These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Edwin Hubble's Silence  

NASA Astrophysics Data System (ADS)

In late 1928 Edwin Hubble was right in the middle of using V. M. Slipher's redshift data to prove that the universe is expanding, when Hubble's boss, George Hale, directed him to drop everything and rush to the Grand Canyon and test it as a possible site for Hale's planned 200-inch telescope. On his way, Hubble stopped at Lowell Observatory and met with V. M. Slipher. The letters both men wrote about this visit suggest that Hubble never said a word about his being in the middle of using Slipher's research to transform the universe. At the least, this silence is symbolic of the silence with which astronomical history has often treated Slipher's work. A survey of the historical literature suggests several reasons for this. Theorists and observers in astronomy (and other sciences) have long had different perspectives about how science works, and those who place more importance on theory have tended to credit the idea of the expanding universe to the theorists. Also, many sources indicate that Edwin Hubble was not a modest man or generous about sharing credit.

Lago, D.

2013-04-01

2

Multiple Galaxy Collisions Surprise Hubble Astronomers  

NSDL National Science Digital Library

Recent surprising discoveries have led Hubble space telescope astronomers to rethink theories on a class of galaxies called ultra-luminous infrared galaxies (ULIRG). It was previously believed that only pairs of galaxies were interacting in ULIRGs, but recent photos from Hubble show multiple collisions of four or even five galaxies smashing together. The images, provided at this site, offer a glimpse of what conditions were like in the early universe when galaxy collisions were commonplace. Users can read the official press release and view a number of images in different sizes and formats at the above URL. Additional resources include two QuickTime movies of astronomer Dr. Kirk Borne discussing his new finding and describing one of the images, and links to related discoveries at the Hubble site.

1999-01-01

3

European astronomers' successes with the Hubble Space Telescope*  

NASA Astrophysics Data System (ADS)

[Figure: Laguna Nebula] Their work spans all aspects of astronomy, from the planets to the most distant galaxies and quasars, and the following examples are just a few European highlights from Hubble's second phase, 1994-96. A scarcity of midget stars Stars less massive and fainter than the Sun are much numerous in the Milky Way Galaxy than the big bright stars that catch the eye. Guido De Marchi and Francesco Paresce of the European Southern Observatory as Garching, Germany, have counted them. With the wide-field WFPC2 camera, they have taken sample censuses within six globular clusters, which are large gatherings of stars orbiting independently in the Galaxy. In every case they find that the commonest stars have an output of light that is only one-hundredth of the Sun's. They are ten times more numerous than stars like the Sun. More significant for theories of the Universe is a scarcity of very faint stars. Some astronomers have suggested that vast numbers of such stars could account for the mysterious dark matter, which makes stars and galaxies move about more rapidly than expected from the mass of visible matter. But that would require an ever-growing count of objects at low brightnesses, and De Marchi and Paresce find the opposite to be the case -- the numbers diminish. There may be a minimum size below which Nature finds starmaking difficult. The few examples of very small stars seen so far by astronomers may be, not the heralds of a multitude of dark-matter stars, but rareties. Unchanging habits in starmaking Confirmation that very small stars are scarce comes from Gerry Gilmore of the Institute of Astronomy in Cambridge (UK). He leads a European team that analyses long-exposure images in the WFPC2 camera, obtained as a by-product when another instrument is examining a selected object. The result is an almost random sample of well-observed stars and galaxies. The most remarkable general conclusion is that the make-up of stellar populations never seems to vary. In dense or diffuse regions, in very young or very old agglomerations, in the Milky Way Galaxy or elsewhere, the relative numbers of stars of different masses are always roughly the same. Evidently Nature mass-produces quotas of large and small stars irrespective of circumstances. This discovery will assist astronomers in making sense of very distant and early galaxies. They can assume that the stars are of the most familiar kinds. Another surprise was spotted by Rebecca Elson in Gilmore's team, in long-exposure images of the giant galaxy M87, in the nearby Virgo cluster. It possesses globular clusters of very different ages. In the Milky Way and its similar spiral neighbour, the Andromeda galaxy, globular clusters contain the oldest stars. While M87 has ancient globular clusters too, some are different in colour and much younger. The theory is that they were manufactured during collisions of the galaxies that merged into M87, making it the egg-shaped giant seen today. If so, the absence of young globular clusters in the Milky Way may mean that our Galaxy has never suffered a major collision. Accidents in the galactic traffic Brighter than a million million suns, a quasar is the most powerful lamp in the Universe. Astronomers understand it to be powered by matter falling into a massive black hole in the heart of a galaxy. Mike Disney of the University of Wales, Cardiff, leads a European team that asks why some thousands of galaxies harbour quasars, in contrast to the billions that do not. In almost every case that he and his colleagues have investigated, using Hubble's WFPC2 camera at its highest resolution, they see the quasar's home galaxy involved in a collision with another galaxy. "It's my opinion that almost any galaxy can be a quasar," Disney says, "if only its central black hole gets enough to eat. In the galactic traffic accidents that Hubble reveals, we can visualize fresh supplies of stars and gas being driven into the black hole's clutches. My American opposite number, John Bahcall, prefers to stress those quasar hosts that look li

