

    We report the first observation of the disappearance of a plasma bubble over geomagnetically conjugate points. It was observed by airglow imagers at Darwin, Australia (magnetic latitude: -22°N) and Sata, Japan (21°N) on 8 August 2002. The plasma bubble was observed in 630-nm airglow images from 1530 (0030 LT) to 1800 UT (0300 LT) and disappeared equatorward at 1800 to 1900 UT (0300 to 0400 LT) in the field of view. The ionograms at Darwin and Yamagawa (20 km north of Sata) show strong spread-F signatures at approximately 16 to 21 UT. At Darwin, the F-layer virtual height suddenly increased from approximately 200 to approximately 260 km at the time of bubble disappearance. However, a similar F-layer height increase was not observed over the conjugate point at Yamagawa, indicating that this F-layer rise was caused not by an eastward electric field but by enhancement of the equatorward thermospheric wind over Darwin. We think that this enhancement of the equatorward neutral wind was caused by an equatorward-propagating large-scale traveling ionospheric disturbance, which was identified in the north-south keogram of 630-nm airglow images. We speculate that polarization electric field associated with this equatorward neutral wind drive plasma drift across the magnetic field line to cause the observed bubble disappearance.

  2. Internal Gravity Wave Induced by the Queen Charlotte Event (27 October 2012, Mw 7.8): Airglow Observation and Modeling.

    NASA Astrophysics Data System (ADS)

    Occhipinti, G.; Bablet, A.; Makela, J. J.

    2015-12-01

    The detection of the tsunami related internal gravity waves (IGWtsuna) by airglow camera has been recently validated by observation (Makela et al., 2011) and modeling (Occhipinti et al., 2011) in the case of the Tohoku event (11 March 2011, Mw 9.0). The airglow is measuring the photon emission at 630 nm, indirectly linked to the plasma density of O2+ (Link & Cogger, 1988) and it is commonly used to detect transient event in the ionosphere (Kelley et al., 2002, Makela et al., 2009, Miller et al., 2009). The modeling of the IGWtsuna clearly reproduced the pattern of the airglow measurement observed over Hawaii and the comparison between the observation and the modeling allows to recognize the wave form and allow to explain the IGWtsuna arriving before the tsunami wavefront at the sea level (Occhipinti et al., 2011). Approaching the Hawaiian archipelagos the tsunami propagation is slowed down (reduction of the sea depth), instead, the IGWtsuna, propagating in the atmosphere/ionosphere, conserves its speed. In this work, we present the modeling of the new airglow observation following the Queen Charlotte event (27 October 2012, Mw 7.8) that has been recently detected, proving that the technique can be generalized for smaller events. Additionally, the effect of the wind on the IGWtsuna, already evocated in the past, is included in the modeling to better reproduce the airglow observations. All ref. here @ www.ipgp.fr/~ninto

  3. Within-Sulfonylurea-Class Evaluation of Time to Intensification with Insulin (ZODIAC-43)

    PubMed Central

    Hartog, Laura C.; Kleefstra, Nanne; Groenier, Klaas H.; Landman, Gijs W. D.; Bilo, Henk J. G.

    2016-01-01

    Background Previous studies have shown that many within-class differences exist between sulfonylureas (SUs), however, whether differences exist regarding the time it takes between initiating an SU and the need to intensify treatment with insulin is unclear. The aim of this study was investigate the relationships between the three frequently used sulphonylureas, prescribed as dual therapy next to metformin, and the time needed to treatment intensification with either insulin or oral triple therapy in patients with type 2 diabetes mellitus. Methods Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) is a prospective observational cohort study set in primary care in the Netherlands. Annually collected data on diabetes medication and clinical variables within ZODIAC are used to evaluate the primary outcome, time to insulin and secondary outcome, time to either insulin or triple oral therapy. For statistical analysis a time-dependent cox proportional hazard model was used. Results 3507 patients were included in the analysis, with a mean age of 61 (SD 11.4) and a median HbA1c of 6.8% [IQR 6.4–7.4] (50.8 mmol/mol [IQR 46.4–57.4]).The hazard ratio (HR) for the primary endpoint was 1.10 (95% CI 0.78–1.54) for metformin/glimepiride and 0.93 (95% CI 0.67–1.30) for metformin/tolbutamide with metformin/gliclazide as reference group. The HR for the secondary outcome was 1.04 (95% CI 0.78–1.40) and 0.85 (95% CI 0.64–1.13), respectively. Conclusion In this large Dutch primary care cohort, new users of neither gliclazide, glimepiride nor tolbutamide as dual therapy with metformin, resulted in differences in the time needed for further treatment intensification. PMID:27327605

  4. Coordinated observations of a nighttime medium-scale traveling ionospheric disturbance in 630-nm airglow and HF radar echoes

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Hosokawa, K.; Shibata, T. F.; Shiokawa, K.; Otsuka, Y.; Nishitani, N.; Ogawa, T.; Koustov, A. V.; Shevtsov, B. M.

    2008-12-01

    A nighttime medium-scale traveling ionospheric disturbance (MSTID) is studied with the SuperDARN Hokkaido HF radar and the OI 630-nm airglow imager located within the radar field of view at Paratunka, Russia (53N, 158E). On 8 December 2007, the MSTID propagating southwestward with a period of ~1 hour was first identified in optics by considering airglow intensity deviations from 1-hour running averages. Over the optical event, the radar was detecting ionospheric F-region echoes with poleward and equatorward Doppler velocities correlating, both spatially and temporally, with the airglow depletions and enhancements, respectively. The occurrence and velocity polarity of the observed echoes are consistent with the onset of the E x B plasma drifts caused by the MSTID-related electric field. These facts indicate that the MSTIDs are accompanied by oscillating polarization electric field structure in the F-region ionosphere.

  5. A study of oxygen 6300 Å airglow production through chemical modification of the nighttime ionosphere

    NASA Astrophysics Data System (ADS)

    Semeter, Joshua; Mendillo, Michael; Baumgardner, Jeffrey; Holt, John; Hunton, Donald E.; Eccles, Vincent

    1996-09-01

    The Release Experiments to Derive Airglow Inducing Reactions (RED AIR) conducted on April 3, 1989, and December 6, 1991, offer a unique set of observations for studying the specific processes associated with the production of the O(3P--1D) emission at 6300 Å. In these experiments, sounding rockets were used to place equal quantities of CO2 above and below hmax of the nocturnal F region. CO2 leads to 6300 Å emission by a three-step process: (1) CO2+O+->O2++CO, (2) O2++e-->O*+O, (3)O*->O+hν6300. Direct measurements of plasma parameters and indirect measurements of the neutral atmosphere densities were used in conjunction with the Fluid Element Simulation (FES) computer code to model the temporal and spatial evolution of the observed 6300 Å airglow enhancement and accompanying plasma depletion. Using the currently accepted set of reaction rates relevant to F region chemistry, the quantum yield of O(1D) from reaction (2) was found to have a mild altitude dependence, decreasing by 16% from 275 to 350 km. Since the initial vibrational distribution of the nascent O2+ was the same for the two releases, this result implies an altitude dependence in the quenching of O2+ vibrational states. Building on previous evidence that O2+ is vibrationally excited in the nighttime thermosphere, we further conclude that this vibrational distribution is altitude dependent. In terms of 6300 Å airglow production, the effect is manifested in an altitude dependence of f(1D). Additionally, quenching by O(3P) was found to contribute very little to the depopulation of the nascent O(1D), with Q0=0 giving the best fit to the RED AIR observations.

  6. Comparison of theories for gravity wave induced fluctuations in airglow emissions

    NASA Technical Reports Server (NTRS)

    Walterscheid, R. L.; Schubert, G.; Hickey, M. P.

    1994-01-01

    A comparison is undertaken of theories for the gravity wave induced fluctuations in the intensity of airglow emissions and the associated temperature of the source region. The comparison is made in terms of Krassovsky's ratio eta(sub E) for a vertically extended emission region (eta(sub E) is the ratio of the vertically integrated normalized intensity perturbation to the vertically integrated intensity-weighted temperature perturbation). It is shown that the formulas for eta(sub E) in the works by Tarasick and Hines (1990) and Schubert et al. (1991) are in agreement for the case of an inviscid atmosphere. The calculation of eta(sub E) using the theory of Tarasick and Hines (1990) requires determination of their function chi; we show that chi is simply related to the 'single-level' Krassovsky's ratio eta of Schubert et al. (1991). The general relationship between chi and eta is applied to a simple chemical-dynamical model of the O2 atmospheric airglow and the altitude dependence of these quantities is evaluated for nonsteady state chemistry. Though the Tarasick and Hines (1990) formula for eta(sub E) does not explicitly depend on the scale heights of the minor constituents involved in airglow chemistry, eta(sub E) implicitly depends upon these scale heights through its dependences on chemical production and loss contained in chi. We demonstrate this dependence of eta(sub E) for the OH nightglow on atomic oxygen scale height by direct numerical evaluation of eta(sub E) in this case the dependence originates in the chemical production of perturbed ozone.

  7. The Venus nitric oxide night airglow: Model calculations based on the Venus thermospheric general circulation model

    SciTech Connect

    Bougher, S.W. ); Gerard, J.C. ); Stewart, A.I.F.; Fesen, C.G. )

    1990-05-01

    Pioneer Venus (PV) orbiter ultraviolet spectrometer (OUVS) images of the nightside airglow in the (0, 1) {delta} band of nitric oxide showed a maximum whose average location was at 0200 local solar time just south of the equator. The average airglow brightness calculated over a portion of the nightside for 35 early orbits during the Pioneer Venus mission was a factor of 4 lower than this maximum. Recent recalibration of the PV OUVS instrument and reanalysis of the data yield new values for this statistical maximum (1.9 {plus minus} 0.6 kR) and the nightside average (400-460 {plus minus} 120 R) nightglow. This emission is produced by radiative recombination of N and O atoms transported from their source on the dayside to the nightside by the Venus thermospheric circulation. The Venus Thermospheric General Circulation Model (VTGCM) has been extended to incorporate odd nitrogen chemistry in order to examine the dynamical and chemical processes required to give rise to this emission. Its predictions of dayside N atom densities are also compared with empirical models based on Pioneer Venus measurements. Calculations are presented corresponding to OUVS data taken during solar maximum. The average production of nitrogen atoms on the dayside is about 9.0 {times} 10{sup 9} atoms cm{sup {minus}2} s{sup {minus}1}. Approximately 30% of this dayside source is required for transport to the nightside to yield the observed dark-disk nightglow features. The statistical location and intensity of the bright spot are well reproduced, as well as the altitude of the airglow layer. The importance of the large-scale transport and eddy diffusion on the global N({sup 4}S) distribution is also evaluated.

  8. An atlas of low latitude 6300A (01) night airglow from OGO-4 observations

    NASA Technical Reports Server (NTRS)

    Reed, E. I.; Fowler, W. B.; Blamont, J. E.

    1972-01-01

    The atomic oxygen emission line at 6300 A, measured in the nadir direction by a photometer on the polar orbiting satellite OGO-4, was plotted between 40 deg N and 40 deg S latitude on a series of maps for the moon-free periods between 30 August 1967 and 10 January 1968 The longitudinal and local time variations which occur during the northern fall-winter season are indicated. The northern tropical arc is more widespread while the southern arc is not present at all longitudes. The conditions under which the observations were made are described, and four airglow maps were selected to show the local time variations.

  9. An observation of polar auroral and airglow from the ISIS-II spacecraft.

    NASA Technical Reports Server (NTRS)

    Shepherd, G. G.; Anger, C. D.; Brace, L. H.; Maier, E. J.; Burrows, J. R.; Heikkila, W. J.; Hoffman, J.; Whitteker, J. H.

    1973-01-01

    This is a preliminary but comprehensive report on coordinated data obtained with the ISIS-II spacecraft, fourth in the ISIS series, launched 1 April 1971, into a near circular 1400 km orbit. The capabilities of the ISIS-I spacecraft have been extended in a number of ways, including the global mapping of the 3914, 5577 and 6300 A emissions. Data obtained during a 30-min pass over the south pole depict the nightside oval and polar cap, as well as mid-latitude airglow effects; these data are described and discussed.

  10. Monitoring Saturn's Upper Atmosphere Density Variations Using Helium 584 Å Airglow

    NASA Astrophysics Data System (ADS)

    Parkinson, Chris

    2016-10-01

    The study of He 584 Å brightness of Saturn is interesting as the EUV planetary airglow have the potential to yield useful information about mixing and other important parameters in its thermosphere. Resonance scattering of sunlight by He atoms is the principal source of the planetary emission of He 585 Å. The helium is embedded in an absorbing atmosphere of H2 and since it is heavier than the background atmosphere, it's concentration falls off rapidly above the homopause. The scattering region (i.e. where the absorption optical depth in H2 is < ~1) generally lies well above the homopause. As the eddy diffusion coefficient, Kzz, increases in the middle atmosphere, relatively more helium is mixed into the scattering region and thus the reflected intensity increases. The principal parameter involved in determining the He 584 Å albedo are the He volume mixing ratio, f, well below the homopause, and Kzz, (which will generally be a function of altitude), the solar He 584 Å flux and line shape, and the atmospheric temperature profile. The main science objective discussed is the estimation of the helium mixing ratio in the lower atmosphere. Specifically, He emissions come from above the homopause where τ =1 in H2 and therefore the interpretation depends mainly on two parameters: He mixing ratio of the lower atmosphere and Kzz. The occultations of Koskinen et al (2015) give Kzz with an accuracy that has never been possible before and the combination of occultations and airglow therefore provide estimates of the mixing ratio in the lower atmosphere. We have made these estimates at several locations that can be reasonably studied with both occultations and airglow and then average the results. Our results point to a greatly improved estimate of the mixing ratio of He in the upper atmosphere and below. The second topic addressed is regarding constraining the dynamics in the atmosphere by using the estimate of the He mixing ratio from the main objective. Once we have an

  11. Measurements of the Michigan Airglow Observatory from 1971 to 1973 at Ester Dome Alaska

    NASA Technical Reports Server (NTRS)

    Mcwatters, K. D.; Meriwether, J. W.; Hays, P. B.; Nagy, A. F.

    1973-01-01

    The Michigan Airglow Observatory (MAO) was located at Ester Dome Observatory, College, Alaska (latitude: 64 deg 53'N, longitude: 148 deg 03'W) since October, 1971. The MAO houses a 6-inch Fabry-Perot interferometer, a 2-channel monitoring photometer and a 4-channel tilting filter photometer. The Fabry-Perot interferometer was used extensively during the winter observing seasons of 1971-72 and 1972-73 to measure temperature and mass motions of the neutral atmosphere above approximately 90 kilometers altitude. Neutral wind data from the 1971-72 observing season as measured by observing the Doppler shift of the gamma 6300 A atomic oxygen emission line are presented.

  12. The EUV Airglow of Titan: Production and Loss of N2 c'4(0) - X

    NASA Technical Reports Server (NTRS)

    Stevens, Michael H.

    2001-01-01

    The N(2) Carroll-Yoshino (CY) c'(4) X (0,0) and (0,1) Rydberg bands between 95 and 99 nm were reported to be the most prominent EUV emission features in Voyager 1 ultraviolet spectrometer (UVS) airglow spectra from Titan's atmosphere. Although c'(4) is strongly excited by photoelectron impact, the (0,0) band is optically thick near peak production, so a multiple-scattering model is employed to calculate (0,v) nadir-viewing intensities. The model accounts for all known loss processes and quantifies the redistribution of photons to (0,v is greater than 0). Results show 7.6 R of (0,1) intensity, in agreement with reported observations (5-10 R), and 0.2 R of (0,0), in spectacular disagreement with reported observations (6-10 R). Nadir-viewing intensities of all other expected NI multiplets and N2 bands in the brightest portion of the EUV airglow spectrum (92.0-101.5 nm) are also calculated using photodissociative ionization of N(2) and photoelectron impact on N(2). It is found that NI multiplets and N(2) bands near (0,0) and unresolved by the UVS combine to produce 8.3 R, consistent with that reported for (0,0) and indicating that it was misidentified in previous analyses. The Ultraviolet Imaging Spectrograph (UVIS) on Cassini should unambiguously distinguish any (0,0) intensity from the brightest features nearby.

  13. Lighting.

    SciTech Connect

    United States. Bonneville Power Administration.

    1992-09-01

    Since lighting accounts for about one-third of the energy used in commercial buildings, there is opportunity to conserve. There are two ways to reduce lighting energy use: modify lighting systems so that they used less electricity and/or reduce the number of hours the lights are used. This booklet presents a number of ways to do both. Topics covered include: reassessing lighting levels, reducing lighting levels, increasing bulb & fixture efficiency, using controls to regulate lighting, and taking advantage of daylight.

  14. Distribution of atomic oxygen in the upper atmosphere deduced from Ogo 6 airglow observations.

    NASA Technical Reports Server (NTRS)

    Donahue, T. M.; Guenther, B.; Thomas, R. J.

    1973-01-01

    The atomic oxygen distribution as a function of altitude between 80 and 120 km and as a function of latitude has been deduced from Ogo 6 557.7-nm airglow photometer data obtained between August 1969 and April 1970. The results indicate that the density ranges from 15 to 50 billion per cu cm at 120 km; that there is a semiannual variation by a factor of 3 in the global average density near 100 km in phase with the satellite drag semiannual effect; and that large latitudinal variations occur with maximums between 40 and 60 deg in the winter hemisphere and sometimes deep minimums in the tropics. The implication of these results for meridional and vertical transport patterns is discussed.

  15. Seasonal dependence of MSTIDs obtained from 630.0 nm airglow imaging at Arecibo

    NASA Astrophysics Data System (ADS)

    Martinis, C.; Baumgardner, J.; Wroten, J.; Mendillo, M.

    2010-06-01

    All-sky imaging data of 630.0 nm airglow emissions are used to study the seasonal and solar activity dependence of medium-scale traveling ionospheric disturbances (MSTIDs) over Arecibo, Puerto Rico (18.3° N, 66.7° W, 28° N mag lat). MSTIDs are typical F-region signatures at midlatitudes, yet limited statistical results in the American sector hindered the progress in our understanding of these dynamical structures. This study compiles data from 2002 to 2007 and shows for the first time that optically-determined MSTIDs at Arecibo present a semiannual pattern with peak occurrence at both solstices. In the Japanese longitude sector, a similar pattern has been found, but one with a main peak during local summer. This paper explains the high occurrence rate during local winter at Arecibo via E-layer/F-layer coupling and inter-hemispheric coupling, thus accounting for a consistent morphology between the two longitude sectors.

  16. A procedure for the extraction of airglow features in the presence of strong background radiation

    NASA Astrophysics Data System (ADS)

    Swift, W. R.; Torr, D. G.; Hamilton, C.; Dougani, H.; Torr, M. R.

    1990-09-01

    A technique is developed that can be used to derive the total intensity of band emissions from twilight airglow measurements when the basic spectral signature of the band to be considered is known. The method is designed to automatically extract total band or line intensities of a signal imbedded in background radiation several orders of magnitude greater in brightness. It is shown that the technique developed can reliably measure the intensity of both weak and strong band and line emissions in the presence of strong twilight background radiation. The method of extraction is shown as part of a general purpose spectral analysis program written in VAX FORTRAN. This extraction procedure has been used successfully on emissions of Fel, Ca(+), N2(+) (1N) (0-0) and (0-1), OH in the near UV. OI red (630nm) and green (558nm) lines in the visible, and the OH Meinel bands and O(+) (2P) 732 nm in the near IR.

  17. Statistical analysis of infrasound signatures in airglow observations: Indications for acoustic resonance

    NASA Astrophysics Data System (ADS)

    Pilger, Christoph; Schmidt, Carsten; Bittner, Michael

    2013-02-01

    The detection of infrasonic signals in temperature time series of the mesopause altitude region (at about 80-100 km) is performed at the German Remote Sensing Data Center of the German Aerospace Center (DLR-DFD) using GRIPS instrumentation (GRound-based Infrared P-branch Spectrometers). Mesopause temperature values with a temporal resolution of up to 10 s are derived from the observation of nocturnal airglow emissions and permit the identification of signals within the long-period infrasound range.Spectral intensities of wave signatures with periods between 2.5 and 10 min are estimated applying the wavelet analysis technique to one minute mean temperature values. Selected events as well as the statistical distribution of 40 months of observation are presented and discussed with respect to resonant modes of the atmosphere. The mechanism of acoustic resonance generated by strong infrasonic sources is a potential explanation of distinct features with periods between 3 and 5 min observed in the dataset.

  18. Magnetic zenith enhancement of HF radio-induced airglow production at HAARP

    NASA Astrophysics Data System (ADS)

    Pedersen, T. R.; McCarrick, M.; Gerken, E.; Selcher, C.; Sentman, D.; Carlson, H. C.; Gurevich, A.

    2003-02-01

    Airglow production at various beam positions relative to the magnetic field was investigated as part of an optics campaign at HAARP in February 2002. Strong emissions up to several hundred Rayleigh at 630.0 nm and more than 50 R at 557.7 nm were produced in a small spot approximately 6° in diameter located near the magnetic zenith when the transmitter beam was directed up the magnetic field. This effect was observed hundreds of times over a wide range of frequencies and ionospheric conditions. The spot at HAARP appears on average just equatorward of the nominal magnetic field direction, deflects somewhat toward the beam center when the beam is scanned, and varies slightly in size with transmitter frequency. Red-to-green ratios as low as 3 were observed, with both wavelengths showing significant onset delay. Identifiable enhancements in red-line emission were produced down to 2 MW ERP in a power ramp experiment.

  19. Imaging and modeling the ionospheric airglow response over Hawaii to the tsunami generated by the Tohoku earthquake of 11 March 2011

    NASA Astrophysics Data System (ADS)

    Makela, J. J.; Lognonné, P.; Hébert, H.; Gehrels, T.; Rolland, L.; Allgeyer, S.; Kherani, A.; Occhipinti, G.; Astafyeva, E.; Coïsson, P.; Loevenbruck, A.; Clévédé, E.; Kelley, M. C.; Lamouroux, J.

    2011-07-01

    Although only centimeters in amplitude over the open ocean, tsunamis can generate appreciable wave amplitudes in the upper atmosphere, including the naturally occurring chemiluminescent airglow layers, due to the exponential decrease in density with altitude. Here, we present the first observation of the airglow tsunami signature, resulting from the 11 March 2011 Tohoku earthquake off the eastern coast of Japan. These images are taken using a wide-angle camera system located at the top of the Haleakala Volcano on Maui, Hawaii. They are correlated with GPS measurements of the total electron content from Hawaii GPS stations and the Jason-1 satellite. We find waves propagating in the airglow layer from the direction of the earthquake epicenter with a velocity that matches that of the ocean tsunami. The first ionospheric signature precedes the modeled ocean tsunami generated by the main shock by approximately one hour. These results demonstrate the utility of monitoring the Earth's airglow layers for tsunami detection and early warning.

  20. Post sunset behavior of the 6300 A atomic oxygen airglow emission

    NASA Technical Reports Server (NTRS)

    Smith, R. E.

    1976-01-01

    A theoretical model of the 6300 A OI airglow emission was developed based on the assumptions that both the charged and neutral portions of the Earth's upper atmosphere are in steady state conditions of diffusive equilibrium. Intensities of 6300 A OI emission line were calculated using electron density true height profiles from a standard C-4 ionosonde and exospheric temperatures derived from Fabry-Perot interferometer measurements of the Doppler broadened 6300 A emission line shape as inputs to the model. Reaction rate coefficient values, production mechanism efficiencies, solar radiation fluxes, absorption cross sections, and models of the neutral atmosphere were varied parametrically to establish a set of acceptable inputs which will consistently predict 6300 A emission intensities that closely agree with intensities observed during the post-sunset twilight period by an airglow observatory consisting of a Fabry-Perot interferometer and a turret photometer. Emission intensities that can only result from the dissociative recombination of molecular oxygen ions were observed during the latter portion of the observational period. Theoretical calculations indicate that contamination of the 6300 A OI emission should be on the order of or less than 3 percent; however, these results are very sensitive to the wavelengths of the individual lines and their intensities relative to the 6300 A OI intensity. This combination of a model atmosphere, production mechanism efficiencies, and quenching coefficient values was used when the dissociative photoexcitation and direct impact excitation processes were contributing to the intensity to establish best estimates of solar radiation fluxes in the Schumann--Runge continuum and associated absorption cross sections. Results show that the Jacchia 1971 model of the upper atmosphere combined with the Ackerman recommended solar radiation fluxes and associated absorption cross sections produces theoretically calculated intensities that more

  1. Observations of airglow during injections of exhaust streams of ``Progress'' orbital maneuvering subsystem

    NASA Astrophysics Data System (ADS)

    Beletsky, Alexandr; Mikhalev, Alexander; Khakhinov, Vitaly; Lebedev, Valentin

    Observations of airglow during injections of exhaust streams of “Progress” orbital maneuvering subsystem A. Mikhalev, V. Khakhinov, A. Beletsky, V. Lebedev Institute of Solar-Terrestrial Physics of Siberian Branch of Russian Academy of Sciences (ISTP SB RAS) 664033, Lermontov str. 126a, p/o Box 291, Irkutsk, Russia ABSTRACT The effect of increasing the intensity of airglow emissions associated with spacecraft engines exhaust to the atmosphere is well-known. We carried out the "Radar-Progress" active space experiment for studying the ionosphere on April 17 2013. The exhaust products of orbital maneuvering subsystem engines of transport spacecraft “Progress” were used as a source of ionosphere disturbances. The engines run from 13:24:37 to 13:24:46 UT. The "Progress" orbit altitude was 412 km. We carried out observations of nightglow in the several spectral lines. The all-sky camera was used for obtaining spatial distribution of the 630 nm emission intensity. An increase in the emission intensity in the area of "Progress" track was observed after starting the engines. According to preliminary estimates, the rate of the glow expansion at the orbit altitude during first 60 seconds after the start was ~ 7 km/c along the orbit and ~ 3.5 km/s across the orbit. The observed glow area reached the largest size of ~ 350 km along the orbit and ~ 250 km across the orbit 120-150 s after start. The study has been supported by the grant 13-05-00456-a and 13-02-00957-a of the Russian Foundation for Basic Research and RF President Grant of Public Support for RF Leading Scientific Schools (NSh-2942.2014.5).

  2. Limb Viewing Hyper Spectral Imager (LiVHySI) for airglow measurements onboard YOUTHSAT-1

    NASA Astrophysics Data System (ADS)

    Bisht, R. S.; Hait, A. K.; Babu, P. N.; Sarkar, S. S.; Benerji, A.; Biswas, A.; Saji, A. K.; Samudraiah, D. R. M.; Kirankumar, A. S.; Pant, T. K.; Parimalarangan, T.

    2014-08-01

    The Limb Viewing Hyper Spectral Imager (LiVHySI) is one of the Indian payloads onboard YOUTHSAT (inclination 98.73°, apogee 817 km) launched in April, 2011. The Hyper-spectral imager has been operated in Earth’s limb viewing mode to measure airglow emissions in the spectral range 550-900 nm, from terrestrial upper atmosphere (i.e. 80 km altitude and above) with a line-of-sight range of about 3200 km. The altitude coverage is about 500 km with command selectable lowest altitude. This imaging spectrometer employs a Linearly Variable Filter (LVF) to generate the spectrum and an Active Pixel Sensor (APS) area array of 256 × 512 pixels, placed in close proximity of the LVF as detector. The spectral sampling is done at 1.06 nm interval. The optics used is an eight element f/2 telecentric lens system with 80 mm effective focal length. The detector is aligned with respect to the LVF such that its 512 pixel dimension covers the spectral range. The radiometric sensitivity of the imager is about 20 Rayleigh at noise floor through the signal integration for 10 s at wavelength 630 nm. The imager is being operated during the eclipsed portion of satellite orbits. The integration in the time/spatial domain could be chosen depending upon the season, solar and geomagnetic activity and/or specific target area. This paper primarily aims at describing LiVHySI, its in-orbit operations, quality, potential of the data and its first observations. The images reveal the thermospheric airglow at 630 nm to be the most prominent. These first LiVHySI observations carried out on the night of 21st April, 2011 are presented here, while the variability exhibited by the thermospheric nightglow at O(1D) 630 nm has been described in detail.

  3. The Zodiacal Cloud Model applied to the Martian atmosphere. Diurnal variations in Meteoric ion layers

    NASA Astrophysics Data System (ADS)

    Diego Carrillo-Sánchez, Juan; Plane, John M. C.; Withers, Paul; Fallows, Kathryn; Nesvorný, David; Pokorný, Petr; Feng, Wuhu

    2016-04-01

    Sporadic metal layers have been detected in the Martian atmosphere by radio occultation measurements using the Mars Express Orbiter and Mars Global Surveyor spacecraft. More recently, metallic ion layers produced by the meteor storm event following the close encounter between Comet Siding Spring (C/2013 A1) and Mars were identified by the Imaging UltraViolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. However, the background metal layers produced by the influx of sporadic meteors have not yet been detected at Mars (contrary to the permanent metal layers identified in the Earth's atmosphere). The Zodiacal Dust Cloud (ZDC) model for particle populations released by asteroids (AST), and dust grains from Jupiter Family Comets (JFC) and Halley-Type Comets (HTC) has been combined with a Monte Carlo sampling method and the Chemical ABlation MODel (CABMOD) to predict the ablation rates of Na, K, Fe, Si, Mg, Ca and Al above 40 km altitude in the Martian atmosphere. CABMOD considers the standard treatment of meteor physics, including the balance of frictional heating by radiative losses and the absorption of heat energy through temperature increases, melting phase transitions and vaporization, as well as sputtering by inelastic collisions with the air molecules. These vertical profiles are input into the Leeds 1-D Mars atmospheric model which includes photo-ionization, and gas-phase ion-molecule and neutral chemistry, in order to explore the evolution of the resulting metallic ions and atoms. We conclude that the formation of the sporadic ion layers observed below 100 km with a plasma density exceeding 104 cm-3 requires the combination of the three different influx sources considered by the ZDC model, with a significant asteroidal contribution. Finally, we explore the changes of the neutral and ionized Mg and Fe layers over a diurnal cycle.

  4. A prospective observational study of quality of diabetes care in a shared care setting: trends and age differences (ZODIAC-19)

    PubMed Central

    van Hateren, Kornelis J J; Drion, Iefke; Kleefstra, Nanne; Groenier, Klaas H; Houweling, Sebastiaan T; van der Meer, Klaas; Bilo, Henk J G

    2012-01-01

    Objective The Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) study was initiated in 1998 to investigate the effects of shared care for patients with type 2 diabetes mellitus (T2DM) in the Netherlands, and to reduce the number of diabetes-related complications. Benchmarking the performance of diabetes care was and is an important aspect of this study. We aimed to investigate trends in diabetes care, within the ZODIAC study for a wide variety of quality indicators during a long follow-up period (1998–2008), with special interest for different age groups. Design Prospective observational cohort study. Setting Primary care, Zwolle, The Netherlands. Participants Patients with T2DM. Methods A dataset of quality measures was collected annually during the patient's visit to the practice nurse or general practitioner. Linear time trends from 1998 to 2008 were estimated using linear mixed models in which we adjusted for age and gender. Age was included in the model as a categorical variable: for each follow-up year all participants were categorised into the categories <60, 60–75 and >75 years. Differences in trends between the age categories were investigated by adding an interaction term to the model. Results The number of patients who were reported to participate increased in the period 1998–2008 from 1622 to 27 438. All quality indicators improved in this study, except for body mass index. The prevalence albuminuria decreased in an 11-year-period from 42% to 21%. No relevant differences between the trends for the three age categories were observed. During all years of follow-up, mean blood pressure and body mass index were the lowest and highest, respectively, in the group of patients <60 years (data not shown). Conclusions Quality of diabetes care within the Dutch ZODIAC study, a shared care project, has considerably improved in the period 1998–2008. There were no relevant differences between trends across various age categories

  5. The US Naval Observatory Zodiacal Zone Catalog (Douglas and Harrington 1990): Documentation for the machine-readable version

    NASA Technical Reports Server (NTRS)

    Warren, Wayne H., Jr.

    1990-01-01

    The machine readable version of the catalog, as it is currently being distributed from the Astronomical Data Center, is described. The Zodiacal Zone Catalog is a catalog of positions and proper motions for stars in the magnitude range where m sub v is between 4 and 10, lying within 16 deg of the ecliptic and north of declination -30 deg. The catalog contains positions and proper motions, at epoch, for equator and equinox J2000.0, magnitudes and spectral types taken mostly from the Smithsonian Astrophysical Observatory Star Catalog, and reference positions and proper motions for equinox and epoch B1950.0.

  6. Mesoscale field-aligned irregularity structures (FAIs) of airglow associated with medium-scale traveling ionospheric disturbances (MSTIDs)

    NASA Astrophysics Data System (ADS)

    Sun, Longchang; Xu, Jiyao; Wang, Wenbin; Yue, Xinan; Yuan, Wei; Ning, Baiqi; Zhang, Donghe; Meneses, F. C.

    2015-11-01

    In this paper, we report the evolution (generation, amplification, and dissipation) of optically observed mesoscale field-aligned irregularity structures (FAIs) (~150 km) associated with a medium-scale traveling ionospheric disturbance (MSTID) event. There have not been observations of mesoscale FAIs of airglow before. The mesoscale FAIs were generated in an airglow-depleted front of southwestward propagating MSTIDs that were simultaneously observed by an all-sky imager, a GPS monitor, and a digisonde around Xinglong (40.4°N, 30.5° magnetic latitude), China, on 17/18 February 2012. A normalized cross-correlation method has been used to obtain the velocities of mesoscale FAIs and MSTIDs. The mesoscale FAIs had an obvious northwestward relative velocity to main-body MSTIDs (about 87.0 m/s on average). The direction of this relative velocity was roughly parallel to the depleted fronts. Furthermore, the evolution of the mesoscale FAIs was mostly controlled by the intensity of the depleted fronts. Occurred in a highly elevated ionosphere that had a total electron content depletion associated with large negative airglow perturbations (-25%), the mesoscale FAIs grew rapidly when they experienced southeastward wind, which had a speed of about 100 m/s and were measured by a Fabry-Perot interferometer. A northeastward polarization electric field within a depleted airglow front can play a controlling role in the development of the mesoscale FAIs. The electric field can significantly elevate the ionosphere and move the mesoscale FAIs northwestward by the E × B drift. The processes for the generation and development of the polarization electric field and the mesoscale FAIs, however, need further study.

  7. Technique to retrieve solar EUV flux and neutral thermospheric O, O2, N2, and temperature from airglow measurements

    NASA Technical Reports Server (NTRS)

    Fennelly, J. A.; Germany, G. A.; Torr, D. G.; Richards, P. G.; Torr, M. R.

    1994-01-01

    We describe a method for retrieving neutral thermospheric composition and solar EUV flux from optical measurements of the O(+)(P-2) 732 nm and O(D-1) 630 nm airglow emissions. The parameters retrieved are the neutral temperature, the O, L2, and N2 density profiles, and a scaling factor for the solar EUV flux spectrum. The temperature, solar EUV flux scaling factor, and atomic oxygen density are first retrieved from the 732 nm emission, which are then used with the 630 nm emission to retrieve the O2 and N2 densities. Between the altitudes of 200 and 400 km the retrieval technique is able to statistically retrieve values to within 3.1% for thermospheric temperature, 3.3% for atomic oxygen, 2.3% for molecular oxygen, and 2.4% for molecular nitrogen. The solar EUV flux scaling factor has a retrieval error of 5.1%. We also present the results of retrievals using existing data taken from both groundbased and spacebased instruments. These include airglow data taken by the Visible Airglow Experiment on the Atmospheric Explorer spacecraft and the Imaging Spectrometric Observatory flown on the ATLAS 1 shuttle mission in 1992.

  8. Helium 584 Å and H Lyman-α Airglow in Giant Planetary Atmospheres: Modeling, Observations, and Implications

    NASA Astrophysics Data System (ADS)

    Parkinson, Christopher; Esposito, Larry W.

    2016-07-01

    The atmosphere of the outer planets is mainly composed of H2 and neutral atomic helium. The study of He 584 Å and H Lyman-α brightnesses is interesting as the EUV and FUV (Extreme and Far Ultraviolet) planetary airglow have the potential to yield useful information about mixing and other important parameters in their thermospheres. Time variation, asymmetries, and polar enhancement of the airglow are also possible and analysis of the public archived NASA mission data sets (i.e. Voyager and Cassini) can help solve some of the outstanding problems associated with these phenomena. The comparison of observations with results from sophisticated photochemical and radiative transfer models can also help ameliorate unexplained differences in the dynamical processes operating within planetary upper atmospheres. Powerful analysis techniques allow us to extract information on atmospheric mixing, temperatures, and temporal changes due to the solar and seasonal cycles from the variations in distribution and intensity of airglow emissions that result. The presentation will discuss the implications of interpretations from comparison of modeling and observations in giant planetary atmospheres.

  9. Upper atmospheric processes as measured by collocated Lidar, infrasound, radiometer and airglow measurements

    NASA Astrophysics Data System (ADS)

    Le Pichon, A.; Blanc, E.; Assink, J. D.; Ceranna, L.; Pilger, C.; Ross, O.; Keckhut, P.; Hauchecorne, A.; Schmidt, C.; Bittner, M.; Wuest, S.; Rüfenacht, R.; Kaempfer, N.; Smets, P.

    2013-12-01

    To better initialize weather forecasting systems, a key challenge is to understand stratosphere-resolving climate models. The ARISE project (http://arise-project.eu/) aims to design a novel infrastructure integrating different atmospheric observation networks to accurately recover the vertical structure of the wind and temperature from the ground to the mesosphere. This network includes Lidar and mesospheric airglow observations, complemented by continuous infrasound measurements. Together with additional ground-based wind radar system, such complementary techniques help to better describe the interaction between atmospheric layers from the ground to the mesosphere and the influence of large scale waves on the atmospheric dynamics. Systematic comparisons between these observations and the ECMWF upper wind and temperature models (http://www.ecmwf.int/) have been performed at the OHP site (Haute-Provence Observatory, France). The main results are outlined below. - Systematic comparisons between Lidar soundings (NDACC, http://ndacc-lidar.org/) and ECMWF highlight differences increasing with altitude. Below 50 km altitude, differences are as large as 20°K. In average, the temperature appears to be overestimated by ~5 m/s in the stratosphere and underestimated by ~10 m/s in the mesopause. - Comparisons with collocated infrasound measurements provide additional useful integrated information about the structure of the stratospheric waveguide. Below 0.5 Hz, most infrasound signals originate from ocean swells in the North Atlantic region. As expected, since most long-range propagating signals travel in the stratospheric waveguide, improved detection capability occurs downwind. Deviations from this trend are either related to short time-scale variability of the atmosphere (e.g., large-scale planetary waves, stratospheric warming effects), or can be explained by changes in the nature of the source. We investigate possible correlation between unexpected propagation paths and

  10. A stereoscopic imaging method for measuring the altitude of the near infrared airglow layer

    NASA Astrophysics Data System (ADS)

    Faivre, M.; Moreels, G.; Pautet, D.; Clairemidi, J.; Colas, F.

    2003-04-01

    A program for determining the altitude of the barycenter of the near-infrared emissive layer at the mesopause level has been undertaken. The objective is to measure the two geometric parameters of the emissive layer: its altitude and thickness in order to correlate these values with the parameters of the dynamic processes that propagate at those altitudes. A first set of correlated observations was obtained in September 2000. Two cameras were set in simultaneous operation at Pic du Midi Observatory (Hautes-Pyrénées, altitude 2860 m) and at Pic de Château-Renard (Hautes-Alpes, altitude 2989 m). The azimuths of the lines of sight were opposite along the line that joined the two observation points. The star images were removed using a numerical filter. Then the perspective inversion method developed by Pautet (Applied Optics 41, 823-831, 2002) was used to provide images of the emissive layer as seen by a virtual camera located vertically above the observation sites. The intensity correlation coefficient is computed for matched pixel blocks. The results for the night of September 8-9, 2000 will be presented. In the region where the fields of view of the cameras superimpose, the altitude for the maximum of the airglow intensity is 87.3 km. This value is the mean value for the altitude determinations. The median value is the same: 87.3 km. The emissive layer profile is retrieved with a height resolution of 0.2 km. The layer is located between the extreme altitudes of 85.4 and 89.9 km. A 2D chart representing the altitude of the layer barycenter is compared with a 2D representation of the emission intensity. In conclusion, a precise method for retrieving the near-IR airglow layer altitude with a precision of 0.2 km has been developed and will be used for measuring the altitude of the layer barycenter at different points of the wave field.

  11. A stereoscopic correlation method for measuring the altitude of the near infrared airglow layer

    NASA Astrophysics Data System (ADS)

    Faivre, M.; Pautet, D.; Moreels, G.; Clairemidi, J.; Colas, F.

    A program for determining the altitude of the barycenter of the near-infrared emssive layer at the mesopause level has been undertaken. The objective is to measure the two geometric parameters of the emissive layer: its altitude and thickness in order to correlate these values with the parameters of the dynamic processes that propagate at those altitudes. A first set of correlated observations was obtained in september 2000. Two cameras were set in simultaneous operation at Pic du Midi Observatory (Hautes-Pyrénées, altitude 2860 m) and at Pic de Château-Renard (Hautes-Alpes, altitude 2989 m). The azimuths of the lines of sight were opposite along the line that joined the two observation points. The star images were removed using a numerical filter. Then the perspective inversion method developed by Pautet (Applied Optics 41, 823-831, 2002) was used to provide images of the emissive layer as seen by a virtual camera located vertically above the observation sites. The intensity correlation coefficient is computed for matched pixel blocks. The results for the night of September 8-9, 2000 will be presented. In the region where the fields of view of the cameras superimpose, the altitude for the maximum of the airglow intensity is 87.3 km. This value is the mean value for the altitude determinations. The median value is the same: 87.3 km. The emissive layer profile is retrieved with a height resolution of 0.2 km. The layer thickness at half-maximum is 1.8 km with an asymetry coefficient equal to 0.2. The layer is located between the extreme altitudes of 85.4 and 89.9 km. In conclusion, a precise method for retrieving the near-IR airglow layer altitude with a precision of 0.2 km has been developed and will be used for measuring the altitude of the layer barycenter at different points of the wave field.