1997-02-01

4

Dismantling Hubble's Legacy?  

NASA Astrophysics Data System (ADS)

Edwin Hubble is famous for a number of discoveries that are well known to amateur and professional astronomers, students and the general public. The origins of these discoveries are examined and it is demonstrated that, in each case, a great deal of supporting evidence was already in place. In some cases the discoveries had either already been made, or competing versions were not adopted for complex scientific and sociological reasons.

Way, M. J.

2013-04-01

5

Dismantling Hubble's Legacy?  

NASA Astrophysics Data System (ADS)

Edwin Hubble is famous for a number of discoveries that are well known to amateur and professional astronomers, students and even the general public. The origins of three of the most well-known discoveries are examined: The distances to nearby spiral nebulae, the classification of extragalactic-nebulae and the Hubble constant. In the case of the first two a great deal of supporting evidence was already in place, but little credit was given. The Hubble Constant had already been estimated in 1927 by Georges Lemaitre with roughly the same value that Hubble obtained in 1929 using redshifts provided mostly by Vesto M. Slipher. These earlier estimates were not adopted or were forgotten by the astronomical community for complex scientific, sociological and psychological reasons.

Way, Michael J.

2014-01-01

6

News and Views: Astronomers discover second spiral galaxy with jets; Hubble jet movies reveal star formation  

NASA Astrophysics Data System (ADS)

Giant jets of superfast particles are a feature of galaxies with supermassive black holes at their centres - but those galaxies are almost always elliptical. Now the second spiral galaxy to show such behaviour has been found, and it turns out to produce these large jets episodically, in a pattern found in one other elliptical galaxy only. Astronomers can now watch star formation as it happens, by watching time-lapse movies made from 14 years of Hubble Space Telescope images of jets from young stars, phenomena that change over periods of a few years.

2011-10-01

7

The Director's Choice: Mellish, Hubble and the discovery of the variable nebula  

NASA Astrophysics Data System (ADS)

In the summer of 1915, amateur astronomer John Edward Mellish joined the staff of Yerkes Observatory as an unpaid observer. Soon after arriving, Mellish discovered what he thought was a comet in the dawn twilight. Yerkes director Edwin Brant Frost promptly notified Harvard Observatory of the discovery only to learn later in the day, too late to prevent distribution of an international telegram, that the object Mellish observed was actually the diffuse nebula NGC 2261. Edwin Powell Hubble, a graduate student in his first year at Yerkes, was assigned the task of determining whether, as Mellish insisted, the nebula had changed. This led to Hubble's first professional papers and his initial fame as the discoverer of `Hubble's Variable Nebula.' Frost's choice, assigning the investigation to Hubble rather than Mellish, reflected his irritation with Mellish over matters that went well beyond the mistaken comet discovery. When Mellish discovered another comet a few weeks later, Frost delayed his notification to Harvard for several days to allow photographic confirmation of the discovery by George Van Biesbroeck, another newcomer at Yerkes. These events highlight staffing problems at Yerkes in 1915, problems that were common to other American observatories. Mellish and Van Biesbroeck were likely the last two amateur astronomers to have an opportunity to `try out' as professionals at Yerkes. By 1915 a stronger requirement for educational credentials was emerging in the astronomical community. On the other hand, like other observatory directors, Frost was experiencing considerable difficulty employing graduate astronomers. With S. W. Burnham already retired, Frost adopted stopgap measures for staffing as E. E. Barnard and others from an earlier generation prepared for retirement. The assignment of the nebula investigation to Hubble indicates that Frost had likely already concluded that Mellish would not be an acceptable substitute for a degreed professional.