  12. Optical imaging of airglow structure in equatorial plasma bubbles at radio scintillation scales

    NASA Astrophysics Data System (ADS)

    Holmes, J. M.; Pedersen, T.; Parris, R. T.; Stephens, B.; Caton, R. G.; Dao, E. V.; Kratochvil, S.; Morton, Y.; Xu, D.; Jiao, Y.; Taylor, S.; Carrano, C. S.

    2015-12-01

    Imagery of optical emissions from F-region plasma is one of the few means available todetermine plasma density structure in two dimensions. However, the smallest spatial scalesobservable with this technique are typically limited not by magnification of the lens or resolutionof the detector but rather by the optical throughput of the system, which drives the integrationtime, which in turn causes smearing of the features that are typically moving at speeds of 100m/s or more. In this paper we present high spatio-temporal imagery of equatorial plasma bubbles(EPBs) from an imaging system called the Large Aperture Ionospheric Structure Imager(LAISI), which was specifically designed to capture short-integration, high-resolution images ofF-region recombination airglow at λ557.7 nm. The imager features 8-inch diameter entranceoptics comprised of a unique F/0.87 lens, combined with a monolithic 8-inch diameterinterference filter and a 2x2-inch CCD detector. The LAISI field of view is approximately 30degrees. Filtered all-sky images at common airglow wavelengths are combined with magneticfield-aligned LAISI images, GNSS scintillation, and VHF scintillation data obtained atAscension Island (7.98S, 14.41W geographic). A custom-built, multi-constellation GNSS datacollection system was employed that sampled GPS L1, L2C, L5, GLONASS L1 and L2, BeidouB1, and Galileo E1 and E5a signals. Sophisticated processing software was able to maintainlock of all signals during strong scintillation, providing unprecedented spatial observability ofL band scintillation. The smallest-resolvable scale sizes above the noise floor in the EPBs, as viewed byLAISI, are illustrated for integration times of 1, 5 and 10 seconds, with concurrentzonal irregularity drift speeds from both spaced-receiver VHF measurements and single-stationGNSS measurements of S4 and σφ. These observable optical scale sizes are placed in thecontext of those that give rise to radio scintillation in VHF and L band signals.

  13. Global variability of the oxygen airglow as observed by WINDII and predicted with the TIME-GCM

    NASA Astrophysics Data System (ADS)

    Liu, Guiping

    This dissertation reports on the global temporal variations of the oxygen airglow emissions from the analysis of seven years of WINDII (Wind Imaging Interferometer) satellite data. To interpret the emission signatures, the observations are compared with the simulations of NCAR's TIME-GCM general circulation model that includes atmospheric photochemistry and dynamics. The nighttime O(1S), O2( b1S+g ), and OH airglow emissions originate from the recombination of atomic oxygen, which acts as a tracer of atmospheric motions. Variations of these emissions thus provide information on wave activity and on the large-scale circulation in the mesosphere and lower thermosphere (MLT). The study focuses on the seasonal climatology of the emission rate for various latitude regions. In the tropics, a dramatic semi-annual variation exists but only for limited local times. The onset of the variation is consistent with the propagating tidal wave. At mid-latitudes, both semi-annual and annual variations occur. They are subject to local time variations, which again manifest the tidal influence. At higher latitudes, an annual behaviour becomes dominant. It may also result from upward and downward motions associated with the large-scale general circulation. However, a mid-summer peak is superimposed, indicating other influences. Further, the long-term trend variation is examined. The emissions at all latitudes follow the variation of F10.7 flux and are in phase with the solar cycle. They also have a two-year period variation that may be caused by the quasi-biennial oscillation. All these emission variations could be ultimately explained in terms of vertical motion. Vertical motion is observed directly as a universal inverse relationship of the airglow emission rate and emission altitude. Finally, the anomalous WINDII airglow profiles with multiple peaks are investigated. Their occurrences coincide with steep emission rate gradients associated with the diurnal tide. Moreover, the

  14. Observation and modeling of mesospheric Na density and OH airglow perturbations by a gravity wave approaching a critical level

    NASA Astrophysics Data System (ADS)

    Snively, Jonathan; Pautet, Pierre-Dominique; Taylor, Michael; Swenson, Gary; Liu, Alan

    2010-05-01

    Atmospheric gravity waves at a broad range of temporal and spatial scales are frequently observed in MLT airglow imaging experiments. Airglow data provide significant insight into gravity wave propagation, directionality, and seasonality, and allow estimations of wave fluxes [e.g., Swenson et al., JGR, 104(D6), 1999]. The USU CEDAR Mesospheric Temperature Mapper (MTM) is a specialized CCD airglow imaging system, which was operated at Maui MALT from November 2001 to December 2006. The MTM captures OH(6,2) and O2(0,1) emissions intensities and associated rotational temperatures. The MTM is able to reveal two-dimensional structure of intensity and temperature perturbations associated with small-scale gravity waves, and has been used to assess zenith temperatures, showing close agreement with simultaneous lidar temperature data [Zhao et al., J. Geophys. Res., 110, D09S07, 2005]. Here we investigate the vertical and horizontal structure of a small-scale gravity wave (~18 minute period and ~37 km horizontal wavelength) captured by the Maui MTM on April 11, 2002. The event was strongly visible in the OH(6,2) image data, showing intensity perturbations ~ 5-10 %, however relatively weak in the O2 data. Lidar temperatures and winds suggest the presence of a critical level shortly above ~90 km, which would have contributed to increased dissipation, and reduced detectability, due to small vertical scale. With imaged intensity and rotational temperature data, along with evolving Na lidar profile data, we reconstruct and simulate the wave event under realistic ambient conditions using a suite of numerical models. Hydroxyl photochemistry and dynamics of O3, H, O, and Na densities are obtained with a two-dimensional nonlinear numerical model for gravity wave dynamics [Snively and Pasko, JGR, 113, A06303, 2008], allowing direct comparison of OH(6,2) intensity and brightness-weighted temperature perturbations [e.g., Makhlouf et al., JGR, 100(D6), 11289, 1995]. The strong sheared

  15. Solar measurements from the Airglow-Solar Spectrometer Instrument (ASSI) on the San Marco 5 satellite

    NASA Technical Reports Server (NTRS)

    Woods, Thomas N.

    1994-01-01

    The analysis of the solar spectral irradiance from the Airglow-Solar Spectrometer Instrument (ASSI) on the San Marco 5 satellite is the focus for this research grant. A pre-print copy of the paper describing the calibrations of and results from the San Marco ASSI is attached to this report. The calibration of the ASSI included (1) transfer of photometric calibration from a rocket experiment and the Solar Mesosphere Explorer (SME), (2) use of the on-board radioactive calibration sources, (3) validation of the ASSI sensitivity over its field of view, and (4) determining the degradation of the spectrometers. We have determined that the absolute values for the solar irradiance needs adjustment in the current proxy models of the solar UV irradiance, and the amount of solar variability from the proxy models are in reasonable agreement with the ASSI measurements. This research grant also has supported the development of a new solar EUV irradiance proxy model. We expected that the magnetic flux is responsible for most of the heating, via Alfen waves, in the chromosphere, transition region, and corona. From examining time series of solar irradiance data and magnetic fields at different levels, we did indeed find that the chromospheric emissions correlate best with the large magnetic field levels.

  16. A Climatology of Ripple Instabilities in the OH Airglow at Cerro Pachon, Chile

    NASA Astrophysics Data System (ADS)

    Gelinas, L. J.; Hecht, J. H.; Walterscheid, R. L.; Rudy, R. J.

    2015-12-01

    Airglow imaging provides a unique means by which to study many wave-related phenomena in the 80 to 100 km altitude regime. Observations reveal quasi-monochromatic disturbances associated with atmospheric gravity waves (AGWs) as well as small-scale instabilities often called ripples. Ripples are wavelike features that resemble AGWs in appearance, but have short horizontal wavelengths (<15 km) and short lifetimes (a few tens of minutes). The end product of the breakdown of ripples is turbulence, leading to increased eddy diffusion. Thus, ripple observations may help refine our understanding of the occurrence of turbulence in the upper Mesosphere and Lower Thermosphere. The Aerospace Corporation's Nightglow Imager (ANI) is located at the Andes Lidar Observatory near the crest of Cerro Pachon, Chile. ANI observes nighttime OH emission (near 1.6 microns) every 2 seconds over an approximate 73 degree field of view, which allows the study of AGW and ripple features over very short temporal and spatial scales. An automated wave detection algorithm is used to identify ripple and quasi monochromatic wave features in the ANI data. Ripples are characterized by their wavelength, orientation, drift speed and location in the image. Quasi-monochromatic waves are quantified by wavelength, wave period and propagation direction. We present a climatology of ripple instabilities at Chile, including comparisons to the background quasi-monochromatic wave field. Lidar and radar data are used to determine the background wind and temperatures, which allows comparisons between ripple observations and evanescent regions and potentially unstable regions identified by Richardson number.

  17. Application of conventional CCD cameras with Fabry-Perot spectrometers for airglow observations

    SciTech Connect

    Coakley, M.M.; Roesler, F.L.

    1994-12-31

    This paper describes Fabry-Perot/CCD annular summing applied to airglow observations. Criteria are developed for determining the optimal rectangular format CCD chip configuration which minimizes dark and read noise. The relative savings in integration time of the imaging Fabry-Perot/CCD system over the pressure-scanned Fabry-Perot/PMT system is estimated for the optimal configuration through calculations of the signal to noise ratios for three extreme (but typical) cases of source and background intensity. The largest savings in integration time in estimated for the daysky thermospheric [O{sup 1}D] (6,300 {angstrom}) case where the bright ({approximately} 5 {times} 10{sup 6}R/{angstrom}) Rayleigh-scattered background dominates the read noise. The long integration times required to obtain useful signal to noise ratios for the faint ({approximately} 10R) nightsky exospheric hydrogen Balmer-{alpha} (6,563 {angstrom}) reduce the importance of the read noise term and yield large savings in integration time. The significance of the read noise term is greatly increased with the very short estimated integration times required for bright ({approximately} 200 R) nightsky lines such as thermospheric [O{sup 1}D]. Alternate CCD formats and applications methods that reduce read noise and provide improved performance in the latter case are compared against the CCD annular summing technique.

  18. A fast SWIR imager for observations of transient features in OH airglow

    NASA Astrophysics Data System (ADS)

    Hannawald, Patrick; Schmidt, Carsten; Wüst, Sabine; Bittner, Michael

    2016-04-01

    Since December 2013 the new imaging system FAIM (Fast Airglow IMager) for the study of smaller-scale features (both in space and time) is in routine operation at the NDMC (Network for the Detection of Mesospheric Change) station at DLR (German Aerospace Center) in Oberpfaffenhofen (48.1° N, 11.3° E).Covering the brightest OH vibrational bands between 1 and 1.7 µm, this imaging system can acquire two frames per second. The field of view is approximately 55 km times 60 km at the mesopause heights. A mean spatial resolution of 200 m at a zenith angle of 45° and up to 120 m for zenith conditions are achieved. The observations show a large variety of atmospheric waves.This paper introduces the instrument and compares the FAIM data with spectrally resolved GRIPS (GRound-based Infrared P-branch Spectrometer) data. In addition, a case study of a breaking gravity wave event, which we assume to be associated with Kelvin-Helmholtz instabilities, is discussed.

  19. Infrasonic Waves in the Middle Atmosphere: Modelling, Airglow Observations and Analyses

    NASA Astrophysics Data System (ADS)

    Pilger, Christoph; Schmidt, Carsten; Bittner, Michael

    Infrasound is typically observed in surface level measurements of the ambient air-pressure. A novel approach performed at the German Remote Sensing Data Center of the German Aerospace Center (DLR-DFD) is the detection of infrasonic signals in temperature time series of the mesopause altitude region (at about 80-100 km). The infrasonic pressure fluctuations correspond to temperature fluctuations in the atmosphere via ideal gas law assumptions. The development and magnitude of these fluctuations can be modelled regarding propagation, attenuation and amplification processes in the atmosphere. The modelling results are quantified in order to compare it to instrumental observations of mesopause temperatures. The observations are performed at DLR-DFD using the airglow measurement technique and the GRIPS instruments (GRound-based Infrared P-branch Spectrometers). Their temporal resolution of 15 seconds permits the observation of signals within the infrasound period range. Spectral intensities are estimated applying the wavelet analysis to the complete data set of more than one year of routine measurements in order to derive a statistical distribution of wave activity in the frequency range from 0.5 to 5 minutes. Selected events are discussed with respect to the origin of the observed structures.

  20. Metal Retrievals in the Mesosphere and lower Thermosphere by remote Sensing of Airglow with SCIAMACHY/Envisat

    NASA Astrophysics Data System (ADS)

    Langowski, M.; von Savigny, C.; Sinnhuber, M.; Aikin, A. C.; Burrows, J. P.

    2013-12-01

    Meteors entering the earth atmosphere containing metals ablate in an altitude of approximately 100 km due to frictional heating. The ablated metals undergo a series of chemical processes, which finally leads to a formation of metal layers between 85-95 km and metal ion layers 5 to 15 km above the metal layer. Although the densities of the metals and their ions are only in the magnitude of a few thousands of particles per cubic centimeter, they strongly emit airglow radiation due to their strong absorption cross sections and oscillator strength. This Airglow can be detected e.g. by grating spectrometers and the the density of the metals and ions can be obtained by inversion of a radiative transfer model. Since the Mesosphere and lower Thermosphere can hardly be accessed by in-situ measurement, as ballons fly to low and satellites typically too high and rockets to sparsly, the airglow emission of the metals and ions is one of the few means in this region to obtain information about transport and wave activities. Furthermore the total meteoric input to earth, which is quite uncertain in a range from 2 to 300 t/day can be estimated from the densties in the metal layers. We present metal and ion retrievals from SCIAMACHY/Envisat which is a satellite based grating spectrometer with a wavelength range of 230 to 2300 nm. The presented results are retrieved from the limb MLT states scanning the atmosphere with tangent altitudes from 50 to 150 km every 2 weeks for one day of data since 2008 until 2012.

  1. Periodic waves in the lower thermosphere observed by OI630 nm airglow images

    NASA Astrophysics Data System (ADS)

    Paulino, I.; Medeiros, A. F.; Vadas, S. L.; Wrasse, C. M.; Takahashi, H.; Buriti, R. A.; Leite, D.; Filgueira, S.; Bageston, J. V.; Sobral, J. H. A.; Gobbi, D.

    2016-02-01

    Periodic wave structures in the thermosphere have been observed at São João do Cariri (geographic coordinates: 36.5° W, 7.4° S; geomagnetic coordinates based on IGRF model to 2015: 35.8° E, 0.48° N) from September 2000 to November 2010 using OI630.0 nm airglow images. During this period, which corresponds to almost one solar cycle, characteristics of 98 waves were studied. Similarities between the characteristics of these events and observations at other places around the world were noted, primarily the spectral parameters. The observed periods were mostly found between 10 and 35 min; horizontal wavelengths ranged from 100 to 200 km, and phase speed from 30 to 180 m s-1. These parameters indicated that some of the waves, presented here, are slightly faster than those observed previously at low and middle latitudes (Indonesia, Carib and Japan), indicating that the characteristics of these waves may change at different places. Most of observed waves have appeared during magnetically quiet nights, and the occurrence of those waves followed the solar activity. Another important characteristic is the quasi-monochromatic periodicity that distinguish them from the single-front medium-scale traveling ionospheric disturbances (MSTIDs) that have been observed previously over the Brazilian region. Moreover, most of the observed waves did not present a phase front parallel to the northeast-southwest direction, which is predicted by the Perkins instability process. It strongly suggests that most of these waves must have had different generation mechanisms from the Perkins instability, which have been pointed out as being a very important mechanism for the generation of MSTIDs in the lower thermosphere.

  2. An assessment of OH airglow interference on the remote sensing of stratospheric HCl via limb sounding in the near-I.R.

    NASA Technical Reports Server (NTRS)

    Mergenthaler, J. L.; Kumer, J. B.

    1986-01-01

    Chemiluminescent emission from the formation of vibrationally excited OH at an altitude of approximately 85 km presents a barrier to earth-limb measurements of NIR emissions originating in the stratosphere. High-resolution measured spectra of OH airglow have not been reported, and thus it is difficult to assess its impact on moderately-high-resolution earth-limb spectroscopy capable of looking between strong OH lines. Low-resolution rocketborne spectrometer earth-limb measurements of OH airglow are mathematically inverted to recover vibrational-state populations that are used to simulate a higher resolution spectrum in the neighbourhood of 2843/cm. Implications for remote sensing HCl are presented.

  3. Lighting

    SciTech Connect

    Audin, L.

    1994-12-31

    EPAct covers a vast territory beyond lighting and, like all legislation, also contains numerous {open_quotes}favors,{close_quotes} compromises, and even some sleight-of-hand. Tucked away under Title XIX, for example, is an increase from 20% to 28% tax on gambling winnings, effective January 1, 1993 - apparently as a way to help pay for new spending listed elsewhere in the bill. Overall, it is a landmark piece of legislation, about a decade overdue. It remains to be seen how the Federal Government will enforce upgrading of state (or even their own) energy codes. There is no mention of funding for {open_quotes}energy police{close_quotes} in EPAct. Merely creating such a national standard, however, provides a target for those who sincerely wish to create an energy-efficient future.

  4. Statistical characteristics of gravity waves observed by an all-sky airglow imager at Maui, HI and Cerro Pachon, Chile

    NASA Astrophysics Data System (ADS)

    Cao, Bing; Liu, Alan Z.

    2016-07-01

    Many long-term observations, such as airglow imaging, have shown that gravity waves exist in the mesopause region most of the time. These waves deposit momentum and energy into the background atmosphere when dissipating, and thus exert strong influence to the atmosphere. In this study, we focus on (1) the climatology of gravity waves characteristics, (2) the intermittency of gravity wave momentum flux and (3) the duration/lifespan of gravity wave events. These properties have important implications for gravity wave parameterizations. This study is based on multi-year all sky OH airglow observations obtained at Maui, HI (20.7° N, 156.3° W) and the Andes Lidar Observatory in Chile (30.3° S, 70.7° W). The statistical distribution of intrinsic wave parameters and the momentum flux are analyzed. The probability density functions of gravity wave momentum flux and duration can be described by simple functions and are related to the gravity wave intermittency. The probability distributions of the two sites have some similarity but with noticeable differences, indicating different effects of the background flow and wave source on the gravity wave intermittency in the mesopause region.

  5. Spatial and Temporal Stability of Airglow Measured in the Meinel Band Window at 1191.3 nm

    NASA Astrophysics Data System (ADS)

    Nguyen, Hien T.; Zemcov, Michael; Battle, John; Bock, James J.; Hristov, Viktor; Korngut, Phillip; Meek, Andrew

    2016-09-01

    We report on the temporal and spatial fluctuations in the atmospheric brightness in the narrow band between Meinel emission lines at 1191.3 nm using a λ/Δλ = 320 near-infrared instrument. We present the instrument design and implementation, followed by a detailed analysis of data taken over the course of a night from Table Mountain Observatory. At low airmasses, the absolute sky brightness at this wavelength is found to be 5330 ± 30 nW m-2 sr-1, consistent with previous measurements of the inter-band airglow at these wavelengths. This amplitude is larger than simple models of the continuum component of the airglow emission at these wavelengths, confirming that an extra emissive or scattering component is required to explain the observations. We perform a detailed investigation of the noise properties of the data and find no evidence for a noise component associated with temporal instability in the inter-line continuum. This result demonstrates that in several hours of ˜100 s integrations the noise performance of the instrument does not appear to significantly degrade from expectations, giving a proof of concept that near-infrared line intensity mapping may be feasible from ground-based sites.

  6. Spatial and Temporal Stability of Airglow Measured in the Meinel Band Window at 1191.3 nm

    NASA Astrophysics Data System (ADS)

    Nguyen, Hien T.; Zemcov, Michael; Battle, John; Bock, James J.; Hristov, Viktor; Korngut, Phillip; Meek, Andrew

    2016-09-01

    We report on the temporal and spatial fluctuations in the atmospheric brightness in the narrow band between Meinel emission lines at 1191.3 nm using a λ/Δλ = 320 near-infrared instrument. We present the instrument design and implementation, followed by a detailed analysis of data taken over the course of a night from Table Mountain Observatory. At low airmasses, the absolute sky brightness at this wavelength is found to be 5330 ± 30 nW m‑2 sr‑1, consistent with previous measurements of the inter-band airglow at these wavelengths. This amplitude is larger than simple models of the continuum component of the airglow emission at these wavelengths, confirming that an extra emissive or scattering component is required to explain the observations. We perform a detailed investigation of the noise properties of the data and find no evidence for a noise component associated with temporal instability in the inter-line continuum. This result demonstrates that in several hours of ∼100 s integrations the noise performance of the instrument does not appear to significantly degrade from expectations, giving a proof of concept that near-infrared line intensity mapping may be feasible from ground-based sites.

  7. OI 630.0 nm Night Airglow Observations during the Geomagnetic Storm on November 20, 2003 at Kolhapur (P43)

    NASA Astrophysics Data System (ADS)

    Sharma, A. K.; et al.

    2006-11-01

    sharma_ashokkumar@yahoo.com The ground based photometric observations of OI 630 nm emission line have been carried out from Kolhapur station (Geog. Lat.16.8˚N, Geo. Long 74.2˚E), India during the period of the largest geomagnetic storm of the solar cycle 23 which occurred on 20 November 2003, with minimum Dst index 472 nT occurring around mid-night hours. We observed that on 19 November 2003 which was geomagnetically quiet day, the airglow activity of OI 630 nm emission was subdued and it was decreasing monotonically. However, on the night of November 20, 2003 the enhancement is observed during geomagnetic storm due to the increased electron density at the altitude of the F region which is related to the downward transport of electron from the plasmasphere to the F-region. Airglow intensity at OI 630.0 nm showed increase around midnight on November 21, 2003 but comparatively on a smaller scale. On this night the DST index was about 100 nT. This implies that the effect of the geomagnetic storm persisted on that night also. These observations have been explained by the penetration magnetospheric electric field to the low latitude region and the subsequent modulation of meridional wind during the magnetic disturbance at night.

  8. Doppler Ducting of Quasi-Ripple Wave Events in the Mesospheric OH and O2 Airglow Emissions

    NASA Astrophysics Data System (ADS)

    Simkhada, D. B.; Taylor, M. J.; Franke, S. J.

    2007-12-01

    Short-lived (< 40 min) ripple events are common and well documented phenomena in the mesospheric airglow emissions. Recent coordinated studies have determined that these small-scale wave patterns are primarily due to instabilities processes as indicated by their Richardson number (Ri < 0.25, dynamic and Ri < 0, convective instability). These events are contrasted by the frequent occurrence of well-defined, much larger scale wave patterns, termed bands that are mainly associated with the passage of freely propagating short- period (< 1 hour) gravity waves through the upper mesosphere. Here we present new coordinated imaging and meteor radar measurements of spatially extensive ripple-like events that outwardly appear to be ripple but are not directly due to instability processes. The measurements were obtained as a part of the joint NSF/AFOSR Maui-MALT program using the Utah State University Mesospheric Temperature Mapper (MTM) sequentially sampling the OH and O2 airglow emissions centered at 87 and 94 km, respectively, and the University of Illinois meteor radar providing hourly wind measurements over the altitude range of 80-100 km. Using two years of data 2003-2004, we have identified 20 quasi-ripple events where the background wind measurements clearly show the events to be strongly Doppler ducted (or evanescent) in nature. These relatively rare events provide important new information on the dynamics of wave ducting at mesospheric heights.

  9. Characteristics of Short-Period Wavelike Features near 90 km Altitude From Airglow and Lidar Observations Over Maui

    NASA Astrophysics Data System (ADS)

    Hecht, J. H.; Rudy, R. J.; Walterscheid, R. L.; Liu, A. Z.; Franke, S. J.; Pautet, P.; Taylor, M. J.

    2006-12-01

    Small scale (less than 15 km horizontal wavelength) wavelike structures, known as ripples are a common occurrence in OH airglow images. Recent case studies attribute their origin to the presence of either convective or dynamical instabilities. However, little is known about their frequency of occurrence and characteristics such as period and wavelength. The Maui-MALT Observatory, located on Mt. Haleakala is instrumented with a Na wind/temperature lidar which allows the determination of whether the atmosphere is dynamically or convectively unstable, and a fast OH airglow camera which takes images every 3 seconds with a sensitivity high enough to see the ripples. This study reports on two months of observations in October/November 2003 and August 2004, 8 nights of which also included Na lidar measurements. The nominal observed period for the ripples is between 2 and 4 minutes. The results suggest that instability features occur in the 85 to 90 km region of the atmosphere around 20 percent of the time. While there are clear night to night variations the average is similar for both the 2003 and 2004 observations. In addition a few of the small-scale structures are not ripples caused by instabilities, but rather are short horizontal wavelength evanescent waves. Their fractional intensity fluctuations are as large or larger than those of the ripple instabilities. Unlike the instabilities, the origin of the evanescent waves is not determined.

  10. Characteristics of short-period wavelike features near 87 km altitude from airglow and lidar observations over Maui

    NASA Astrophysics Data System (ADS)

    Hecht, J. H.; Liu, A. Z.; Walterscheid, R. L.; Franke, S. J.; Rudy, R. J.; Taylor, M. J.; Pautet, P.-D.

    2007-08-01

    Small-scale (less than 15 km horizontal wavelength) wavelike structures known as ripples are a common occurrence in OH airglow images. Recent case studies attribute their origin to the presence of either convective or dynamical instabilities. However, little is known about their frequency of occurrence and period. The Maui-MALT Observatory, located at Mt. Haleakala, is instrumented with a Na wind/temperature lidar, which allows the determination of whether the atmosphere is dynamically or convectively unstable, and a fast OH airglow camera which takes images every 3 s with a sensitivity high enough to see the ripples. This study reports on 2 months of observations in October/November 2003 and in August 2004, eight nights of which also included Na lidar measurements. The imager results suggest that instability features occur in the 85- to 90-km region of the atmosphere for around 20% of the time. The nominal observed period for the ripples is between 2 and 4 min. While there are clear night-to-night variations, the average observed period is similar for both the 2003 and 2004 observations. In addition, a few of the small-scale structures are not ripples caused by instabilities but rather have features consistent with their being short horizontal wavelength evanescent waves. Their fractional intensity fluctuations are as large or larger than those of the ripple instabilities. Unlike the instabilities, the origin of the evanescent waves is not determined.

  11. The O I 135.6 nm airglow observations of the midlatitude summer nighttime anomaly by TIMED/GUVI

    NASA Astrophysics Data System (ADS)

    Hsu, M. L.; Lin, C. H.; Hsu, R. R.; Liu, J. Y.; Paxton, L. J.; Su, H. T.; Tsai, H. F.; Rajesh, P. K.; Chen, C. H.

    2011-07-01

    This study presents the O I 135.6 nm airglow observation of the middle-latitude electron density enhancement during local summer nighttime by Global Ultraviolet Imager (GUVI) on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) spacecraft. The nighttime density enhancement at magnetic middle latitudes in the Southern Hemisphere, known as the Weddell Sea Anomaly (WSA), had been studied by using multipoint observations, and a similar anomalous nighttime enhancement was also found in the Northern Hemisphere recently. The resemblance of both anomalies at magnetic middle latitudes in the Northern and Southern Hemispheres suggests that they should be categorized as the midlatitude summer nighttime anomaly (MSNA). To further explore the three-dimensional structure of the MSNA and its day-to-day variation, the two-dimensional global radiance maps and the vertical electron density profiles derived from disk and limb scans of the TIMED/GUVI 135.6 nm airglow observations are utilized in this study. These global observations show that the northern MSNA mainly occurs in Asia, Europe, and the North Atlantic Ocean regions, while the southern MSNA occurs in the South America-Antarctica region, near the WSA region. The GUVI day-to-day observations in 2006 further illustrate that the southern MSNA appears nightly in January-February and November-December, while the northern MSNA appears in 36 out of 41 total observation nights in May-June.

  12. Tidal influence on O(1S) airglow emission rate distributions at the geographic equator as observed by WINDII

    NASA Technical Reports Server (NTRS)

    Shephere, G. G.; Mclandress, C.; Solheim, B. H.

    1995-01-01

    WINDII, the Wind Imaging Interferometer on the Upper Atmosphere Research Satellite, observes winds, temperatures and emission rates in the upper mesosphere and thermosphere. In this paper we report on nighttime observations of the vertical distribution of the O(1S) 557.7 nm emission near the geographic equator for March/April, 1993. The airglow volume emission rate distribution is found to be strongly dependent on local time. Beginning at dusk, an intense airglow emission layer descends from a mean altitude of 95 km, reaching 89 km by midnight after which the emission rapidly decays. Shortly after midnight it reappears weakly at a higher altitude and remains at this level as the emission rate gradually increases towards dawn. This strong local time dependence leads us to conclude that the effect is tidally driven. Comparison with the Forbes (1982a,b) model suggest that total density perturbations and changes in the atomic oxygen mixing ratio may the cause of the changes in emission rate distribution between dusk and midnight. The reappearance of the emission after midnight may be caused by downward winds bringing oxygen-rich air from above.

  13. Spectrophotometry of faint light sources with a tilting-filter photometer.

    PubMed

    Eather, R H; Reasoner, D L

    1969-02-01

    The design considerations that are necessary to optimize the performance of a tilting-filter photometer are presented. Such a photometer is described, and some typical measurements of aurora and airglow illustrate the application of this technique to low light level spectrophotometry. The digital approach used with photomultipliers at these low light levels is also discussed. Comparison of the tilting-filter photometer with other spectral scanning instruments reveals a superiority for many applications. A final section discusses possible space applications.

  14. Atmospheric entry survival of large micrometeorites: Implications for their sources and for the cometary contribution to the zodiacal cloud

    NASA Astrophysics Data System (ADS)

    Flynn, George J.

    1992-12-01

    Atmospheric entry heating simulations indicate that a large fraction of the micrometeorites larger than 100 microns in diameter which survive atmospheric entry must have entered the Earth's atmosphere with velocities very near the Earth's escape velocity. Thus, these particles must have been captured by Earth from heliocentric orbits with small eccentricities and low inclinations, indicating a main-belt asteroidal source. Space exposure ages measured on these large micrometeorites are also consistent with a main-belt asteroidal source. However, dynamical calculations have previously indicated that particles larger than 100 microns in diameter were likely to be destroyed by catastrophic collisions in the time required for orbital evolution from the main-belt to Earth capture by Poynting-Robertson drag. The absence of a large amount of collisional debris in the less than 50 microns size range indicates these large micrometeorites are not the few, rare survivors of a mostly collisionally disrupted population. The measured space exposure ages, which are about an order of magnitude larger than their calculated catastrophic collision lifetimes, confirm the survival of these large micrometeorites for times much longer than the calculated catastrophic collision lifetimes. Since collisions with cometary dust less than 20 microns in size were expected to be the major contributor to the collisional destruction of these larger particles, the contribution of cometary material to the zodiacal cloud is likely to be much smaller than previously believed.

  15. The new Arecibo Observatory Remote Airglow Facility in Culebra Island, Puerto Rico: current status and future projects

    NASA Astrophysics Data System (ADS)

    Santos, P. T.; Kerr, R. B.; Robles, E.; Garzon, D. P.

    2012-12-01

    The concept of having the Arecibo Observatory Remote Airglow Observatory (AO-RAF) at Culebra island became apparent a couple of years ago as a solution to mitigate the ever cumulative quantity of cloud, fog, and rain that has distressed observations at the Arecibo Observatory during major optical campaigns and observations. Culebra Island (18.33° N 65.33° W) is situated approximately 27 km east of the main island of Puerto Rico, with dimensions of about 11 km long and 5 km wide. A statistical analysis and comparison of cloud cover, precipitation and humidity over Puerto Rico and adjacent islands showed that Culebra is the best site with optimal weather conditions for the optical experiments due to its geographical characteristics. This work presents the initial projects to the AO-RAF as well the future development.

  16. Solar Energy Deposition Rates in the Mesosphere Derived from Airglow Measurements: Implications for the Ozone Model Deficit Problem

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Garcia, Rolando R.; Roble, Raymond G.; Hagan, Maura

    2000-01-01

    We derive rates of energy deposition in the mesosphere due to the absorption of solar ultraviolet radiation by ozone. The rates are derived directly from measurements of the 1.27-microns oxygen dayglow emission, independent of knowledge of the ozone abundance, the ozone absorption cross sections, and the ultraviolet solar irradiance in the ozone Hartley band. Fifty-six months of airglow data taken between 1982 and 1986 by the near-infrared spectrometer on the Solar-Mesosphere Explorer satellite are analyzed. The energy deposition rates exhibit altitude-dependent annual and semi-annual variations. We also find a positive correlation between temperatures and energy deposition rates near 90 km at low latitudes. This correlation is largely due to the semiannual oscillation in temperature and ozone and is consistent with model calculations. There is also a suggestion of possible tidal enhancement of this correlation based on recent theoretical and observational analyses. The airglow-derived rates of energy deposition are then compared with those computed by multidimensional numerical models. The observed and modeled deposition rates typically agree to within 20%. This agreement in energy deposition rates implies the same agreement exists between measured and modeled ozone volume mixing ratios in the mesosphere. Only in the upper mesosphere at midlatitudes during winter do we derive energy deposition rates (and hence ozone mixing ratios) consistently and significantly larger than the model calculations. This result is contrary to previous studies that have shown a large model deficit in the ozone abundance throughout the mesosphere. The climatology of solar energy deposition and heating presented in this paper is available to the community at the Middle Atmosphere Energy Budget Project web site at http://heat-budget.gats-inc.com.

  17. Model studies of time-dependent ducting for high-frequency gravity waves and associated airglow responses in the upper atmosphere

    NASA Astrophysics Data System (ADS)

    Yu, Yonghui

    This doctoral dissertation has mainly concentrated on modeling studies of shorter period acoustic-gravity waves propagating in the upper atmosphere. Several cases have been investigated in the literature, which are focusing on the propagation characteristics of highfrequency gravity wave packets. The dissertation consists of five main divisions of which each has its own significance to be addressed, and these five chapters are also bridged in order with each other to present a theme about gravity wave ducting dynamics, energetics, and airglows. The first chapter is served as an introduction of the general topic about atmospheric acoustic-gravity waves. Some of the historical backgrounds are provided as an interesting refreshment and also as a motivation reasoning this scientific research for decades. A new 2-D, time-dependent, and nonlinear model is introduced in the second chapter (the AGE-TIP model, acronymically named atmospheric gravity waves for the Earth plus tides and planetary waves). The model is developed during this entire doctoral study and has carried out almost all research results in this dissertation. The third chapter is a model application for shorter period gravity waves ducted in a thermally stratified atmosphere. In spite of mean winds the thermal ducting occurs because ducted waves are fairly common occurrences in airglow observations. One-dimensional Fourier analysis is applied to identify the ducted wave modes that reside within multiple thermal ducts. Besides, the vertical energy flux and the wave kinetic energy density are derived as wave diagnostic variables to better understand the time-resolved vertical transport of wave energy in the presence of multiple thermal ductings. The fourth chapter is also a model application for shorter period gravity waves, but it instead addresses the propagation of high-frequency gravity waves in the presence of mean background wind shears. The wind structure acts as a significant directional filter to the

  18. Preliminary observations and simulation of nocturnal variations of airglow temperature and emission rates at Pune (18.5°N), India

    NASA Astrophysics Data System (ADS)

    Fadnavis, S.; Feng, W.; Shepherd, Gordon G.; Plane, J. M. C.; Sonbawne, S.; Roy, Chaitri; Dhomse, S.; Ghude, S. D.

    2016-11-01

    Preliminary observations of the nocturnal variations of the OH(6-2) and O2b(0-1) nighttime airglow in the mesosphere and lower thermosphere are investigated in the context of tidal influence for the tropical latitude station Pune (18.5°N, 73.85°E). This is the only tropical Spectral Airglow Temperature Imager (SATI) station where the tidal variations of mesosphere and lower thermosphere (MLT) temperature have been determined from ground based SATI observations. The SATI observations obtained since October 2012 reveal the influence of the migrating semidiurnal tides during solstice at this tropical station. There is variability in amplitude and phase obtained from SATI observations. In this paper, SATI observations on 10 Dec 2012 and 3 March 2013 are compared with Whole Atmosphere Community Climate Model (WACCM) simulations. The amplitude of semidiurnal tides is ~25 K/30 K on 10 Dec 2012 during solstice for OH/O2 temperature. During equinox SATI data indicates existence of semidiurnal tide also. The airglow observations are compared with simulations from the WACCM. The model underestimates the amplitude of the semi diurnal tide during equinox (1.6 K/2.7 K at 87 km/96 km) and solstice (~3.8 K/4.8 K at 87 km/96 km) for these days. The reason may be related to dampening of tides in the model due to the effect of strong latitudinal shear in zonal wind. The diurnal variation of airglow emission - which the model simulates well - is related to the vertical advection associated with the tides and downward mixing of atomic oxygen.

  19. Technique to retrieve solar EUV flux and neutral thermospheric O, O{sub 2}, N{sub 2} and temperature from airglow measurements

    SciTech Connect

    Fennelly, J.A.; Germany, G.A.; Torr, D.G.; Richards, P.G.; Torr, M.R.

    1994-12-31

    The authors describe a method for retrieving neutral thermospheric composition and solar EUV flux from optical measurements of the O+({sup 2}P) 732 nm and O({sup 1}D) 630 nm airglow emissions. The parameters retrieved are the neutral temperature, the O, O{sub 2}, and N{sub 2} density profiles, and a scaling factor for the solar EUV flux spectrum. The temperature, solar EUV flux scaling factor, and atomic oxygen density are first retrieved from the 732 nm emission, which are then used with the 630 nm emission to retrieve the O{sub 2} and N{sub 2} densities. Between the altitudes of 200 and 400 km the retrieval technique is able to statistically retrieve values to within 3.1% for thermospheric temperature, 3.3% for atomic oxygen, 2.3% for molecular oxygen, and 2.4% for molecular nitrogen. The solar EUV flux scaling factor has a retrieval error of 5.1%. They also present the results of retrievals using existing data taken from both groundbased and spacebased instruments. These include airglow data taken by the Visible Airglow Experiment on the Atmosphere Explorer spacecraft and the Imaging Spectrometric Observatory flown on the ATLAS 1 shuttle mission in 1992.

  20. Spaced sensor measurements of artificial airglow emission at 630 nm of ionosphere caused by ``Sura'' facility radiation in November 2013

    NASA Astrophysics Data System (ADS)

    Nasyrov, Igor; Grach, Savely; Gumerov, Rustam; Shindin, Alexey; Kogogin, Denis; Dementiev, Vladislav

    Some first results on simultaneous observation artificial airglow emission at 630 nm during HF pumping of the ionosphere by “Sura” facility from two spatial situated experimental sites are reported. The measurements of artificial airglow are usually conducted in red and green lines of atomic oxygen (the radiation of levels O((1) D) and O((1) S) under their excitation by electronic impact) with wave lengths of 630 and 557.7 nm and excitation energy of 1.96 and 4.17 eV accordingly. An enhancement of airglow intensity in the red line is related at present to the electron heating by powerful radio waves. The idea of the experiment was to estimate the heated volume three-dimensional structure and drift motion one. The experiment was carried out in November 2013 at the “Sura” radio facility, situated near Nizhny Novgorod, Russia (geographical coordinates 56.13(o) N, 46.10(o) E, geomagnetic field declination and inclination are ˜ 10.0(o) east and ˜ 71.5(o) , respectively). Conditions of ionosphere were checked by means of "Cady" ionosonde during “Sura” runs. According to the ionospheric conditions, on the 7(th) of November the “Sura” facility operated at frequency 4.540 MHz. At this frequency the effective radiated power was about 120MW. The HF beam width at the “Sura” facility is ˜ 12(o) . A square wave pump modulation of 5 min on, 5 min off, was used. Measurements were carried out in the period from 14:40 to 17:30 UTC. Optical imaging was performed on two spatial experimental sites: “Vasilsursk” (situated about 500 m from antenna system of “Sura” facility); “Raifa” (situated about 170 km from “Sura” facility at the Magnetic Observatory of Kazan Federal University, geographical coordinates 55.93(o) N, 48.75(o) E). They both were fitted out Peltier-cooled front-illuminated bare CCD cameras with 16-bit slow-scan read-out (S1C3). On “Vasilsursk” site the images were binned down to 256× 256 pixels in addition to cooling, in order

  1. The D-Region Ledge at Nighttime: Why are Elves Collocated with the OH Meinel Band Airglow Layer?

    NASA Astrophysics Data System (ADS)

    Wu, Y. J.; Williams, E. R.; Hsu, R. R.

    2014-12-01

    The Imager of Sprite and Upper Atmosphere Lightning (ISUAL) onboard the Taiwanese satellite Formosat-2 has continuously observed transient luminous events (TLEs) within the +/-60 degree range of latitude for a decade since May 2004. The lightning electromagnetic pulse is responsible for Elves , the dominate TLE type which accounts for approximately 80% of the total TLE count according to the ISUAL global survey. By analyzing the limb-viewed images with a wavelength filter of 622.8-754nm, 72% of elves are found to be 'glued' to the OH Meinel band (~630nm) nightglow layer within its thickness of 8km, with the OH layer normally at an altitude of 87 km (Huang et al., 2010).This collocation of elves and airglow layer is frequently dismissed as coincidence, since the physical mechanisms for the formation of the two optical phenomena are macroscopically quite different. However, a common ingredient in the atmospheric chemistry is monatomic oxygen. O is needed to make O3 and ultimately hydroxyl OH, the main radiative species of the airglow layer. O is also needed to form nitric oxide NO, the species with the lowest known ionization potential (9.26 eV) in the D-region. Thomas (1990) has documented steep increases in O concentration in the 83-85 km altitude range and Hale (1985) has found steep increases in electrical conductivity in the 84-85 km range, both with rocket measurements. A great simplification of the nighttime ionosphere is the presence of a single photon energy—10.2 eV—Lyman-α, originating in monatomic H in the Earth's geocorona. A simple Chapman layer calculation for the altitude of maximum photo-dissociation of O2, using the measured absorption cross-section of O2 at the Lyman-α energy, shows an altitude of maximum O production at 85 km. Elve emission in the nitrogen first positive band is enhanced by the presence of free electrons from ionized NO, but too large a conductivity will lead to the exclusion of the radiation field from the lightning return

  2. Observation and modeling of Na density and OH airglow temperature and intensity perturbations by a gravity wave approaching a critical level

    NASA Astrophysics Data System (ADS)

    Snively, J. B.; Pautet, P.; Taylor, M. J.; Swenson, G. R.

    2009-12-01

    Atmospheric gravity waves at a broad range of temporal and spatial scales are frequently observed in MLT airglow imaging experiments. Airglow data provide significant insight into gravity wave propagation, directionality, and seasonality, and allow estimations of wave fluxes [e.g., Swenson et al., JGR, 104(D6), 1999]. The USU CEDAR Mesospheric Temperature Mapper (MTM) is a specialized CCD airglow imaging system, which was operated at Maui MALT from November 2001 to December 2006. The MTM captures OH(6,2) and O2(0,1) emissions intensities and associated rotational temperatures. The MTM has been used previously to assess zenith temperatures, showing close agreement with simultaneous lidar temperature data [Zhao et al., J. Geophys. Res., 110, D09S07, 2005]. It is additionally able to reveal two-dimensional structure of intensity and temperature perturbations associated with small-scale gravity waves. Here we investigate the vertical and horizontal structure of a small-scale gravity wave (~18 minute period and ~37 km horizontal wavelength) captured by the Maui MTM on April 11, 2002. The event was strongly visible in the OH(6,2) image data, showing intensity perturbations ~ 5-10 %, however relatively weak in the O2 data. Lidar temperatures and winds suggest the presence of a critical level shortly above ~90 km, which would have contributed to increased dissipation, and reduced detectability, due to small vertical scale. Using imaged intensity and rotational temperature data, along with evolving Na lidar data, we reconstruct and simulate the wave event under realistic ambient conditions using a suite of numerical models. Hydroxyl photochemistry and dynamics of O3, H, O, and Na densities are obtained with a two-dimensional nonlinear numerical model for gravity wave dynamics [Snively and Pasko, JGR, 113, A06303, 2008], allowing direct comparison of OH(6,2) intensity and brightness-weighted temperature perturbations [e.g., Makhlouf et al., JGR, 100(D6), 11289, 1995]. The

  3. Climatology of the O+ temperatures over Arecibo for the historical deep solar minimum using Incoherent Scatter Radar and airglow data.

    NASA Astrophysics Data System (ADS)

    Santos, P. T.; Brum, C. G. M.; Kerr, R.; Noto, J.

    2014-12-01

    At Arecibo Observatory (AO) a comprehensive description of the ionosphere and thermosphere environment is achieved by the synergy between the Incoherent Scatter Radar (ISR) and the optical instruments nested on site. An example of this synergy is present in his work where optical and radar techniques were reconciled in order to obtain the O+ temperature variability for 2008 and 2009. During this period, a historical deep solar minimum condition was registered with a remarkable absence of sunspots for a long period (translated into a decreasing in the EUV-UV irradiance). This particular feature implies in an important tool to investigate the variability of O+ temperature, once that any variation can be related to season (modulated by the neutral atmosphere) and/or another modulator different than solar energy input. The OII 7320 Å twilight airglow data used in this work were obtained during new moon periods using a high-spectral resolution Fabry-Perot Interferometer (FPI) with CCD array detection. The FPI was configured with 0.9 cm plate spacing, which produced a free spectral range of 0.298Å and a spectral resolution of 0.03Å, sufficient to sample line width temperatures as low as 500K. A very narrow 3Å Full Width at Half Maximum (FWHM) three-cavity interference filter was also used.

  4. Solar Cycle Dependence Of Temperature, Odd-Oxygen, Odd-Hydrogen, And Airglow In The Mesopause Region Observed By SABER

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.; Hunt, L. A.; Mertens, C. J.; Marshall, T.; Russell, J. M.; Thompson, R. E.; Gordley, L. L.

    2013-12-01

    We present the first consistent, global set of temperature, pressure, odd-oxygen, odd-hydrogen and airglow measurements in the mesopause region spanning a complete solar cycle. The measurements are derived from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the NASA TIMED satellite. These data clearly indicate the influence of solar variability on the atmosphere structure and composition. In general, the values of most parameters decrease with decreasing solar activity. However, odd-hydrogen is observed to increase with decreasing solar activity. While the data indicate a direct relation between solar activity and atmospheric response, the role of dynamical variability in modulating the direct solar response has not yet been investigated, particularly on regional scales (e.g.,tropical, mid-latitude, or polar). We describe the SABER observations in detail and discuss how they can be used with general circulation models to assess the coupled role of dynamics and solar variability in determining the overall atmospheric response.

  5. An intense traveling airglow front in the upper mesosphere-lower thermosphere with characteristics of a bore observed over Alice Springs, Australia, during a strong 2 day wave episode

    NASA Astrophysics Data System (ADS)

    Walterscheid, R. L.; Hecht, J. H.; Gelinas, L. J.; Hickey, M. P.; Reid, I. M.

    2012-11-01

    The Aerospace Corporation's Nightglow Imager observed a large step function change in airglow in the form of a traveling front in the OH Meinel (OHM) and O2atmospheric (O2A) airglow emissions over Alice Springs, Australia, on 2 February 2003. The front exhibited nearly a factor of 2 stepwise increase in the OHM brightness and a stepwise decrease in the O2A brightness. There was significant (˜25 K) cooling behind the airglow fronts. The OHM airglow brightness behind the front was among the brightest for Alice Springs that we have measured in 7 years of observations. The event was associated with a strong phase-locked 2 day wave (PL/TDW). We have analyzed the wave trapping conditions for the upper mesosphere and lower thermosphere using a combination of data and empirical models and found that the airglow layers were located in a region of ducting. The PL/TDW-disturbed wind profile was effective in supporting a high degree of ducting, whereas without the PL/TDW the ducting was minimal or nonexistent. The change in brightness in each layer was associated with a strong leading disturbance followed by a train of weak barely visible waves. In OHM the leading disturbance was an isolated disturbance resembling a solitary wave. The characteristics of the wave train suggest an undular bore with some turbulent dissipation at the leading edge.

  6. Results from a high-speed imaging system for the observation of transient features in OH-Airglow with focus on small-scale structures

    NASA Astrophysics Data System (ADS)

    Hannawald, Patrick; Kazlova, Aliaksandra; Schmidt, Carsten; Wüst, Sabine; Bittner, Michael

    2016-04-01

    The OH-airglow layer in about 87 km altitude is suited to investigate atmospheric dynamics in a unique way, allowing continuous observations of the night-sky throughout the year. Especially, atmospheric gravity waves are prominent features in the data of airglow imaging systems. In the year 2014 the imaging system FAIM (Fast Airglow IMager) for the study of small-scale features (both in space and time) was operational at the NDMC (Network for the detection of mesospheric change) station Oberpfaffenhofen. The instrument covers many of the brightest OH vibrational bands between 1.0 μm and 1.7 μm and acquires images with a temporal resolution of 2 frames per second. It measures the night sky with an aperture angle of about 20° and a zenith angle of 45° oriented to the Southern Germany Alpine region. Hence, the field of view (FOV) is about 50 km times 60 km in the height of the mesopause (87 km) with a mean spatial resolution of about 200 m. With this resolution, the focus of the instrument is on small-scale wave structures ranging from about 1 km to 30 km and instability structures like so-called ripples or Kelvin-Helmholtz-Instabilities. Case studies will be presented showing dissipating gravity waves and the results of spectral analyses will give an overview of the prominent directions of propagation and the horizontal wavelengths within the year 2014. This work is funded by the Bavarian State Ministry of the Environment and Consumer Protection by grant no. TUS01UFS-67093. The project aims to analyse the influence of the Alpine region on the generation of atmospheric waves.

  7. Gravity waves in mesopause region induced by thunderstorms over Northern China observed by a no-gap OH airglow imager network

    NASA Astrophysics Data System (ADS)

    Xu, Jiyao

    2016-07-01

    A no-gap OH airglow all-sky imager network was established in northern China in February 2012. The network is composed of 6 all-sky airglow imagers that make observations of OH airglow gravity waves and cover an area of about 2000 km east and west and about 1400 km south and north. A large number of gravity wave events in the mesopause region induced by thunderstorms were observed by the network during the past 4 years. A comparison of the observations in 2012, 2013, and 2014 are made, which shows that there were more strong thunderstorms take place in 2013 in the northern China and produce more Concentric Gravity Wave (CGW) events. Especially, a series of CGW events were observed by the network nearly every night during the first half of August 2013. These events were also observed by satellite sensors from FY-2, AIRS/Aqua, and VIIRS/Suomi NPP. Combination of the ground imager network with satellites provides multi-level observations of the CGWs from the stratosphere to the mesopause region. In this talk, two representative CGW events in August 2013 are studied in detail and movies of the two events are displayed. One is the CGW on the night of 13 August 2013, likely launched by a single thunderstorm. The temporal and spatial analyses indicate that the CGW horizontal wavelengths agree with the GW dispersion relation within 300 km from the storm center. A gravity wave with horizontal wavelength of about 20 km propagates horizontally to more than 800 km in the mesopause region, probably due to a ducting layer. Another CGW event was induced by two very strong thunderstorms on 09 August 2013. Multi-scale waves with horizontal wavelengths ranging from less than 10 km to 200 km were observed. Many ripples were found, probably due to the breaking of strong gravity waves with large relative OH intensity perturbations of 10%.

  8. Gravity Wave Energetics Determined From Coincident Space-Based and Ground-Based Observations of Airglow Emissions

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Significant progress was made toward the goals of this proposal in a number of areas during the covered period. Section 5.1 contains a copy of the originally proposed schedule. The tasks listed below have been accomplished: (1) Construction of space-based observing geometry gravity wave model. This model has been described in detail in the paper accompanying this report (Section 5.2). It can simulate the observing geometry of both ground-based, and orbital instruments allowing comparisons to be made between them. (2) Comparisons of relative emission intensity, temperatures, and Krassovsky's ratio for space- and ground-based observing geometries. These quantities are used in gravity wave literature to describe the effects of the waves on the airglow. (3) Rejection of Bates [1992], and Copeland [1994] chemistries for gravity wave modeling purposes. Excessive 02(A(sup 13)(Delta)) production led to overproduction of O2(b(sup 1)(Sigma)), the state responsible for the emission of O2. Atmospheric band. Attempts were made to correct for this behavior, but could not adequately compensate for this. (4) Rejection of MSX dataset due to lack of coincident data, and resolution necessary to characterize the waves. A careful search to identify coincident data revealed only four instances, with only one of those providing usable data. Two high latitude overpasses and were contaminated by auroral emissions. Of the remaining two mid-latitude coincidences, one overflight was obscured by cloud, leaving only one ten minute segment of usable data. Aside from the statistical difficulties involved in comparing measurements taken in this short period, the instrument lacks the necessary resolution to determine the vertical wavelength of the gravity wave. This means that the wave cannot be uniquely characterized from space with this dataset. Since no observed wave can be uniquely identified, model comparisons are not possible.

  9. First results from a high-speed infrared imaging system for the observation of gravity waves in OH airglow

    NASA Astrophysics Data System (ADS)

    Bittner, Michael; Hannawald, Patrick; Schmidt, Carsten; Wüst, Sabine

    2015-04-01

    The OH-airglow-layer is concentrated at a height of about 87 km with a half-width of approximately 3 km. Observing the infrared emissions of the vibrational-rotational excited OH moelcules offers a unique possibility for studying atmospheric dynamics. Especially, atmospheric gravity waves are prominent features in the measurements. Since December 2013 the new imaging system FAIm (Fast Infrared Imager) for the study of smaller-scale features (both in space and time)is operational at the NDMC (Network for the Detection of Mesospheric Change, http://wdc.dlr.de/ndmc)station Oberpfaffenhofen. Covering the brightest OH vibrational bands between 1.3 and 1.7micrometer, the imaging system can acquire 2 frames per second. The field of view is approximately 50 km x 60 km at the mesopause height with a mean spatial resolution of 200 m. More than 370 nights of observation have successfully been performed already. The observations show a large variety of atmospheric waves with horizontal wavelengths down to less than 3km, different directions of propagation and phase velocities varying from nearly 0 m/s (quasi stationary waves) to more than 50 m/s. We present the experimental setup and will show first results. Especially, spatio-temporal sequences of the generation of smaller scale gravity wave fields as well as their turbulent dissipation will be shown. An outlook will be given to planned future simultaneous measurements from different stations in the alpine region in order to achieve some stereoscopic information about gravity wave fields.

  10. Studying the Fine Structure and Temporal Variations of the Zodiacal Cloud and Asteroidal Dust Bands Using the 3-Year Near-IR COBE-DIRBE Data

    NASA Technical Reports Server (NTRS)

    Jayaraman, Sumita

    1999-01-01

    The report presents the results of the data analyses of the DIRBE-COBE data set to study the structure of the zodiacal cloud in the near-infrared wavebands at 1.2, 2.2, and 3.4 microns. The cloud has been divided into two components which have been analyzed and studied separately. The annual variation of the flux in the smooth or low frequency component has been measured in all three bands and the presence of any asymmetries due to the Earth's resonant ring have been studied. The high frequency component which primarily consisted of the asteroidal dust bands. Extensive and careful co-addition was done to extract the central bands in all three wavebands. The ten-degree bands are present in the 1.2 and 2.2 microns but not in the 3.4 micron waveband.

  11. Serum Proenkephalin A Levels and Mortality After Long-Term Follow-Up in Patients with Type 2 Diabetes Mellitus (ZODIAC-32)

    PubMed Central

    van Hateren, Kornelis J. J.; Landman, Gijs W. D.; Arnold, Jarinke F. H.; Joosten, Hanneke; Groenier, Klaas H.; Navis, Gerjan J.; Sparwasser, Andrea; Bakker, Stephan J. L.; Bilo, Henk J. G.; Kleefstra, Nanne

    2015-01-01

    Background Two previous studies concluded that proenkephalin A (PENK-A) had predictive capabilities for stroke severity, recurrent myocardial infarction, heart failure and mortality in patients with stroke and myocardial infarction. Objectives This study aimed to investigate the value of PENK-A as a biomarker for predicting mortality in patients with type 2 diabetes mellitus. Methods Patients with type 2 diabetes mellitus were included from the prospective observational ZODIAC (Zwolle Outpatient Diabetes project Integrating Available Care) study. The present analysis incorporated two ZODIAC cohorts (1998 and 2001). Since blood was drawn for 1204 out of 1688 patients (71%), and information on relevant confounders was missing in 47 patients, the final sample comprised 1157 patients. Cox proportional hazard models were used for evaluating the relationship between PENK-A and (cardiovascular) mortality. Risk prediction capabilities were assessed with Harrell’s C statistics and the integrated discrimination improvement (IDI). Results After a follow-up period of 14 years, 525 (45%) out of 1157 patients had died, of which 224 (43%) were attributable to cardiovascular factors. Higher Log PENK-A levels were not independently associated with increased (cardiovascular) mortality. Patients with PENK-A values in the highest tertile had a 49% (95%CI 1%-121%) higher risk of cardiovascular mortality compared to patients in the reference category (lowest tertile). C-values were not different after removing PENK-A from the Cox models and there were no significant differences in IDI values. Conclusions The associations between PENK-A and mortality were strongly attenuated after accounting for all traditional risk factors. Furthermore, PENK-A did not seem to have additional value beyond conventional risk factors when predicting all-cause and cardiovascular mortality. PMID:26218633

  12. Long-term Trends in Mesospheric Temperatures at high and low latitudes derived from OH airglow spectra of Kiruna FTS and Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Kim, Yongha; Kim, Jeong-Han; Kim, Gawon; Lee, Youngsun

    2016-07-01

    We have analyzed mesospheric temperatures from OH airglow measurements with Fourier Transform Spectrometer (FTS) in the period of 2003 - 2012 at Kiruna (67.9°N, 21.1°E). We also derived mesospheric temperatures from rotational emission lines of the OH airglow (8-3) band in the sky spectra of Sloan Digital Sky Survey (SDSS) in the period of 2000 - 2014. The main objective of SDSS is to make a detailed 3-dimensional map of the universe by observing images and spectra of various celestial objects at Apache Point Observatory (APO, 32°N 105°W). From both temperature sets we first estimated the solar responses of mesospheric temperatures to F10.7 variation and the seasonal variation of mesospheric temperatures. After removing the solar response, we found the long-term mesospheric temperature trends of -4 ˜-6.6 K/decade at Kiruna and -0.02 ± 0.7 K/decade at Apache Point. Our results indicate significant cooling trend at the high latitude but very little or no cooling at the low latitude. Although both trends are comparable and consistent with other studies, the temperature trend from SDSS spectra should be regarded as unique contribution to global monitoring of climate change because the SDSS project is completely independent of climate studies.

  13. Propagation direction of the nighttime mesospheric gravity waves in the OH airglow images at Tromsø, Norway in winter 2009

    NASA Astrophysics Data System (ADS)

    Oyama, S.; Shiokawa, K.; Suzuki, S.; Nozawa, S.; Otsuka, Y.; Tsutsumi, M.; Hall, C. M.; Meek, C.; Manson, A. H.

    2010-12-01

    An important aspect of the wind dynamics in the mesosphere is to know characteristics of the atmospheric gravity waves, such as propagation direction, zonal and meridional wavenumbers, horizontal wavelength, apparent phase speed, and intensity perturbation amplitude, because it is widely known that the atmospheric gravity waves transport momentum from the lower atmosphere to the mesosphere and the lower thermosphere. Statistical analysis of the OH airglow images measured with all-sky cooled-CCD imagers at low and middle latitudes suggest seasonal, latitudinal dependencies of the wave characteristics. In particular, the wave propagation direction shows clear seasonal variations dependent on latitudes and may also be on longitudes. For example, northward or northeastward propagations are predominant in summer at Rikubetsu (43.5°N, 143.8°E) and the MU radar site (34.9°N, 136.1°E), Japan; but westward and southwestward propagation are predominant in winter at Rikubetsu and the MU radar site, respectively. Another statistical result at equatorial region suggests that eastward and westward directions are predominant in winter and summer, respectively, at Kototabang (0.2°S, 100.3°E), although the propagation direction can be found in all directions. These seasonal, geographical dependencies of the wave propagation direction are controlled by wind filtering, ducting processes, and relative location to the wave source in the lower atmosphere. A new all-sky airglow imager (imager #12 of the Optical Mesosphere Thermosphere Imagers (OMTIs)) was installed at the Ramfjordmoen research station in Norway (69.6°N, 19.2°E) in January 2009. The imager has a filter wheel to programmatically select one of the six optical filters (557.7 nm, 630.0 nm, OH band (720-1000 nm), 589.3 nm, 572.5 nm, and 732.0 nm) for one exposure interval. This study focuses on the OH airglow images to study the mesospheric gravity waves in winter. The gravity waves predominantly propagate north

  14. THE TRANSIT LIGHT CURVE OF AN EXOZODIACAL DUST CLOUD

    SciTech Connect

    Stark, Christopher C.

    2011-10-15

    Planets embedded within debris disks gravitationally perturb nearby dust and can create clumpy, azimuthally asymmetric circumstellar ring structures that rotate in lock with the planet. The Earth creates one such structure in the solar zodiacal dust cloud. In an edge-on system, the dust 'clumps' periodically pass in front of the star as the planet orbits, occulting and forward-scattering starlight. In this paper, we predict the shape and magnitude of the corresponding transit signal. To do so, we model the dust distributions of collisional, steady-state exozodiacal clouds perturbed by planetary companions. We examine disks with dusty ring structures formed by the planet's resonant trapping of in-spiraling dust for a range of planet masses and semi-major axes, dust properties, and disk masses. We synthesize edge-on images of these models and calculate the transit signatures of the resonant ring structures. The transit light curves created by dusty resonant ring structures typically exhibit two broad transit minima that lead and trail the planetary transit. We find that Jupiter-mass planets embedded within disks hundreds of times denser than our zodiacal cloud can create resonant ring structures with transit depths up to {approx}10{sup -4}, possibly detectable with Kepler. Resonant rings produced by planets more or less massive than Jupiter produce smaller transit depths. Observations of these transit signals may provide upper limits on the degree of asymmetry in exozodiacal clouds.

  15. Primary results from the Berkeley EUV airglow rocket spectrometer: O I and N2 FUV/EUV dayglow in the thermosphere and lower exosphere

    NASA Astrophysics Data System (ADS)

    Cotton, Daniel M.; Chakrabarti, Supriya; Gladstone, G. Randall

    1993-12-01

    The Berkeley extreme-ultraviolet airglow rocket spectrometer (BEARS) made spectroscopic measurements of far and extreme UV, atomic oxygen emissions from a Black Brandt XII (12.041 WT) sounding rocket launched from Wallops Island, Virginia, on September 30, 1988. BEARS' primary instrument, a near-normal Rowland mount spectrometer, measured several atomix oxygen and molecular nitrogen dayglow features at high spectral resolution (1.5 A): O I (989, 1027, 1304, and 1356 A); and N2 Lyman-Birge-Hopfield (4, 0) and (3, 0) bands at 1325 and 1354 A. The instrument collected over 800 s of data spanning altitudes of 150 - 963 km with look directions between 95 deg and 125 deg from zenith. We have analyzed the data using electrons and radiative transport models in a forward modeling approach. The model and data are generally in good agreement. However, there are some discrepancies, which are discussed in terms of remote sensing capabilities and improvements to the models.

  16. Radar detectability studies of slow and small Zodiacal Dust Cloud Particles: I. The case of Arecibo 430 MHz meteor head echo observations

    PubMed Central

    Janches, D.; Plane, J.M.C.; Nesvorný, D.; Feng, W.; Vokrouhlický, D.; Nicolls, M.J.

    2016-01-01

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorný et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth’s upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (~16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision. PMID:27642186

  17. Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles: I. The Case of Arecibo 430 MHz Meteor Head Echo Observations

    NASA Technical Reports Server (NTRS)

    Janches, D.; Plane, J. M. C.; Nesvorny, D.; Feng, W.; Vokrouhlicky, D.; Nicolls, M. J.

    2014-01-01

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorny et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (approximately 16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision.

  18. Radar detectability studies of slow and small Zodiacal Dust Cloud Particles: I. The case of Arecibo 430 MHz meteor head echo observations

    PubMed Central

    Janches, D.; Plane, J.M.C.; Nesvorný, D.; Feng, W.; Vokrouhlický, D.; Nicolls, M.J.

    2016-01-01

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorný et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth’s upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (~16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision.

  19. Radar detectability studies of slow and small Zodiacal Dust Cloud Particles: I. The case of Arecibo 430 MHz meteor head echo observations.

    PubMed

    Janches, D; Plane, J M C; Nesvorný, D; Feng, W; Vokrouhlický, D; Nicolls, M J

    2014-11-20

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorný et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (~16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision.

  20. Radar detectability studies of slow and small zodiacal dust cloud particles. I. The case of Arecibo 430 MHz meteor head echo observations

    SciTech Connect

    Janches, D.; Nesvorný, D.; Vokrouhlický, D.; Nicolls, M. J. E-mail: j.m.c.plane@leeds.ac.uk E-mail: davidn@boulder.swri.edu E-mail: Michael.Nicolls@sri.com

    2014-11-20

    Recent model development of the Zodiacal Dust Cloud (ZDC) argues that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper, we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization, and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when (1) we invoke the lower limit of the model predicted flux (∼16 t d{sup –1}) and (2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high-speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones for low-speed meteors. However, even at this lower limit, the model overpredicts the slow portion of the Arecibo radial velocity distributions by a factor of three, suggesting that the model requires some revision.

  1. Observation of the June 22, 2015 G4 storm by HiT&MiS: an Echelle Spectrograph for Auroral and Airglow Studies

    NASA Astrophysics Data System (ADS)

    Aryal, S.; Hewawasam, K.; Maguire, R.; Chakrabarti, S.; Cook, T.; Martel, J.; Baumgardner, J. L.

    2015-12-01

    Observation of the June 22, 2015 G4 storm by HiT&MiS: an Echelle Spectrograph for Auroral and Airglow Studies Saurav Aryal1 , Kuravi Hewawasam1, Ryan Maguire1, Supriya Chakrabarti1, Timothy Cook1, Jason Martel1 and Jeffrey L Baumgardner2, (1) University of Massachusetts Lowell, Lowell, MA, United States, (2)Boston University, Boston, MA, United StatesA High-Throughput and Multi-slit Imaging Spectrograph (HiT&MIS) has been developed by our group. The spectrograph uses an echelle grating that operates at high dispersion orders (28-43) such that extended sources for airglow and auroral emissions can be observed at high resolution (about 0.02 nm). By using four slits (instead of the conventional one slit setup), with the appropriate foreoptics it images extended emissions along a long field of view of about 0.1° × 50°. It observes spectral regions around six prominent atmospheric emission lines (HI 656.3 nm, HI 486.1 nm, OI 557.7 nm, OI 630.0 nm, OI 777.4 nm and N+2 427.8 nm) using order sorting interference filters at the entrance slits and a filter mosaic on an image plane. We present observations from the instrument during the June 22, 2015 G4 storm. OI 557.7 nm (green line) and OI 630.0 nm (red line) showed strong brightness enhancements that lasted throughout the night from 8 P.M June 22, 2015 to 3 AM June 23,2015 when compared to the same times after the storm had passed.

  2. Long-term ozone decline and its effect on night airglow intensity of Li 6708 Å at Varanasi (25°N, 83°E) and Halley Bay (76°S, 27°W)

    NASA Astrophysics Data System (ADS)

    Jana, P. K.; Saha, I.; Mukhopadhyay, S.

    2011-04-01

    A critical analysis has been made on the long-term yearly and seasonal variations of ozone concentration at Varanasi (25°N, 83°E), India and Halley Bay (76°S, 27°W), a British Antarctic Service Station. The effect of O3 depletion on night airglow emission of Li 6708 Å line at Varanasi and Halley Bay has been studied. Calculations based on chemical kinetics show that the airglow intensity of Li 6708 Å line has also been affected due to the depletion of O3 concentration. The yearly variations and seasonal variations of intensities of Li 6708 Å line for the above two stations are shown and compared. It has been shown that the rate of decrease of intensity of Li 6708 Å line was comparatively more at Halley Bay due to dramatic decrease of Antarctic O3 concentration.

  3. Reanalysis of the Near-infrared Extragalactic Background Light Based on the IRTS Observations

    NASA Astrophysics Data System (ADS)

    Matsumoto, T.; Kim, M. G.; Pyo, J.; Tsumura, K.

    2015-07-01

    We reanalyze data of the near-infrared background taken by IRTS using up-to-date observational results of zodiacal light (ZL), integrated star light, and diffuse Galactic light. We confirm the existence of residual isotropic emission, which is slightly lower but almost the same as previously reported. At wavelengths longer than 2 μm, the result is fairly consistent with the recent observation with AKARI. We also perform the same analysis using a different ZL model by Wright and detect residual isotropic emission that is slightly lower than that based on the original Kelsall model. Both models show residual isotropic emission that is significantly brighter than the integrated light of galaxies.

  4. REANALYSIS OF THE NEAR-INFRARED EXTRAGALACTIC BACKGROUND LIGHT BASED ON THE IRTS OBSERVATIONS

    SciTech Connect

    Matsumoto, T.; Kim, M. G.; Pyo, J.; Tsumura, K.

    2015-07-01

    We reanalyze data of the near-infrared background taken by IRTS using up-to-date observational results of zodiacal light (ZL), integrated star light, and diffuse Galactic light. We confirm the existence of residual isotropic emission, which is slightly lower but almost the same as previously reported. At wavelengths longer than 2 μm, the result is fairly consistent with the recent observation with AKARI. We also perform the same analysis using a different ZL model by Wright and detect residual isotropic emission that is slightly lower than that based on the original Kelsall model. Both models show residual isotropic emission that is significantly brighter than the integrated light of galaxies.

  5. Cassini UVIS Observations of Titan Ultraviolet Airglow Spectra with Laboratory Modeling from Electron- and Proton-Excited N2 Emission Studies

    NASA Astrophysics Data System (ADS)

    Ajello, J. M.; West, R. A.; Malone, C. P.; Gustin, J.; Esposito, L. W.; McClintock, W. E.; Holsclaw, G. M.; Stevens, M. H.

    2011-12-01

    Joseph M. Ajello, Robert A. West, Rao S. Mangina Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 Charles P. Malone Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 & Department of Physics, California State University, Fullerton, CA 92834 Michael H. Stevens Space Science Division, Naval Research Laboratory, Washington, DC 20375 Jacques Gustin Laboratoire de Physique Atmosphérique et Planétaire, Université de Liège, Liège, Belgium A. Ian F. Stewart, Larry W. Esposito, William E. McClintock, Gregory M. Holsclaw Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 E. Todd Bradley Department of Physics, University of Central Florida, Orlando, FL 32816 The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed photon emissions of Titan's day and night limb-airglow and disk-airglow on multiple occasions, including three eclipse observations from 2009 through 2010. The 77 airglow observations analyzed in this paper show EUV (600-1150 Å) and FUV (1150-1900 Å) atomic multiplet lines and band emissions (lifetimes less than ~100 μs), including the Lyman-Birge-Hopfield (LBH) band system, arising from photoelectron induced fluorescence and solar photo-fragmentation of molecular nitrogen (N2). The altitude of peak UV emission on the limb of Titan during daylight occurred inside the thermosphere/ionosphere (near 1000 km altitude). However, at night on the limb, the same emission features, but much weaker in intensity, arise in the lower atmosphere below 1000 km (lower thermosphere, mesosphere, haze layer) extending downwards to near the surface at ~300 km, possibly resulting from proton- and/or heavier ion-induced emissions as well as secondary-electron-induced emissions. The eclipse observations are unique. UV emissions were observed during only one of the three eclipse events, and no Vegard-Kaplan (VK) or LBH emissions were seen. Through regression analysis using

  6. Modelling UV sky for future UV missions

    NASA Astrophysics Data System (ADS)

    Sreejith, A. G.; Safanova, M.; Mohan, R.; Murthy, Jayant

    Software simulators are now widely used in all areas of science, especially in application to astronomical missions: from instrument design to mission planning, and to data interpretation. We present a simulator to model the diffuse ultraviolet sky, where the different contributors are separately calculated and added together to produce a sky image of the size specified by the instrument requirements. Each of the contributors to the background, instrumental dark current, airglow, zodiacal light and diffuse galactic light, is dependent on various factors. Airglow is dependent on the time of day, zodiacal light on the time of year, angle from the Sun and from the ecliptic, and diffuse UV emission depends on the look direction. To provide a full description of any line of sight, we have also added stars. The diffuse UV background light can dominate in many areas of the sky and severely impact space telescopes viewing directions due to over brightness. The simulator, available as a downloadable package and as a simple web-based tool, can be applied to separate missions and instruments. For demonstration, we present the example used for two UV missions: the UVIT instrument on the Indian ASTROSAT mission to be launched in the next year and a prospective wide-field mission to search for transients in the UV.

  7. Predicting UV sky for future UV missions

    NASA Astrophysics Data System (ADS)

    Safonova, M.; Mohan, R.; Sreejith, A. G.; Murthy, Jayant

    2013-02-01

    Software simulators are now widely used in all areas of science, especially in application to astronomical missions: from instrument design to mission planning, and to data interpretation. We present a simulator to model the diffuse ultraviolet sky, where the different contributors are separately calculated and added together to produce a sky image of the size specified by the instrument requirements. Each of the contributors to the background, instrumental dark current, airglow, zodiacal light and diffuse Galactic light, depends on different factors. Airglow is dependent on the time of day; zodiacal light depends on the time of year, angle from the Sun and from the ecliptic; diffuse UV emission depends on the line of sight. To provide a full description of the sky along any line of sight, we have also added stars. The UV background light can dominate in many areas of the sky and severely limit viewing directions due to overbrightness. The simulator, available as a downloadable package and as a web-based tool, can be applied to preparation of real space missions and instruments. For demonstration, we present the example use for the two near-future UV missions: UVIT instrument on the Indian Astrosat mission and a new proposed wide-field (∼1000 square degrees) transient explorer satellite.

  8. Study of galactic light, extragalactic light, and galactic structure using pioneer 10 observations of background starlight

    SciTech Connect

    Toller, G.N.

    1981-01-01

    An observational and theoretical study of the diffuse astronomical background sky brightness (background starlight) is carried out. The brightness is determined over 95% of the sky using Pioneer 10 photometric measurements in sky regions where the zodiacal light is negligible (heliocentric distances approx. greater than or equal to 3. A.U.). Brightness levels are presented at blue (3950 to 4850 A) and red (5900 to 6800 A) wavelengths. The B-R color index distribution is established over the celestial sphere. Pioneer 10 results are compared with previous star count and ground based photometric studies to separate background starlight into its constituent parts: integrated starlight, diffuse galactic light (DGL), and cosmic light. Significant errors are found in published star count results at low galactic latitudes. The galactic latitude (b'') and longitude (1'') dependences of integrated starlight and the variation of DGL with b'' are determined. An upper limit of 3.9 S/sub 10/(V)/sub G2V/ at the 90% confidence level is deduced for the cosmic light brightness at blue wavelengths near the galactic poles. The integrated light from discrete galaxies adequately explains this component of the background starlight.

  9. Influence of celestial light on lunar surface brightness determinations: Application to earthshine studies

    NASA Astrophysics Data System (ADS)

    Thejll, P.; Gleisner, H.; Flynn, C.

    2015-01-01

    Aims: We consider the influence of celestial-sphere brightness on determinations of terrestrial albedo from earthshine intensity measurements. In particular, the contributions from zodiacal light and starlight are considered. Methods: Using published data for the zodiacal light (ZL) and stellar brightness distribution across the sky, we calculate the expected contribution to the sky at the position of the Moon in typical earthshine observations, and the magnitude relative to typical earthshine intensities. We derive terrestrial albedo with and without the ZL correction in order to gauge the magnitude of the effect. Results: We find that celestial-sphere surface brightness can be so large that a considerable and unacceptable error level would have an impact on half of typical earthshine-based albedo-determinations if left unaccounted for. Considering the empirical uncertainty on ZL, we show that almost all our earthshine data can be used if a sky correction is made. In real observations we find up to a 1% effect on albedo results of correcting for the celestial brightness. Conclusions: Correction for ZL and starlight brightness is essential to earthshine measurements if climate-science relevant levels of terrestrial albedo accuracy are to be achieved, something that has not yet been realized. With ZL and starlight corrections the earthshine method can potentially yield accurate terrestrial albedo values.

  10. The Light of the Night Sky in EUSO: Duty Cycle and Background

    NASA Technical Reports Server (NTRS)

    Adams, J.; Berat, C.; Lebrun, D.; Montanet, F.

    2003-01-01

    The EUSO detector, which will be installed on the International Space Station, will detect the light produced by the EAS generated by the UHECR when entering the Earth's atmosphere. The EUSO telescope will operate only during dark night. The light background in the EUSO detector is of outmost importance. To determine the detector duty cycle, it is necessary to know the periods in which it will be in the obscurity, taking into account both sun and moon precise ephemerides and the ISS trajectory. For signal to background determination and trigger efficiency study, the photon background has to be evaluated, taking into account the various UV light sources at night: natural sources as airglow, stars and diffuse light of the night sky, and artificial sources.

  11. Highly varying daytime sodium airglow emissions over an equatorial station: a case study based on the measurements using a grating monochromator

    NASA Astrophysics Data System (ADS)

    Hossain, Md Mosarraf; Vineeth, Chandrashekheran Nair; Sumod, Sukumaran Nair Geetha Kumari; Pant, Tarun Kumar

    2014-12-01

    A case study is performed to investigate the probable reasons behind substantial daytime sodium (Na) D1 airglow intensity (589.6 nm) variations measured using a ground-based monochromator during the three near consecutive days of February 2007 from Trivandrum (8.5°N, 77°E), India. The roles of both the resonance fluorescence and the chemistry have been considered in this study. It appears that fluorescence plays only a minor role towards the observed five to nine times of large intensity variations among these days. From investigations on the role of chemistry, it seems that through the Chapman chemical scheme, Na abundance contribute favorably, while the O3 concentrations and the ambient temperature do not play any role as such for the observed intensity variations. From further investigations, it transpires that because of pressure differences (approximately 0.0002 to 0.0003 hPa/day) in the emitting altitude region among these days, the variations in collisional quenching of excited NaO*(A2Σ+) (first excited electronic state of NaO that produces D line) contribute considerably towards the observed intensity variations. From consideration of all the possible factors, it appears that whereas resonance fluorescence plays only a minor role, chemistry has contributed to greater extent towards the observed significant intensity differences among these days.

  12. OH(v=1 to 9) Relative Population Levels Inferred from VIRTIS/Rosetta Airglow Observations in the Earth's Atmosphere (Invited)

    NASA Astrophysics Data System (ADS)

    Migliorini, A.; Gerard, J. C.; Soret, L.; Piccioni, G.; Capaccioni, F.; Filacchione, G.; Snels, M.

    2015-08-01

    On its way to the comet 67P/Churyumov-Gerasimenko, the Rosetta spacecraft performed three flybys with the Earth, in March 2005, November 2007 and November 2009. The last one was quite suitable to observe the nightside of our planet. The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board Rosetta was especially adapted to study the hydroxyl nightglow emissions in the infrared spectral range. The OH v=1,2 sequences were measured simultaneously. We thus investigate the relative population levels of the v=1 to 9 vibrational levels at the same time. Results, obtained using our simple 1-dimension model, are presented for the relative population levels; in particular, the value of level v=1 is derived for the first time, relative to levels up to 9. The vibrational population decreases with increasing vibrational quantum number. Our results are in satisfactorily agreement with previous observations and models developed for mid-latitudes conditions. They favor the models where sudden death deactivation by atomic oxygen is the major process controlling the vibrational population. The observed behavior results to be distinctly different than the OH airglow observations made in the Venus atmosphere with the VIRTIS instrument on board Venus Express, where quenching by CO2 seems to occur with collisional cascades. The authors thank ESA, ASI and all the national space agencies, which support the Rosetta mission (Grants: ASI-INAF I/062/08/0 and ASI-INAF I/050/10/0).

  13. Measuring Anthropogenic Sky Glow Using a Natural Sky Brightness Model

    NASA Astrophysics Data System (ADS)

    Duriscoe, Dan M.

    2013-11-01

    Anthropogenic sky glow (a result of light pollution) combines with the natural background brightness of the night sky when viewed by an observer on the earth's surface. In order to measure the anthropogenic component accurately, the natural component must be identified and subtracted. A model of the moonless natural sky brightness in the V-band was constructed from existing data on the Zodiacal Light, an airglow model based on the van Rhijn function, and a model of integrated starlight (including diffuse galactic light) constructed from images made with the same equipment used for sky brightness observations. The model also incorporates effective extinction by the atmosphere and is improved at high zenith angles (>80°) by the addition of atmospheric diffuse light. The model may be projected onto local horizon coordinates for a given observation at a resolution of 0.05° over the hemisphere of the sky, allowing it to be accurately registered with data images obtained from any site. Zodiacal Light and integrated starlight models compare favorably with observations from remote dark sky sites, matching within ± 8 nL over 95% of the sky. The natural airglow may be only approximately modeled, errors of up to ± 25 nL are seen when the airglow is rapidly changing or has considerable character (banding); ± 8 nL precision may be expected under favorable conditions. When subtracted from all-sky brightness data images, the model significantly improves estimates of sky glow from anthropogenic sources, especially at sites that experience slight to moderate light pollution.

  14. Stray light field dependence for the James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Lightsey, Paul A.

    2016-07-01

    The James Webb Space Telescope (JWST) is a large space based astronomical telescope that will operate at cryogenic temperatures. The architecture has the telescope exposed to space, with a large sun shield providing thermal isolation and protection from direct illumination from the sun. The instruments will have the capability to observe over a spectral range from 0.6 μm to 29 μm wavelengths. Stray light analysis has been performed to characterize the stray light getting to the instrument focal planes from the celestial sky. A Radiance Transfer Function (RTF) is defined for the susceptibility of stray light to sky radiance relative to the observatory frame of reference. The stray light is calculated by overlaying the radiance maps of the celestial sky background (both galactic and zodiacal background) onto the RTF map. The product of the two is summed to obtain the total stray light background at the instrument detectors. The orientation of the observatory for observing a given field location in the sky depends on the direction of the sun, hence the day of the year. The variability of stray light with time of year for observing a given sky locations is determined.

  15. Comparison of rotational temperature derived from ground-based OH airglow observations with TIMED/SABER to evaluate the Einstein coefficients

    NASA Astrophysics Data System (ADS)

    Liu, Weijun; Xu, Jiyao; Smith, A. K.; Yuan, Wei

    2015-11-01

    Ground-based observations of the OH(9-4, 8-3, 6-2, 5-1, and 3-0) band airglows over Xinglong, China (40°24'N, 117°35'E) from December 2011 to 2014 are used to calculate rotational temperatures. The temperatures are calculated using five commonly used Einstein coefficient data sets. The kinetic temperature from Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics/Sounding the Atmosphere by Broadband Emission of Radiation (SABER) is completely independent of the OH rotational temperature. SABER temperatures are weighted vertically by weighting functions calculated for each emitting vibrational state from two SABER OH volume emission rate profiles. By comparing the ground-based OH rotational temperature with SABER's, five Einstein coefficient data sets are evaluated. The results show that temporal variations of the rotational temperatures are well correlated with SABER's; the linear correlation coefficients are higher than 0.72, but the slopes of the fit between the SABER and rotational temperatures are not equal to 1. The rotational temperatures calculated using each set of Einstein coefficients produce a different bias with respect to SABER; these are evaluated over each of the vibrational levels to assess the best match. It is concluded that rotational temperatures determined using any of the available Einstein coefficient data sets have systematic errors. However, of the five sets of coefficients, the rotational temperature derived with Langhoff et al.'s (1986) set is most consistent with SABER. In order to get a set of optimal Einstein coefficients for rotational temperature derivation, we derive their ratios from ground-based OH spectra and SABER temperatures statistically using 3 years of data. The use of a standard set of Einstein coefficients will be beneficial for comparing rotational temperatures observed at different sites.