Williams, T. R.

2000-12-01

8

Edwin Amenta January 2011  

E-print Network

, Professor Baseball: Searching for Redemption and the Perfect Lineup on the Softball Diamonds of Central Park Press, 1998). REFEREED ARTICLES AND BOOK CHAPTERS Edwin Amenta, "Historical Institutionalism." Chapter Theory." Chapter 2 in The Handbook of Politics: State and Civil Society in Global Perspective, eds. Kevin

Loudon, Catherine

9

Blind Astronomers  

NASA Astrophysics Data System (ADS)

The phrase "blind astronomer” is used as an allegorical oxymoron. However, there were and are blind astronomers. What of famous blind astronomers? First, it must be stated that these astronomers were not martyrs to their craft. It is a myth that astronomers blind themselves by observing the Sun. As early as France's William of Saint-Cloud (circa 1290) astronomers knew that staring at the Sun was ill-advised and avoided it. Galileo Galilei did not invent the astronomical telescope and then proceed to blind himself with one. Galileo observed the Sun near sunrise and sunset or through projection. More than two decades later he became blind, as many septuagenarians do, unrelated to their profession. Even Isaac Newton temporarily blinded himself, staring at the reflection of the Sun when he was a twentysomething. But permanent Sun-induced blindness? No, it did not happen. For instance, it was a stroke that left Scotland's James Gregory (1638-1675) blind. (You will remember the Gregorian telescope.) However, he died days later. Thus, blindness little interfered with his occupation. English Abbot Richard of Wallingford (circa 1291 - circa 1335) wrote astronomical works and designed astronomical instruments. He was also blind in one eye. Yet as he further suffered from leprosy, his blindness seems the lesser of Richard's maladies. Perhaps the most famous professionally active, blind astronomer (or almost blind astronomer) is Dominique-Francois Arago (1786-1853), director until his death of the powerful nineteenth-century Paris Observatory. I will share other _ some poignant _ examples such as: William Campbell, whose blindness drove him to suicide; Leonhard Euler, astronomy's Beethoven, who did nearly half of his life's work while almost totally blind; and Edwin Frost, who "observed” a total solar eclipse while completely sightless.

Hockey, Thomas A.

2011-01-01

10

Hubble's diagram and cosmic expansion  

PubMed Central

Edwin Hubble's classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168–173]. The chief result, that a galaxy's distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble's Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble's distances have a large systematic error, Hubble's velocities come chiefly from Vesto Melvin Slipher, and the interpretation in terms of the de Sitter effect is out of the mainstream of modern cosmology, this article opened the way to investigation of the expanding, evolving, and accelerating universe that engages today's burgeoning field of cosmology. PMID:14695886

Kirshner, Robert P.

2004-01-01

11

Hubble: 20 Years of Discovery  

NASA Video Gallery

Hubble's discoveries have revolutionized nearly all areas of current astronomical research from planetary science to cosmology. Actor and writer Brent Spiner narrates a visual journey back in time ...

12

HubbleSite: Hubble Discoveries  

NSDL National Science Digital Library

This web site presents Hubble's fascinating discoveries through pictures, videos, and stories describing the universe's past, present, and future. This website provides two videos: "Piercing the Sky," a look at how telescope advances have changed astronomer's understanding of the universe, and "Cosmic Collision," a video discussing galaxy collisions. There is also an overview of Hubbleâs contributions in "New Views of the Universe." "Decade of Discovery" features pictures, videos, and stories. "Hubble Deep Field" provides a multimedia journey back in time. Scientists describe planet formation and other fascinating celestial phenomena in "Tour the Cosmos."