  16. Polarimetric Studies of Solar Light Scattered by Interplanetary Dust Particles and the Eye-Sat Project

    NASA Astrophysics Data System (ADS)

    Levasseur-Regourd, A. C.; Lasue, J.

    2014-12-01

    Studying intensity and linear polarization of the solar light scattered by interplanetary dust is of interest for various reasons. This so-called zodiacal light constitutes a faint polarized glow that constitutes a changing foreground for observations of faint extended astronomical sources. Besides, analysis of its polarization provides information on properties of the dust particles, such as spatial density, morphology and complex refractive index. Previous observations, mostly from the Earth and with a resolution in the 10° range, have been used to infer that the local polarization at 90° phase angle increases with increasing solar distance. Numerical simulations suggest that, in the inner solar system, interplanetary dust particles consist of a mixture of absorbing and less absorbing materials, and that radial changes originate in a decrease of organic materials with decreasing solar distance under alteration or evaporation processes. To improve the quality of data on zodiacal light polarimetry, Eye-Sat nanosat is being developed in the context of the JANUS CNES cubesats program for students. The project is now in phase C-D, for a piggy-back launch in 2016. Eye-Sat triple cubesat is anticipated to demonstrate the feasibility of a series of new on-board technologies. Moreover, during its one-year mission, zodiacal light intensity and polarization are to be measured, for the first time with a spatial resolution of about 1° over a wide portion of the sky and in four different wavelengths (visible to near-IR), leading to a better assessment of interplanetary dust properties. Finally, a significant fraction of the interplanetary dust is estimated to come from comets, the most pristine objects to be found in the inner solar system. While similarities have indeed been noticed between polarimetric properties of interplanetary and cometary dust particles, the latter being currently extensively documented by the Rosetta mission to comet 67P

  17. Bili lights

    MedlinePlus

    Phototherapy for jaundice; Bilirubin - bili lights; Neonatal care - bili lights; Newborn care - bili lights ... Phototherapy involves shining fluorescent light from the bili lights on bare skin. A specific wavelength of light can break down bilirubin into a form that ...

  18. Observations of Natural and Artificial Airglow in the Mesosphere at the 56äaN latitude

    NASA Astrophysics Data System (ADS)

    Kagan, L. M.; Nicolls, M. J.; Kelley, M. C.

    In a recent paper Kagan et al Phys Rev Lett 9494 9 095004 2005 we have reported vibrationally excited OH 9-3 Meinel band emissions generated by high-power radiowaves launched by the Sura facility in Russia 56 10 r N 44 20 r E The key in these observations is that the light detected in a 2 nm wide filter centered on 630 nm was seen 1-2 s after launching radiowaves This short response and the behavior of the 630-nm emission intensity during the heating cycle rule out the 630 nm emission from atomic oxygen Several minutes after on the same night and with the same 630 0 -1 -nm filter we observed a natural phenomenon seen as an intensity depletion stretched in the east-west direction to the north of the Sura facility Next night we observed the similar event with two filters 557 7 -1 - and 630 0 -1 -nm accompanied by weak gravity wave activity There were tropospheric clouds part of the night but for the clear sky conditions the abovementioned natural phenomenon reminded mesospheric bores First reported by Taylor et al Geophys Res Lett 22 20 2849-2852 1995 as a spectacular gravity wave event this phenomenon was attributed to an internal undular bore in mesosphere by Dewan and Picard J Geophys Res 103 D6 6295-6305 1998 who later outlined the necessary conditions for mesospheric bores Dewan and Picard J Geophys Res 106 D3 2921-2927 2001 The hydroxyl and OI 557 7 nm emissions naturally occur centered on 87 km and 95 km

  19. Monitoring the night sky with the Cerro Tololo All-Sky camera for the TMT and LSST projects

    NASA Astrophysics Data System (ADS)

    Walker, David E.; Schwarz, Hugo E.; Bustos, Edison

    2006-06-01

    The All-Sky camera used in the LSST and TMT site testing campaigns is described and some early results are shown. The All-Sky camera takes images of the entire visible hemisphere of sky every 30s in blue, red, Y and Z filters giving enhanced contrast for the detection of clouds, airglow and the near-infrared. Animation is used to show movement of clouds. An additional narrow band filter is centered on the most prominent line of the sodium vapor lamp spectra and is used to monitor any man-made light pollution near the site. The camera also detects aircraft lights and contrails, satellites, meteor(ite)s, local light polluters, and can be used for stellar extinction monitoring and for photometry of transient astronomical objects. For outreach and education the All-Sky camera can show wandering planets, diurnal rotation of the sky, the zodiacal light, and similar astronomical basics.

  20. Lighting: Green Light.

    ERIC Educational Resources Information Center

    Maniccia, Dorine

    2003-01-01

    Explains that by using sustainable (green) building practices, schools and universities can make their lighting systems more efficient, noting that embracing green design principles can help schools attract students. Discusses lighting-control technologies (occupancy sensing technology, daylighting technology, and scheduling based technologies),…

  1. Spectroscopy of diffuse light in dust clouds. Scattered light and the solar neighbourhood radiation field

    NASA Astrophysics Data System (ADS)

    Lehtinen, K.; Mattila, K.

    2013-01-01

    Context. The optical surface brightness of dark nebulae is mainly due to scattering of integrated starlight by classical dust grains. It contains information on the impinging interstellar radiation field, cloud structure, and grain scattering properties. We have obtained spectra of the scattered light from 3500 to 9000 Å in two globules, the Thumbprint Nebula and DC 303.8-14.2. Aims. We use observations of the scattered light to study the impinging integrated starlight spectrum as well as the scattered Hα and other line emissions from all over the sky. We search also for the presence of other than scattered light in the two globules. Methods. We obtained long-slit spectra encompassing the whole globule plus adjacent sky in a one-slit setting, thus enabling efficient elimination of airglow and other foreground sky components. We calculated synthetic integrated starlight spectra for the solar neighbourhood using HIPPARCOS-based stellar distributions and the spectral library of Pickles. Results. Spectra are presented separately for the bright rims and dark cores of the globules. The continuum spectral energy distributions and absorption line spectra can be well modelled with the synthetic integrated starlight spectra. Emission lines of Hα +[N II], Hβ, and [S II] are detected and are interpreted in terms of scattered light plus an in situ warm ionized medium component behind the globules. We detected an excess of emission over the wavelength range 5200-8000 Å in DC 303.8-14.2 but the nature of this emission remains open. Based on observations collected at the European Southern Observatory, Chile, under programme ESO No. 073.C-0239(A). Appendix A is available in electronic form at http://www.aanda.org.

  2. Extragalactic background light measurements and applications.

    PubMed

    Cooray, Asantha

    2016-03-01

    This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB. PMID:27069645

  3. Extragalactic background light measurements and applications

    PubMed Central

    Cooray, Asantha

    2016-01-01

    This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB. PMID:27069645

  4. Extragalactic background light measurements and applications.

    PubMed

    Cooray, Asantha

    2016-03-01

    This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB.

  5. Light Pollution

    ERIC Educational Resources Information Center

    Riegel, Kurt W.

    1973-01-01

    Outdoor lighting is light pollution which handicaps certain astronomical programs. Protective measures must be adopted by the government to aid observational astronomy without sacrificing legitimate outdoor lighting needs. (PS)

  6. Light Duty.

    ERIC Educational Resources Information Center

    Rogers, Jeff

    1996-01-01

    Discusses multipurpose athletic-field lighting specifications to enhance lighting quality and reduce costs. Topics discussed include lamp choice, lighting spillover and glare prevention, luminary assemblies and poles, and the electrical dimming and switching systems. (GR)

  7. Low-Resolution Spectrum of the Extragalactic Background Light with the AKARI InfraRed Camera

    NASA Astrophysics Data System (ADS)

    Tsumura, Kohji; Matsumoto, Toshio; Matsuura, Shuji; Sakon, Itsuki; Wada, Takehiko

    2013-12-01

    The Extragalactic Background Light (EBL) as integrated light from outside of our Galaxy includes information about the early universe and the Dark Ages. We analyzed spectral data of the astrophysical diffuse emission obtained with the low-resolution spectroscopy mode on the AKARI Infra-Red Camera (IRC) in the 1.8-5.3μm wavelength region. Although previous EBL observations in this wavelength region were restricted to observations by DIRBE and IRTS, this study adds a new independent result with negligible contamination of Galactic stars owing to higher sensitivity for point sources. Two other major foreground components, zodiacal light (ZL) and diffuse Galactic light (DGL), were subtracted by taking correlations with ZL brightness estimated by the DIRBE ZL model and with the 100μm dust thermal emission, respectively. The isotropic emission was obtained as EBL, which shows significant excess over integrated light of galaxies at < 4μm. The obtained EBL is consistent with the previous measurements by IRTS and DIRBE.

  8. Zodiacal Exoplanets in Time (ZEIT). I. A Neptune-sized Planet Orbiting an M4.5 Dwarf in the Hyades Star Cluster

    NASA Astrophysics Data System (ADS)

    Mann, Andrew W.; Gaidos, Eric; Mace, Gregory N.; Johnson, Marshall C.; Bowler, Brendan P.; LaCourse, Daryll; Jacobs, Thomas L.; Vanderburg, Andrew; Kraus, Adam L.; Kaplan, Kyle F.; Jaffe, Daniel T.

    2016-02-01

    Studying the properties of young planetary systems can shed light on how the dynamics and structure of planets evolve during their most formative years. Recent K2 observations of nearby young clusters (10-800 Myr) have facilitated the discovery of such planetary systems. Here we report the discovery of a Neptune-sized planet transiting an M4.5 dwarf (K2-25) in the Hyades cluster (650-800 Myr). The light curve shows a strong periodic signal at 1.88 days, which we attribute to spot coverage and rotation. We confirm that the planet host is a member of the Hyades by measuring the radial velocity of the system with the high-resolution near-infrared spectrograph Immersion Grating Infrared Spectrometer. This enables us to calculate a distance based on K2-25's kinematics and membership to the Hyades, which in turn provides a stellar radius and mass to ≃5%-10%, better than what is currently possible for most Kepler M dwarfs (12%-20%). We use the derived stellar density as a prior on fitting the K2 transit photometry, which provides weak constraints on eccentricity. Utilizing a combination of adaptive optics imaging and high-resolution spectra, we rule out the possibility that the signal is due to a bound or background eclipsing binary, confirming the transits’ planetary origin. K2-25b has a radius ({3.43}-0.31+0.95 R⊕) much larger than older Kepler planets with similar orbital periods (3.485 days) and host-star masses (0.29 M⊙). This suggests that close-in planets lose some of their atmospheres past the first few hundred million years. Additional transiting planets around the Hyades, Pleiades, and Praesepe clusters from K2 will help confirm whether this planet is atypical or representative of other close-in planets of similar age.

  9. On the Sources and Effects of Light Incident in Permanently Shadowed Regions on the Moon

    NASA Astrophysics Data System (ADS)

    Stubbs, T. J.; Glenar, D. A.; Killen, R. M.

    2013-12-01

    Light from a wide variety of sources is incident on the surface within so called permanently shadowed regions (PSRs) near the lunar poles that are never directly exposed to sunlight. In this study we collate predictions for these various light sources that cover a broad range of wavelengths from the infrared to the far-UV, and consider their potential importance for the conditions within PSRs, which could have implications for, amongst other things, the stability of volatiles and the suitability of the Moon as a platform for astronomical observatories. This is achieved by characterizing the sources of light incident within a typical near-polar PSR from: (i) Zodiacal light created by sunlight scattered from dust in the inner solar system; (ii) Lyman-alpha resonantly scattered by interplanetary hydrogen; (iii) the broadband galactic background from other stars; (iv) emission lines from exospheric species that vary in intensity depending on the space environment at the Moon, which is typically dominated by sodium and potassium; and (v) sunlight scattered by exospheric dust. For the latter, we consider dust that is present in the lunar exosphere due to a few different processes, including impact-generated ejecta, electrostatic transport, saltation-like cascades, as well as dust agitated by exploration and in-situ resource utilization (ISRU) activities.

  10. Light Visor

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Seasonal Affective Disorder is a form of depression brought on by reduced light. For some people, this can lead to clinical depression. NASA has conducted research in light therapy and employs it to help astronauts adjust internal rhythms during orbital flight. Dr. George Brainard, a medical researcher and NASA consultant, has developed a portable light therapy device, which is commercially available. The Light Visor allows continuous light therapy and can be powered by either batteries or electricity. Dr. Brainard continues to research various aspects of light therapy.

  11. A study of galactic light, extragalactic light, and galactic structure using Pioneer 10 observations of background starlight

    NASA Astrophysics Data System (ADS)

    Toller, G. N.

    The diffuse astronomical background sky brightness (background starlight) was determined over 95 percent of the sky using Pioneer 10 photometric measurements in sky regions where the zodiacal light is negligible. Brightness levels are presented at blue (3950-4850A) and red (5900-6800A) wavelengths. The B-R color index distribution is established over the celestial sphere. A computer model of our galaxy was constructed which computes the emitted and observed brightness from any volume element. The relation between DGL, direct starlight, and extinction along the line of sight is established. A small influence of galactic spiral structure on surface brightness levels exists at 1 = 2 deg (Sagittarius arm), 1 = 69 deg (Orion arm), and 1 = 288 deg (Carina arm). A correlation between brightness features and interstellar extinction is established. Analysis of the distribution of brightness peaks and dips and the location of the brightness symmetry plane establishes the Sun's elevation above the galactic plane as 12.2 + or - 2.1 pc.

  12. Implementation of a High-Altitude Balloon Payload to Study Thermospheric Wind Speeds through Redline Airglow Emissions of Atomic Oxygen at 630 nm via a Split-field Etalon Doppler Imager Utilizing a Fabry-Perot Interferometer.

    NASA Astrophysics Data System (ADS)

    Terry, L. B.; Fullmer, R.; Swenson, C.; Marchant, A.; Hooser, P.; Victors, J.; Muchmore, K.; Yin, L.

    2015-12-01

    Little data exists on the wind velocity characteristics of the upper atmosphere. The Red Line Air Glow Experiment is designed to measure the relative density and velocity of the thermosphere at altitudes approximately ranging between 250 and 350 km. To accomplish this, a Split-Field Etalon Imager will make doppler shift interferometry measurements of the oxygen redline at 630 nm wavelength airglow a using a high altitude balloon platform floating at 36 km. The imager collects up to 10 images per hour. Velocity resolution is within a 5 m/s. The Etalon is thermally controlled to within 1 deg C to achieve this goal. The pointing direction of the sensor is determined post-filght using GPS, IMU and three sun imaging sensors. An experimental star camera is included with a potential pointing accuracy of under 5 arc-min. The instrument first flew from Fort Sumner N,M., on August 26, 2014. Due to the short duration (3.5 hours) of the data collection period on this flight, a second flight was requested and awarded, to take place around September 10, 2015. This flight will allow for data collection over a 24 hour period. Both flight results will be included in the final presentation. This project was designed and built by an undergraduate team including students from physics, aerospace, electrical and mechanical engineering and management at both Utah State University and the University of Maryland Eastern Shores as a NASA's Undergraduate Student Instrument Project (USIP).

  13. Implementation of a High-Altitude Balloon Payload to Study Thermospheric Wind Speeds through Redline Airglow Emissions of Atomic Oxygen at 630 nm via a Split-field Etalon Doppler Imager Utilizing a Fabry-Perot Interferometer.

    NASA Astrophysics Data System (ADS)

    Terry, L. B.; Hooser, P.; Victors, J.; Muchmore, K.; Yin, L.; Fullmer, R.; Marchant, A.; Mogavero, M.; Dingwell, B.; Tuttle, J.; Swenson, C.; Polidan, J.; English, M.

    2014-12-01

    Little data exists on the wind velocity characteristics of the upper atmosphere. The Red Line Air Glow Experiment is designed to measure the relative density and velocity of the thermosphere at altitudes approximately ranging between 250 and 350 km. To accomplish this, a Split-Field Etalon Imager will make doppler shift interferometry measurements of the oxygen redline at 630 nm wavelength airglow a using a high altitude balloon platform floating at 36 km. The imager collects up to 10 images per hour. Velocity resolution is within a 5 m/s. The Etalon is thermally controlled to within 1 deg C to achieve this goal. The pointing direction of the sensor is determined post-filght using GPS, IMU and three sun imaging sensors. An experimental star camera is included with a potential pointing accuracy of under 5 arc-min. The instrument is currently scheduled for flight from Fort Sumner N,M., on August 15, 2014. Flight results will be included in the final presentation. This project was designed and built by an undergraduate team including students from physics, aerospace, electrical and mechanical engineering and management at both Utah State University and the University of Maryland Eastern Shores as a NASA's Undergraduate Student Instrument Project (USIP). .

  14. Light Reflector

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Ultra Sales, Inc.'s fluorescent lighting fixture gets a boost in reflectivity through installation of Lightdriver, a thin tough thermoplastic film plated with aluminum, capable of reflecting 95 percent of visible light striking it. Lightdriver increases brightness without adding bulbs, and allows energy savings by removing some bulbs because the mirrorlike surface cuts light loss generally occasioned by conventional low reflectivity white painted surface above the bulbs in many fluorescent fixtures. Forty-five percent reduction in lighting electricity is attainable.

  15. Lighting Utilization.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with lighting utilization. Its objective is for the student to be able to outline the development of lighting use and conservation and identify major types and operating characteristics of lamps used in electric lighting. Some topics…

  16. SCHOOL LIGHTING

    ERIC Educational Resources Information Center

    1965

    SEVERAL ARTICLES ON SCHOOL LIGHTING ARE CONTAINED IN THIS JOURNAL. THE TITLES AND AUTHORS INCLUDED ARE AS FOLLOWS--(1) "TODAY'S CONCEPTS IN SCHOOL LIGHTING" BY CHARLES D. GIBSON, (2) "CHALLENGE OF TOMMORROW'S LIGHTING" BY S.K. GUTH AND E.H. WITTE, (3) "PEEK PREVIEW OF THE WINDOWLESS SCHOOL" BY JAMES J. MORISSEAU, (4) "MAINTENANCE BEGINS BEFORE…

  17. Light Source

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Research on food growth for long duration spacecraft has resulted in a light source for growing plants indoors known as Qbeam, a solid state light source consisting of a control unit and lamp. The light source, manufactured by Quantum Devices, Inc., is not very hot, although it generates high intensity radiation. When Ron Ignatius, an industrial partner of WCSAR, realized that terrestrial plant research lighting was not energy efficient enough for space use, he and WCSAR began to experiment with light emitting diodes. A line of LED products was developed, and QDI was formed to market the technology. An LED-based cancer treatment device is currently under development.

  18. The Optical Extragalactic Background Light: Revisions and Further Comments

    NASA Astrophysics Data System (ADS)

    Bernstein, Rebecca A.

    2007-09-01

    We revise the measurements in our previous work of foreground zodiacal light (ZL) and diffuse Galactic light (DGL) that were used to measure the extragalactic background light (EBL). These changes result in a decrease of 8 and an increase of 0.3 in units of 10-9 ergs s-1 cm-2 sr-1 Å-1 (``cgs'' units) in the ZL and DGL flux, respectively. We therefore obtain revised values for the EBL of 6+/-4, 10+/-5, and 7+/-4 cgs in the HST WFPC2 U (F300W), V (F555W), and I (F814W) bands, respectively, from sources fainter than mV~23 AB mag. The revisions are dominated by the details of the tropospheric scattering models used to measure the ZL. We discuss these results in the context of faint number counts and diffuse EBL measurements at other wavelengths. In particular, we note that unless the slope of the galaxy counts increases beyond mV~30 AB mag, unresolved sources will contribute <0.2 cgs, which is far below the uncertainties achievable for any diffuse EBL measurement in the foreseeable future. Therefore, the best constraints on faint sources come from the resolved sources themselves. As in our earlier work, models are still required to derive the bolometric EBL (0.1-1000 μm) due to uncertainties in the mid-infrared consequently, our previous discussions of the bolometric EBL are not affected by the revisions presented here. Finally, we discuss the nature of the extended point-spread function (PSF) of ground-based telescopes and its impact on surface brightness measurements. In particular, we show that the slope and amplitude of extended PSFs vary considerably between telescopes and with time. We find no conclusive, single cause of extended PSFs, although atmospheric scattering is ruled out.

  19. Vandetanib plus docetaxel versus docetaxel as second-line treatment for patients with advanced non-small-cell lung cancer (ZODIAC): a double-blind, randomised, phase 3 trial

    PubMed Central

    Herbst, Roy S; Sun, Yan; Eberhardt, Wilfried E E; Germonpré, Paul; Saijo, Nagahiro; Zhou, Caicun; Wang, Jie; Li, Longyun; Kabbinavar, Fairooz; Ichinose, Yukito; Qin, Shukui; Zhang, Li; Biesma, Bonne; Heymach, John V; Langmuir, Peter; Kennedy, Sarah J; Tada, Hiroomi; Johnson, Bruce E

    2011-01-01

    Summary Background Vandetanib is a once-daily oral inhibitor of vascular endothelial growth factor receptor, epidermal growth factor receptor, and rearranged during transfection (RET) tyrosine kinases. In a randomised phase 2 study in patients with previously treated non-small-cell lung cancer (NSCLC), adding vandetanib 100 mg to docetaxel significantly improved progression-free survival (PFS) compared with docetaxel alone, including a longer PFS in women. These results supported investigation of the combination in this larger, definitive phase 3 trial (ZODIAC). Methods Between May, 2006, and April, 2008, patients with locally advanced or metastatic (stage IIIB–IV) NSCLC after progression following first-line chemotherapy were randomly assigned 1:1 through a third-party interactive voice system to receive vandetanib (100 mg/day) plus docetaxel (75 mg/m2 IV every 21 days; maximum six cycles) or placebo plus docetaxel. The primary objective was comparison of PFS between the two groups in the intention-to-treat population. Women were a coprimary analysis population. This study has been completed and is registered with ClinicalTrials.gov, number NCT00312377. Findings 1391 patients received vandetanib plus docetaxel (n=694 [197 women]) or placebo plus docetaxel (n=697 [224 women]). Vandetanib plus docetaxel led to a significant improvement in PFS versus docetaxel alone (hazard ratio [HR] 0·79, 97·58% CI 0·70–0·90; p<0·0001); median PFS was 4·0 months in the vandetanib group versus 3·2 months in placebo group. A similar improvement in PFS with vandetanib plus docetaxel versus placebo plus docetaxel was seen in women (HR 0·79, 0·62–1·00, p=0·024); median PFS was 4·6 months in the vandetanib group versus 4·2 months in the placebo group. Among grade 3 or higher adverse events, rash (63/689 [9%] vs 7/690 [1%]), neutropenia (199/689 [29%] vs 164/690 [24%]), and febrile neutropenia (61/689 [9%] vs 48/690 [7%]) were more common with vandetanib plus docetaxel

  20. Emergency Lighting

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A lighting system originally developed for NASA's Apollo and Skylab manned spacecraft resulted in a industrial spinoff and creation of a whole new company to produce and market the product line. The company is UDEC Corp., Waltham, Mass. UDEC's "Multi-Mode" electronic lighting systems are designed for plant emergency and supplemental use, such as night lighting, "always-on" stairwell lights and illuminated exit signs. Their advantages stem from the qualities demanded for spacecraft installation: extremely high fight output with very low energy drain, compactness, light weight, and high reliability. The Multi-Mode system includes long-life fluorescent lamps operated by electronic circuitry, a sealed battery that needs no maintenance for 10 years, and a solid-state battery charger. A typical emergency installation consists of a master module with battery and an eight watt lamp, together with four remote "Satellight" modules powered by the master's battery. As a night lighting system for maintenance or I security, UDEC fixtures can bypass the battery and 1 operate on normal current at a fraction of the energy 1 demand of conventional night lighting. Industrial customers have realized savings of better than ninety percent with UDEC night lights. UDEC started as a basement industry in 1972 but the company has already sold more than 1,000 lighting systems to building operators.

  1. On applicability of the photochemical-equilibrium approach for retrieval of O and H mesospheric distributions from the satellite-based measurements of the airglow emission and ozone concentration

    NASA Astrophysics Data System (ADS)

    Feigin, Alexander; Belikovich, Mikhail; Kulikov, Mikhail

    2016-04-01

    Atomic oxygen and hydrogen are known to be among key components for the photochemistry and energy balance of the Earth's atmosphere between approximately 80 and 100 km altitude (mesopause region). Therefore, obtaining information about the vertical distributions of O and H concentrations is an important task in studies of this region. Solving of this problem is rather difficult due to the absence of regular methods which allow one to direct measurements of distributions of these components in mesosphere. However, indirect methods used to retrieve O and H distributions from the satellite-based measurements of the OH and O2(1D) airglow emission, as well as the data of IR and microwave O3 measurements have a sufficiently long development history. These methods are rooted in the use of the condition of photochemical equilibrium of ozone density in the range of altitudes from 50 to 100 km. A significant factor is that an insufficient volume of such measurement data forces researchers to use approximate ("truncated") photochemical-equilibrium conditions. In particular, it is assumed that in the daytime the ozone production reaction is perfectly balanced by ozone photodissociation, whereas during the night the only ozone sink is the reaction of ozone with atomic hydrogen, which, in its turn, leads to formation of excited OH and airglow emission of the latter. The presentation analyzes applicability of the photochemical-equilibrium conditions both in the total and truncated forms for description of the spatio-temporal evolution of mesospheric ozone during a year. The analysis is based on year-long time series generated by a 3D chemical transport model, which reproduces correctly various types of atmosphere dynamics in the range of altitudes from 50 to 100 km. These data are used to determine statistics of the ratio between the correct (calculated dynamically) distributions of the O3 density and its uncontracted and truncated equilibrium values for the conditions of the

  2. EDITORIAL: Slow light Slow light

    NASA Astrophysics Data System (ADS)

    Boyd, Robert; Hess, Ortwin; Denz, Cornelia; Paspalakis, Emmanuel

    2010-10-01

    Research into slow light began theoretically in 1880 with the paper [1] of H A Lorentz, who is best known for his work on relativity and the speed of light. Experimental work started some 60 years later with the work of S L McCall and E L Hahn [2] who explored non-linear self-induced transparency in ruby. This field of research has burgeoned in the last 10 years, starting with the work of L Vestergaard Hau and coworkers on slow light via electromagnetically induced transparency in a Bose-Einstein condensate [3]. Many groups are now able to slow light down to a few metres per second or even stop the motion of light entirely [4]. Today, slow light - or more often `slow and fast light' - has become its own vibrant field with a strongly increasing number of publications. In broad scope, slow light research can be categorized in terms of the sort of physical mechanism used to slow down the light. One sort of slow light makes use of material dispersion. This dispersion can be the natural dispersion of the ordinary refractive index or can be the frequency dependence of some nonlinear optical process, such as electromagnetically induced transparency, coherent population oscillations, stimulated light scattering, or four-wave mixing processes. The second sort of slow light makes use of the wavelength dependence of artificially structured materials, such as photonic crystals, optical waveguides, and collections of microresonators. Material systems in which slow light has been observed include metal vapours, rare-earth-doped materials, Raman and Brillioun gain media, photonic crystals, microresonators and, more recently, metamaterials. A common feature of all of these schemes is the presence of a sharp single resonance or multiple resonances produced by an atomic transition, a resonance in a photonic structure, or in a nonlinear optical process. Current applications of slow light include a series of attractive topics in optical information processing, such as optical data

  3. Zodiacal Dust: Measurements by Mariner IV.

    PubMed

    Alexander, W M; McCracken, C W; Bohn, J L

    1965-09-10

    Data from the Mariner IV dust-particle experiment reveal an increase by a factor of 5 in the flux of interplanetary dust particles as the heliocentric distance from the sun increases. There is a variation in the slope of the cumulative flux-mass distribution, with the steepest slope for the distribution occurring between the planets. No enhancement of the flux in the vicinity of Mars was detected.

  4. Animals of the Chinese Zodiac. [Lesson Plan].

    ERIC Educational Resources Information Center

    2002

    The Chinese lunar calendar dates back to the second millennium BC. Unlike the western calendar, which numbers the years progressively from the birth of Jesus Christ, the Chinese calendar is cyclical. Each cycle is made up of 12 years--after the 12th year, the cycle is repeated. The Chinese associate each year of a 12-year cycle with an animal, and…

  5. Combination Light

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Rayovac TANDEM is an advanced technology combination work light and general purpose flashlight that incorporates several NASA technologies. The TANDEM functions as two lights in one. It features a long range spotlight and wide angle floodlight; simple one-hand electrical switching changes the beam from spot to flood. TANDEM developers made particular use of NASA's extensive research in ergonomics in the TANDEM's angled handle, convenient shape and different orientations. The shatterproof, water resistant plastic casing also draws on NASA technology, as does the shape and beam distance of the square diffused flood. TANDEM's heavy duty magnet that permits the light to be affixed to any metal object borrows from NASA research on rare earth magnets that combine strong magnetic capability with low cost. Developers used a NASA-developed ultrasonic welding technique in the light's interior.

  6. Light Learning.

    ERIC Educational Resources Information Center

    Cutshall, Sandy

    2002-01-01

    Describes a career and technical education program on photonics, the study, research, and development of equipment and concepts used in the transmission of information through light, including fiber optics and experimental laser technologies. (JOW)

  7. Light's twist

    PubMed Central

    Padgett, Miles

    2014-01-01

    That light travels in straight lines is a statement of the obvious. However, the energy and momentum flow within light beams can twist to form vortices such as eddies in a stream. These twists carry angular momentum, which can make microscopic objects spin, be used to encode extra information in communication systems, enable the design of novel imaging systems and allow new tests of quantum mechanics. PMID:25484612

  8. Controlling Light Harvesting with Light.

    PubMed

    Gwizdala, Michal; Berera, Rudi; Kirilovsky, Diana; van Grondelle, Rienk; Krüger, Tjaart P J

    2016-09-14

    When exposed to intense sunlight, all organisms performing oxygenic photosynthesis implement various photoprotective strategies to prevent potentially lethal photodamage. The rapidly responding photoprotective mechanisms, occurring in the light-harvesting pigment-protein antennae, take effect within tens of seconds, while the dramatic and potentially harmful light intensity fluctuations manifest also on shorter time scales. Here we show that, upon illumination, individual phycobilisomes from Synechocystis PCC 6803, which, in vivo under low-light conditions, harvest solar energy, and have the built-in capacity to switch rapidly and reversibly into light-activated energy-dissipating states. Simultaneously measured fluorescence intensity, lifetime, and spectra, compared with a multicompartmental kinetic model, revealed that essentially any subunit of a phycobilisome can be quenched, and that the core complexes were targeted most frequently. Our results provide the first evidence for fluorescence blinking from a biologically active system at physiological light intensities and suggest that the light-controlled switches to intrinsically available energy-dissipating states are responsible for a novel type of photoprotection in cyanobacteria. We anticipate other photosynthetic organisms to employ similar strategies to respond instantly to rapid solar light intensity fluctuations. A detailed understanding of the photophysics of photosynthetic antenna complexes is of great interest for bioinspired solar energy technologies. PMID:27546794

  9. Controlling Light Harvesting with Light.

    PubMed

    Gwizdala, Michal; Berera, Rudi; Kirilovsky, Diana; van Grondelle, Rienk; Krüger, Tjaart P J

    2016-09-14

    When exposed to intense sunlight, all organisms performing oxygenic photosynthesis implement various photoprotective strategies to prevent potentially lethal photodamage. The rapidly responding photoprotective mechanisms, occurring in the light-harvesting pigment-protein antennae, take effect within tens of seconds, while the dramatic and potentially harmful light intensity fluctuations manifest also on shorter time scales. Here we show that, upon illumination, individual phycobilisomes from Synechocystis PCC 6803, which, in vivo under low-light conditions, harvest solar energy, and have the built-in capacity to switch rapidly and reversibly into light-activated energy-dissipating states. Simultaneously measured fluorescence intensity, lifetime, and spectra, compared with a multicompartmental kinetic model, revealed that essentially any subunit of a phycobilisome can be quenched, and that the core complexes were targeted most frequently. Our results provide the first evidence for fluorescence blinking from a biologically active system at physiological light intensities and suggest that the light-controlled switches to intrinsically available energy-dissipating states are responsible for a novel type of photoprotection in cyanobacteria. We anticipate other photosynthetic organisms to employ similar strategies to respond instantly to rapid solar light intensity fluctuations. A detailed understanding of the photophysics of photosynthetic antenna complexes is of great interest for bioinspired solar energy technologies.

  10. Yearly variation and annual cycle of total column ozone over New Delhi (29°N, 77°E), India and Halley Bay (76°S, 27°W), British Antarctic Survey Station and its effect on night airglow intensity of OH(8, 3) for the period 1979-2005

    NASA Astrophysics Data System (ADS)

    Jana, P. K.; Saha, D. K.; Sarkar, D.

    2012-12-01

    A critical analysis made on the long-term monthly, seasonal, yearly variation and annual cycle of total column ozone (TCO) concentration at New Delhi (29°N, 77°E), India and Halley Bay (76°S, 27°W), a British Antarctic Service Station reveals more decline in yearly mean ozone concentration at Halley Bay than at New Delhi from 1979 to 2005. The nature of variations of monthly mean TCO during the months of August and September was the most identical with that of yearly mean ozone values at New Delhi and Halley Bay, respectively, for the same period. Annual cycles of TCO over these stations are completely different for the above period. The effect of O3 depletion on night airglow emission of OH(8, 3) line at New Delhi and Halley Bay has been studied. Calculations based on chemical kinetics show that the airglow intensity of OH(8, 3) has also been affected due to the depletion of O3 concentration. The yearly variations and annual cycle of intensities of OH(8, 3) line for the above two stations are depicted and compared. It has been shown that the rate of decrease of intensity of OH(8, 3) line was comparatively more at Halley Bay due to dramatic decrease of Antarctic O3 concentration.

  11. CONSTRUCTION OF AN EARTH MODEL: ANALYSIS OF EXOPLANET LIGHT CURVES AND MAPPING THE NEXT EARTH WITH THE NEW WORLDS OBSERVER

    SciTech Connect

    Oakley, P. H. H.; Cash, W.

    2009-08-01

    The orbital light curve of a terrestrial exoplanet will likely contain valuable information about the surface and atmospheric features of the planet, both in its overall shape and hourly variations. We have constructed an empirically based code capable of simulating observations of the Earth from any orientation, at any time of year with continuously updated cloud and snow coverage with a New Worlds Observatory. By simulating these observations over a full orbital revolution at a distance of 10 pc we determine that the detection of an obliquity or seasonal terrain change is possible at low inclinations. In agreement with other studies, a 4 m New Worlds Observer can accurately determine the rotation rate of the planet at a success rate from {approx}30% to 80% with only 5 days of observations depending on the signal to noise of the observations. We also attempt simple inversions of these diurnal light curves to sketch a map of the reflecting planet's surface features. This mapping technique is only successful with highly favorable systems and in particular requires that the cloud coverage must be lower than the Earth's average. Our test case of a 2 M {sub +} planet at 7 pc distance with low exo-zodiacal light and 25% cloud coverage produced crude, but successful results. Additionally, with these highly favorable systems NWO may be able to discern the presence of liquid surface water (or other smooth surfaces) though it requires a complex detection available only at crescent phases in high inclination systems.

  12. Light's Darkness

    ScienceCinema

    Padgett, Miles [University of Glasgow, Glasgow, Scotland

    2016-07-12

    Optical vortices and orbital angular momentum are currently topical subjects in the optics literature. Although seemingly esoteric, they are, in fact, the generic state of light and arise whenever three or more plane waves interfere. To be observed by eye the light must be monochromatic. Laser speckle is one such example, where the optical energy circulates around each black spot, giving a local orbital angular momentum. This talk with report three on-going studies. First, when considering a volume of interfering waves, the laser specs map out threads of complete darkness embedded in the light. Do these threads form loops? Links? Or even knots? Second, when looking through a rapidly spinning window, the image of the world on the other side is rotated: true or false? Finally, the entanglement of orbital angular momentum states means measuring how the angular position of one photons sets the angular momentum of another: is this an angular version of the EPR (Einstein, Podolsky, and Rosen) paradox?

  13. Lighting installations

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    Model computations that give the lay-out of a lighting installation have to be implemented in the real world. There, deviations from the ideal performance of just about every element of the installation will be felt. A list of possible sources of non-ideal behavior, based on practical experience, are: lamps, ballasts, reflectors, mounting position, sagging of lamps, and soiling. It is clear that with all possible deviations from the ideal the homogeneity of a real lighting installation can never be as good as the one computed. The only way to make sure it is nearly as good is by measurement of the actual light distribution. Then, an occasional adjustment or replacement may often yield a satisfactory result. This measurement should really be part of the installation contract.

  14. School Lighting.

    ERIC Educational Resources Information Center

    Rennhackkamp, W. M. H.

    Research gathered by the Functional Efficiency Division of the National Building Research Institute, South Africa, is aimed at providing lighting conditions under which the school child can produce his maximum effort with the least strain and fatigue. These favorable conditions are outlined along with specific examples of their realization in…

  15. No-Light Light Bulbs

    ERIC Educational Resources Information Center

    Modern Schools, 1976

    1976-01-01

    A thumbnail sketch of some of the light bulbs manufactured for a purpose other than seeing. These "dark" lamps perform varied tasks including keeping food fresh, detecting and preventing disease, spurring plant growth, heating, and copying printed material. (Author/MLF)

  16. Light Sources and Lighting Circuits

    NASA Astrophysics Data System (ADS)

    Honda, Hisashi; Suwa, Takumi; Yasuda, Takeo; Ohtani, Yoshihiko; Maehara, Akiyoshi; Okada, Atsunori; Komatsu, Naoki; Mannami, Tomoaki

    According to the Machinery Statistics of the Ministry of Economy, Trade and Industry, the production of incandescent lamps in Japan in 2007 was 990 million units (90.0% of the previous year's total), in which the production of incandescent lamps for general lighting was 110 million units (90.0% of the previous year's total) and of tungsten-halogen lamps was 44 million units (96.6% of the previous year's total). The production of fluorescent lamps was 927 million units (93.9% of the previous year's total), in which general fluorescent lamps, excluding those for LCD back lighting, was 320 million units (87.2% of the previous year's total). Also, the production of HID lamps was 10 million units (101.5% of the previous year's total). On the other hand, when the numbers of sales are compared with the sales of the previous year, incandescent lamps for general use was 99.8%, tungsten-halogen lamps was 96.9%, fluorescent lamps was 95.9%, and HID lamps was 98.9%. Self-ballasted fluorescent lamps alone showed an increase in sales as strong as 29 million units, or 121.7% of the previous year's sales. It is considered that the switchover of incandescent lamps to HID lamps was promoted for energy conservation and carbon dioxide reduction with the problem of global warming in the background. In regard to exhibitions, Lighting Fair 2007 was held in Tokyo in March, and LIGHTFAIR INTERNATIONAL 2007 was held in New York in May. Regarding academic conferences, LS:11 (the 11th International Symposium on the Science & Technology of Light Sources) was held in Shanghai in May, and the First International Conference on White LEDs and Solid State Lighting was held in Tokyo in November. Both conferences suggested that there are strong needs and concerns now about energy conservation, saving natural resources, and restrictions of hazardous materials. In regard to incandescent lamps, the development of products aiming at higher efficacy, electric power savings, and longer life was advanced by

  17. EDITORIAL: Controlling light with light

    NASA Astrophysics Data System (ADS)

    Hesselink, Lambertus; Feinberg, Jack; Roosen, Gerald

    2008-11-01

    The field of photorefractive physics and optics is mature and, although there is no significant commercial activity using photorefractive media, researchers in the field have had an extraordinary impact on many related areas of research and development. For example, in the late 1990s many of the telecom innovations and products were based on the interaction between light and matter. Examples include optical switches, filters, gratings, routers and light sources. The theory of multiple interacting beams of light inside a photosensitive medium, many of which were developed or further explored in photorefractive media, has found application in medicine, engineering, communication systems, displays and other photonics devices. On the occasions of the 30th anniversary of the theory of coupled wave analysis and the 10th anniversary of the meetings on Photorefractive Effects and Devices, it seemed appropriate to the meeting organizers of PR'07 to broaden the scope to include other related fields. The name of the meeting was changed to Controlling Light with Light: Photorefractive Effects, Photosensitivity, Fiber Gratings, Photonic Materials and More to attract a larger audience than traditionally would attend the more narrowly focused photorefractive meeting. To further disseminate the results of the 2007 meeting, Gerald Roosen proposed a special publication of original full research articles arising from key presentations at the meeting. The selection of papers in this Cluster Issue of Journal of Physics D: Applied Physics is the result of that initiative. We would like to thank all the authors for their contributions, the committee members for their valuable insight and efforts in helping to organize the meeting, and the Optical Society of America for their professional assistance throughout the preparation period of the meeting as well as during the three beautiful days in Lake Tahoe, CA.

  18. THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): A SOUNDING ROCKET PAYLOAD TO STUDY THE NEAR INFRARED EXTRAGALACTIC BACKGROUND LIGHT

    SciTech Connect

    Zemcov, M.; Bock, J.; Hristov, V.; Levenson, L. R.; Mason, P.; Arai, T.; Matsumoto, T.; Matsuura, S.; Tsumura, K.; Wada, T.; Battle, J.; Cooray, A.; Keating, B.; Renbarger, T.; Kim, M. G.; Lee, D. H.; Nam, U. W.; Sullivan, I.; Suzuki, K.

    2013-08-15

    The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, and electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.

  19. Light fantastic

    NASA Astrophysics Data System (ADS)

    2010-05-01

    The laser has become so ubiquitous that it would be impossible to acknowledge everyone who has played a role in its success. As Roy Glauber said at the 2005 Nobel-prize banquet, when it comes to lasers, "many hands make light work". And he should know: the prize Glauber shared with fellow optics pioneers John Hall and Theodore Hänsch is one of more than 10 Nobels awarded (so far!) for laser-related research. This timeline marking 50 years of the laser contains Physics World's pick of events from laser history, including prizes (gold text), applications (green) and "firsts" (blue).

  20. Lighting the Learning Environment.

    ERIC Educational Resources Information Center

    Fielding, Randall

    2000-01-01

    Explores the benefits and pitfalls of day lighting, indirect light, and full-spectrum lamps for general illumination and accent lighting in classrooms. Discussions include lighting considerations in areas where computers are used and fixture cost factors versus efficiency. (GR)

  1. Traffic Lights: Red Light Spells Danger.

    ERIC Educational Resources Information Center

    Reed, Chris

    2001-01-01

    A "traffic light" model provides youth groups with a means to evaluate the risk level of specific behaviors and agree upon the management of such behaviors. Designed for outdoor pursuits, the model may be used in other environments. Suggestions for ways to discuss red-light, yellow-light, and green-light behaviors are included. (SV)

  2. STRONG NEW CONSTRAINTS ON THE EXTRAGALACTIC BACKGROUND LIGHT IN THE NEAR- TO MID-INFRARED

    SciTech Connect

    Orr, M. R.; Krennrich, F.; Dwek, E.

    2011-06-01

    Direct measurements of the extragalactic background light (EBL) in the near-IR to mid-IR waveband are extremely difficult due to an overwhelming foreground from the zodiacal light that outshines the faint cosmological diffuse radiation field by more than an order of magnitude. Indirect constraints on the EBL are provided by {gamma}-ray observations of active galactic nuclei. Using the combination of the Fermi Gamma-Ray Space Telescope together with the current generation of ground-based air Cherenkov telescopes (H.E.S.S., MAGIC, and VERITAS) provides unprecedented sensitivity and spectral coverage for constraining the EBL in the near- to mid-IR. In this paper, we present new limits on the EBL based on the analysis of the broadband spectra of a select set of {gamma}-ray blazars covering 200 MeV to several TeV. The EBL intensity at 15 {mu}m is constrained to be 1.36 {+-} 0.58 nW m{sup -2} sr{sup -1}. We find that the fast evolution and baseline EBL models of Stecker et al., as well as the model of Kneiske et al., predict significantly higher EBL intensities in the mid-IR (15 {mu}m) than is allowed by the constraints derived here. In addition, the model of Franceschini et al. and the fiducial model of DomInguez et al. predict near- to mid-IR ratios smaller than that derived from our analysis. Namely, their intensities in the near-IR are too low while their intensities in the mid-IR are marginally too high. All of the aforementioned models are inconsistent with our analysis at the >3{sigma} level.

  3. Observations of the White Light Corona from Solar Orbiter and Solar Probe Plus

    NASA Astrophysics Data System (ADS)

    Howard, R. A.; Thernisien, A. F.; Vourlidas, A.; Plunkett, S. P.; Korendyke, C. M.; Sheeley, N. R.; Morrill, J. S.; Socker, D. G.; Linton, M. G.; Liewer, P. C.; De Jong, E. M.; Velli, M. M.; Mikic, Z.; Bothmer, V.; Lamy, P. L.

    2011-12-01

    The SoloHI instrument on Solar Orbiter and the WISPR instrument on Solar Probe+ will make white light coronagraphic images of the corona as the two spacecraft orbit the Sun. The minimum perihelia for Solar Orbiter is about 60 Rsun and for SP+ is 9.5 Rsun. The wide field of view of the WISPR instrument (about 105 degrees radially) corresponds to viewing the corona from 2.2 Rsun to 20 Rsun. Thus the entire Thomson hemisphere is contained within the telescope's field and we need to think of the instrument as being a traditional remote sensing instrument and then transitioning to a local in-situ instrument. The local behavior derives from the fact that the maximum Thomson scattering will favor the electron plasma close to the spacecraft - exactly what the in-situ instruments will be sampling. SoloHI and WISPR will also observe scattered light from dust in the inner heliosphere, which will be an entirely new spatial regime for dust observations from a coronagraph, which we assume to arise from dust in the general neighborhood of about half way between the observer and the Sun. As the dust grains approach the Sun, they evaporate and do not contribute to the scattering. A dust free zone has been postulated to exist somewhere inside of 5 Rsun where all dust is evaporated, but this has never been observed. The radial position where the evaporation occurs will depend on the precise molecular composition of the individual grains. The orbital plane of Solar Orbiter will gradually increase up to about 35 degrees, enabling a very different view through the zodiacal dust cloud to test the models generated from in-ecliptic observations. In this paper we will explore some of the issues associated with the observation of the dust and will present a simple model to explore the sensitivity of the instrument to observe such evaporations.

  4. Lighting Options for Homes.

    SciTech Connect

    Baker, W.S.

    1991-04-01

    This report covers many aspects of various lighting options for homes. Types of light sources described include natural light, artificial light, incandescent lamps, fluorescent lamps, and high intensity discharge lamps. A light source selection guide gives the physical characteristics of these, design considerations, and common applications. Color, strategies for efficient lighting, and types of lighting are discussed. There is one section giving tips for various situations in specific rooms. Rooms and types of fixtures are shown on a matrix with watts saved by using the recommended type lighting for that room and room location. A major emphasis of this report is saving energy by utilizing the most suitable, recommended lighting option. (BN)

  5. Mobile lighting apparatus

    DOEpatents

    Roe, George Michael; Klebanoff, Leonard Elliott; Rea, Gerald W; Drake, Robert A; Johnson, Terry A; Wingert, Steven John; Damberger, Thomas A; Skradski, Thomas J; Radley, Christopher James; Oros, James M; Schuttinger, Paul G; Grupp, David J; Prey, Stephen Carl

    2013-05-14

    A mobile lighting apparatus includes a portable frame such as a moveable trailer or skid having a light tower thereon. The light tower is moveable from a stowed position to a deployed position. A hydrogen-powered fuel cell is located on the portable frame to provide electrical power to an array of the energy efficient lights located on the light tower.

  6. Light up My Life

    ERIC Educational Resources Information Center

    Kellett, Sarah

    2015-01-01

    Simply stated, light is nature's way of transferring energy through space. Discussions of light usually refer to visible light, which is perceived by the human eye and is responsible for the sense of sight. We see however, only a small part of the light spectrum. Light connects us as we sit and tell yarns around camp fires. Yet, one in every four…

  7. A revolution in lighting

    NASA Astrophysics Data System (ADS)

    Pust, Philipp; Schmidt, Peter J.; Schnick, Wolfgang

    2015-05-01

    Key materials discoveries have prompted the rise of inorganic light-emitting diodes in the lighting industry. Remaining challenges are being addressed to further extend the impact of this technology in lighting, displays and other applications.

  8. Light 'Em Up.

    ERIC Educational Resources Information Center

    Wiese, Paul J.; Lindstrom, Chuck

    1998-01-01

    Provides advice on designing sports-field lighting that can help balance design with cost and lighting-system performance. Areas addressed include system installation, pole placement, light-spillage control, and maintenance. (GR)

  9. Optics for natural lighting

    NASA Technical Reports Server (NTRS)

    Edwards, H. B.

    1978-01-01

    Energy-saving optics utilize sky and sun for lighting. Innovative optical arrangements for transmitting outdoor light into building interiors are decribed using flat white and mirrored surfaces for converging and diverging light pipes.

  10. Integrated spatial light modulator

    NASA Astrophysics Data System (ADS)

    Yu, Dong X.; Storti, George M.; Wrigley, Charles Y.

    1992-08-01

    We described here an integrated spatial light modulator (SLM) employing Quantex electron trapping (ET) materials. The light modulation is accomplished by emission of ET material, upon incident coherent infrared light, where a pattern is written to by previous visible light excitation. The ET based spatial light modulators offer unique advantages over other SLM devices, such as capability of converting incoherent input to coherent light output and of integrating the modulator, the photodetector, and the memory into a single, rugged unit.

  11. PFP Emergency Lighting Study

    SciTech Connect

    BUSCH, M.S.

    2000-02-02

    NFPA 101, section 5-9 mandates that, where required by building classification, all designated emergency egress routes be provided with adequate emergency lighting in the event of a normal lighting outage. Emergency lighting is to be arranged so that egress routes are illuminated to an average of 1.0 footcandle with a minimum at any point of 0.1 footcandle, as measured at floor level. These levels are permitted to drop to 60% of their original value over the required 90 minute emergency lighting duration after a power outage. The Plutonium Finishing Plant (PFP) has two designations for battery powered egress lights ''Emergency Lights'' are those battery powered lights required by NFPA 101 to provide lighting along officially designated egress routes in those buildings meeting the correct occupancy requirements. Emergency Lights are maintained on a monthly basis by procedure ZSR-12N-001. ''Backup Lights'' are battery powered lights not required by NFPA, but installed in areas where additional light may be needed. The Backup Light locations were identified by PFP Safety and Engineering based on several factors. (1) General occupancy and type of work in the area. Areas occupied briefly during a shiftly surveillance do not require backup lighting while a room occupied fairly frequently or for significant lengths of time will need one or two Backup lights to provide general illumination of the egress points. (2) Complexity of the egress routes. Office spaces with a standard hallway/room configuration will not require Backup Lights while a large room with several subdivisions or irregularly placed rooms, doors, and equipment will require Backup Lights to make egress safer. (3) Reasonable balance between the safety benefits of additional lighting and the man-hours/exposure required for periodic light maintenance. In some plant areas such as building 236-Z, the additional maintenance time and risk of contamination do not warrant having Backup Lights installed in all rooms

  12. Dynamic Light and Shade.

    ERIC Educational Resources Information Center

    Hogarth, Burne

    This student artist's handbook provides illustrations and instructions for rendering three-dimensional form with light and shade. Focus is on realistic representation and imitation of natural phenomena. Fifteen chapters cover: (1) "Black-and-White Silhouette; (2) "Minimal Light"; (3) "Five Categories of Light and Shade"; (4) "Single-Source Light";…

  13. Let There Be Light!

    ERIC Educational Resources Information Center

    Enriquez, Denise

    1999-01-01

    Discusses the importance of proper lighting in spaces dedicated to reading and computer use, such as libraries. Topics include glare and reflection; contrast; shadows; damage to paper and bindings from light; aesthetic issues; different categories of lighting; types of fixtures; and achieving a balance by varying lighting and fixtures. (LRW)

  14. Lighting in Schools.

    ERIC Educational Resources Information Center

    Department of Education and Science, London (England).

    The application of good lighting principles to school design is discussed. Part 1 of the study is concerned with the general principles of light and vision as they affect lighting in schools. Parts 2 and 3 deal with the application of these principles to daylighting and artificial lighting. Part 4 discusses the circumstances in which the…

  15. Pedestrian Friendly Outdoor Lighting

    SciTech Connect

    Miller, N. J.; Koltai, R. N.; McGowan, T. K.

    2013-12-01

    The GATEWAY program followed two pedestrian-scale lighting projects that required multiple mockups – one at Stanford University in California and the other at Chautauqua Institution in upstate New York. The report provides insight into pedestrian lighting criteria, how they differ from street and area lighting criteria, and how solid-state lighting can be better applied in pedestrian applications.

  16. Quality studies of the data taking conditions for the Auger fluorescence detector

    SciTech Connect

    Caruso, R.; Fonte, R.; Insolia, A.; Petrera, S.; Rodriquez Martino, J.; /Rome U.,Tor Vergata

    2005-07-01

    As more than half of the Fluorescence Detector (FD) of the Auger Observatory is completed, data taking is becoming a routine job. It is then necessary to follow strict procedures to assure the quality of the data. An overview of the data taking methods is given. The nature of the FD background signal is due to the night sky brightness (stars and planet faint light, moonlight, twilight, airglow, zodiacal and artificial light) and to the electronic background (photomultiplier and electronic noise). The analysis of the fluctuations in the FADC signal (variance analysis), directly proportional to the background mean light level, performed for each night of data taking is used to monitor the FD background signal. The data quality is analyzed using different techniques, described in detail. Examples of trigger rates, number of stereo events, dead time due to moonlight, weather or hardware problems are given. The analysis comprises several months of data taking, giving an overview of the FD capabilities, performance and allowing a systematic study of data and their correlation with the environment.

  17. Concept of white light in stage lighting

    NASA Astrophysics Data System (ADS)

    Rinaldi, Mauricio R.

    2002-06-01

    In perceiving objects, generally we see them in a white light situation. But, actually, there is not an absolute white, in such a manner that the different light sources have a determined kind of white, what it is known as color temperature. Even the white light may be of different kinds (different color temperature), the individual mind tends to perceive it as the same kind of white, that is to say, there is in our mind a psychological function by which we operate an integration in the perception in order to do the object perceptually invariable. On the other hand, it is a common practice in stage lighting to use color light sources. It is a well known phenomenon that a color of light produces a change in the object color perception. However, when we go to theater, we see the objects as having their real color, even if the lighting is not white. In this paper the concept of white light in stage lighting is presented, showing its possibilities of aesthetical expression.

  18. Lights illuminate surfaces superluminally

    NASA Astrophysics Data System (ADS)

    Nemiroff, Robert J.; Zhong, Qi; Lilleskov, Elias

    2016-07-01

    When a light bulb is turned on, light moves away from it at speed c, by definition. When light from this bulb illuminates a surface, however, this illumination front is not constrained to move at speed c. A simple proof is given that this illumination front always moves faster than c. Generalized, when any compact light source itself varies, this information spreads across all of the surfaces it illuminates at speeds faster than light.

  19. The Properties of Light

    NASA Astrophysics Data System (ADS)

    Haglund, Richard F.

    The mystery of light has formed the core of creation stories in every culture, and attracted the earnest attentions of philosophers since at least the fifth century BCE. Their questions have ranged from how and what we see, to the interaction of light with material bodies, and finally to the nature of light itself. This chapter begins with a brief intellectual history of light from ancient Greece to the end of the 19th century. After introducing the physical parameterization of light in terms of standard units, three concepts of light are introduced: light as a wave, light as a quantum particle, and light as a quantum field. After highlighting the distinctive characteristics of light beams from various sources - thermal radiation, luminescence from atoms and molecules, and synchrotron light sources - the distinctive physical characteristics of light beams are examined in some detail. The chapter concludes with a survey of the statistical and quantum-mechanical properties of light beams. In the appropriate limits, this treatment not only recovers the classical description of light waves and the semiclassical view of light as a stream of quanta, but also forms a consistent description of quantum phenomena - such as interference phenomena generated by single photons - that have no classical analogs.

  20. Measurements of Extragalactic Background Light from the Far UV to the Far IR from Deep Ground- and Space-based Galaxy Counts

    NASA Astrophysics Data System (ADS)

    Driver, Simon P.; Andrews, Stephen K.; Davies, Luke J.; Robotham, Aaron S. G.; Wright, Angus H.; Windhorst, Rogier A.; Cohen, Seth; Emig, Kim; Jansen, Rolf A.; Dunne, Loretta

    2016-08-01

    We combine wide and deep galaxy number-count data from the Galaxy And Mass Assembly, COSMOS/G10, Hubble Space Telescope (HST) Early Release Science, HST UVUDF, and various near-, mid-, and far-IR data sets from ESO, Spitzer, and Herschel. The combined data range from the far UV (0.15 μm) to far-IR (500 μm), and in all cases the contribution to the integrated galaxy light (IGL) of successively fainter galaxies converges. Using a simple spline fit, we derive the IGL and the extrapolated IGL in all bands. We argue that undetected low-surface-brightness galaxies and intracluster/group light are modest, and that our extrapolated-IGL measurements are an accurate representation of the extragalactic background light (EBL). Our data agree with most earlier IGL estimates and with direct measurements in the far IR, but disagree strongly with direct estimates in the optical. Close agreement between our results and recent very high-energy experiments (H.E.S.S. and MAGIC) suggests that there may be an additional foreground affecting the direct estimates. The most likely culprit could be the adopted model of zodiacal light. Finally we use a modified version of the two-component model to integrate the EBL and obtain measurements of the cosmic optical background (COB) and cosmic infrared background of {24}-4+4 nW m-2 sr-1 and {26}-5+5 nW m-2 sr-1 respectively (48%:52%). Over the next decade, upcoming space missions such as Euclid and the Wide Field Infrared Space Telescope will have the capacity to reduce the COB error to <1%, at which point comparisons to the very high-energy data could have the potential to provide a direct detection and measurement of the reionization field.

  1. Measurements of Extragalactic Background Light from the Far UV to the Far IR from Deep Ground- and Space-based Galaxy Counts

    NASA Astrophysics Data System (ADS)

    Driver, Simon P.; Andrews, Stephen K.; Davies, Luke J.; Robotham, Aaron S. G.; Wright, Angus H.; Windhorst, Rogier A.; Cohen, Seth; Emig, Kim; Jansen, Rolf A.; Dunne, Loretta

    2016-08-01

    We combine wide and deep galaxy number-count data from the Galaxy And Mass Assembly, COSMOS/G10, Hubble Space Telescope (HST) Early Release Science, HST UVUDF, and various near-, mid-, and far-IR data sets from ESO, Spitzer, and Herschel. The combined data range from the far UV (0.15 μm) to far-IR (500 μm), and in all cases the contribution to the integrated galaxy light (IGL) of successively fainter galaxies converges. Using a simple spline fit, we derive the IGL and the extrapolated IGL in all bands. We argue that undetected low-surface-brightness galaxies and intracluster/group light are modest, and that our extrapolated-IGL measurements are an accurate representation of the extragalactic background light (EBL). Our data agree with most earlier IGL estimates and with direct measurements in the far IR, but disagree strongly with direct estimates in the optical. Close agreement between our results and recent very high-energy experiments (H.E.S.S. and MAGIC) suggests that there may be an additional foreground affecting the direct estimates. The most likely culprit could be the adopted model of zodiacal light. Finally we use a modified version of the two-component model to integrate the EBL and obtain measurements of the cosmic optical background (COB) and cosmic infrared background of {24}-4+4 nW m‑2 sr‑1 and {26}-5+5 nW m‑2 sr‑1 respectively (48%:52%). Over the next decade, upcoming space missions such as Euclid and the Wide Field Infrared Space Telescope will have the capacity to reduce the COB error to <1%, at which point comparisons to the very high-energy data could have the potential to provide a direct detection and measurement of the reionization field.

  2. Feasibility of Heliospheric Imaging from Near Earth

    NASA Astrophysics Data System (ADS)

    DeForest, C. E.; Howard, T. A.

    2015-05-01

    Imaging solar wind structures via Thomson scattered sunlight has proved important to understanding the inner heliosphere. The principal challenge of heliospheric imaging is background subtraction: typical solar wind features are fainter than the zodiacal light and starfield by 2-3 orders of magnitude. Careful post-processing is required to separate the solar wind signal from the static background. Remnant background, and not photon noise, is the dominant noise source in current STEREO data. We demonstrate that 10× shorter exposure times would not strongly affect the noise level in these data. Further, we demonstrate that current processing techniques are sufficient to separate not only the existing background of the STEREO images but also diffuse variable backgrounds such as are expected to be seen from low Earth orbit. We report on a hare-and-hounds style study, demonstrating blind signal extraction from STEREO/HI-2 data that have been degraded by the addition of large-scale, time-dependent artifacts to simulate viewing through airglow or high-altitude aurora. We demonstrate removal of these effects via image processing, with little degradation compared to the original. Even with as few as three highly degraded source images over 48 hr, it is possible to detect and track large coronal mass ejections more than 40° from the Sun. This implies that neither the high altitude aurora discovered by Coriolis/SMEI, nor airglow effects seen from low Earth orbit, are impediments to a hypothetical next-generation heliospheric imager in low Earth orbit; and also that post-processing is as important to heliospheric image qualitiy as are optical contamination effects.

  3. FEASIBILITY OF HELIOSPHERIC IMAGING FROM NEAR EARTH

    SciTech Connect

    DeForest, C. E.; Howard, T. A.

    2015-05-10

    Imaging solar wind structures via Thomson scattered sunlight has proved important to understanding the inner heliosphere. The principal challenge of heliospheric imaging is background subtraction: typical solar wind features are fainter than the zodiacal light and starfield by 2-3 orders of magnitude. Careful post-processing is required to separate the solar wind signal from the static background. Remnant background, and not photon noise, is the dominant noise source in current STEREO data. We demonstrate that 10× shorter exposure times would not strongly affect the noise level in these data. Further, we demonstrate that current processing techniques are sufficient to separate not only the existing background of the STEREO images but also diffuse variable backgrounds such as are expected to be seen from low Earth orbit. We report on a hare-and-hounds style study, demonstrating blind signal extraction from STEREO/HI-2 data that have been degraded by the addition of large-scale, time-dependent artifacts to simulate viewing through airglow or high-altitude aurora. We demonstrate removal of these effects via image processing, with little degradation compared to the original. Even with as few as three highly degraded source images over 48 hr, it is possible to detect and track large coronal mass ejections more than 40° from the Sun. This implies that neither the high altitude aurora discovered by Coriolis/SMEI, nor airglow effects seen from low Earth orbit, are impediments to a hypothetical next-generation heliospheric imager in low Earth orbit; and also that post-processing is as important to heliospheric image qualitiy as are optical contamination effects.

  4. Lighting Turns On Learning

    ERIC Educational Resources Information Center

    Modern Schools, 1974

    1974-01-01

    Attempts to resolve the two factors instrumental in ineffectively lighted new classrooms: planning without taking newer design techniques into consideration and confusion regarding the lighting objectives in the classroom. (Author/EA)

  5. The Light Airplane

    NASA Technical Reports Server (NTRS)

    Driggs, Ivan H.

    1925-01-01

    This report begins with a review and analysis of the work being done to develop light airplanes in the U.S. and abroad. A technical discussion of the construction and innovations in light airplanes is then presented.

  6. Lights in the darkness

    NASA Astrophysics Data System (ADS)

    Buckmaster, Harvey A.

    2015-06-01

    In reply to the feature article “Lighting up the world” (March pp31-33) about Study After Sunset, an initiative to bring safe, off-grid lighting to school-age children in areas without mains electricity.

  7. Automatic lighting controls demonstration

    SciTech Connect

    Rubinstein, F.; Verderber, R.

    1990-03-01

    The purpose of this work was to demonstrate, in a real building situation, the energy and peak demand reduction capabilities of an electronically ballasted lighting control system that can utilize all types of control strategies to efficiently manage lighting. The project has demonstrated that a state-of-the-art electronically ballasted dimmable lighting system can reduce energy and lighting demand by as least 50% using various combinations of control strategies. By reducing light levels over circulation areas (tuning) and reducing after hours light levels to accommodate the less stringent lighting demands of the cleaning crew (scheduling), lighting energy consumption on weekdays was reduced an average of 54% relative to the initial condition. 10 refs., 14 figs., 3 tabs.

  8. BETTER LIGHTING THROUGH RESEARCH.

    ERIC Educational Resources Information Center

    CROUCH, C.L.

    RESEARCH REVOLUTIONIZES SCHOOL LIGHTING AND BUILDINGS. NEW EDUCATIONAL CONCEPTS DEMAND FLEXIBLE LIGHTING DESIGN. VISUAL AND AUDITORY AIDS MUST BE CONSIDERED. LIGHT REQUIRED ON THE TASK DEPENDS ON THE DETAIL TO BE SEEN INVOLVING ITS CONFIGURATION, SIZE, AND CONTRAST WITH ITS BACKGROUND. THE BRIGHTNESS OF SURROUNDINGS MUST BE DESIGNED TO BALANCE…

  9. Seeing the Light

    ERIC Educational Resources Information Center

    Sportel, Samuel; Bruxvoort, Crystal; Jadrich, James

    2009-01-01

    Conceptually, students are typically introduced to light as a type of wave. However, children struggle to understand this model because it is highly abstract. Light can be represented more concretely using the photon model. According to this scientific model, light emanates from sources as tiny "packets" of energy (called "photons") that move in…

  10. CSM/LM Lighting

    NASA Technical Reports Server (NTRS)

    Interbartolo, Michael

    2009-01-01

    Objectives include: a)Identify the types and uses of the various lighting components: Interior (CM, LM), Exterior (CSM, LM); b) Explain the purpose and locations of electroluminescent (EL) and radioluminescent (RL)lighting techniques; c) Understand the use of various D&C lighting components; and d) Understand in-flight anomalies.

  11. Architectural Physics: Lighting.

    ERIC Educational Resources Information Center

    Hopkinson, R. G.

    The author coordinates the many diverse branches of knowledge which have dealt with the field of lighting--physiology, psychology, engineering, physics, and architectural design. Part I, "The Elements of Architectural Physics", discusses the physiological aspects of lighting, visual performance, lighting design, calculations and measurements of…

  12. Emergency lighting gets 'smarter'.

    PubMed

    Daniels, Alan

    2012-10-01

    Alan Daniels, business development director of emergency lighting specialist, P4, describes the latest trends in, and requirements for, emergency lighting, a vital part of the building services footprint in hospitals and other healthcare premises. He also explains how those responsible for the safe operation of emergency lighting system can ensure they comply with their obligations under the law.

  13. Light in man's environment.

    PubMed

    Marshall, J

    2016-02-01

    Light in the form of solar radiation influenced early civilisations and resulted in the independent development of a number of sun-worshipping dieties. These were of particular importance as hunter gatherers transformed into settled agricultural societies. All artificial light sources were synonymous with fire, and early civilisations began to expand their visual day by burning brands, oil, and candles. Fire-based light sources extended for thousands of years and were still present in the era of gas lighting. Light meant fire risk. The advent of incandescent bulbs and the era of electric lighting really only expanded in the early part of the twentieth century. Fluorescent lighting became available in the 1940s, and today the drive for low energy has resulted in a plethora of novel light sources-in particular, light-emitting diodes (LEDs). Evolution governed the development of the eye in relation to roughly 12 h of light gradually changing to 12 h of darkness. Today almost daylight levels can be achieved abruptly at the flick of a switch. Many studies have demonstrated the spectral dependence of eye health, with the retinal hazard zone associated with wavelengths in the blue, peaking at 441 nm- many of today's low-energy sources peak in this region. Given the increased longevity and artificial light sources emitting at biologically unfriendly wavelengths, attention has to be directed towards light in man's environment as a risk factor in age-related ocular diseases.

  14. Plant Light Measurement & Calculations.

    ERIC Educational Resources Information Center

    Hershey, David R.

    1991-01-01

    The differences between measuring light intensity for the human eye and for plant photosynthesis are discussed. Conversion factors needed to convert various units of light are provided. Photosynthetic efficiency and the electricity costs for plants to undergo photosynthesis using interior lighting are described. (KR)

  15. Outdoor Lighting Ordinances

    NASA Astrophysics Data System (ADS)

    Davis, S.

    2004-05-01

    A principal means to prevent poor exterior lighting practices is a lighting control ordinance. It is an enforceable legal restriction on specific lighting practices that are deemed unacceptable by the government body having jurisdiction. Outdoor lighting codes have proven to be effective at reducing polluting and trespassing light. A well written exterior lighting code will permit all forms of necessary illumination at reasonable intensities, but will demand shielding and other measures to prevent trespass and light pollution. A good code will also apply to all forms of outdoor lighting, including streets, highways, and exterior signs, as well as the lighting on dwellings, commercial and industrial buildings and building sites. A good code can make exceptions for special uses, provided it complies with an effective standard. The IDA Model Lighting Ordinance is a response to these requests. It is intended as an aid to communities that are seeking to take control of their outdoor lighting, to "take back the night" that is being lost to careless and excessive use of night lighting.

  16. Pressurized lighting system

    NASA Technical Reports Server (NTRS)

    Phlieger, G. A.

    1973-01-01

    Safe lighting assembly has been constructed for hostile environments. Assembly is ventilated by inert gas to prolong life of lamps. Lighting assembly contains control box, number of lamps connected in parallel, several pilot lights, and ventilating circuit. Control box is provided with components for monitoring and controlling flow of ventilating gas through lamp assemblies.

  17. Light in man's environment.

    PubMed

    Marshall, J

    2016-02-01

    Light in the form of solar radiation influenced early civilisations and resulted in the independent development of a number of sun-worshipping dieties. These were of particular importance as hunter gatherers transformed into settled agricultural societies. All artificial light sources were synonymous with fire, and early civilisations began to expand their visual day by burning brands, oil, and candles. Fire-based light sources extended for thousands of years and were still present in the era of gas lighting. Light meant fire risk. The advent of incandescent bulbs and the era of electric lighting really only expanded in the early part of the twentieth century. Fluorescent lighting became available in the 1940s, and today the drive for low energy has resulted in a plethora of novel light sources-in particular, light-emitting diodes (LEDs). Evolution governed the development of the eye in relation to roughly 12 h of light gradually changing to 12 h of darkness. Today almost daylight levels can be achieved abruptly at the flick of a switch. Many studies have demonstrated the spectral dependence of eye health, with the retinal hazard zone associated with wavelengths in the blue, peaking at 441 nm- many of today's low-energy sources peak in this region. Given the increased longevity and artificial light sources emitting at biologically unfriendly wavelengths, attention has to be directed towards light in man's environment as a risk factor in age-related ocular diseases. PMID:26742864

  18. Light On the Behavior of Light Bulbs.

    ERIC Educational Resources Information Center

    Armstrong, H. L.

    1985-01-01

    Discusses a problem (on page 523 of "College Physics," by Sears, Zemansky, and Young, published by Addison-Wesley, 1980) concerning light bulbs and resistance. Shows why the assumption of constant resistance is unrealistic and provides guidelines for revision. (DH)

  19. Deep IRAC Imaging Lensing Galaxy Clusters for JWST 'First Light' Search

    NASA Astrophysics Data System (ADS)

    Yan, Haojing; Conselice, Christopher; Windhorst, Rogier; Cohen, Seth; Alpaslan, Mehmet; Zitrin, Adi; Broadhurst, Tom; Frye, Brenda; Driver, Simon; Robotham, Aaron; Hopkins, Andrew; Wyithe, Staurt; Jansen, Rolf; Hathi, Nimish; Mechtley, Matthew; Ryan, Russell; Rutkowski, Michael; Finkelstein, Steven; Koekemoer, Anton

    2016-08-01

    JWST has a key goal to search for First Light objects beyond z>10. Our 110-hr JWST GTO program, 'Webb Medium-Deep Fields' (WMDF), will target both blank and lensed fields to probe both the bright and the faint ends of the galaxy luminosity function at z > 10. While a number of well studied lensing clusters exist, not all of them are optimal for the JWST search of First Light objects, either because of their low Ecliptic latitudes (and hence high Zodiacal background) or because of their strong intra-cluster light (ICL) at the critical curve regions corresponding to the redshifts of interest. For this reason, our WMDF candidate lensing targets will include some recently discovered, high-mass (log[M/Msun] ~ 15) galaxy clusters, which we choose either because of their high Ecliptic latitude (beta > 40 deg) or because of their extreme compactness that minimizes the impact of the ICL. As part of our effort to collect ancillary data for these new systems to finalize the target list, we propose IRAC observations for 13 of them that are lacking sufficient data. These 3.6/4.5um data will be critical for our guaranteed JWST program: (1) they will greatly facilitate the modeling of the straylight that JWST will suffer in 1--5 um (the key range to search for z>10--20 objects), a problem that has recently been identified. If left untreated, such straylight components would severely hamper the detection of faint sources in a lensing field. The JWST observations alone would be difficult to separate the ICL from the straylight at the level needed. (2) the new 3.6/4.5um data will best match our deep optical imaging and spectroscopy at HST, Gemini, LBT and MMT. We will derive accurate photometric redshifts for any lensed background galaxies (at z<6) and most member galaxies in the outskirts, which will be critical in refining the mass profile through strong/weak lensing analysis. Finally, we note that these data will be highly valuable for the study of these clusters themselves

  20. Dictionary of lighting engineering

    SciTech Connect

    Zimmermann, R.

    1989-01-01

    Distributors in the socialist countries, FRG, Switzerland and Austria: VEB Verlag Technik, Berlin, FRG Lighting engineering has developed progressively in all industrialized countries during the past few years. This development has been accompanied by a growing number of publications offering a flood of information and documentation in various languages, mainly in English, German, Russian, French and Japanese, and involving a more and more extensive and specific vocabulary. In this book, following fields are covered: fundamentals of lighting engineering; generation of light; measurement of light, radiation and color; lighting engineering and radiation detectors.

  1. Quantifying light pollution

    NASA Astrophysics Data System (ADS)

    Cinzano, P.; Falchi, F.

    2014-05-01

    In this paper we review new available indicators useful to quantify and monitor light pollution, defined as the alteration of the natural quantity of light in the night environment due to introduction of manmade light. With the introduction of recent radiative transfer methods for the computation of light pollution propagation, several new indicators become available. These indicators represent a primary step in light pollution quantification, beyond the bare evaluation of the night sky brightness, which is an observational effect integrated along the line of sight and thus lacking the three-dimensional information.

  2. Lighting ordinances: why? how?

    NASA Astrophysics Data System (ADS)

    Crawford, D. L.

    1996-11-01

    For those interested in combating the adverse effects of light pollution, both on astronomy and on the general public, one of the strongest "allies" is the existence of an outdoor lighting control ordinance. Such a law sets a community standard for good lighting, thus minimizing glare, light trespass, the clutter of bad lighting, and energy waste. The process of obtaining such an ordinance can be quite time consuming, but it has the added value of educating most of the segments of a community about the issues, and of building allies to the cause.

  3. High Intensity Lights

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Xenon arc lamps developed during the Apollo program by Streamlight, Inc. are the basis for commercial flashlights and emergency handlights. These are some of the brightest portable lights made. They throw a light some 50 times brighter than automobile high beams and are primarily used by police and military. The light penetrates fog and smoke and returns less back-scatter light. They are operated on portable power packs as boat and auto batteries. An infrared model produces totally invisible light for covert surveillance.

  4. Light Emitting Diode (LED)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A special lighting technology was developed for space-based commercial plant growth research on NASA's Space Shuttle. Surgeons have used this technology to treat brain cancer on Earth, in two successful operations. The treatment technique called photodynamic therapy, requires the surgeon to use tiny pinhead-size Light Emitting Diodes (LEDs) (a source releasing long wavelengths of light) to activate light-sensitive, tumor-treating drugs. Laser light has been used for this type of surgery in the past, but the LED light illuminates through all nearby tissues, reaching parts of a tumor that shorter wavelengths of laser light carnot. The new probe is safer because the longer wavelengths of light are cooler than the shorter wavelengths of laser light, making the LED less likely to injure normal brain tissue near the tumor. It can also be used for hours at a time while still remaining cool to the touch. The LED probe consists of 144 tiny pinhead-size diodes, is 9-inches long, and about one-half-inch in diameter. The small balloon aids in even distribution of the light source. The LED light source is compact, about the size of a briefcase, and can be purchased for a fraction of the cost of a laser. The probe was developed for photodynamic cancer therapy by the Marshall Space Flight Center under a NASA Small Business Innovative Research program grant.

  5. Photonic crystal light source

    DOEpatents

    Fleming, James G.; Lin, Shawn-Yu; Bur, James A.

    2004-07-27

    A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

  6. Navigation lights color study

    NASA Astrophysics Data System (ADS)

    Barbosa, Jose G.; Alberg, Matthew T.

    2015-05-01

    The chromaticity of navigation lights are defined by areas on the International Commission on Illumination (CIE) 1931 chromaticity diagram. The corner coordinates for these areas are specified in the International Regulations for Prevention of Collisions at Sea, 1972 (72 COLREGS). The navigation light's color of white, red, green, and yellow are bounded by these areas. The chromaticity values specified by the COLREGS for navigation lights were intended for the human visual system (HVS). The HVS can determine the colors of these lights easily under various conditions. For digital color camera imaging systems the colors of these lights are dependent on the camera's color spectral sensitivity, settings, and color correction. At night the color of these lights are used to quickly determine the relative course of vessels. If these lights are incorrectly identified or there is a delay in identifying them this could be a potential safety of ship concern. Vessels that use camera imaging systems exclusively for sight, at night, need to detect, identify, and discriminate navigation lights for navigation and collision avoidance. The introduction of light emitting diode (LED) lights and lights with different spectral signatures have the potential to be imaged very differently with an RGB color filter array (CFA) color camera than with the human eye. It has been found that some green navigation lights' images appear blue verse green. This has an impact on vessels that use camera imaging systems exclusively for navigation. This paper will characterize color cameras ability to properly reproducing navigation lights' color and survey a set of navigation light to determine if they conform to the COLREGS.

  7. Measuring scintillation light using Visible Light

    NASA Astrophysics Data System (ADS)

    Chavarria, Alvaro

    2006-11-01

    A new search for the neutron electric dipole moment (EDM) using ultra cold neutrons proposes an improvement on the neutron EDM by two orders of magnitude over the current limit (to 10-28 e*cm). Detection of scintillation light in superfluid ^4He is at the heart of this experiment. One possible scheme to detect this light is to use wavelength-shifting fibers in the superfluid ^4He to collect the scintillation light and transport it out of the measuring cell. The fiber terminates in a visible light photon counter (VLPC). VLPCs are doped, silicon based, solid state photomultipliers with high quantum efficiency (up to 80%) and high gain ( 40000 electrons per converted photon). Moreover, they are insensitive to magnetic fields and operate at temperatures of 6.5K. A test setup has been assembled at Duke University using acrylic cells wrapped in wavelength-shifting fibers that terminate on VLPCs. This setup is being used to evaluate the feasibility of this light detection scheme. The results obtained in multiple experiments done over the past summer (2006) and the current status of the project will be presented at the conference.Reference:A New Search for the Neutron Electric Dipole Moment, funding pre-proposal by the EDM collaboration; R. Golub and S. Lamoreaux, Phys. Rep. 237, 1 (1994).

  8. Studying Light Color using White LED Lighting

    NASA Astrophysics Data System (ADS)

    Yamagishi, Misako; Yamaba, Kazuo; Nagata, Manori; Kubo, Chiho; Nokura, Kunihiro

    Recently, white Light Emitting Diodes (LEDs) are receiving attention worldwide as new lighting devices. This study examined effects of a lighting application on performance using white LEDs. The light color—the correlated color temperature (CCT) —was assessed. It affected to psychological states and physiological conditions. Three CCT conditions were respectively set for the experiment: 2500 K, 5000 K, and 8200 K. In all, 20 younger subjects (20-30 years old), 15 middle-aged to elderly subjects (45-60 years old) and 12 elderly subjects (over 65 years-old) participated. They were presented a Numerical Verification (NV) task for performance measurement. The psychological states on performance were evaluated using the lighting assessment questionnaire. The physiological conditions were recorded using an electrocardiograph. Results show that the effects of CCT differ among age groups. Especially, the performance of younger subjects might differ from CCT conditions; elderly subjects are affected by CCT condition because of their visual acuity or response to contrast of objects.

  9. Light Emitting Diodes (LEDs)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A special lighting technology was developed for space-based commercial plant growth research on NASA's Space Shuttle. Surgeons have used this technology to treat brain cancer on Earth, in two successful operations. The treatment technique, called Photodynamic Therapy, requires the surgeon to use tiny, pinhead-size Light Emitting Diodes (LEDs) (a source that releases long wavelengths of light ) to activate light-sensitive, tumor-treating drugs. 'A young woman operated on in May 1999 has fully recovered with no complications and no evidence of the tumor coming back,' said Dr. Harry Whelan, a pediatric neurologist at the Medical Hospital of Wisconsin in Milwaukee. Laser light has been used for this type of surgery in the past, but the LED light illuminates through all nearby tissues, reaching parts of a tumor that shorter wavelengths of laser light carnot. The new probe is safer because the longer wavelengths of light are cooler than the shorter wavelengths of laser light, making the LED less likely to injure normal brain tissue near the tumor. It can be used for hours at a time while still remaining cool to the touch. The LED light source is compact, about the size of a briefcase, and can be purchased for a fraction of the cost of a laser. The LEDs, developed and managed by NASA's Marshall Space Flight Center, have been used on seven Space Shuttle flights inside the Microgravity Astroculture Facility. This technology has also been successfully used to further commercial research in crop growth.

  10. Light metal production

    DOEpatents

    Fan, Qinbai

    2016-04-19

    An electrochemical process for the production of light metals, particularly aluminum. Such a process involves contacting a light metal source material with an inorganic acid to form a solution containing the light metal ions in high concentration. The solution is fed to an electrochemical reactor assembly having an anode side containing an anode and a cathode side containing a cathode, with anode side and the cathode side separated by a bipolar membrane, with the solution being fed to the anode side. Light metal ions are electrochemically transferred through the bipolar membrane to the cathode side. The process further involves reducing the light metal ions to light metal powder. An associated processing system is also provided.

  11. National Synchrotron Light Source

    ScienceCinema

    BNL

    2016-07-12

    A tour of Brookhaven's National Synchrotron Light Source (NSLS), hosted by Associate Laboratory Director for Light Sources, Stephen Dierker. The NSLS is one of the world's most widely used scientific research facilities, hosting more than 2,500 guest researchers each year. The NSLS provides intense beams of infrared, ultraviolet, and x-ray light for basic and applied research in physics, chemistry, medicine, geophysics, environmental, and materials sciences.

  12. Strange Light Nuclei

    SciTech Connect

    Nakamura, Satoshi N.

    2014-04-01

    "Strange" means 1) unusual or surprising, especially in a way that is difficult to explain or understand or 2) having strangeness degree of freedom. Light nuclear systems with strangeness, light hypernuclei, are perfect playground to study baryon force which would be a bridge between well established nuclear force in low energy region and QCD, the first principle of the strong interaction. Overview of study of light hypernuclei is given and recent experimental findings are reviewed.