Administration, National A.

2005-06-28

13

External Resource: Hubble Deep Space Field Academy  

NSDL National Science Digital Library

This Space Telescope Science Institute web page contains resources for students to 'walk' in the footsteps of astronomers as they explore the farthest regions of the known universe. Using astronomers' methods, students will observe the Hubble Deep Field

1900-01-01

14

Hubble Space Telescope Deep Field Lesson Package  

NSDL National Science Digital Library

This product consists of four classroom activities, lithographs, and teachers guide. Students examine the Hubble Deep Field image and simulate the process astronomers use to count, classify, and identify objects in the image.

1997-01-01

15

HUBBLE REVEALS 'BACKWARDS' SPIRAL GALAXY  

NASA Technical Reports Server (NTRS)

Astronomers have found a spiral galaxy that may be spinning to the beat of a different cosmic drummer. To the surprise of astronomers, the galaxy, called NGC 4622, appears to be rotating in the opposite direction to what they expected. Pictures by NASA's Hubble Space Telescope helped astronomers determine that the galaxy may be spinning clockwise by showing which side of the galaxy is closer to Earth. A Hubble telescope photo of the oddball galaxy is this month's Hubble Heritage offering. The image shows NGC 4622 and its outer pair of winding arms full of new stars [shown in blue]. Astronomers are puzzled by the clockwise rotation because of the direction the outer spiral arms are pointing. Most spiral galaxies have arms of gas and stars that trail behind as they turn. But this galaxy has two 'leading' outer arms that point toward the direction of the galaxy's clockwise rotation. To add to the conundrum, NGC 4622 also has a 'trailing' inner arm that is wrapped around the galaxy in the opposite direction it is rotating. Based on galaxy simulations, a team of astronomers had expected that the galaxy was turning counterclockwise. NGC 4622 is a rare example of a spiral galaxy with arms pointing in opposite directions. What caused this galaxy to behave differently from most galaxies? Astronomers suspect that NGC 4622 interacted with another galaxy. Its two outer arms are lopsided, meaning that something disturbed it. The new Hubble image suggests that NGC 4622 consumed a small companion galaxy. The galaxy's core provides new evidence for a merger between NGC 4622 and a smaller galaxy. This information could be the key to understanding the unusual leading arms. Galaxies, which consist of stars, gas, and dust, rotate very slowly. Our Sun, one of many stars in our Milky Way Galaxy, completes a circuit around the Milky Way every 250 million years. NGC 4622 resides 111 million light-years away in the constellation Centaurus. The pictures were taken in May 2001 with Hubble's Wide Field Planetary Camera 2. The science team, consisting of Ron Buta and Gene Byrd from the University of Alabama, Tuscaloosa, and Tarsh Freeman of Bevill State Community College in Alabama, observed NGC 4622 in ultraviolet, infrared, and blue and green filters. Their composite image and science findings were presented at the meeting of the American Astronomical Society in January of 2002. Image Credit: NASA and the Hubble Heritage Team (STScI/AURA) Acknowledgment: Dr. Ron Buta (U. Alabama), Dr. Gene Byrd (U. Alabama) and Tarsh Freeman (Bevill State Community College)

2002-01-01

16

Hubble vision : further adventures with the Hubble Space Telescope  

NASA Astrophysics Data System (ADS)

The first edition of Hubble Vision became an international bestseller and won world-wide, critical acclaim. This eagerly awaited second edition is the most comprehensive, most authoritative and best illustrated popular book available on the Hubble Space Telescope. It provides a magnificent portfolio of the latest and greatest images from the HST, woven together with a lucid text explaining the most exciting discoveries and setting them in the context of our current understanding in astronomy. This second edition has been completely revised, updated and expanded to include all the latest astronomical discoveries - from supernovae and protostars to gravitational lensing, black holes and the early universe. It is now even better illustrated, with nearly 25% more figures, and more than 100 entirely new. The unique combination of authors - an award-winning science writer and a key scientist involved in the development of the mission - ensure that the text is both engaging and authoritative. Hubble Vision offers a view of the Universe as never seen before. It will capture the imagination of all those interested in the astronomical quest of understanding our Universe - from high-school students to general readers and amateur astronomers. * Stellar fireworks within Colliding galaxies * The sharpest views of Mars yet * Newborn stars in M16 * A gallery of the latest images of planetary nebulae as never seen before * The deepest, most penetrating view into space ever : the Hubble Deep Field * Views into the heart of a comet (Hale-Bopp) * New views of Jupiter and Io

Petersen, Carolyn Collins; Brandt, John C.