  13. Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Schubert, E. Fred

    2003-06-01

    Light emitting diodes (LEDs) are devices that are used in a myriad of applications, such as indicator lights in instruments, signage, illuminations, and communication. This graduate textbook covers all aspects of the technology and physics of infrared, visible-spectrum, and white light-emitting diodes (LEDs) made from III-V semiconductors. It reviews elementary properties of LEDs such as the electrical and optical characteristics. Exercises and illustrative examples reinforce the topics discussed.

  14. High efficiency incandescent lighting

    SciTech Connect

    Bermel, Peter; Ilic, Ognjen; Chan, Walker R.; Musabeyoglu, Ahmet; Cukierman, Aviv Ruben; Harradon, Michael Robert; Celanovic, Ivan; Soljacic, Marin

    2014-09-02

    Incandescent lighting structure. The structure includes a thermal emitter that can, but does not have to, include a first photonic crystal on its surface to tailor thermal emission coupled to, in a high-view-factor geometry, a second photonic filter selected to reflect infrared radiation back to the emitter while passing visible light. This structure is highly efficient as compared to standard incandescent light bulbs.

  15. Theodolite Ring Lights

    NASA Technical Reports Server (NTRS)

    Clark, David

    2006-01-01

    Theodolite ring lights have been invented to ease a difficulty encountered in the well-established optical-metrology practice of using highly reflective spherical tooling balls as position references. A theodolite ring light produces a more easily visible reflection and eliminates the need for an autocollimating device. A theodolite ring light is a very bright light source that is well centered on the optical axis of the instrument. It can be fabricated, easily and inexpensively, for use on a theodolite or telescope of any diameter.

  16. Dissecting a Light Echo

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for audio animation

    This animation illustrates how a light echo works, and how an optical illusion of material moving outward is created.

    A light echo occurs when a star explodes, acting like a cosmic flashbulb. The light from this explosion zips through nearby dust clumps, illuminating and heating them up slightly. This brief period of warming causes them to glow in infrared, like a chain of Christmas bulbs lighting up one by one.

    The animation starts by showing the explosion of a star, which results in a flash of light that moves outward in all directions. The direction of our line of sight from Earth is indicated by the blue arrow.

    When the light flash reaches surrounding dust, shown here as three dark clouds, the dust is heated up, creating infrared light that begins to travel toward Earth (indicated by the red arrows). Dust closest to the explosion lights up first, while the explosion's shock wave takes longer to reach more distant material. This results in light from different parts of the cloud reaching Earth at different times, creating the illusion of motion over time.

    As the animation shows, the inclination of the cloud toward our line of sight can result in the material seeming to move both away from and toward the central star.

  17. Light source modeling for automotive lighting devices

    NASA Astrophysics Data System (ADS)

    Zerhau-Dreihoefer, Harald; Haack, Uwe; Weber, Thomas; Wendt, Dierk

    2002-08-01

    Automotive lighting devices generally have to meet high standards. For example to avoid discomfort glare for the oncoming traffic, luminous intensities of a low beam headlight must decrease by more than one order of magnitude within a fraction of a degree along the horizontal cutoff-line. At the same time, a comfortable homogeneous illumination of the road requires slowly varying luminous intensities below the cutoff line. All this has to be realized taking into account both, the legal requirements and the customer's stylistic specifications. In order to be able to simulate and optimize devices with a good optical performance different light source models are required. In the early stage of e.g. reflector development simple unstructured models allow a very fast development of the reflectors shape. On the other hand the final simulation of a complex headlamp or signal light requires a sophisticated model of the spectral luminance. In addition to theoretical models based on the light source's geometry, measured luminance data can also be used in the simulation and optimization process.

  18. Natural light illumination system.

    PubMed

    Whang, Allen Jong-Woei; Chen, Yi-Yung; Yang, Shu-Hua; Pan, Po-Hsuan; Chou, Kao-Hsu; Lee, Yu-Chi; Lee, Zong-Yi; Chen, Chi-An; Chen, Cheng-Nan

    2010-12-10

    In recent years, green energy has undergone a lot of development and has been the subject of many applications. Many research studies have focused on illumination with sunlight as a means of saving energy and creating healthy lighting. Natural light illumination systems have collecting, transmitting, and lighting elements. Today, most daylight collectors use dynamic concentrators; these include Sun tracking systems. However, this design is too expensive to be cost effective. To create a low-cost collector that can be easily installed on a large building, we have designed a static concentrator, which is prismatic and cascadable, to collect sunlight for indoor illumination. The transmission component uses a large number of optical fibers. Because optical fibers are expensive, this means that most of the cost for the system will be related to transmission. In this paper, we also use a prismatic structure to design an optical coupler for coupling n to 1. With the n-to-1 coupler, the number of optical fibers necessary can be greatly reduced. Although this new natural light illumination system can effectively guide collected sunlight and send it to the basement or to other indoor places for healthy lighting, previously there has been no way to manage the collected sunlight when lighting was not desired. To solve this problem, we have designed an optical switch and a beam splitter to control and separate the transmitted light. When replacing traditional sources, the lighting should have similar characteristics, such as intensity distribution and geometric parameters, to those of traditional artificial sources. We have designed, simulated, and optimized an illumination lightpipe with a dot pattern to redistribute the collected sunlight from the natural light illumination system such that it equals the qualities of a traditional lighting system. We also provide an active lighting module that provides lighting from the natural light illumination system or LED auxiliary

  19. American Zodiac: Astronomical signs in Dickinson, Melville, and Poe

    NASA Astrophysics Data System (ADS)

    Ricca, Bradley James

    2003-11-01

    Science and literature, two means of inquiry now thought in opposition (if not posed as outright contradiction) emerged for a moment in the nineteenth century as provocatively complimentary in their methods of reading. In America, astronomy in particular provided a rich, complex subject for writers of the imagination to think about in terms of content and methodology. The purpose of my study is to uncover these unacknowledged astronomical referents in the works of Emily Dickinson, Herman Melville, and Edgar Allan Poe, and engage them as interpretive contexts in new readings of their most esoteric projects; specifically, Dickinson's solstice and circumference poetry, the Plinlimmon pamphlet in Melville's Pierre, and Poe's Eureka. After providing historical context through the shared public experience of the 1833 Leonid Meteor Storm, I uncover several astronomical and scientific sources for these writers: Denison Olmsted for Dickinson; Gauss and Plotinus for Melville; and Kepler and Alexander von Humboldt for Poe, among others. Exploring these sources in close readings of their works, I find that these authors employ astronomical facts in very different, metaphorical ways in response to the larger challenge of navigating their own poetics between the emerging new laws of science and the immeasurability of human feeling evoked by the unknown Universe.

  20. The Impact of Zodiac Signs on Human Nature and Fate

    NASA Astrophysics Data System (ADS)

    Gasparyan, Naira

    2015-07-01

    Horoscope signs have unavoidable impact on human behaviour and interests, health and even fate. Moreover, intermingled with the impact of planets they become a powerful force able to bring about unbelievable changes. The investigation reveals that horoscopes have existed in the Armenian reality since ancient times. The most striking fact about their eistence is that in order to have and use zodiak signs in one's national culture, the nation should first of all have sufficient knowledge in Astrological Sciences since the system of zodiak signs has a direct reference to the cognitive processes and scientific knowledge of the universe, astrological issues and sometimes even there is a hint on hidden signs and messages. Anania Shirakatsi, one of the learned Armenians, had to display much diplomacy with the Armenian Church and religion when discussing the topic in his manuscripts. His observations are still of much importance and vitality even today.

  1. Sources of Interplanetary Dust and the Zodiacal Cloud (Invited)

    NASA Astrophysics Data System (ADS)

    Flynn, G. J.

    2013-12-01

    Every Solar System object is a potential source of interplanetary dust (IDPs) produced by impact cratering, disruption, or emission. Two major sources were identified by infrared observation of dust trails - asteroids and comets, and modeling shows collisions in the Kuiper Belt could also contribute significantly (Flynn, 1996). Gravitational focusing substantially enhances the flux into the Earth's atmosphere of particles in near-circular orbits, e.g. asteroidal dust, over dust in eccentric orbits (Flynn, 1989). Modeling by Kortenkamp et al. (1998) indicates that the asteroid families contribute a large fraction of the dust accreted by the Earth and fewer than 25% of accreted IDPs come from comets. The most significant constraint on the source(s) of the ~5 to 20 micron diameter IDPs comes from the survival of the larger, 100 to 10,000 micron, micrometeorites. Space exposure ages of micrometeorites, inferred from spallogenic Ne and radiogenic nuclides, range from ~10^5 to 2x10^7 years (Olinger et al., 1990; Raisbeck and Yiou, 1989; Nishiizumi et al., 1991), consistent with the timescale for orbital evolution of these micrometeorites from the asteroid belt to Earth under Poynting-Robertson drag. The elemental and mineralogical compositions of micrometeorites show strong similarities to ordinary chondrites, the dominant objects of the main belt. Relative abundances of the radionuclides demonstrate that micrometeorites were irradiated in space as small objects (<1 cm), so they are not material released from meteorites either during atmospheric entry or in space shortly before Earth encounter. Further, Nishiizumi et al. (1991) concluded that the exposure took place in the inner solar system, not in highly eccentric orbits, suggesting the micrometeorites were generated by collisions in the asteroid belt and evolved to Earth-crossing orbits by Poynting-Robertson drag. However, numerous calculations of the catastrophic disruption lifetimes of 100 to 10,000 micron particles in the inner solar system (Dohnanyi, 1978; Leinert et al., 1983; Grun et al., 1985; Steel and Elford, 1986) are one to three orders-of-magnitude lower than the observed space exposures of these particles. The possibility that only rare survivors from the micrometeorite population reach Earth is can be ruled out, because disruption of most micrometeorites, which are at the peak of the mass influx to Earth, during orbital evolution to the Earth encounter would produce numerous 5 to 20 micron fragments. But the 5 to 20 micron IDPs collected from the stratosphere are carbon-rich (Schramm et al., 1989) while the micrometeorites are low-carbon ordinary chondrites. The disruption lifetime calculations for micrometeorites are based in the assumption that the observed flux of IDPs, the particles that disrupt the micrometeorites, are in elliptical, or comet-like, orbits. If the IDPs are in nearly circular orbits, as would be expected for particles generated in the asteroid belt and spiraling inwards under Poynting-Robertson drag, the collision probability is greatly reduced. The survival of main-belt asteroidal micrometeorites indicates that much of the flux of 5 to 20 micron IDPs must originate either from a main belt asteroidal source of from cometary sources that have had their orbits nearly completely circularized by planetary gravitational perturbations.

  2. The Traffic Light Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2014-01-01

    Traffic lights are an important part of the transportation infrastructure, regulating traffic flow and maintaining safety when crossing busy streets. When they go awry or become nonfunctional, a great deal of havoc and danger can be present. During power outages, the street lights go out all over the affected area. It would be good to be able to…

  3. Light-emitting Diodes

    PubMed Central

    Opel, Daniel R.; Hagstrom, Erika; Pace, Aaron K.; Sisto, Krisanne; Hirano-Ali, Stefanie A.; Desai, Shraddha

    2015-01-01

    Background: In the early 1990s, the biological significance of light-emitting diodes was realized. Since this discovery, various light sources have been investigated for their cutaneous effects. Study design: A Medline search was performed on light-emitting diode lights and their therapeutic effects between 1996 and 2010. Additionally, an open-label, investigator-blinded study was performed using a yellow light-emitting diode device to treat acne, rosacea, photoaging, alopecia areata, and androgenetic alopecia. Results: The authors identified several case-based reports, small case series, and a few randomized controlled trials evaluating the use of four different wavelengths of light-emitting diodes. These devices were classified as red, blue, yellow, or infrared, and covered a wide range of clinical applications. The 21 patients the authors treated had mixed results regarding patient satisfaction and pre- and post-treatment evaluation of improvement in clinical appearance. Conclusion: Review of the literature revealed that differing wavelengths of light-emitting diode devices have many beneficial effects, including wound healing, acne treatment, sunburn prevention, phototherapy for facial rhytides, and skin rejuvenation. The authors’ clinical experience with a specific yellow light-emitting diode device was mixed, depending on the condition being treated, and was likely influenced by the device parameters. PMID:26155326

  4. Light-Emitting Pickles

    ERIC Educational Resources Information Center

    Vollmer, M.; Mollmann, K-P.

    2015-01-01

    We present experiments giving new insights into the classical light-emitting pickle experiment. In particular, measurements of the spectra and temperatures, as well as high-speed recordings, reveal that light emission is connected to the polarity of the electrodes and the presence of hydrogen.

  5. Christmas Light Display

    NASA Astrophysics Data System (ADS)

    Ross, Arthur; Renfro, Timothy

    2012-03-01

    The Digital Electronics class at McMurry University created a Christmas light display that toggles the power of different strands of lights, according to what frequencies are played in a song, as an example of an analog to digital circuit. This was accomplished using a BA3830S IC six-band audio filter and six solid-state relays.

  6. Unique Lighting Handbook.

    ERIC Educational Resources Information Center

    Edmund Scientific Co., Barrington, NJ.

    For those who wish to enter the world of light shows, this handbook provides facts, ideas, techniques, suggestions, and sources for the many hard-to-get materials and products. Blacklight, flashing light, musicvision, and lumia (the anti-shape) are discussed. Instructions are given on how to create special effects with overhead projectors, 35mm.…

  7. Enriching lighting design.

    PubMed

    Brawley, Elizabeth C

    2009-01-01

    Good lighting is perhaps the most important and least understood element in designing healthcare environments. Both physically and mentally challenged individuals become more vulnerable and dependent on their environment to compensate for sensory impairments, including dimming eyesight, which interferes to some degree with daily activities as well as social and leisure activities - the things that provide emotional and social well-being. Too few building designs today result in lighting that meets the needs of these individuals, regardless of age. Typical lighting in most care environments is inadequate to meet lighting needs affecting both vision and the photobiological (non-visual) needs of synchronization of circadian rhythm, which impacts sleep and depression. Well-designed lighting is one of the most important design elements that will support an individual's ability to perform normal daily activities and decrease the level of disability associated with these impairments. Daylight contains the spectrum to which the circadian clock is most sensitive and provides higher light levels during the day. Easily accessible outdoor gardens encourage individuals outside, providing the necessary regular exposure to direct bright light that sunlight provides. The combination good interior lighting and regular daylight exposure contributes to regaining and maintaining an active and fulfilling lifestyle - greatly improving quality of life.

  8. Explosively pumped laser light

    DOEpatents

    Piltch, Martin S.; Michelotti, Roy A.

    1991-01-01

    A single shot laser pumped by detonation of an explosive in a shell casing. The shock wave from detonation of the explosive causes a rare gas to luminesce. The high intensity light from the gas enters a lasing medium, which thereafter outputs a pulse of laser light to disable optical sensors and personnel.

  9. Lighting for Schools.

    ERIC Educational Resources Information Center

    Benya, James R.

    This publication highlights some of the benefits of proper daylighting design in educational facilities, discusses energy efficient electric lighting choices schools can make that are long lasting and require little maintenance, and offers six steps for designing lighting systems that use half the energy of earlier conventional designs. Several…

  10. Lighting in Architectural Design.

    ERIC Educational Resources Information Center

    Phillips, Derek

    The primary function of this book is to treat the topic of lighting design in such a manner as to bridge the gap between architects and illuminating engineers. The work is divided into three parts: Part I, Principles of Design, offers information and analysis of how natural and artificial lighting affects building design, how illumination levels…

  11. Handrail Lighting Module

    NASA Technical Reports Server (NTRS)

    Mattei, John P.

    1988-01-01

    Lightweight, space-saving combined handrail-and-flourescent-light unit serves decorative or safety functions. Fluorescent lamp mounted inside clear tubular plastic housing shaped to form handrail. Designed for either temporary or permanent installation or part of emergency lighting system.

  12. Lighting for Education.

    ERIC Educational Resources Information Center

    Ontario Ministry of Colleges and Universities, Toronto.

    Some of the qualities and quantities that must be juggled to produce good lighting for educational facilities are analyzed with photographs, tables, and drawings. The three categories of lamps used for school lighting (incandescent, fluorescent, and high intensity discharge) are described; a lamp selection guide gives the design characteristics of…

  13. Shedding Some Light.

    ERIC Educational Resources Information Center

    Whitney, Tim

    1998-01-01

    Discusses the basics of designing natural and artificial light in an indoor athletic facility. Also examines individual lighting requirements of typical rooms such as weight and fitness rooms, aerobics and multipurpose rooms, gymnasiums, field houses, pools, and racquetball and squash courts. (GR)

  14. Light intensity compressor

    DOEpatents

    Rushford, Michael C.

    1990-01-01

    In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

  15. Light intensity compressor

    DOEpatents

    Rushford, Michael C.

    1990-02-06

    In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

  16. Demand-controlled lighting

    NASA Technical Reports Server (NTRS)

    Owens, L. J.

    1977-01-01

    Automatic lighting is controlled by photocell that measures intensity of available light. Photocell drives motor which operates mercury switches controlling indoor illumination sources. Device effects increase in indoor illumination intensity when illumination input to cell is insufficient. Reverse is true if input is too great.

  17. Shedding Light on Learning.

    ERIC Educational Resources Information Center

    Graves, Ben E.

    1985-01-01

    Summarizes findings of an Alberta light/color study that looked at mood, noise levels, IQ test scores, blood pressure, and absences under fluorescent or full-spectrum light in two color schemes in four elementary schools with 700 students. (MLF)

  18. Stray Light Analysis

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Based on a Small Business Innovation Research contract from the Jet Propulsion Laboratory, TracePro is state-of-the-art interactive software created by Lambda Research Corporation to detect stray light in optical systems. An image can be ruined by incidental light in an optical system. To maintain image excellence from an optical system, stray light must be detected and eliminated. TracePro accounts for absorption, specular reflection and refraction, scattering and aperture diffraction of light. Output from the software consists of spatial irradiance plots and angular radiance plots. Results can be viewed as contour maps or as ray histories in tabular form. TracePro is adept at modeling solids such as lenses, baffles, light pipes, integrating spheres, non-imaging concentrators, and complete illumination systems. The firm's customer base includes Lockheed Martin, Samsung Electronics and other manufacturing, optical, aerospace, and educational companies worldwide.

  19. Light dispersion in space

    NASA Astrophysics Data System (ADS)

    Barbosa, L. C.

    2015-09-01

    Considering an idea of F. Arago in 1853 regarding light dispersion through the light ether in the interstellar space, this paper presents a new idea on an alternative interpretation of the cosmological red shift of the galaxies in the universe. The model is based on an analogy with the temporal material dispersion that occurs with light in the optical fiber core. Since intergalactic space is transparent, according to the model, this phenomenon is related to the gravitational potential existing in the whole space. Thus, it is possible to find a new interpretation to Hubble's constant. In space, light undergoes a dispersion process in its path, which is interpreted by a red shift equation of the type Δz = HL, since H = (d2n/dλ2 Δv Δλ), where H means the Hubble constant, n is the refractive index of the intergalactic space, Δλ is the spectral width of the extragalactic source, and Δv is the variation of the speed of light caused by the gravitational potential. We observe that this "constant" is governed by three new parameters. Light traveling the intergalactic space undergoes red shift due to this mechanism, while light amplitude decreases with time, and the wavelength always increases, thus producing the same type of behavior given by Hubble's Law. It can be demonstrated that the dark matter phenomenon is produced by the apparent speed of light of the stars on the periphery of the galaxies, without the existence of dark energy. Based on this new idea, the model of the universe is static, lacking expansion. Other phenomena may be interpreted based on this new model of the universe. We have what we call temporal gravitational dispersion of light in space produced by the variations of the speed of light, due to the presence of the gravitational potential in the whole space.

  20. 3. View from former light tower to Cape Elizabeth Light ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View from former light tower to Cape Elizabeth Light Tower, view northeast, southwest side of Cape Elizabeth Tower - Cape Elizabeth Light Station, Near Two Lights State Park at end of Two Lights Road, off State Highway 77, Cape Elizabeth, Cumberland County, ME

  1. AUTOMATIC LIGHT CONTROL

    DOEpatents

    Artzt, M.

    1957-08-27

    A control system for a projection kinescope used in a facsimile scanning system and, in particular, meams for maintaining substantially constant the light emanating from the flying spot on the face of the kinescope are described. In general, the invention provides a feeler member disposed in such a position with respect to a projecting lens as to intercept a portion of the light striking the lens. Suitable circuitry in conjunction with a photomultiplier tube provides a signal proportional to the light intensity of the flying spot. The grid bias on the kinescope is controlled by this signal to maintain the intensity of the spot substantially constant.

  2. City Lights of Europe

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Growth in 'mega-cities' is altering the landscape and the atmosphere in such a way as to curtail normal photosynthesis. By using data from The Defense Meteorological Satellite Program's Operational Linescan System, researchers have been able to look at urban sprawl by monitoring the emission of light from cities at night. By overlaying these 'light maps' onto other data such as soil and vegetation maps, the research shows that urbanization can have a variable but measurable impact on photosynthetic productivity. For more information, read Bright Lights, Big City Image by the NASA GSFC Scientific Visualization Studio

  3. White light velocity interferometer

    DOEpatents

    Erskine, David J.

    1999-01-01

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

  4. White light velocity interferometer

    DOEpatents

    Erskine, D.J.

    1997-06-24

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

  5. White light velocity interferometer

    DOEpatents

    Erskine, David J.

    1997-01-01

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

  6. White light velocity interferometer

    DOEpatents

    Erskine, D.J.

    1999-06-08

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

  7. Ultrabroadband Airy light bullets

    NASA Astrophysics Data System (ADS)

    Piksarv, Peeter; Valdmann, Andreas; Valtna-Lukner, Heli; Saari, Peeter

    2014-04-01

    We present the measurements of the spatiotemporal impulse responses of two optical systems for launching ultrashort Airy pulses, incl. ultrabroadband nonspreading Airy beams whose main lobe size remains invariantly small over propagation. First, a spatial light modulator and, second, a custom refractive element with continuous surface profile were used to impose the required cubic phase on the input field. White-light spectral interferometry setup based on the SEA TADPOLE technique was applied for full spatio-temporal characterization of the impulse response with ultrahigh temporal resolution approaching a single cycle of the light wave. The results were compared to the theoretical model.

  8. Ultrabroadband Airy light bullets

    NASA Astrophysics Data System (ADS)

    Piksarv, P.; Valdmann, A.; Valtna-Lukner, H.; Saari, P.

    2014-08-01

    We present the measurements of the spatiotemporal impulse responses of two optical systems for launching ultrashort Airy pulses, including ultrabroadband nonspreading Airy beams whose main lobe size remains invariantly small over propagation. First, a spatial light modulator and, second, a custom refractive element with continuous surface profile were used to impose the required cubic phase on the input field. A white-light spectral interferometry setup based on the SEA TADPOLE technique was applied for full spatio-temporal characterization of the impulse response with ultrahigh temporal resolution approaching a single cycle of the light wave. The results were compared to the theoretical model.

  9. Green Light Pulse Oximeter

    DOEpatents

    Scharf, John Edward

    1998-11-03

    A reflectance pulse oximeter that determines oxygen saturation of hemoglobin using two sources of electromagnetic radiation in the green optical region, which provides the maximum reflectance pulsation spectrum. The use of green light allows placement of an oximetry probe at central body sites (e.g., wrist, thigh, abdomen, forehead, scalp, and back). Preferably, the two green light sources alternately emit light at 560 nm and 577 nm, respectively, which gives the biggest difference in hemoglobin extinction coefficients between deoxyhemoglobin, RHb, and oxyhemoglobin, HbO.sub.2.

  10. Light, Color, and Mirrors.

    ERIC Educational Resources Information Center

    Tiburzi, Brian; Tamborino, Laurie; Parker, Gordon A.

    2000-01-01

    Describes an exercise in which students can use flashlights, mirrors, and colored paper to discover scientific principles regarding optics. Addresses the concepts of angles of incidence and reflection, colored vs. white light, and mirror images. (WRM)

  11. Shedding Light on Nanomedicine

    PubMed Central

    Tong, Rong

    2012-01-01

    Light is electromagnetic radiation that can convert its energy into different forms (e.g., heat, chemical energy, and acoustic waves). This property has been exploited in phototherapy (e.g., photothermal therapy and photodynamic therapy) and optical imaging (e.g., fluorescence imaging) for therapeutic and diagnostic purposes. Light-controlled therapies can provide minimally or non-invasive spatiotemporal control as well as deep tissue penetration. Nanotechnology provides a numerous advantages, including selective targeting of tissues, prolongation of therapeutic effect, protection of active payloads, and improved therapeutic indices. This review explores the advances that nanotechnology can bring to light-based therapies and diagnostics, and vice versa, including photo-triggered systems, nanoparticles containing photoactive molecules, and nanoparticles that are themselves photoactive. Limitations of light-based therapies such as photic injury and phototoxicity will be discussed. PMID:22887840

  12. Ferroelectric Light Control Device

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Kim, Jae-Woo (Inventor); Elliott, Jr., James R. (Inventor)

    2008-01-01

    A light control device is formed by ferroelectric material and N electrodes positioned adjacent thereto to define an N-sided regular polygonal region or circular region there between where N is a multiple of four.

  13. Serum Free Light Chains

    MedlinePlus

    ... changes in the ratio of kappa and lambda production, which indicate an excess of one clone of ... test to detect abnormal monoclonal protein (M-protein) production and to calculate a kappa/lambda free light ...

  14. Polarised light sheet tomography.

    PubMed

    Reidt, Sascha L; O'Brien, Daniel J; Wood, Kenneth; MacDonald, Michael P

    2016-05-16

    The various benefits of light sheet microscopy have made it a widely used modality for capturing three-dimensional images. It is mostly used for fluorescence imaging, but recently another technique called light sheet tomography solely relying on scattering was presented. The method was successfully applied to imaging of plant roots in transparent soil, but is limited when it comes to more turbid samples. This study presents a polarised light sheet tomography system and its advantages when imaging in highly scattering turbid media. The experimental configuration is guided by Monte Carlo radiation transfer methods, which model the propagation of a polarised light sheet in the sample. Images of both reflecting and absorbing phantoms in a complex collagenous matrix were acquired, and the results for different polarisation configurations are compared. Focus scanning methods were then used to reduce noise and produce three-dimensional reconstructions of absorbing targets.

  15. Exotic Light Nuclei

    ERIC Educational Resources Information Center

    Cerny, Joseph; Poskanzer, Arthur M.

    1978-01-01

    Among the light elements, nuclei with unequal numbers of protons and neutrons are highly unstable. Some survive just long enough to be detected and exhibit unusual regimes of radioactive decay. ( Autor/MA)

  16. Light on curved backgrounds

    NASA Astrophysics Data System (ADS)

    Batic, D.; Nelson, S.; Nowakowski, M.

    2015-05-01

    We consider the motion of light on different spacetime manifolds by calculating the deflection angle, lensing properties and by probing into the possibility of bound states. The metrics in which we examine the light motion include, among other items, a general relativistic dark matter metric, a dirty black hole, and a worm hole metric, the last two inspired by noncommutative geometry. The lensing in a holographic screen metric is discussed in detail. We study also the bending of light around naked singularities like, e.g., the Janis-Newman-Winicour metric and include other cases. A generic property of light behavior in these exotic metrics is pointed out. For the standard metric like the Schwarzschild and Schwarzschild-de Sitter cases, we improve the accuracy of the lensing results for the weak and strong regimes.

  17. National Synchrotron Light Source

    SciTech Connect

    2009-03-10

    A tour of Brookhaven's National Synchrotron Light Source (NSLS). The NSLS is one of the world's most widely used scientific research facilities, hosting more than 2,500 guest researchers each year. The NSLS provides intense beams of infrared, ultraviole

  18. National Synchrotron Light Source

    ScienceCinema

    None

    2016-07-12

    A tour of Brookhaven's National Synchrotron Light Source (NSLS). The NSLS is one of the world's most widely used scientific research facilities, hosting more than 2,500 guest researchers each year. The NSLS provides intense beams of infrared, ultraviole

  19. Modeling LED street lighting.

    PubMed

    Moreno, Ivan; Avendaño-Alejo, Maximino; Saucedo-A, Tonatiuh; Bugarin, Alejandra

    2014-07-10

    LED luminaires may deliver precise illumination patterns to control light pollution, comfort, visibility, and light utilization efficiency. Here, we provide simple equations to determine how the light distributes in the streets. In particular, we model the illuminance spatial distribution as a function of Cartesian coordinates on a floor, road, or street. The equations show explicit dependence on the luminary position (pole height and arm length), luminary angle (fixture tilt), and the angular intensity profile (radiation pattern) of the LED luminary. To achieve this, we propose two mathematical representations to model the sophisticated intensity profiles of LED luminaries. Furthermore, we model the light utilization efficiency, illumination uniformity, and veiling luminance of glare due to one or several LED streetlamps.

  20. Cauldron of Light

    NASA Video Gallery

    In this animation, a seething cauldron of light appears to bubble and ooze around the remains of a giant star that astronomers have been watching tear itself apart for the last 300 years. This movi...

  1. The Wonders of Light

    NASA Astrophysics Data System (ADS)

    García-Matos, Marta; Torner, Lluís

    2015-06-01

    1. Cold; 2. Gentle; 3. Sharp; 4. Focus; 5. Virus attacks; 6. Optogenetics; 7. Fast; 8. Random walks; 9. Displays; 10. Connected; 11. Privacy; 12. Riddles; 13. New materials; 14. Catch that energy!; 15. Lighting; 16. Sensing.

  2. Polarized Light Corridor Demonstrations.

    ERIC Educational Resources Information Center

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  3. Hyperspectral light field imaging

    NASA Astrophysics Data System (ADS)

    Leitner, Raimund; Kenda, Andreas; Tortschanoff, Andreas

    2015-05-01

    A light field camera acquires the intensity and direction of rays from a scene providing a 4D representation L(x,y,u,v) called the light field. The acquired light field allows to virtually change view point and selectively re-focus regions algorithmically, an important feature for many applications in imaging and microscopy. The combination with hyperspectral imaging provides the additional advantage that small objects (beads, cells, nuclei) can be categorised using their spectroscopic signatures. Using an inverse fluorescence microscope, a LCTF tuneable filter and a light field setup as a test-bed, fluorescence-marked beads have been imaged and reconstructed into a 4D hyper-spectral image cube LHSI(x,y,z,λ). The results demonstrate the advantages of the approach for fluorescence microscopy providing extended depth of focus (DoF) and the fidelity of hyper-spectral imaging.

  4. Cosmic Light EDU kit

    NASA Astrophysics Data System (ADS)

    Doran, Rosa

    2015-08-01

    In 2015 we celebrate the International Year of Light, a great opportunity to promote awareness about the importance of light coming from the Cosmos and what messages it is bringing to mankind. In parallel a unique moment to attract the attention of stakeholders on the dangers of light pollution and its impact in our lives and our pursuit of more knowledge. In this presentation I want to present one of the conrnerstones of IYL2015, a partnership between the Galileo Teacher Training Program, Universe Awareness and Globe at Night, the Cosmic Light EDU kit. The aim of this project is to assemble a core set of tools and resources representing our basic knowledge pilars about the Universe and simple means to preserve our night sky.

  5. Dark light Higgs bosons.

    SciTech Connect

    Draper, P.; Liu, T.; Wagner, C. E. M.; Wang, L.-T.; Zhang, H.

    2011-03-24

    We study a limit of the nearly Peccei-Quinn-symmetric next-to-minimal supersymmetric standard model possessing novel Higgs and dark matter (DM) properties. In this scenario, there naturally coexist three light singletlike particles: a scalar, a pseudoscalar, and a singlinolike DM candidate, all with masses of order 0.1-10 GeV. The decay of a standard model-like Higgs boson to pairs of the light scalars or pseudoscalars is generically suppressed, avoiding constraints from collider searches for these channels. For a certain parameter window annihilation into the light pseudoscalar and exchange of the light scalar with nucleons allow the singlino to achieve the correct relic density and a large direct-detection cross section consistent with the DM direct-detection experiments, CoGeNT and DAMA/LIBRA, preferred region simultaneously. This parameter space is consistent with experimental constraints from LEP, the Tevatron, ?, and flavor physics.

  6. Polarised light sheet tomography.

    PubMed

    Reidt, Sascha L; O'Brien, Daniel J; Wood, Kenneth; MacDonald, Michael P

    2016-05-16

    The various benefits of light sheet microscopy have made it a widely used modality for capturing three-dimensional images. It is mostly used for fluorescence imaging, but recently another technique called light sheet tomography solely relying on scattering was presented. The method was successfully applied to imaging of plant roots in transparent soil, but is limited when it comes to more turbid samples. This study presents a polarised light sheet tomography system and its advantages when imaging in highly scattering turbid media. The experimental configuration is guided by Monte Carlo radiation transfer methods, which model the propagation of a polarised light sheet in the sample. Images of both reflecting and absorbing phantoms in a complex collagenous matrix were acquired, and the results for different polarisation configurations are compared. Focus scanning methods were then used to reduce noise and produce three-dimensional reconstructions of absorbing targets. PMID:27409945

  7. Shining a Light on Electronics

    ERIC Educational Resources Information Center

    Statler, James D.

    2009-01-01

    While they produced a limited amount of light when first introduced, light-emitting diode (LED) lights offered the benefit of rarely burning out. As a result, they were initially used primarily as indicator lights. Advances in the technology have made available LEDs that produce far brighter light, and one application that has come to market is…

  8. 10. LIGHT TOWER, VIEW NORTHEAST FROM LIGHT PLATFORM, SOUTHWEST SIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. LIGHT TOWER, VIEW NORTHEAST FROM LIGHT PLATFORM, SOUTHWEST SIDE OF BOAT HOUSE AND KEEPER'S HOUSE, WITH DETAIL OF RAILING IN FOREGROUND - Grindle Point Light Station, Western end of Ferry Road on Grindle Point, Islesboro, Waldo County, ME

  9. Indoor Lighting Facilities

    NASA Astrophysics Data System (ADS)

    Matsushima, Koji; Saito, Yoshinori; Ichikawa, Shigenori; Kawauchi, Takao; Tanaka, Tsuneo; Hirano, Rika; Tazuke, Fuyuki

    According to the statistics by the Ministry of Land, Infrastructure and Transport, the total floor space of all building construction started was 188.87 million m2 (1.5% increase y/y), marking the fourth straight year of increase. Many large-scale buildings under construction in central Tokyo become fully occupied by tenants before completion. As for office buildings, it is required to develop comfortable and functional office spaces as working styles are becoming more and more diversified, and lighting is also an element of such functionalities. The total floor space of construction started for exhibition pavilions, multipurpose halls, conference halls and religious architectures decreased 11.1% against the previous year. This marked a decline for 10 consecutive years and the downward trend continues. In exhibition pavilions, the light radiation is measured and adjusted throughout the year so as not to damage the artworks by lighting. Hospitals, while providing higher quality medical services and enhancing the dwelling environment of patients, are expected to meet various restrictions and requirements, including the respect for privacy. Meanwhile, lighting designs for school classrooms tend to be homogeneous, yet new ideas are being promoted to strike a balance between the economical and functional aspects. The severe economic environment continues to be hampering the growth of theaters and halls in both the private and public sectors. Contrary to the downsizing trend of such facilities, additional installations of lighting equipment were conspicuous, and the adoption of high efficacy lighting appliances and intelligent function control circuits are becoming popular. In the category of stores/commercial facilities, the construction of complex facilities is a continuing trend. Indirect lighting, high luminance discharge lamps with excellent color rendition and LEDs are being effectively used in these facilities, together with the introduction of lighting designs

  10. Ocular hazards of light

    NASA Technical Reports Server (NTRS)

    Sliney, David H.

    1994-01-01

    The eye is protected against bright light by the natural aversion response to viewing bright light sources. The aversion response normally protects the eye against injury from viewing bright light sources such as the sun, arc lamps and welding arcs, since this aversion limits the duration of exposure to a fraction of a second (about 0.25 s). The principal retinal hazard resulting from viewing bright light sources is photoretinitis, e.g., solar retinitis with an accompanying scotoma which results from staring at the sun. Solar retinitis was once referred to as 'eclipse blindness' and associated 'retinal burn'. Only in recent years has it become clear that photoretinitis results from a photochemical injury mechanism following exposure of the retina to shorter wavelengths in the visible spectrum, i.e., violet and blue light. Prior to conclusive animal experiments at that time, it was thought to be a thermal injury mechanism. However, it has been shown conclusively that an intense exposure to short-wavelength light (hereafter referred to as 'blue light') can cause retinal injury. The product of the dose-rate and the exposure duration always must result in the same exposure dose (in joules-per-square centimeter at the retina) to produce a threshold injury. Blue-light retinal injury (photoretinitis) can result from viewing either an extremely bright light for a short time, or a less bright light for longer exposure periods. This characteristic of photochemical injury mechanisms is termed reciprocity and helps to distinguish these effects from thermal burns, where heat conduction requires a very intense exposure within seconds to cause a retinal coagulation otherwise, surrounding tissue conducts the heat away from the retinal image. Injury thresholds for acute injury in experimental animals for both corneal and retinal effects have been corroborated for the human eye from accident data. Occupational safety limits for exposure to UVR and bright light are based upon this

  11. Light from down under.

    PubMed

    Fine, Maoz; Sabbah, Shai; Shashar, Nadav; Hoegh-Guldberg, Ove

    2013-12-01

    Coral-algae symbiosis is a key feature of tropical corals and is highly dependent on the efficiency with which solar energy is attenuated by the coral. Scleractinian corals are among the most efficient light collectors in nature because of the modulation of the internal light field in the coral skeleton. Interestingly, coral skeleton particles composing the sandy bottoms in reef margins sustain these optical characteristics. In the present study, we examined two free-living coral species - Heterocyathus aequicostatus (Caryophyllidae) and Heteropsammia cochlea (Dendrophylliidae) - common on biogenic coarse carbonate sand of the Great Barrier Reef but absent from fine sand at the same depth. In coarse carbonate sand, light penetrates a few millimeters below the surface and propagates along horizontal distances of a few centimeters. In fine sand, almost all of the light is reflected back to the water column. For photosynthetic sand-dwelling organisms such as the studied species, with over one-third of their surface area facing the substrate, light flux to their underside may be beneficial. A correlation was found between the diameter of these corals and the distance that light may travel in the sand under the coral. Laboratory and field measurements show that the symbiotic algae on the underside of the corallites are photosynthetically active even when the coral is partially buried, implying sufficient light penetration. Other organisms in the study site, such as fungid corals and foraminiferans, with different morphologies, have different light-trapping strategies but are also photosynthesizing on their underside. The importance of the substrate type to the performance of the three main partners of the symbiosis (coral, endosymbiotic algae and a sipunculan worm) is highlighted, and is a striking example of co-evolution.

  12. The psychiatry of light.

    PubMed

    Schwartz, Richard S; Olds, Jacqueline

    2015-01-01

    Bright light therapy and the broader realm of chronotherapy remain underappreciated and underutilized, despite their empirical support. Efficacy extends beyond seasonal affective disorder and includes nonseasonal depression and sleep disorders, with emerging evidence for a role in treating attention-deficit/hyperactivity disorder, delirium, and dementia. A practical overview is offered, including key aspects of underlying biology, indications for treatment, parameters of treatment, adverse effects, and transformation of our relationship to light and darkness in contemporary life. PMID:25839643

  13. Solid state lighting component

    DOEpatents

    Yuan, Thomas; Keller, Bernd; Ibbetson, James; Tarsa, Eric; Negley, Gerald

    2010-10-26

    An LED component comprising an array of LED chips mounted on a planar surface of a submount with the LED chips capable of emitting light in response to an electrical signal. The LED chips comprise respective groups emitting at different colors of light, with each of the groups interconnected in a series circuit. A lens is included over the LED chips. Other embodiments can comprise thermal spreading structures included integral to the submount and arranged to dissipate heat from the LED chips.

  14. Solid state lighting component

    DOEpatents

    Keller, Bernd; Ibbetson, James; Tarsa, Eric; Negley, Gerald; Yuan, Thomas

    2012-07-10

    An LED component comprising an array of LED chips mounted on a planar surface of a submount with the LED chips capable of emitting light in response to an electrical signal. The LED chips comprise respective groups emitting at different colors of light, with each of the groups interconnected in a series circuit. A lens is included over the LED chips. Other embodiments can comprise thermal spreading structures included integral to the submount and arranged to dissipate heat from the LED chips.

  15. Light weight aluminum optics

    NASA Astrophysics Data System (ADS)

    Catura, R. C.; Vieira, J. R.

    1985-09-01

    Light weight mirror blanks were fabricated by dip-brazing a core of low mass aluminum foam material to thin face sheets of solid aluminum. The blanks weigh 40% of an equivalent size solid mirror and were diamond turned to provide reflective surfaces. Optical interferometry was used to assess their dimensional stability over 7 months. No changes in flatness are observed (to the sensitivity of the measurements of a half wavelength of red light).

  16. Fingerprints in the Light

    NASA Technical Reports Server (NTRS)

    2005-01-01

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

    This graph, or spectrum, shows the light from a dusty, distant galaxy located 11 billion light-years away. The galaxy is invisible to optical telescopes, but NASA's Spitzer Space Telescope was able to capture the light from it and dozens of other similar galaxies using heat-seeking infrared eyes.

    Spectra are created when an instrument called a spectrograph spreads light out into its basic parts, like a prism turning sunlight into a rainbow. They contain the signatures, or 'fingerprints,' of molecules that contribute to an object's light.

    In this case, the galaxy's spectrum reveals the fingerprint for silicate dust (large dip at right), a planetary building block like sand, only smaller. This particular fingerprint is important because it helped astronomers determine how far away the galaxy lies, or more specifically, how much the galaxy's light had stretched, or 'redshifted,' during its journey to Spitzer's eyes. Because the universe is expanding, a galaxy's light will shift toward reddish wavelengths as it moves away from us. This galaxy was found to have a redshift of 1.95, which means that its light took about 11 billion years to get here.

    The presence of the silicate fingerprint is also significant because it implies that galaxies were ripe for planetary formation 11 billion years ago - back to a time when the universe was 3 billion years old. The universe is currently believed to be 13.5 billion years old. This is the furthest back in time that silicate dust has been detected around a galaxy.

    These data were taken by Spitzer's infrared spectrograph in July, 2004.

  17. Cauldron of Light

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image to view the animation

    In this animation, a seething cauldron of light appears to bubble and ooze around the remains of a giant star that astronomers have been watching tear itself apart for the last 300 years. This movie flips quickly between different observations taken over three years by NASA's Spitzer Space Telescope.

    Beginning in the center, the well-studied Cassiopeia A supernova remnant is shown. Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died.

    Panning outward, 'light echoes' create the illusion of motion in the clouds, as different areas of the material are lit up in succession by the light flash of the supernova. A light echo occurs when a star explodes, acting like a cosmic flashbulb. The light from this explosion zips through nearby dust clumps, illuminating and heating them up slightly. This brief period of warming causes them to glow in infrared, like a chain of Christmas bulbs lighting up one by one. The result is an optical illusion, in which the dust appears to be flying outward at the speed of light.

    In reality, the clouds are stationary, at least in the brief time over which these observations were taken. The inclination of the clouds cause some light echoes to appear to expand away from the supernova remnant, while others move towards it or boil in many directions with seeming turbulence.

  18. Conversion of orange light into blue light.

    PubMed

    Rai, Nirupama; Jha, Y; Kamal, K P; Kumar, S; Rai, V K

    2010-08-01

    Frequency upconversion in triply ionized praseodymium doped glass with composition TeO(2)-Na(2)O (TNO) system under the excitation with a laser light from a dye laser has been reported and the covalency, bonding parameter, nephalauxetic effect which provides the information about the nature of bonding between the lanthanide ions and the surrounding oxygens for the present glassy material calculated. The energy transfer route followed by the two excited praseodymium ions is observed to be the leading process for the upconversion emission.

  19. Earth's City Lights

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Earth's city lights was created with data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). Originally designed to view clouds by moonlight, the OLS is also used to map the locations of permanent lights on the Earth's surface. The brightest areas of the Earth are the most urbanized, but not necessarily the most populated. (Compare western Europe with China and India.) Cities tend to grow along coastlines and transportation networks. Even without the underlying map, the outlines of many continents would still be visible. The United States interstate highway system appears as a lattice connecting the brighter dots of city centers. In Russia, the Trans-Siberian railroad is a thin line stretching from Moscow through the center of Asia to Vladivostok. The Nile River, from the Aswan Dam to the Mediterranean Sea, is another bright thread through an otherwise dark region. Even more than 100 years after the invention of the electric light, some regions remain thinly populated and unlit. Antarctica is entirely dark. The interior jungles of Africa and South America are mostly dark, but lights are beginning to appear there. Deserts in Africa, Arabia, Australia, Mongolia, and the United States are poorly lit as well (except along the coast), along with the boreal forests of Canada and Russia, and the great mountains of the Himalaya. The Earth Observatory article Bright Lights, Big City describes how NASA scientists use city light data to map urbanization. Image by Craig Mayhew and Robert Simmon, NASA GSFC, based on DMSP data

  20. New light on OSL

    NASA Astrophysics Data System (ADS)

    Bøtter-Jensen, L.; Mejdahl, V.; Murray, A. S.

    1999-02-01

    We have tested recently released green and blue light emitting diodes (LEDs) for the optical stimulation of quartz, with a view to using these in routine optically stimulated luminescence (OSL) dating and retrospective dosimetry. We compare results obtained with blue LEDs with those obtained using broad-band blue/green light filtered from a halogen lamp. We describe two practical blue LED OSL configurations and conclude that a small number of blue LEDs provide the same stimulation efficiency for quartz as can be obtained from filtered halogen lamps and other commonly used sources. From the direct comparison of OSL decay curves produced by the two light sources, and by examination of the dependence of blue LED OSL on preheat temperature, we conclude that there is no evidence that the blue LED light stimulates deep traps in a different manner from broad-band halogen light. Preliminary intercomparisons, using 34 quartz samples taken from both heated and unheated materials, between equivalent doses obtained using blue LEDs and using broad-band blue/green light from a halogen lamp show that, on average, the two data sets are indistinguishable (blue/halogen=0.98±0.02). We conclude that blue LEDs offer a practical alternative to existing stimulation sources. They have the significant advantage that the output can be controlled electronically; thus the power can be readily controlled by software.

  1. Light Pollution and Wildlife

    NASA Astrophysics Data System (ADS)

    Duffek, J.

    2008-12-01

    for Educational Program IYA Dark Skies Education Session Fall American Geophysical Union San Francisco, December 15-19, 2008 Light Pollution and Wildlife This is a very exciting time to be a part of the mission to keep the nighttime skies natural. The International Year of Astronomy (IYA) 2009 is developing programs for all areas of Dark Skies Awareness. For many years the issue of light pollution focused on the impact to the astronomy industry. While this is an important area, research has shown that light pollution negatively impacts wildlife, their habitat, human health, and is a significant waste of energy. Since the message and impact of the effects of light pollution are much broader now, the message conveyed to the public must also be broader. Education programs directed at youth are a new frontier to reach out to a new audience about the adverse effects of too much artificial light at night. The International Dark-Sky Association (IDA) has developed educational presentations using the National Science Teachers Association Education Standards. These programs focus on youth between the ages of 5 to 17exploring new territory in the education of light pollution. The IDA education programs are broken down into three age groups; ages 5-9, 8-13, 12 and older. The presentations come complete with PowerPoint slides, discussion notes for each slide, and workbooks including age appropriate games to keep young audiences involved. A new presentation reflects the growing area of interest regarding the effects of too much artificial light at night on wildlife. This presentation outlines the known problems for ecosystems caused by artificial light at night. Insects are attracted to artificial lights and may stay near that light all night. This attraction interferes with their ability to migrate, mate, and look for food. Such behavior leads to smaller insect populations. Fewer insects in turn affect birds and bats, because they rely on insects as a food source. The IDA

  2. Lighting Control Energy Savings

    SciTech Connect

    LBL,

    1985-01-01

    CONTROLITE 1.0 is a lighting energy analysis program designed to calculate the energy savings and cost benefits obtainable using lighting controls in buildings. The program can compute the lighting energy reductions that result from using daylighting, scheduling, and other control strategies. When modeling daylight control systems, the program uses QUICKLITE to compute the daylight illuminances at specified points 5 times a day, 12 days a year (the 21st of each month), and for two sky conditions (clear and overcast skies). Fourier series techniques are used to fit a continuous curve through the computed illuminance points. The energy use for each of the 12 days is then computed given user-specified power-in/light-out characteristics of the modeled control system. The monthly and annual energy usage for overcast and clear conditions are found separately by fitting two long-term Fourier series curves to the energy use computed for each of the 12 days. Finally, the monthly energy use is calculated by taking a weighted average for the monthly energy use computed for the overcast and clear sky conditions. The program only treats the energy use directly attributable to lighting. The impact of lighting control strategies on building thermal loads is not computed. The program allows input of different control schedules (i.e., on/off times for the lighting system) for each day of the week, but every week of the year is treated the same; thus, holidays cannot be modeled explicitly. When used for daylighting purposes, CONTROLITE1.0 understands only clear and overcast conditions. User-supplied values for the proportion of clear and overcast hours for each month of the year are required to accommodate different climatic conditions.

  3. Lighting Control Energy Savings

    1985-01-01

    CONTROLITE 1.0 is a lighting energy analysis program designed to calculate the energy savings and cost benefits obtainable using lighting controls in buildings. The program can compute the lighting energy reductions that result from using daylighting, scheduling, and other control strategies. When modeling daylight control systems, the program uses QUICKLITE to compute the daylight illuminances at specified points 5 times a day, 12 days a year (the 21st of each month), and for two skymore » conditions (clear and overcast skies). Fourier series techniques are used to fit a continuous curve through the computed illuminance points. The energy use for each of the 12 days is then computed given user-specified power-in/light-out characteristics of the modeled control system. The monthly and annual energy usage for overcast and clear conditions are found separately by fitting two long-term Fourier series curves to the energy use computed for each of the 12 days. Finally, the monthly energy use is calculated by taking a weighted average for the monthly energy use computed for the overcast and clear sky conditions. The program only treats the energy use directly attributable to lighting. The impact of lighting control strategies on building thermal loads is not computed. The program allows input of different control schedules (i.e., on/off times for the lighting system) for each day of the week, but every week of the year is treated the same; thus, holidays cannot be modeled explicitly. When used for daylighting purposes, CONTROLITE1.0 understands only clear and overcast conditions. User-supplied values for the proportion of clear and overcast hours for each month of the year are required to accommodate different climatic conditions.« less

  4. Light diffusing fiber optic chamber

    DOEpatents

    Maitland, Duncan J.

    2002-01-01

    A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.

  5. Indoor Lighting Facilities

    NASA Astrophysics Data System (ADS)

    Matsushima, Koji; Saito, Yoshinori; Ichikawa, Shigenori; Kawauchi, Takao; Tanaka, Tsuneo; Hirano, Rika; Tazuke, Fuyuki

    According to the statistics on building construction floor area from the Ministry of Land, Infrastructure, Transport and Tourism, the total floor area of building construction started in Japan in 2007 was 160,991 thousand square meters, or 14.8% less than the area of the previous year, and the reduction was the first reduction in the past five years. The office markets in Tokyo and Nagoya were active, as represented by the supplies of skyscrapers, and energy saving measures, such as the adoption of high efficiency lighting equipment, the control for initial stage illuminance, daylight harvesting, and the use of occupancy sensors, were well established. In the field of public construction, including museums, multi-purpose halls, and religious buildings, the total area of the new construction was 10.8% less than the total for the previous year, and this reduction was a continuation of an eleven-year trend. In spaces with high ceiling, the innovation for easy replacement of light sources used with reflection mirror systems and optical fibers was noted. Hospitals adapted to the expectation for improved services in their selection of lighting facilities to improve the residential environment for patients while taking into consideration the needs of the aging population, by their use of devices in corridors to help maintain a continuity of light. In libraries, a pendant system was developed to illuminate both ceilings and book shelves. In the field of theaters and halls, the time limit for repairing existing systems had come for the large facilities that were opened during the theater and hall construction boom of the 1960s through 1980s, and around 26 renovations were done. Almost all the renovations were conversions to intelligent dimming systems and lighting control desks. In the field of stores and commercial facilities, the atmosphere and glitter of the selling floor was produced by new light sources, such as ceramic metal halide lamps and LEDs, which have high

  6. Laser light scattering review

    NASA Astrophysics Data System (ADS)

    Schaetzel, Klaus

    1989-08-01

    Since the development of laser light sources and fast digital electronics for signal processing, the classical discipline of light scattering on liquid systems experienced a strong revival plus an enormous expansion, mainly due to new dynamic light scattering techniques. While a large number of liquid systems can be investigated, ranging from pure liquids to multicomponent microemulsions, this review is largely restricted to applications on Brownian particles, typically in the submicron range. Static light scattering, the careful recording of the angular dependence of scattered light, is a valuable tool for the analysis of particle size and shape, or of their spatial ordering due to mutual interactions. Dynamic techniques, most notably photon correlation spectroscopy, give direct access to particle motion. This may be Brownian motion, which allows the determination of particle size, or some collective motion, e.g., electrophoresis, which yields particle mobility data. Suitable optical systems as well as the necessary data processing schemes are presented in some detail. Special attention is devoted to topics of current interest, like correlation over very large lag time ranges or multiple scattering.

  7. Laser light scattering review

    NASA Technical Reports Server (NTRS)

    Schaetzel, Klaus

    1989-01-01

    Since the development of laser light sources and fast digital electronics for signal processing, the classical discipline of light scattering on liquid systems experienced a strong revival plus an enormous expansion, mainly due to new dynamic light scattering techniques. While a large number of liquid systems can be investigated, ranging from pure liquids to multicomponent microemulsions, this review is largely restricted to applications on Brownian particles, typically in the submicron range. Static light scattering, the careful recording of the angular dependence of scattered light, is a valuable tool for the analysis of particle size and shape, or of their spatial ordering due to mutual interactions. Dynamic techniques, most notably photon correlation spectroscopy, give direct access to particle motion. This may be Brownian motion, which allows the determination of particle size, or some collective motion, e.g., electrophoresis, which yields particle mobility data. Suitable optical systems as well as the necessary data processing schemes are presented in some detail. Special attention is devoted to topics of current interest, like correlation over very large lag time ranges or multiple scattering.

  8. Lead in Christmas lights.

    PubMed

    Laquatra, Joseph; Coyne, Lelia M; Pierce, Mark R

    2008-12-01

    A recent California proposition led to awareness that lead is a stabilizer in the Polyvinyl Chloride (PVC) jacketing that covers conductors in Christmas lights. The objective of this study is to examine the level of accessible lead in Christmas lights. Following U.S. Environmental Protection Agency (U.S. EPA) Lead Inspectors' procedures, researchers at Cornell University and in Nebraska conducted wipe samples and total lead content samples of newly purchased and older Christmas light sets. Samples were analyzed for lead content. Lead was present in varying amounts on all samples. The amount of lead from the Nebraska samples, normalized to length of strings, was independent of analyzing laboratory, analysis method, age of string, and repeat sampling, both immediately and after extended storage. A later analysis of these same strings by the Cornell team showed diminished quantities. Amounts of surface lead normalized to crude estimates of the area of light string indicated surface concentrations in excess of U.S. EPA clearance level for lead on window sills. Whether exposure to lead in Christmas lights affects blood lead levels in humans is unknown. No standards exist for lead content in this product, and no protocols exist for conducting tests on it. Therefore, consumers may wish to exercise caution to reduce possible exposure.

  9. Horticultural lighting using HID/light pipe systems

    SciTech Connect

    Bulley, N.R.; Phillips, D.

    1985-01-01

    The recent development of a light pipe makes it possible to separate a light source from the area to be illuminated. The paper reports on the light intensity and distribution for selected lamp/light pipe systems for use in commercial plant growth chambers, propagation rooms and tissue culture facilities.

  10. Light echoes - Novae

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.

    1988-01-01

    The sudden brilliance of a nova eruption will be reflected on surrounding dust grains to create a phantom nebula. Previous searches for these light echoes have used relatively short exposures with photograhic detectors. This paper reports on a search around eight recent novae with long exposures using a CCD camera. Despite an increase of sensitivity by over an order of magnitude, no light echoes were detected. It is found that the average grain density must be less than about 10 to the -9th per cu cm for distances from 0.1 pc to 1000 pc from the novae. The light echo around Nova Persei 1901 was caused by reflection off clouds with grain densities of several times 10 to the -9th per cu cm which are at distances between 0.1 pc and 10 pc. Echoes from dust in a circumstellar shell or ejected during a previous eruption will be effectively unobservable.

  11. SIRTF stray light analysis

    NASA Technical Reports Server (NTRS)

    Elliott, David G.; Dinger, Ann S.

    1991-01-01

    The Space Infrared Telescope Facility (SIRTF) is a 1-meter cryogenic infrared telescope. Stray light is kept below the natural background by restrictions on sun, Earth, and moon off-axis angles; by conservative baffle design; by the use of advanced diffuse black coatings; and by superfluid helium cooling. The aperture stop is located at the primary mirror rather than at the secondary mirror to increase the aperture and reduce the central obscuration. Stray light from off-axis sources is greater with the aperture stop at the primary than with the aperture stop at the secondary, but the modulation of the signal produced by tilting of the secondary mirror for chopping is less. Stray light from telescope thermal emission is lower with the aperture stop at the primary.

  12. MEMS Incandescent Light Source

    NASA Technical Reports Server (NTRS)

    Tuma, Margaret; King, Kevin; Kim, Lynn; Hansler, Richard; Jones, Eric; George, Thomas

    2001-01-01

    A MEMS-based, low-power, incandescent light source is being developed. This light source is fabricated using three bonded chips. The bottom chip consists of a reflector on Silicon, the middle chip contains a Tungsten filament bonded to silicon and the top layer is a transparent window. A 25-micrometer-thick spiral filament is fabricated in Tungsten using lithography and wet-etching. A proof-of-concept device has been fabricated and tested in a vacuum chamber. Results indicate that the filament is electrically heated to approximately 2650 K. The power required to drive the proof-of-concept spiral filament to incandescence is 1.25 W. The emitted optical power is expected to be approximately 1.0 W with the spectral peak at 1.1 microns. The micromachining techniques used to fabricate this light source can be applied to other MEMS devices.

  13. Pupillary efficient lighting system

    DOEpatents

    Berman, Samuel M.; Jewett, Don L.

    1991-01-01

    A lighting system having at least two independent lighting subsystems each with a different ratio of scotopic illumination to photopic illumination. The radiant energy in the visible region of the spectrum of the lighting subsystems can be adjusted relative to each other so that the total scotopic illumination of the combined system and the total photopic illumination of the combined system can be varied independently. The dilation or contraction of the pupil of an eye is controlled by the level of scotopic illumination and because the scotopic and photopic illumination can be separately controlled, the system allows the pupil size to be varied independently of the level of photopic illumination. Hence, the vision process can be improved for a given level of photopic illumination.

  14. Sneaky light stop

    SciTech Connect

    Eifert, Till; Nachman, Benjamin

    2015-04-01

    A light supersymmetric top quark partner (stop) with a mass nearly degenerate with that of the standard model (SM) top quark can evade direct searches. The precise measurement of SM top properties such as the cross-section has been suggested to give a handle for this ‘stealth stop’ scenario. We present an estimate of the potential impact a light stop may have on top quark mass measurements. The results indicate that certain light stop models may induce a bias of up to a few GeV, and that this effect can hide the shift in, and hence sensitivity from, cross-section measurements. Due to the different initial states, the size of the bias is slightly different between the LHC and the Tevatron. The studies make some simplifying assumptions for the top quark measurement technique, and are based on truth-level samples.

  15. Sneaky light stop

    SciTech Connect

    Eifert, Till; Nachman, Benjamin

    2015-02-20

    A light supersymmetric top quark partner (stop) with a mass nearly degenerate with that of the standard model (SM) top quark can evade direct searches. The precise measurement of SM top properties such as the cross-section has been suggested to give a handle for this ‘stealth stop’ scenario. We present an estimate of the potential impact a light stop may have on top quark mass measurements. The results indicate that certain light stop models may induce a bias of up to a few GeV, and that this effect can hide the shift in, and hence sensitivity from, cross-section measurements. Due to the different initial states, the size of the bias is slightly different between the LHC and the Tevatron. The studies make some simplifying assumptions for the top quark measurement technique, and are based on truth-level samples.

  16. Sneaky light stop

    DOE PAGES

    Eifert, Till; Nachman, Benjamin

    2015-02-20

    A light supersymmetric top quark partner (stop) with a mass nearly degenerate with that of the standard model (SM) top quark can evade direct searches. The precise measurement of SM top properties such as the cross-section has been suggested to give a handle for this ‘stealth stop’ scenario. We present an estimate of the potential impact a light stop may have on top quark mass measurements. The results indicate that certain light stop models may induce a bias of up to a few GeV, and that this effect can hide the shift in, and hence sensitivity from, cross-section measurements. Duemore » to the different initial states, the size of the bias is slightly different between the LHC and the Tevatron. The studies make some simplifying assumptions for the top quark measurement technique, and are based on truth-level samples.« less

  17. Light sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Gariazzo, S.; Giunti, C.; Laveder, M.; Li, Y. F.; Zavanin, E. M.

    2015-03-01

    The theory and phenomenology of light sterile neutrinos at the eV mass scale is reviewed. The reactor, gallium and Liquid Scintillator Neutrino Detector anomalies are briefly described and interpreted as indications of the existence of short-baseline oscillations which require the existence of light sterile neutrinos. The global fits of short-baseline oscillation data in 3 + 1 and 3 + 2 schemes are discussed, together with the implications for β-decay and neutrinoless double-β decay. The cosmological effects of light sterile neutrinos are briefly reviewed and the implications of existing cosmological data are discussed. The review concludes with a summary of future perspectives. This review is dedicated to the memory of Hai-Wei Long, our dear friend and collaborator, who passed away on 29 May 2015. He was an exceptionally kind person and an enthusiastic physicist. We deeply miss him.

  18. Light sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Gariazzo, S.; Giunti, C.; Laveder, M.; Li, Y. F.; Zavanin, E. M.

    2016-03-01

    The theory and phenomenology of light sterile neutrinos at the eV mass scale is reviewed. The reactor, gallium and Liquid Scintillator Neutrino Detector anomalies are briefly described and interpreted as indications of the existence of short-baseline oscillations which require the existence of light sterile neutrinos. The global fits of short-baseline oscillation data in 3 + 1 and 3 + 2 schemes are discussed, together with the implications for β-decay and neutrinoless double-β decay. The cosmological effects of light sterile neutrinos are briefly reviewed and the implications of existing cosmological data are discussed. The review concludes with a summary of future perspectives. This review is dedicated to the memory of Hai-Wei Long, our dear friend and collaborator, who passed away on 29 May 2015. He was an exceptionally kind person and an enthusiastic physicist. We deeply miss him.

  19. High Intensity Lighting

    NASA Astrophysics Data System (ADS)

    1982-01-01

    Nightime illumination is an important part of round-the-clock pre-launch preparations because NASA uses TV and film cameras to monitor each step of the preliminaries and at times to identify the cause of malfunction during countdown. Generating a one billion candlepower beam visible 50 miles away, the lamps developed by Duro-Test Corporation provide daylight quality light that eliminates color distortion in film and TV coverage. The lighting system was first used at Kennedy Space Center in 1968 for the launch of Apollo 8. Modified versions are available in wide range of applications, such as the battery of spotlights with colored filters that light up Niagara Falls, as well as the lamps used in the projectors for the Smithsonian's IMAX Theatre, indoor theatres with supersized screens and outdoor projection systems.

  20. 3D light robotics

    NASA Astrophysics Data System (ADS)

    Glückstad, Jesper; Palima, Darwin; Villangca, Mark; Banas, Andrew

    2016-04-01

    As celebrated by the Nobel Prize 2014 in Chemistry light-based technologies can now overcome the diffraction barrier for imaging with nanoscopic resolution by so-called super-resolution microscopy1. However, interactive investigations coupled with advanced imaging modalities at these small scale domains gradually demand the development of a new generation of disruptive tools, not only for passively observing at nanoscopic scales, but also for actively reaching into and effectively handling constituents in this size domain. This intriguing mindset has recently led to the emergence of a novel research discipline that could potentially be able to offer the full packet needed for true "active nanoscopy" by use of so-called light-driven micro-robotics or Light Robotics in short.

  1. Light emitting ceramic device

    DOEpatents

    Valentine, Paul; Edwards, Doreen D.; Walker, Jr., William John; Slack, Lyle H.; Brown, Wayne Douglas; Osborne, Cathy; Norton, Michael; Begley, Richard

    2010-05-18

    A light-emitting ceramic based panel, hereafter termed "electroceramescent" panel, is herein claimed. The electroceramescent panel is formed on a substrate providing mechanical support as well as serving as the base electrode for the device. One or more semiconductive ceramic layers directly overlay the substrate, and electrical conductivity and ionic diffusion are controlled. Light emitting regions overlay the semiconductive ceramic layers, and said regions consist sequentially of a layer of a ceramic insulation layer and an electroluminescent layer, comprised of doped phosphors or the equivalent. One or more conductive top electrode layers having optically transmissive areas overlay the light emitting regions, and a multi-layered top barrier cover comprising one or more optically transmissive non-combustible insulation layers overlay said top electrode regions.

  2. LEDs in automotive lighting

    NASA Astrophysics Data System (ADS)

    Eichhorn, Karsten

    2006-02-01

    Light emitting diodes (LED) are becoming more and more significant in interior and exterior automotive lighting. The long service life, energy and space savings, shock and vibration resistance and new styling potential are the main advantages of using LEDs in automotive applications. Today, most central high mounted stop lamps use LEDs. In rear combination lamps the number of LEDs in amber and red is increasing rapidly. This year, a first rear combination lamp using LEDs for all functionalities including the back-up lamp function was realized. In addition, first signal functions in headlamps using white High Power LEDs were launched onto the market. The long service life characteristic makes LEDs especially predestined for the DRL function combined with the position/parking light. Exterior automotive applications, including requirements and performance will be discussed and an outlook will be given on future scenarios.

  3. Fractality of light's darkness.

    PubMed

    O'Holleran, Kevin; Dennis, Mark R; Flossmann, Florian; Padgett, Miles J

    2008-02-01

    Natural light fields are threaded by lines of darkness. For monochromatic light, the phenomenon is familiar in laser speckle, i.e., the black points that appear in the scattered light. These black points are optical vortices that extend as lines throughout the volume of the field. We establish by numerical simulations, supported by experiments, that these vortex lines have the fractal properties of a Brownian random walk. Approximately 73% of the lines percolate through the optical beam, the remainder forming closed loops. Our statistical results are similar to those of vortices in random discrete lattice models of cosmic strings, implying that the statistics of singularities in random optical fields exhibit universal behavior. PMID:18352372

  4. White light emitting diodes

    NASA Astrophysics Data System (ADS)

    Baur, J.; Schlotter, P.; Schneider, J.

    Using blue-emitting GaN LEDs on SiC substrate chips as primary light sources, we have fabricated green, yellow, red and white light emitting diodes (LUCOLEDs). The generation of mixed colors, as turquoise and magenta, is also demonstrated. The underlying physical principle is that of luminescence downconversion (Stokes shift), as typical for organic dye molecules and many inorganic phosphors. For white light generation via the LUCOLED principle, the phosphor Y3Al5O12:Ce3+(4f1) is ideally suited. The optical characteristics of Ce3+(4f1) in Y3Al5O12(YAG) are discussed in detail. Possibilities to "tune" the white color by various substitutions in the garnet lattice are shortly outlined.

  5. Slow light beam splitter.

    PubMed

    Xiao, Yanhong; Klein, Mason; Hohensee, Michael; Jiang, Liang; Phillips, David F; Lukin, Mikhail D; Walsworth, Ronald L

    2008-07-25

    We demonstrate a slow light beam splitter using rapid coherence transport in a wall-coated atomic vapor cell. We show that particles undergoing random and undirected classical motion can mediate coherent interactions between two or more optical modes. Coherence, written into atoms via electromagnetically induced transparency using an input optical signal at one transverse position, spreads out via ballistic atomic motion, is preserved by an antirelaxation wall coating, and is then retrieved in outgoing slow light signals in both the input channel and a spatially-separated second channel. The splitting ratio between the two output channels can be tuned by adjusting the laser power. The slow light beam splitter may improve quantum repeater performance and be useful as an all-optical dynamically reconfigurable router.

  6. Radioluminescent lighting technology

    SciTech Connect

    Not Available

    1990-01-01

    The glow-in-the-dark stereotype that characterizes the popular image of nuclear materials is not accidental. When the French scientist, Henri Becquerel, first discovered radioactivity in 1896, he was interested in luminescence. Radioluminescence, the production of light from a mixture of energetic and passive materials, is probably the oldest practical application of the unstable nucleus. Tritium-based radioluminescent lighting, in spite of the biologically favorable character of the gaseous tritium isotope, was included in the general tightening of environmental and safety regulations. Tritium light manufacturers would have to meet two fundamental conditions: (1) The benefit clearly outweighed the risk, to the extent that even the perceived risk of a skeptical public would be overcome. (2) The need was significant enough that the customer/user would be willing and able to afford the cost of regulation that was imposed both in the manufacture, use and eventual disposal of nuclear materials. In 1981, researchers at Oak Ridge National Laboratory were investigating larger radioluminescent applications using byproduct nuclear material such as krypton-85, as well as tritium. By 1982, it appeared that large source, (100 Curies or more) tritium gas tube, lights might be useful for marking runways and drop zones for military operations and perhaps even special civilian aviation applications. The successful development of this idea depended on making the light bright enough and demonstrating that large gas tube sources could be used and maintained safely in the environment. This successful DOE program is now in the process of being completed and closed-out. Working closely with the tritium light industry, State governments and other Federal agencies, the basic program goals have been achieved. This is a detailed report of what they have learned, proven, and discovered. 91 refs., 29 figs., 5 tabs. (JF)

  7. Neuroendocrine effects of light

    NASA Astrophysics Data System (ADS)

    Reiter, Russel J.

    1991-09-01

    The light/dark cycle to which animals, and possibly humans, are exposed has a major impact on their physiology. The mechanisms whereby specific tissues respond to the light/dark cycle involve the pineal hormone melatonin. The pineal gland, an end organ of the visual system in mammals, produces the hormone melatonin only at night, at which time it is released into the blood. The duration of elevated nightly melatonin provides every tissue with information about the time of day and time of year (in animals that are kept under naturally changing photoperiods). Besides its release in a circadian mode, melatonin is also discharged in a pulsatile manner; the physiological significance, if any, of pulsatile melatonin release remains unknown. The exposure of animals including man to light at night rapidly depresses pineal melatonin synthesis and, therefore, blood melatonin levels drop precipitously. The brightness of light at night required to depress melatonin production is highly species specific. In general, the pineal gland of nocturnally active mammals, which possess rod-dominated retinas, is more sensitive to inhibition by light than is the pineal gland of diurnally active animals (with cone-dominated retinas). Because of the ability of the light/dark cycle to determine melatonin production, the photoperiod is capable of influencing the function of a variety of endocrine and non-endocrine organs. Indeed, melatonin is a ubiquitously acting pineal hormone with its effects on the neuroendocrine system having been most thoroughly investigated. Thus, in nonhuman photoperiodic mammals melatonin regulates seasonal reproduction; in humans also, the indole has been implicated in the control of reproductive physiology.

  8. Spatial Light Amplifier Modulators

    NASA Technical Reports Server (NTRS)

    Eng, Sverre T.; Olsson, N. Anders

    1992-01-01

    Spatial light amplifier modulators (SLAM's) are conceptual devices that effect two-dimensional spatial modulation in optical computing and communication systems. Unlike current spatial light modulators, these provide gain. Optical processors incorporating SLAM's designed to operate in reflection or transmission mode. Each element of planar SLAM array is optical amplifier - surface-emitting diode laser. Array addressed electrically with ac modulating signals superimposed on dc bias currents supplied to lasers. SLAM device provides both desired modulation and enough optical gain to enable splitting of output signal into many optical fibers without excessive loss of power.

  9. Light sheet microscopy.

    PubMed

    Weber, Michael; Mickoleit, Michaela; Huisken, Jan

    2014-01-01

    This chapter introduces the concept of light sheet microscopy along with practical advice on how to design and build such an instrument. Selective plane illumination microscopy is presented as an alternative to confocal microscopy due to several superior features such as high-speed full-frame acquisition, minimal phototoxicity, and multiview sample rotation. Based on our experience over the last 10 years, we summarize the key concepts in light sheet microscopy, typical implementations, and successful applications. In particular, sample mounting for long time-lapse imaging and the resulting challenges in data processing are discussed in detail.

  10. Short Course in Highway Lighting.

    ERIC Educational Resources Information Center

    Federal Highway Administration (DOT), Washington, DC.

    This course guide in highway lighting includes an overview of trends in highway lighting, illustrated information on three light sources for today's luminaires, a reference guide to lamp classification, specifications for highway lighting equipment, and instructions for calculating appropriate use. Maintenance notes on highway illumination and…

  11. Get More from Your Lighting.

    ERIC Educational Resources Information Center

    Bachner, John Philip

    1999-01-01

    Explains how improved lighting can pay for installation of a new system or upgrading existing lighting in an educational facility. Examples explore the use of high-benefit lighting to enhance other activities and reduce crime and security patrolling costs. Also discussed is the upgrading of one school's sports arena lighting that produced…

  12. Contrast Rendition in School Lighting.

    ERIC Educational Resources Information Center

    Sampson, Foster K.

    Eighteen significantly different classroom lighting systems were measured and analyzed in order to determine how contrasts from different light sources affect the ability to see visual tasks in the school room. Using criteria and techniques established from previous lighting research, the lighting systems are evaluated according to their…

  13. Freeform reflectors for architectural lighting.

    PubMed

    Zhu, Ruidong; Hong, Qi; Zhang, Hongxia; Wu, Shin-Tson

    2015-12-14

    We propose an improved method to design freeform reflectors for architectural lighting: one for accent lighting and another for large area wall washing. The designed freeform reflectors effectively distribute light fluxes over the target surfaces, and generate appropriate illumination patterns for comfortable visual environments, which provides greater flexibility for lighting designs, allows many challenging designs, and improves energy-efficiency simultaneously.

  14. Lighting the Way

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2007-01-01

    In recent years, more education administrators and designers have embraced the potential benefits of daylighting. They have been persuaded that using natural light to illuminate facilities enables schools and universities to conserve energy and provide a learning environment in which students perform better. For daylighting advocates, the…

  15. Lights and Larvae

    ERIC Educational Resources Information Center

    TItlow, Josh; Anderson, Heidi; Cooper, Robin

    2014-01-01

    Switching genes between organisms and controlling an animal's brain using lasers may seem like science fiction, but with advancements in a technique called optogenetics, such experiments are now common in neuroscience research. Optogenetics combines recombinant DNA technology with a controlled light source to help researchers address…

  16. Light antiprotonic atoms

    SciTech Connect

    Gotta, Detlev

    2005-10-19

    The present knowledge on strong-interaction effects in light antiprotonic atoms is reviewed. Data were obtained during the LEAR era, where the high flux made possible the use of high-resolution devices like semiconductor detectors and a crystal spectrometer. Open questions and possible extensions at the future antiproton facilities are discussed.

  17. Solid State Lighting

    SciTech Connect

    Hastbacka, Mildred; Dieckmann, John; Bouza, Antonio

    2013-03-30

    The article discusses solid state lighting technologies. This topic was covered in two previous ASHRAE Journal columns (2010). This article covers advancements in technologies and the associated efficacies. The life-cycle, energy savings and market potential of these technologies are addressed as well.

  18. Light and Cool

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2010-01-01

    When the subject of buildings and daylighting arises, most people's thoughts will turn first to windows. To the uninitiated, it seems a simple formula: more windows, more daylight; fewer windows, less daylight. But designers know that effective use of daylighting in a building design involves more than just letting in light to otherwise darkened…

  19. Lighting upFGFRsignaling

    PubMed Central

    Zhang, Kai; Cui, Bianxiao

    2014-01-01

    Summary In this issue of Chemistry & Biology, Heo and colleagues describe their work on optogenetic control of the fibroblast growth factor receptor (FGFR) signaling. By engineering a chimeric receptor, the authors demonstrate that FGFR intracellular signaling can be controlled in space and time by blue light. PMID:25036775

  20. Light microscopy digital imaging.

    PubMed

    Joubert, James; Sharma, Deepak

    2011-10-01

    This unit presents an overview of digital imaging hardware used in light microscopy. CMOS, CCD, and EMCCDs are the primary sensors used. The strengths and weaknesses of each define the primary applications for these sensors. Sensor architecture and formats are also reviewed. Color camera design strategies and sensor window cleaning are also described in the unit.

  1. Windows and lighting program

    SciTech Connect

    Not Available

    1990-06-01

    More than 30% of all energy use in buildings is attributable to two sources: windows and lighting. Together they account for annual consumer energy expenditures of more than $50 billion. Each affects not only energy use by other major building systems, but also comfort and productivity -- factors that influence building economics far more than does direct energy consumption alone. Windows play a unique role in the building envelope, physically separating the conditioned space from the world outside without sacrificing vital visual contact. Throughout the indoor environment, lighting systems facilitate a variety of tasks associated with a wide range of visual requirements while defining the luminous qualities of the indoor environment. Windows and lighting are thus essential components of any comprehensive building science program. Despite important achievements in reducing building energy consumption over the past decade, significant additional savings are still possible. These will come from two complementary strategies: (1) improve building designs so that they effectively apply existing technologies and extend the market penetration of these technologies; and (2) develop advanced technologies that increase the savings potential of each application. Both the Windows and Daylighting Group and the Lighting System Research Group have made substantial contributions in each of these areas, and continue to do so through the ongoing research summarized here. 23 refs., 16 figs.

  2. Fluorescence and Light Scattering

    ERIC Educational Resources Information Center

    Clarke, Ronald J.; Oprysa, Anna

    2004-01-01

    The aim of the mentioned experiment is to aid students in developing tactics for distinguishing between signals originating from fluorescence and light scattering. Also, the experiment provides students with a deeper understanding of the physicochemical bases of each phenomenon and shows that the techniques are actually related.

  3. Bringing Light onto Shadows

    ERIC Educational Resources Information Center

    Barrow, Lloyd H.

    2007-01-01

    "What starts out long but gets shorter then longer each day?" Shadows! This student's clever riddle was an opportunity to investigate how the Sun's daily position in the sky influences shadow length. Thus began a mini-lesson which was created to help third-grade students understand that a shadow occurs when an opaque object blocks light (Shapiro…

  4. Abundances of light elements.

    PubMed Central

    Pagel, B E

    1993-01-01

    Recent developments in the study of abundances of light elements and their relevance to cosmological nucleosynthesis are briefly reviewed. The simplest model, based on standard cosmology and particle physics and assuming homogeneous baryon density at the relevant times, continues to stand up well. PMID:11607388

  5. Light water reactor program

    SciTech Connect

    Franks, S.M.

    1994-12-31

    The US Department of Energy`s Light Water Reactor Program is outlined. The scope of the program consists of: design certification of evolutionary plants; design, development, and design certification of simplified passive plants; first-of-a-kind engineering to achieve commercial standardization; plant lifetime improvement; and advanced reactor severe accident program. These program activities of the Office of Nuclear Energy are discussed.

  6. Lighting up Savings.

    ERIC Educational Resources Information Center

    Ryerson, Charles

    1996-01-01

    Suggests group relamping in educational facilities as a more efficient method than spot replacement of failed lamps. It can reduce operating costs, improve lighting quality, and help with federal and state regulations compliance. The implementation of group relamping is discussed in terms of planning, energy savings, and environmental issues. (RE)

  7. Photoacoustics with coherent light

    PubMed Central

    Bossy, Emmanuel; Gigan, Sylvain

    2016-01-01

    Since its introduction in the mid-nineties, photoacoustic imaging of biological tissue has been one of the fastest growing biomedical imaging modality, and its basic principles are now considered as well established. In particular, light propagation in photoacoustic imaging is generally considered from the perspective of transport theory. However, recent breakthroughs in optics have shown that coherent light propagating through optically scattering medium could be manipulated towards novel imaging approaches. In this article, we first provide an introduction to the relevant concepts in the field, and then review the recent works showing that it is possible to exploit the coherence of light in conjunction with photoacoustics. We illustrate how the photoacoustic effect can be used as a powerful feedback mechanism for optical wavefront shaping in complex media, and conversely show how the coherence of light can be exploited to enhance photoacoustic imaging, for instance in terms of spatial resolution or for designing minimally invasive endoscopic devices. Finally, we discuss the current challenges and perspectives down the road towards practical applications in the field of photoacoustic imaging. PMID:27069874

  8. Lighting for Our Schools.

    ERIC Educational Resources Information Center

    Rankin, John C.

    In this speech, the author traces the history of lighting in schools, discusses the variables affecting the amount of illuminance needed, and provides a table of illuminances recommended for Ontario schools. Other factors that affect vision--glare, veiling reflection, color, and brightness balance--are outlined. Planners are admonished to…

  9. The Bright Lights

    ERIC Educational Resources Information Center

    Progressive Architecture, 1976

    1976-01-01

    High intensity discharge lighting sources share the compactness and beam controllability of incandescent sources, but are far more efficient and longer-lived. They share the efficiency and long life of fluorescent sources, but are compact and optically controllable, and are available in higher wattages. (Author/MLF)

  10. Conceptualization of Light Refraction

    ERIC Educational Resources Information Center

    Sokolowski, Andrzej

    2013-01-01

    There have been a number of papers dealing quantitatively with light refraction. Yet the conceptualization of the phenomenon that sets the foundation for a more rigorous math analysis is minimized. The purpose of this paper is to fill that gap. (Contains 3 figures.)

  11. Light's Disappearing Act.

    ERIC Educational Resources Information Center

    Murphy, Richard S.; Kwasnoski, John B.

    1985-01-01

    With an aquarium and a few tools, a simple apparatus to quantitatively illustrate absorption rates of light passing through fresh, salt, and other waters (such as distilled water) can be constructed. Students learn that extinction rates are different and that the intensity/depth relationship is exponential. (DH)

  12. Monochromators as Light Stretchers.

    ERIC Educational Resources Information Center

    Rubin, B.; Herman, R. M.