17

High-Impact Astronomical Observatories  

E-print Network

We derive the ranking of the astronomical observatories with the highest impact in astronomy based on the citation analysis of papers published in 2006. We also present a description of the methodology we use to derive this ranking. The current ranking is lead by the Sloan Digital Sky Survey, followed by Swift and the Hubble Space Telescope.

Madrid, Juan P

2009-01-01

18

Edwin M. McMillan, A biographical sketch  

SciTech Connect

Edwin M. McMillan was one of the great scientists of the middle years of this century. He made notable contributions to nuclear, and particle physics, the chemistry of transuranic elements, and accelerator physics.

Lofgren, E.J.

1994-07-01

19

Hubble's universe.  

NASA Astrophysics Data System (ADS)

Hubble gets powerful new eyes; giant "twisters" in the Lagoon nebula; a big picture that will make you feel small; pillars of creation in the Eagle nebula; springtime storms blow up on Mars; a strange twist to the Helix nebula; gas giants of the Solar System; spectacular death throes of the stars; planetary systems in the making.

Young, S.

1997-04-01

20

Edwin Smith Papyrus Case 8: a reappraisal.  

PubMed

There are 3 translations of the Edwin Smith Papyrus: Breasted's (1930), Allen's (2005), and Sanchez and Meltzer's (2012). Case 8 is similarly presented in all 3 translations, although with increasing detail in the later works. The patient in Case 8 had a comminuted skull fracture under intact skin. There were palpable pulsations at the fracture site. There was deviation of the eye on the side of the injury and an ipsilateral spastic hemiparesis in an ambulant patient with bleeding from the nose and ear. Explanations of the paralysis have included a contrecoup lesion and compression of the contralateral cerebral peduncle against the tentorial incisura. Brainstem compression due to herniation is accompanied by loss of consciousness. Extensive contrecoup lesions consistent with the extent of the described paresis would also be associated with probable coma. The paralysis was spastic, but spasticity takes weeks to develop after trauma. Yet this patient's trauma was fresh, as there was still bleeding from the nose and the ear. It is suggested the paresis antedated the trauma, which was not its cause. The reasons for this suggestion are presented in this paper. PMID:24484229

Ganz, Jeremy C

2014-05-01

21

Astronomical observatories  

NASA Technical Reports Server (NTRS)

The layout and equipment of astronomical observatories, the oldest scientific institutions of human society are discussed. The example of leading observatories of the USSR allows the reader to familiarize himself with both their modern counterparts, as well as the goals and problems on which astronomers are presently working.

Ponomarev, D. N.

1983-01-01

22

Hubble vision. Further adventures with the Hubble Space Telescope.  

NASA Astrophysics Data System (ADS)

This second edition of Hubble vision (for the first one see Abstr. 64.003.030) is a comprehensive, most authoritative, and best illustrated popular book on the Hubble Space Telescope. It provides a magnificent portfolio of the latest and greatest images from the HST, woven together with a lucid text explaining the most exciting discoveries and setting them in the context of our current understanding in astronomy. This second edition has been completely revised, updated, and expanded to include all the latest astronomical discoveries - from supernovae and protostars to gravitational lensing, black holes, and the early universe. It is now even better illustrated, with more than 100 new figures. Throughout, the text provides sufficient scientific background for any reader to understand and appreciate the remarkable discoveries being made by this, the foremost observatory of our age.

Collins Petersen, C.; Brandt, J. C.