    1981-01-01

    A known but often overlooked property of optical monochromators is discussed in view of its current applications. It is shown that grating and prism monochromators hold on to light for time durations proportional to resolving power and that the dispersing ability of monochromators extends to pulses of arbitrarily short duration. (SK)

  13. Volumetric Light-Field Excitation

    PubMed Central

    Schedl, David C.; Bimber, Oliver

    2016-01-01

    We explain how to concentrate light simultaneously at multiple selected volumetric positions by means of a 4D illumination light field. First, to select target objects, a 4D imaging light field is captured. A light field mask is then computed automatically for this selection to avoid illumination of the remaining areas. With one-photon illumination, simultaneous generation of complex volumetric light patterns becomes possible. As a full light-field can be captured and projected simultaneously at the desired exposure and excitation times, short readout and lighting durations are supported. PMID:27363565

  14. Green light in photomorphogenic development

    NASA Astrophysics Data System (ADS)

    Maruhnich, Stefanie Anne

    Light quality, quantity, and duration provide essential environmental cues that shape plant growth and development. Over the last century, researchers have worked to discover how plants sense, integrate, and respond to red, blue, and far-red light. Green light is often considered a “benign” wavelength with little to no effect in plant development. However, sparse experiments in the literature demonstrate that green effects are often counterintuitive to normal light responses and oppose red- and blue-light-induced responses. Green light effects on plant growth and development are described here through the use of custom, tunable LED, light-emitting diode, chambers. These light sources allow for specific light qualities and quantities to be administered. The effects of green wavebands were assessed when red and blue photomorphogenic systems were active to answer the question: Are the effects of an inhibitor (green light) more evident in the presence of inducers (red and blue light)? In seedlings, supplemental green light increased hypocotyl elongation opposite to classical inhibition of hypocotyl elongation associated with growth in light and induced by red and blue wavebands. Results indicate that added green light induced a reversion of light-grown phenotypes. In mature plants, supplemental green light induced phenotypes typical of the shade-avoidance syndrome, including elongated petioles, smaller leaf areas, and leaf hyponasty. These responses are typical of lower-light conditions or far-red enriched environments. Contrary to far-red-light-induced shade-avoidance, data indicate green delays flowering. In Arabidopsis and strawberry plants, anthocyanin levels also decreased when green light was added to red and blue light treatments, which is again opposite to normal light-induced phenotypes. Photoreceptor mutants were tested and indicate green light effects in early development are cryptochromedependent. However, green-light-induced shade-avoidance responses

  15. Volumetric Light-Field Excitation.

    PubMed

    Schedl, David C; Bimber, Oliver

    2016-01-01

    We explain how to concentrate light simultaneously at multiple selected volumetric positions by means of a 4D illumination light field. First, to select target objects, a 4D imaging light field is captured. A light field mask is then computed automatically for this selection to avoid illumination of the remaining areas. With one-photon illumination, simultaneous generation of complex volumetric light patterns becomes possible. As a full light-field can be captured and projected simultaneously at the desired exposure and excitation times, short readout and lighting durations are supported. PMID:27363565

  16. Volumetric Light-Field Excitation.

    PubMed

    Schedl, David C; Bimber, Oliver

    2016-07-01

    We explain how to concentrate light simultaneously at multiple selected volumetric positions by means of a 4D illumination light field. First, to select target objects, a 4D imaging light field is captured. A light field mask is then computed automatically for this selection to avoid illumination of the remaining areas. With one-photon illumination, simultaneous generation of complex volumetric light patterns becomes possible. As a full light-field can be captured and projected simultaneously at the desired exposure and excitation times, short readout and lighting durations are supported.

  17. Volumetric Light-Field Excitation

    NASA Astrophysics Data System (ADS)

    Schedl, David C.; Bimber, Oliver

    2016-07-01

    We explain how to concentrate light simultaneously at multiple selected volumetric positions by means of a 4D illumination light field. First, to select target objects, a 4D imaging light field is captured. A light field mask is then computed automatically for this selection to avoid illumination of the remaining areas. With one-photon illumination, simultaneous generation of complex volumetric light patterns becomes possible. As a full light-field can be captured and projected simultaneously at the desired exposure and excitation times, short readout and lighting durations are supported.

  18. NASA Lighting Research, Test, & Analysis

    NASA Technical Reports Server (NTRS)

    Clark, Toni

    2015-01-01

    The Habitability and Human Factors Branch, at Johnson Space Center, in Houston, TX, provides technical guidance for the development of spaceflight lighting requirements, verification of light system performance, analysis of integrated environmental lighting systems, and research of lighting-related human performance issues. The Habitability & Human Factors Lighting Team maintains two physical facilities that are integrated to provide support. The Lighting Environment Test Facility (LETF) provides a controlled darkroom environment for physical verification of lighting systems with photometric and spetrographic measurement systems. The Graphics Research & Analysis Facility (GRAF) maintains the capability for computer-based analysis of operational lighting environments. The combined capabilities of the Lighting Team at Johnson Space Center have been used for a wide range of lighting-related issues.

  19. SWIR Hemispherical Air-Glow Plotting System SHAPS

    NASA Astrophysics Data System (ADS)

    Gonglewski, John D.; Myers, Michael M.; Dayton, David C.; Fertig, Gregory; Allen, Jeffrey; Nolasco, Rudolph; Maia, Franscisco

    2010-10-01

    It is well known that luminance from photo-chemical reactions of hydroxyl ions in the upper atmosphere (~85 km altitude) produces a significant amount of night time radiation in the short wave infra-red (SWIR) band of wave length 0.9 to 1.7 μm. Numerous studies of these phenomena have demonstrated that the irradiance shows significant temporal and spatial variations in the night sky. Changes in weather patterns, seasons, sun angle, moonlight, etc have the propensity to alter the SWIR air glow irradiance pattern. By performing multiple SWIR measurements a mosaic representation of the celestial hemisphere was constructed and used to investigate these variations over time and space. The experimental setup consisted of two sensors, an InGaAs SWIR detector and a visible astronomical camera, co-located and bore sighted on an AZ-EL gimbal. This gimbal was programmed to view most of the sky using forty five discrete azimuth and elevation locations. The dwell time at each location was 30 seconds with a total cycle time of less than 30 minutes. The visible astronomical camera collected image data simultaneous with the SWIR camera in order to distinguish SWIR patterns from clouds. Data was reduced through batch processing producing polar representations of the sky irradiance as a function of azimuth, elevation, and time. These spatiotemporal variations in the irradiance, both short and long term, can be used to validate and calibrate physical models of atmospheric chemistry and turbulence. In this paper we describe our experimental setup and present some results of our measurements made over several months in a rural marine environment on the Island of Kauai Hawaii.

  20. Large storms: Airglow and related measurements. VLF observations, volume 4

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The data presented show the typical values and range of ionospheric and magnetospheric characteristics, as viewed from 1400 km with the ISIS 2 instruments. The definition of each data set depends partly on geophysical parameters and partly on satellite operating mode. Preceding the data set is a description of the organizational parameters and a review of the objectives and general characteristics of the data set. The data are shown as a selection from 12 different data formats. Each data set has a different selection of formats, but uniformity of a given format selection is preserved throughout each data set. Each data set consists of a selected number of passes, each comprising a format combination that is most appropriae for the particular data set. Description of ISIS 2 instruments are provided.

  1. Observations of thunderstorm-related 630 nm airglow depletions

    NASA Astrophysics Data System (ADS)

    Kendall, E. A.; Bhatt, A.

    2015-12-01

    The Midlatitude All-sky imaging Network for Geophysical Observations (MANGO) is an NSF-funded network of 630 nm all-sky imagers in the continental United States. MANGO will be used to observe the generation, propagation, and dissipation of medium and large-scale wave activity in the subauroral, mid and low-latitude thermosphere. This network is actively being deployed and will ultimately consist of nine all-sky imagers. These imagers form a network providing continuous coverage over the western United States, including California, Oregon, Washington, Utah, Arizona and Texas extending south into Mexico. This network sees high levels of both medium and large scale wave activity. Apart from the widely reported northeast to southwest propagating wave fronts resulting from the so called Perkins mechanism, this network observes wave fronts propagating to the west, north and northeast. At least three of these anomalous events have been associated with thunderstorm activity. Imager data has been correlated with both GPS data and data from the AIRS (Atmospheric Infrared Sounder) instrument on board NASA's Earth Observing System Aqua satellite. We will present a comprehensive analysis of these events and discuss the potential thunderstorm source mechanism.

  2. Advanced mesospheric temperature mapper for high-latitude airglow studies.

    PubMed

    Pautet, P-D; Taylor, M J; Pendleton, W R; Zhao, Y; Yuan, T; Esplin, R; McLain, D

    2014-09-10

    Over the past 60 years, ground-based remote sensing measurements of the Earth's mesospheric temperature have been performed using the nighttime hydroxyl (OH) emission, which originates at an altitude of ∼87  km. Several types of instruments have been employed to date: spectrometers, Fabry-Perot or Michelson interferometers, scanning-radiometers, and more recently temperature mappers. Most of them measure the mesospheric temperature in a few sample directions and/or with a limited temporal resolution, restricting their research capabilities to the investigation of larger-scale perturbations such as inertial waves, tides, or planetary waves. The Advanced Mesospheric Temperature Mapper (AMTM) is a novel infrared digital imaging system that measures selected emission lines in the mesospheric OH (3,1) band (at ∼1.5  μm) to create intensity and temperature maps of the mesosphere around 87 km. The data are obtained with an unprecedented spatial (∼0.5  km) and temporal (typically 30″) resolution over a large 120° field of view, allowing detailed measurements of wave propagation and dissipation at the ∼87  km level, even in the presence of strong aurora or under full moon conditions. This paper describes the AMTM characteristics, compares measured temperatures with values obtained by a collocated Na lidar instrument, and presents several examples of temperature maps and nightly keogram representations to illustrate the excellent capabilities of this new instrument. PMID:25321674

  3. CONCAM All-Sky Maps of Airglow and Opacity

    NASA Astrophysics Data System (ADS)

    Nemiroff, R. J.; Shamir, L.; CONCAM Collaboration

    2003-12-01

    A major goal of the global CONtinuous CAMera (CONCAM) network is to support astronomical observing sites with real-time all-sky images and information. To date, this aim has been fulfilled mostly by CONCAM's role as an optical cloud monitor -- creating rapid ground-truth fisheye images that can be visually inspected so that real-time observing decisions can be made. These images are available immediately over the web through http://concam.net/, where they are also archived The high quality of raw CONCAM data, however, allows us to go further and build a data pipeline from which automated stellar photometry can be done for a few hundred of the brightest stars. When combined with CONCAM all-sky brightness data, we show that a simultaneous solution for sky opacity and emissivity is possible at stellar positions. These data can then be interpolated into all-sky maps. With current CONCAM3 equipment, maps with a broadband accuracy of about 0.25 magnitudes for altitudes above 25 degrees is demonstrated. Such maps might contribute to a more quantitative assessment of the brightness, clarity, and variability of the night sky background above the world's largest telescopes both in real time and in subsequent data reduction. Progress on creating these maps as part of the CONCAM data processing pipeline will be discussed.

  4. First-Light Galaxies or Intrahalo Stars: Multi-Wavelength Measurements of the Infrared Background Anisotropies

    NASA Astrophysics Data System (ADS)

    Cooray, Asantha

    explained with DGL. The proposed research supports Goal 2 of the NASA 2011 Strategic Plan to Expand scientific understanding of the Earth and the universe which we live, specifically to address the sub-goal 2.4 to discover how the universe works and explore how it began and evolved. The proposal is relevant to NASA's 2007 Science Plan in addressing the Science Question How do planets, stars, galaxies, and cosmic structure come into being?. The training of next-generation astrophysicists in the form of undergraduate students, graduate students, and postdoctoral fellows leading to experience and background in the analysis and interpretation of space-based astronomical data support the Goal 6 of the NASA 2011 Strategic Plan to Share NASA with the public, educators, and students to provide opportunities to participate in our Mission, foster innovation, and contribute to a strong national economy. The PI's efforts to involve undergraduates in his research programs will specifically improve retention of students in STEM disciplines by providing opportunities and activities along the full length of the education pipeline (subgoal 6.1). The IR fluctuation study supports JWST, Euclid, and WFIRST since we study the ensemble properties of the faint emission buried in existing deep and wide space-based IR data. We expect some fraction of the fluctuations to be from first-light galaxies that JWST seeks to detect and characterize individually. Euclid and WFIRST can make very deep and wide multi-band fluctuation measurements, depending on the final choice of bands (WFIRST) and observation/deep-field strategy (Euclid and WFIRST). This work could also motivate a small instrument for space-borne measurement of the absolute sky brightness from 5 AU, where the Zodiacal foreground is expected to be 100 times fainter than at 1.

  5. The International Year of Light and Light-based Technologies

    NASA Astrophysics Data System (ADS)

    Pendrill, Ann-Marie

    2015-05-01

    I report on the opening ceremony of the International Year of Light and Light-based Technologies 2015 (IYL2015), which took place at the UNESCO headquarters in Paris, France, on 19-20 January 2015. Over the two days, more than 1000 participants from all over the world learned more about the fundamental properties of light and advanced photonics applications, the history of optics and its applications through the centuries, light poverty and light pollution, and light for everyday life, health and research.

  6. The speed of light

    NASA Astrophysics Data System (ADS)

    Costa, Benjamin; Larson, Katherine; Bossari, Joshua

    2003-04-01

    Benjamin Costa Katherine Larson Joshua Borsari Advisor: Dr. Jong-Ping Shu Our project analyzes the Michelson- Morley "ether" experiment from three different perspectives: classical physics, special relativity, and from a revised special relativity. The heart of the project is centered on our revised edition of special relativity. Moreover, this modified theory of special relativity is focused on the question: Can the theory of relativity be formulated solely on the basis of the first principle of relativity(without assuming the constancy of the speed of light)? We are essentially trying to prove that the speed of light is not constant in a one way trip, but is constant throughout an entire round trip."

  7. Light Localisation and Lasing

    NASA Astrophysics Data System (ADS)

    Ghulinyan, Mher; Pavesi, Lorenzo

    2014-12-01

    List of contributors; Preface; 1. Light propagation and emission in complex photonic media W. L. Vos, A. Lagendijk and A. P. Mosk; 2. Transport of localized waves via modes and channels A. Genack and Z. Shi; 3. Modes structure and interaction in random lasers M. Leonetti and C. Lopez; 4. Ordered and disordered light transport in couple microring resonators S. Mookherjea; 5. One-dimensional photonic quasicrystals M. Ghulinyan; 6. 2D pseudo-random and deterministic aperiodic lasers H. Cao, H. Noh and L. Dal Negro; 7. 3D photonic quasicrystal and deterministic aperiodic structures A. Ledermann, M. Renner and G. von Freymann; 8. Cavity quantum electrodynamics with three-dimensional photonic bandgap crystals W. L. Vos and L. A. Woldering; References; Index.

  8. OLEDS FOR GENERAL LIGHTING

    SciTech Connect

    Anil Duggal; Don Foust; Chris Heller; Bill Nealon; Larry Turner; Joe Shiang; Nick Baynes; Tim Butler; Nalin Patel

    2004-02-29

    The goal of this program was to reduce the long term technical risks that were keeping the lighting industry from embracing and developing organic light-emitting diode (OLED) technology for general illumination. The specific goal was to develop OLEDs for lighting to the point where it was possible to demonstrate a large area white light panel with brightness and light quality comparable to a fluorescence source and with an efficacy comparable to that of an incandescent source. it was recognized that achieving this would require significant advances in three area: (1) the improvement of white light quality for illumination, (2) the improvement of OLED energy efficiency at high brightness, and (3) the development of cost-effective large area fabrication techniques. The program was organized such that, each year, a ''deliverable'' device would be fabricated which demonstrated progress in one or more of the three critical research areas. In the first year (2001), effort concentrated on developing an OLED capable of generating high illumination-quality white light. Ultimately, a down-conversion method where a blue OLED was coupled with various down-conversion layers was chosen. Various color and scattering models were developed to aid in material development and device optimization. The first year utilized this approach to deliver a 1 inch x 1 inch OLED with higher illumination-quality than available fluorescent sources. A picture of this device is shown and performance metrics are listed. To their knowledge, this was the first demonstration of true illumination-quality light from an OLED. During the second year, effort concentrated on developing a scalable approach to large area devices. A novel device architecture consisting of dividing the device area into smaller elements that are monolithically connected in series was developed. In the course of this development, it was realized that, in addition to being scalable, this approach made the device tolerant to the most

  9. EDITORIAL: LED light sources (light for the future) LED light sources (light for the future)

    NASA Astrophysics Data System (ADS)

    Grandjean, N.

    2010-09-01

    Generating white light from electricity with maximum efficacy has been a long quest since the first incandescent lamp was invented by Edison at the end of the 19th century. Nowadays, semiconductors are making reality the holy grail of converting electrons into photons with 100% efficiency and with colours that can be mixed for white light illumination. The revolution in solid-state lighting (SSL) dates to 1994 when Nakamura reported the first high-brightness blue LED based on GaN semiconductors. Then, white light was produced by simply combining a blue dye with a yellow phosphor. After more than a decade of intensive research the performance of white LEDs is quite impressive, beating by far the luminous efficacy of compact fluorescent lamps. We are likely close to replacing our current lighting devices by SSL lamps. However, there are still technological and fabrication cost issues that could delay large market penetration of white LEDs. Interestingly, SSL may create novel ways of using light that could potentially limit electricity saving. Whatever the impact of SSL, it will be significant on our daily life. The purpose of this special cluster issue is to produce a snapshot of the current situation of SSL from different viewing angles. In an introductory paper, Tsao and co-workers from Sandia National Laboratories, present an energy-economics perspective of SSL considering societal changes and SSL technology evolution. In a second article, Narukawa et al working at Nichia Corporation—the pioneer and still the leading company in SSL—describe the state of the art of current research products. They demonstrate record performance with white LEDs exhibiting luminous efficacy of 183 lm W-1 at high-current injection. Then, a series of topical papers discuss in detail various aspects of the physics and technology of white LEDs Carrier localization in InGaN quantum wells has been considered the key to white LEDs' success despite the huge density of defects. A

  10. Light amplification using semiconductors

    SciTech Connect

    Dupuis, R.D.

    1987-06-01

    During the summer of 1953, John von Neumann discussed his ideas concerning light amplification using semiconductors with Edward Teller. In September of that year, von Neumann sent a manuscript containing his ideas and calculations on this subject to Teller for his comments. To the best of our knowledge, von Neumann did not take time to work further on these ideas, and the manuscript remained unpublished. These previously unpublished writings of John von Neumann on the subject of light amplification in semiconductors are printed as a service to the laser community. While von Neumann's original manuscript and his letter to Teller are available to anyone who visits the Library of Congress, it is much more convenient to have this paper appear in an archival journal.

  11. Braiding light quanta

    NASA Astrophysics Data System (ADS)

    Iadecola, Thomas; Schuster, Thomas; Chamon, Claudio

    The possibility that anyons -- quantum particles other than fermions or bosons -- can emerge in condensed matter systems has motivated generations of physicists. In addition to being of fundamental scientific importance, so-called non-Abelian anyons are particularly sought-after for potential applications to quantum computing. However, experimental evidence of anyons in electronic systems remains inconclusive. We propose to demonstrate non-Abelian braiding by injecting coherent states of light into ``topological guided modes'' in specially-fabricated photonic waveguide arrays. These modes are photonic analogues of topological zero modes in electronic systems. Light traveling inside spatially well-separated topological guided modes can be braided, leading to the accumulation of non-Abelian phases. We propose an optical interference experiment to probe this non-Abelian braiding directly. T.I. is supported by a National Science Foundation Graduate Research Fellowship under Grant No. DGE-1247312.

  12. Sun light European Project

    NASA Astrophysics Data System (ADS)

    Soubielle, Marie-Laure

    2015-04-01

    2015 has been declared the year of light. Sunlight plays a major role in the world. From the sunbeams that heat our planet and feed our plants to the optical analysis of the sun or the modern use of sun particles in technologies, sunlight is everywhere and it is vital. This project aims to understand better the light of the Sun in a variety of fields. The experiments are carried out by students aged 15 to 20 in order to share their discoveries with Italian students from primary and secondary schools. The experiments will also be presented to a group of Danish students visiting our school in January. All experiments are carried out in English and involve teams of teachers. This project is 3 folds: part 1: Biological project = what are the mechanisms of photosynthesis? part 2: Optical project= what are the components of sunlight and how to use it? part 3: Technical project= how to use the energy of sunlight for modern devices? Photosynthesis project Biology and English Context:Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the Sun, into chemical energy that can later fuel the organisms' activities. This chemical energy is stored in molecules which are synthesized from carbon dioxide and water. In most cases, oxygen is released as a waste product. Most plants perform photosynthesis. Photosynthesis maintains atmospheric oxygen levels and supplies all of the organic compounds and most of the energy necessary for life on Earth. Outcome: Our project consists in understanding the various steps of photosynthesis. Students will shoot a DVD of the experiments presenting the equipments required, the steps of the experiments and the results they have obtained for a better understanding of photosynthesis Digital pen project Electricity, Optics and English Context: Sunlight is a complex source of light based on white light that can be decomposed to explain light radiations or colours. This light is a precious source to create

  13. Fusion pumped light source

    DOEpatents

    Pappas, Daniel S.

    1989-01-01

    Apparatus is provided for generating energy in the form of light radiation. A fusion reactor is provided for generating a long, or continuous, pulse of high-energy neutrons. The neutron flux is coupled directly with the lasing medium. The lasing medium includes a first component selected from Group O of the periodic table of the elements and having a high inelastic scattering cross section. Gamma radiation from the inelastic scattering reactions interacts with the first component to excite the first component, which decays by photon emission at a first output wavelength. The first output wavelength may be shifted to a second output wavelength using a second liquid component responsive to the first output wavelength. The light outputs may be converted to a coherent laser output by incorporating conventional optics adjacent the laser medium.

  14. Scattering Of Light Nuclei

    SciTech Connect

    Quaglioni, S; Navratil, P; Roth, R

    2009-12-15

    The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab initio approaches.We present a new ab initio many-body approach which derives from the combination of the ab initio no-core shell model with the resonating-group method [4]. By complementing a microscopic cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, this approach is capable of describing simultaneously both bound and scattering states in light nuclei. We will discuss applications to neutron and proton scattering on sand light p-shell nuclei using realistic nucleon-nucleon potentials, and outline the progress toward the treatment of more complex reactions.

  15. Light cone matrix product

    SciTech Connect

    Hastings, Matthew B

    2009-01-01

    We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.

  16. Fundamentals of Polarized Light

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael

    2003-01-01

    The analytical and numerical basis for describing scattering properties of media composed of small discrete particles is formed by the classical electromagnetic theory. Although there are several excellent textbooks outlining the fundamentals of this theory, it is convenient for our purposes to begin with a summary of those concepts and equations that are central to the subject of this book and will be used extensively in the following chapters. We start by formulating Maxwell's equations and constitutive relations for time- harmonic macroscopic electromagnetic fields and derive the simplest plane-wave solution that underlies the basic optical idea of a monochromatic parallel beam of light. This solution naturally leads to the introduction of such fundamental quantities as the refractive index and the Stokes parameters. Finally, we define the concept of a quasi-monochromatic beam of light and discuss its implications.

  17. Light from cosmic strings

    SciTech Connect

    Steer, Daniele A.; Vachaspati, Tanmay

    2011-02-15

    The time-dependent metric of a cosmic string leads to an effective interaction between the string and photons--the ''gravitational Aharonov-Bohm'' effect--and causes cosmic strings to emit light. We evaluate the radiation of pairs of photons from cosmic strings and find that the emission from cusps, kinks and kink-kink collisions occurs with a flat spectrum at all frequencies up to the string scale. Further, cusps emit a beam of photons, kinks emit along a curve, and the emission at a kink-kink collision is in all directions. The emission of light from cosmic strings could provide an important new observational signature of cosmic strings that is within reach of current experiments for a range of string tensions.

  18. Solar light bulb

    SciTech Connect

    Smith, D.A.

    1983-07-26

    A system for generating light directly using solar energy is provided herein. It includes a concentrator and accumulator for the sun's rays to generate a concentrated beam of visible solar radiation. A distributor shaft is provided for distributing the beam of visible solar radiation. A fork is provided in the distributor shaft to define a plurality of branch lines, each provided with a mirror at the intersection to direct the beam down the respective branch line to permit parallel fractions of the beam to be reflected off the respective mirrors and to pass down the respective branch line. A solar bulb is provided including a double walled upper bulbous portion including the inlet from the branch line and a pair of heat outlet tubes, and a double walled lower bulbous portion, the upper portion thereof being divergently reflective, with the lower portion having walls which are either transparent or translucent to provide greater light diffusion, and the space between the two walls being maintained under vacuum to provide heat insulation values. A structure is provided within the solar bulb for the absorption and radiation of the concentrated beam of visible solar radiation. Preferably structure is provided connected to the solar bulb to draw in outside air in the summer to direct it past the solar bulb and to air vent hot air produced at the solar bulb to the outside, thereby providing light with minimal heat in the summer. The same structure is operated in the winter to draw in household air to direct it past the solar bulb and to recirculate such heated air produced at the solar bulb to the house, thereby providing light and heat in the winter.

  19. Radioluminescent lighting program description

    SciTech Connect

    1987-11-01

    For more than 30 years the Department of Energy (DOE) and its predecessor agencies have conducted research and development aimed at beneficial uses of products derived from its nuclear activities. An important and promising element of radiation technology is the Program for Radioluminescent (RL) development. For years simple RL devices, such as aircraft exit signs, have served necessary functions in society. Electrons exciting phosphors and producing light is a fundamental concept to which the layman can immediately relate, while gaining a balanced perspective concerning risk and safety. DOE`s RL lighting development program has advanced the technology with infrared RL markers for helipads which are not detectable without the aid of special viewers. These devices were used to aid in the evacuation of wounded from Grenada. Visible RL airfield lighting has been used to promote aviation safety in remote Eskimo communities in Alaska, and non-electric taxiway signs and markers in the corrosive saline soils of Florida airports. The current plan is to consolidate past accomplishments and develop RL devices and systems using advanced technology for new applications. The potential for improved performance that solid-matrix RL techniques offer has stimulated interest in a variety of innovative applications for which electric lighting has long been the only practical alternative. The program described in this document is intended to provide for an optimum development and application of RL technology while supporting the transfer of this technology to the private sector and providing an institutional perspective from which the longer range applications and ramifications of this technology can be anticipated.

  20. Fiber optic light sensor.

    PubMed

    Chudyk, Wayne; Flynn, Kyle F

    2015-06-01

    We describe a low-cost fiber optic sensor for measuring photosynthetically active radiation (PAR) in turbulent flow. Existing technology was combined in a novel way for probe development addressing the need for a small but durable instrument for use in flowing water. Optical components including fiber optics and a wide-spectrum light detector were used to separate light collection from electronic detection so that measurements could be completed in either the field or laboratory, in air or underwater. Connection of the detector to Arduino open-source electronics and a portable personal computer (PC) enabled signal processing and allowed data to be stored in a spreadsheet for ease of analysis. Calibration to a commercial cosine-corrected instrument showed suitable agreement with the added benefit that the small sensor face allowed measurements in tight spaces such as close to the streambed or within leafy or filamentous plant growth. Subsequently, we applied the probe in a separate study where over 35 experiments were successfully completed to characterize downward light attenuation in filamentous algae in turbulent flow. PMID:26009160

  1. Fiber optic light sensor.

    PubMed

    Chudyk, Wayne; Flynn, Kyle F

    2015-06-01

    We describe a low-cost fiber optic sensor for measuring photosynthetically active radiation (PAR) in turbulent flow. Existing technology was combined in a novel way for probe development addressing the need for a small but durable instrument for use in flowing water. Optical components including fiber optics and a wide-spectrum light detector were used to separate light collection from electronic detection so that measurements could be completed in either the field or laboratory, in air or underwater. Connection of the detector to Arduino open-source electronics and a portable personal computer (PC) enabled signal processing and allowed data to be stored in a spreadsheet for ease of analysis. Calibration to a commercial cosine-corrected instrument showed suitable agreement with the added benefit that the small sensor face allowed measurements in tight spaces such as close to the streambed or within leafy or filamentous plant growth. Subsequently, we applied the probe in a separate study where over 35 experiments were successfully completed to characterize downward light attenuation in filamentous algae in turbulent flow.

  2. Nuclear light bulb

    NASA Technical Reports Server (NTRS)

    Latham, Tom

    1991-01-01

    The nuclear light bulb engine is a closed cycle concept. The nuclear light bulb concept provides containment by keeping the nuclear fuel fluid mechanically suspended in a cylindrical geometry. Thermal heat passes through an internally cooled, fused-silica, transparent wall and heats hydrogen propellant. The seeded hydrogen propellant absorbs radiant energy and is expanded through a nozzle. Internal moderation was used in the configuration which resulted in a reduced critical density requirement. This result was supported by criticality experiments. A reference engine was designed that had seven cells and was sized to fit in what was then predicted to be the shuttle bay mass and volume limitations. There were studies done of nozzle throat cooling schemes to remove the radiant heat. Elements of the nuclear light bulb program included closed loop critical assembly tests done at Los Alamos with UF6 confined by argon buffer gas. It was shown that the fuel region could be seeded with constituents that would block UV radiation from the uranium plasma. A combination of calculations and experiments showed that internal moderation produced a critical mass reduction. Other aspects of the research are presented.

  3. 'Light bar' attitude indicator

    NASA Technical Reports Server (NTRS)

    Enevoldson, E. K.; Horton, V. W.

    1982-01-01

    The development and evaluation of a light bar attitude indicator to help maintain proper aircraft attitude during high altitude night flying is described. A standard four-inch ADI was modified to project an artificial horizon across the instrument panel for pitch and roll information. A light bulb was put in the center of the ADI and a thin slit cut on the horizon, resulting in a thin horizontal sheet of light projecting from the instrument. The intensity of the projected beam is such that it can only be seen in a darkened room or at night. The beam on the instrument panel of the T-37 jet trainer is shown, depicting various attitudes. The favorable comments of about 50 pilots who evaluated the instrument are summarized, including recommendations for improving the instrument. Possible uses for the instrument to ease the pilot task are listed. Two potential problems in using the device are the development of pilot complacency and an upright-inverted ambiguity in the instrument.

  4. 30. BEDROOM #3 INTERIOR SHOWING 1 LIGHT OVER 1 LIGHT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. BEDROOM #3 INTERIOR SHOWING 1 LIGHT OVER 1 LIGHT WINDOW ON EAST WALL AND PARTIALLY OPENED DOOR TO WINDOWED CLOSET. VIEW TO EAST. - Big Creek Hydroelectric System, Powerhouse 8, Operator Cottage, Big Creek, Big Creek, Fresno County, CA

  5. Physics of light

    NASA Astrophysics Data System (ADS)

    Doria, R.

    2012-10-01

    A fourth interpretation for the principle of light invariance is proposed. After Maxwell equations, relativity, Lorentz group, another possibility stands into consider the Lorentz group representations as species. By specie one means fields with same nature under light invariance. For instance, given a (1/2,1/2) representation, instead of just one specific field, we should associate to it the potential fields specie. Thus, starting from such fields specie interpretation the features of a certain potential field AμI will be determined in terms of its associated fields set {AμI}, where I means a diversity index. It says that, the original field equation to be searched for a given field description is that one corresponding to the associated group of fields, and not more, for the field being taken isolated. It introduces the meaning of parts enfolded in the whole through whole relativistic equations. There is a more primitive equation to be understood. Instead Maxwell equation this fourth light invariance interpretation is guiding us to a more basic equation describing a fields set {AμI}. It will be entitled as Global Maxwell equation. Three steps are necessary for characterizing this Global Maxwell equation. The first one is to derive on abelian terms a generic expression for the fields set {AμI}. Further, show the diversity between these associated fields. Prove that every field carries a different quantum number (spin, mass, charges; C, P, T, CPT). The third one is on the photon singularity. Being the light invariance porter, it should be distinguished from others fields. This is done through the group gauge directive symmetry and Noether current. A Global Lorentz force complements the Global Maxwell by introducing three types of force. The first one generalizes the usual Lorentz force while the last two introduce relationships between fields and masses and fields with fields. A Physics of Light is derived. Based on such interpretation relating fields with same

  6. [Characteristics of laser light].

    PubMed

    Takac, S; Stojanović, S

    1999-01-01

    Laser is one of the greatest technical discoveries of the 20th century. It is important in basic sciences, but particularly in diagnosis and therapy of various pathologic conditions of human organism. It is electromagnetic radiation, not X-irradiation and, as such, it is not expected to produce new generation of iatrogenic malignancies. Laser falls between infrared and ultraviolet on the spectrum mainly in the visible light spectrum. Properties of laser light are: monochromacity (the same color), coherence (all of the light waves are in phase both spatially and temporally), collimation (all rays are parallel to each other and do not diverge significantly even over long distances). Lasers were first conceived by Einstein in 1917 when he wrote his "Zur Quantum Theorie der Strahlung" (the quantum theory of radiation) which enumerated concepts of stimulated and spontaneous emission and absorption. Drs. Arthur Schawlow and Charles Townes, in 1956, extended lasers into the optical frequency range and Maiman, in 1960, operated the first laser using ruby as the active medium (ruby laser). Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. To understand the acronym, it is necessary to understand the basic physics of the atom. However, if the atom that is in the excited state is struck by another photon of energy before it returns to the ground state, two photons of equal frequency and energy, travelling in the same direction and in perfect spatial and temporal harmony, are produced. This phenomenon is termed stimulated emission of radiation. An external power source hyperexcites the atoms in the laser medium so that the number of atoms possessing upper energy levels exceeds the number of atoms in a power energy level, a condition termed a population inversion. This "pumping system" which imparts additional energy to the atoms may be optical, mechanical, or chemical. These atoms in a hyperexcited state spontaneously emit photons of light. The

  7. Physics of light

    SciTech Connect

    Doria, R.

    2012-09-24

    A fourth interpretation for the principle of light invariance is proposed. After Maxwell equations, relativity, Lorentz group, another possibility stands into consider the Lorentz group representations as species. By specie one means fields with same nature under light invariance. For instance, given a ((1/2),(1/2)) representation, instead of just one specific field, we should associate to it the potential fields specie. Thus, starting from such fields specie interpretation the features of a certain potential field A{sub {mu}I} will be determined in terms of its associated fields set {l_brace}A{sub {mu}I}{r_brace}, where I means a diversity index. It says that, the original field equation to be searched for a given field description is that one corresponding to the associated group of fields, and not more, for the field being taken isolated. It introduces the meaning of parts enfolded in the whole through whole relativistic equations. There is a more primitive equation to be understood. Instead Maxwell equation this fourth light invariance interpretation is guiding us to a more basic equation describing a fields set {l_brace}A{sub {mu}I}{r_brace}. It will be entitled as Global Maxwell equation. Three steps are necessary for characterizing this Global Maxwell equation. The first one is to derive on abelian terms a generic expression for the fields set {l_brace}A{sub {mu}I}{r_brace}. Further, show the diversity between these associated fields. Prove that every field carries a different quantum number (spin, mass, charges; C, P, T, CPT). The third one is on the photon singularity. Being the light invariance porter, it should be distinguished from others fields. This is done through the group gauge directive symmetry and Noether current. A Global Lorentz force complements the Global Maxwell by introducing three types of force. The first one generalizes the usual Lorentz force while the last two introduce relationships between fields and masses and fields with fields. A

  8. Pollution-free road lighting

    NASA Astrophysics Data System (ADS)

    Schreuder, Duco A.

    They relate to reducing road accidents and some forms of crime but also enhance the social safety of residents and pedestrians and the amenity for residents. Road traffic in developing countries is much more hazardous than in industrialized countries. Accident rates in 'low' income countries may be as much as 35 times higher than in 'high' income countries. Thus, it might be much more cost-effective to light roads in the developing world than in the industrialized world. Fighting light pollution is more pressing in developing countries as most of the major high-class astronomical observatories are there. Astronomical observations are disturbed by light from outdoor lighting installations, part of which is scattered in the atmosphere to form 'sky glow'. The International Lighting Commission CIE has published a Technical Report giving general guidance for lighting designers and policy makers on the reduction of the sky glow. Lighting improves visibility, essential for almost all human activity. However, light that hits the road contributes to visibility only if it is reflected. In poorly designed lighting equipment much of the lumen output of the lamps is sent directly upwards. This can be avoided by properly defined light fittings. The light output of fittings is determined by their optical quality and by the installation maintenance factor. Open fittings are to be preferred. If mounted horizontally, they make street lighting with the least light pollution.

  9. Light pollution simulations for planar ground-based light sources.

    PubMed

    Kocifaj, Miroslav

    2008-02-20

    The light pollution model is employed to analyze spatial behavior of luminance at the night sky under cloudless and overcast conditions. Enhanced light excess is particularly identified at cloudy skies, because the clouds efficiently contribute to the downward luminous flux. It is evident that size of ground-based light sources can play an important role in the case of overcast sky conditions. Nevertheless, the realistically sized light sources are rarely embedded into light pollution modeling, and rather they are replaced by simple point sources. We discuss the discrepancies between sky luminance distributions when at first the planar light sources are considered and at second the point-source approximation is accepted. The found differences are noticeable if the size of the light source, distance to the observer, and altitude of a cloudy layer are comparable one to the other. Compared with point-source approximation, an inclusion of the size factor into modeling the light sources leads to partial elimination of the steep changes of sky luminance (typical for point sources of light). The narrow and sharp light pillars normally presented on the sky illuminated by point light sources can disappear or fuse together when two or more nearby light sources are considered with their real sizes. Sky elements situated close to the horizon will glow efficiently if luminous flux originates from two-dimensional ground-based entities (such as cities or villages).

  10. 2. Southern Light Tower and Northern Light Tower, view north, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Southern Light Tower and Northern Light Tower, view north, south sides - Kennebec River Light Station, South side of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

  11. Lighting quality for aluminum and prismatic light guides

    NASA Astrophysics Data System (ADS)

    García-Fernández, Berta; Vázquez-Molini, Daniel; Fernández-Balbuena, Antonio Álvarez

    2011-10-01

    The use of high reflectance aluminum lighting guides is most frequently used material for actual natural lighting systems. Spectral Reflectance over the entire length of a light guide changes the color of the output light at the end of the guide. When light guides are made of a prismatic film, the influence of the reflectance is minimizing and absortance is not important when the sheets are thin. Color Rendering index and color temperature will be important parameters in order to evaluate Lighting quality and therefore in Museums, office buildings and production centers to get the normative approval. In this paper a theoretical simulation and 3D ray tracing for aluminum and prismatic light guides of different shapes (rectangular and cylindrical) and lengths over the entire visible spectrum are studied. Output light color temperature related to several illuminants and CRI are evaluated for the simulated aluminum and prismatic light guides. Thus, prismatic light guides seem more robust in lighting quality maintenance regardless of conditionals like angle acceptance for TIR guiding, aluminum guides are efficient and maintain light quality only for short distances.

  12. Organic light emitting diode with light extracting layer

    DOEpatents

    Lu, Songwei

    2016-06-14

    A light extraction substrate includes a glass substrate having a first surface and a second surface. A light extraction layer is formed on at least one of the surfaces. The light extraction layer is a coating, such as a silicon-containing coating, incorporating nanoparticles.

  13. Lighting for Safety and Security.

    ERIC Educational Resources Information Center

    Fleming, Colette

    2000-01-01

    Discusses ways to use lighting to provide a safe environment, reduce vandalism, improve visibility, and reduce overall liability for colleges. Guidelines for outdoor, parking, and emergency lighting are discussed. (GR)

  14. Lighting for Today and Tomorrow.

    ERIC Educational Resources Information Center

    Murphy, Peter

    2000-01-01

    Discusses how technology has contributed to brighter, less expensive, and more efficient lighting. Four key areas where suspended Direct/Indirect lighting out performs parabolic troffers are examined. (GR)

  15. Issues of Rural Light Pollution

    NASA Astrophysics Data System (ADS)

    Osborn, W. H.; Hammer, R. L.; Hammer, A.

    2001-12-01

    Light pollution is generally considered mostly an urban problem. Common sources of light pollution are poorly designed lighting of streets, parking lots, businesses and advertizing signs and for security. These sources, and the amount of light pollution generated, increase with population density. Nevertheless, light pollution can also be significant in rural areas. Rural light pollution differs from that in urban settings, both in the types of pollution and in the means that must be employed to control it. In the country the offending sources are often isolated lights such as from farm barns, vacation cottages, radio and cell phone towers, and road intersections. A culture of strong property rights and privacy rights affects attempts to control rural light pollution. We describe how some of these issues may be addressed based on the results from an Eagle Scout project carried out in central Michigan.

  16. The Control of Lighting Heat

    ERIC Educational Resources Information Center

    Modern Schools, 1973

    1973-01-01

    The trend toward increased lighting has accelerated the acceptance of heat recovery systems. A heating-lighting-cooling system is a responsible and efficient use of energy for future school buildings. (Author/MLF)

  17. Light sensitivity of methanogenic archaebacteria

    SciTech Connect

    Olson, K.D.; McMahon, C.W.; Wolfe, R.S. )

    1991-09-01

    Representatives of four families of methanogenic archaebacteria (archaea), Methanobacterium thermoautotrophicum {Delta}H, Methanobacterium thermoautotrophicum Marburg, Methanosarcina acetivorans, Methanococcus voltae, and Methanomicrobium mobile, were found to be light sensitive. The facultative anaerobic eubacteria Escherichia coli and Salmonella typhimurium, however, were tolerant of light when grown anaerobically under identical light conditions. Interference filters were used to show that the growth of the methanogens is inhibited by light in the blue end of the visible spectrum (370 to 430 nm).

  18. Photodetector with enhanced light absorption

    DOEpatents

    Kane, James

    1985-01-01

    A photodetector including a light transmissive electrically conducting layer having a textured surface with a semiconductor body thereon. This layer traps incident light thereby enhancing the absorption of light by the semiconductor body. A photodetector comprising a textured light transmissive electrically conducting layer of SnO.sub.2 and a body of hydrogenated amorphous silicon has a conversion efficiency about fifty percent greater than that of comparative cells. The invention also includes a method of fabricating the photodetector of the invention.

  19. Pedestrian Friendly Outdoor Lighting

    SciTech Connect

    Miller, Naomi J.; Koltai, Rita; McGowan, Terry

    2013-12-31

    This GATEWAY report discusses the problems of pedestrian lighting that occur with all technologies with a focus on the unique optical options and opportunities offered by LEDs through the findings from two pedestrian-focused projects, one at Stanford University in California, and one at the Chautauqua Institution in upstate New York. Incorporating user feedback this report reviews the tradeoffs that must be weighed among visual comfort, color, visibility, efficacy and other factors to stimulate discussion among specifiers, users, energy specialists, and in industry in hopes that new approaches, metrics, and standards can be developed to support pedestrian-focused communities, while reducing energy use.

  20. Coherent white light amplification

    DOEpatents

    Jovanovic, Igor; Barty, Christopher P.

    2004-05-25

    A system for coherent simultaneous amplification of a broad spectral range of light that includes an optical parametric amplifier and a source of a seed pulse is described. A first angular dispersive element is operatively connected to the source of a seed pulse. A first imaging telescope is operatively connected to the first angular dispersive element and operatively connected to the optical parametric amplifier. A source of a pump pulse is operatively connected to the optical parametric amplifier. A second imaging telescope is operatively connected to the optical parametric amplifier and a second angular dispersive element is operatively connected to the second imaging telescope.