23

Finding the Right Formula: Edwin H. Walker Jr  

ERIC Educational Resources Information Center

Edwin H. Walker Jr earned his doctorate in chemistry at age 27 and has barely looked back. With 13 publications under his belt before coming out of graduate school, he has also given more than 20 poster presentations in national venues, most recently at the American Chemical Society. He can also include securing a half-million-dollar National…

Keels, Crystal L.

2005-01-01

24

Edwin L. Herr: Preeminent Scholar, Leader, Advocate, and Mentor  

ERIC Educational Resources Information Center

This profile celebrates and chronicles selected themes and highlights of the ideas, scholarly accomplishments, leadership, humanity, and work ethic of Edwin L. Herr, one of the major forces in the counseling profession, for purposes of archiving elements of his history and stimulating continuity of his ideas, achievements, and dedication.

Engels, Dennis W.

2012-01-01

25

On Digital Money and Card Technologies Edwin M. Knorr \\Lambda  

E-print Network

On Digital Money and Card Technologies Edwin M. Knorr \\Lambda Department of Computer Science fields: digital money and card technologies (especially smart cards), for possible PhD research topics. We believe that digital money and card technologies will revolutionize life in the 21st century

Knorr, Edwin M.

26

The Truth about Kant on Lies James Edwin Mahon  

E-print Network

201 11 The Truth about Kant on Lies James Edwin Mahon As one philosopher has remarked, "one cannot help noticing the heat with which [Kant] treats the question of lying."1 To this it must added, one cannot help noticing the heat with which other philosophers treat the question of Kant on lying. More

Marsh, David

27

"Ask Argonne" - Edwin Campos, Research Meteorologist, Part 1  

SciTech Connect

Dr. Edwin Campos is a Research Meteorologist at Argonne National Laboratory. For the last two decades, he has studied weather, and in particular, clouds. Clouds are one of the most uncertain variables in climate predictions and are often related to transportation hazards. Clouds can also impact world-class sporting events like the Olympics. You may have questions about the role of clouds, or weather, on our daily lives. How is severe weather monitored for airports? What is the impact of clouds and wind on the generation of electricity? One of the projects Edwin is working on is short-term forecasting as it relates to solar electricity. For this, Edwin's team is partnering with industry and academia to study new ways of forecasting clouds, delivering technologies that will allow the incorporation of more solar power into the electric grid. Post a question for Edwin as a comment below, and it might get answered in the follow-up video we'll post in the next few weeks.

Edwin Campos

2013-05-08

28

Astronomical kaleidoscope  

NASA Astrophysics Data System (ADS)

The entry contains two Moon eclipses (a picture of a total eclipse and a photo of a penumbral one), photographs of monuments of few greatest astronomers: Nikolay Kopernik, Tiho Brahe and Johannes Kepler, a photo from the JENAM-1995 (Catania, Sicily) as well as photographs of few astronomers related with Moldova and Romania: V. Grigorevskii, N. Donitch, V.Nadolschi, D. Mangeron, two nice clocks in Prague, as well as a map of the Sanctuary in Orheiul -Vechi (Bessarabia) with an supposed ancient calendar.

Gaina, Alex

2005-10-01

29

Astronomical Ecosystems  

NASA Astrophysics Data System (ADS)

Just as quetzals and jaguars require specific ecological habitats to survive, so too must planets occupy a tightly constrained astronomical habitat to support life as we know it. With this theme in mind we relate the transferable features of our elementary astronomy course, "The Astronomical Basis of Life on Earth." Over the last five years, in a team-taught course that features a spring break field trip to Costa Rica, we have introduced astronomy through "astronomical ecosystems," emphasizing astronomical constraints on the prospects for life on Earth. Life requires energy, chemical elements, and long timescales, and we emphasize how cosmological, astrophysical, and geological realities, through stabilities and catastrophes, create and eliminate niches for biological life. The linkage between astronomy and biology gets immediate and personal: for example, studies in solar energy production are followed by hikes in the forest to examine the light-gathering strategies of photosynthetic organisms; a lesson on tides is conducted while standing up to our necks in one on a Pacific beach. Further linkages between astronomy and the human timescale concerns of biological diversity, cultural diversity, and environmental sustainability are natural and direct. Our experience of teaching "astronomy as habitat" strongly influences our "Astronomy 101" course in Oklahoma as well. This "inverted astrobiology" seems to transform our student's outlook, from the universe being something "out there" into something "we're in!" We thank the SNU Science Alumni support group "The Catalysts," and the SNU Quetzal Education and Research Center, San Gerardo de Dota, Costa Rica, for their support.

Neuenschwander, D. E.; Finkenbinder, L. R.

2004-05-01

30

Astronomer's Proposal Tool  

NASA Technical Reports Server (NTRS)

Astronomer's Proposal Tool (APT) is a computer program that assists astronomers in preparing their Phase 1 and Phase 2 Hubble Space Telescope science programs. APT is a successor to the Remote Proposal Submission System 2 (RPS2) program, which has been rendered obsolete by more recent advances in computer software and hardware. APT exploits advances associated with widespread use of the Internet, multiplatform visual development software tools, and overall increases in the power of desktop computer hardware, all in such a way as to make the preparation and submission of proposals more intuitive and make observatory operations less cumbersome. APT provides documentation and help that are friendly, up to date, and easily accessible to users of varying levels of expertise, while defining an extensible framework that is responsive to changes in both technology and observatory operations. APT consists of two major components: (1) a set of software tools that are intuitive, visual, and responsive and (2) an integrated software environment that unifies all the tools and makes them interoperable. The APT tools include the Visual Target Tuner, Proposal Editor, Exposure Planner, Bright Object Checker, and Visit Planner.

Krueger, Tony

2005-01-01

31

Hubble's new view of the cosmos  

PubMed

Since the December 1993 repair of NASA's Hubble Space Telescope's (HST) optics by the crew of the Space Shuttle Endeavour, the rapid-fire scientific achievements have brought a new era of discovery to the field of astronomy. Hubble has confirmed some astronomical theories, challenged others, and often come up with complete surprises. Some images are so unexpected that astronomers have to develop new theories to explain what they are seeing. The HST has detected galaxies out to the visible horizon of the cosmos, and has made an attempt at pinning down the universe's expansion rate. Both of these key research areas should ultimately yield answers to age-old questions: What has happened since the beginning of time, and will the universe go on forever? PMID:11538725

Villard, R

1996-05-01

32

How I Became an Astronomer  

NASA Technical Reports Server (NTRS)

Life as an astronomer has taken me to view eclipses of the Sun from the Gaspe' Peninsula to the Pacific Ocean and the China and Coral Seas, and to observe the stars at observatories across the USA and as far south as Chile. I've also enjoyed working with NASA's telescopes in space, including the Hubble Space Telescope and the International Ultraviolet Explorer. It seems funny to reflect that it all began in the Sixth Grade by a fluke - the consequence of a hoax letter whose author I never identified.

Maran, Stephen P.

2001-01-01

33

HUBBLE'S INFRARED GALAXY GALLERY  

NASA Technical Reports Server (NTRS)

Astronomers have used the NASA Hubble Space Telescope to produce an infrared 'photo essay' of spiral galaxies. By penetrating the dust clouds swirling around the centers of these galaxies, the telescope's infrared vision is offering fresh views of star birth. These six images, taken with the Near Infrared Camera and Multi-Object Spectrometer, showcase different views of spiral galaxies, from a face-on image of an entire galaxy to a close-up of a core. The top row shows spirals at diverse angles, from face-on, (left); to slightly tilted, (center); to edge-on, (right). The bottom row shows close-ups of the hubs of three galaxies. In these images, red corresponds to glowing hydrogen, the raw material for star birth. The red knots outlining the curving spiral arms in NGC 5653 and NGC 3593, for example, pinpoint rich star-forming regions where the surrounding hydrogen gas is heated by intense ultraviolet radiation from young, massive stars. In visible light, many of these regions can be hidden from view by the clouds of gas and dust in which they were born. The glowing hydrogen found inside the cores of these galaxies, as in NGC 6946, may be due to star birth; radiation from active galactic nuclei (AGN), which are powered by massive black holes; or a combination of both. White is light from middle-age stars. Clusters of stars appear as white dots, as in NGC 2903. The galaxy cores are mostly white because of their dense concentration of stars. The dark material seen in these images is dust. These galaxies are part of a Hubble census of about 100 spiral galaxies. Astronomers at Space Telescope Science Institute took these images to fill gaps in the scheduling of a campaign using the NICMOS-3 camera. The data were non-proprietary, and were made available to the entire astronomical community. Filters: Three filters were used: red, blue, and green. Red represents emission at the Paschen Alpha line (light from glowing hydrogen) at a wavelength of 1.87 microns. Blue shows the galaxies in near-infrared light, measured between 1.4 and 1.8 microns (H-band emission). Green is a mixture of the two. Distance of galaxies from Earth: NGC 5653 - 161 million light-years; NGC 3593 - 28 million light-years; NGC 891 - 24 million light-years; NGC 4826 - 19 million light-years; NGC 2903 - 25 million light-years; and NGC 6946 - 20 million light-years. Credits: Torsten Boeker, Space Telescope Science Institute, and NASA NOTE TO EDITORS: Image files and photo caption are available on the Internet at: http://oposite.stsci.edu/pubinfo/pr/1999/10 or via links in http://oposite.stsci.edu/pubinfo/latest.html and http://oposite.stsci.edu/pubinfo/pictures.html Higher resolution digital versions of (300 dpi JPEG and TIFF) of the release photo are available at: http://oposite.stsci.edu/pubinfo/pr/1999/10/extra-photos.html STScI press releases and other information are available automatically by sending an Internet electronic mail message to pio-request@stsci.edu. In the body of the message (not the subject line) users should type the word 'subscribe' (don't use quotes). The system will respond with a confirmation of the subscription, and users will receive new press releases as they are issued. To unsubscribe, send mail to pio-request@stsci.edu. Leave the subject line blank, and type 'unsubscribe' (don't use quotes) in the body of the message.

2002-01-01

34

Hubble Witnesses Comet Crash  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Quick Time Movie for PIA02122 Hubble Witnesses Comet Crash

[figure removed for brevity, see original site] Figure 1: Hubble Witnesses Comet Crash

These pictures of comet Tempel 1 were taken by NASA's Hubble Space Telescope. They show the comet before and after it ran over NASA's Deep Impact probe.

2005-01-01

35

HUBBLE SPIES MOST DISTANT SUPERNOVA EVER SEEN  

NASA Technical Reports Server (NTRS)

Using NASA's Hubble Space Telescope, astronomers pinpointed a blaze of light from the farthest supernova ever seen, a dying star that exploded 10 billion years ago. The detection and analysis of this supernova, called 1997ff, is greatly bolstering the case for the existence of a mysterious form of dark energy pervading the cosmos, making galaxies hurl ever faster away from each other. The supernova also offers the first glimpse of the universe slowing down soon after the Big Bang, before it began speeding up. This panel of images, taken with the Wide Field and Planetary Camera 2, shows the supernova's cosmic neighborhood; its home galaxy; and the dying star itself. Astronomers found this supernova in 1997 during a second look at the northern Hubble Deep Field [top panel], a tiny region of sky first explored by the Hubble telescope in 1995. The image shows the myriad of galaxies Hubble spied when it peered across more than 10 billion years of time and space. The white box marks the area where the supernova dwells. The photo at bottom left is a close-up view of that region. The white arrow points to the exploding star's home galaxy, a faint elliptical. Its redness is due to the billions of old stars residing there. The picture at bottom right shows the supernova itself, distinguished by the white dot in the center. Although this stellar explosion is among the brightest beacons in the universe, it could not be seen directly in the Hubble images. The stellar blast is so distant from Earth that its light is buried in the glow of its host galaxy. To find the supernova, astronomers compared two pictures of the 'deep field' taken two years apart. One image was of the original Hubble Deep Field; the other, the follow-up deep-field picture taken in 1997. Using special computer software, astronomers then measured the light from the galaxies in both images. Noting any changes in light output between the two pictures, the computer identified a blob of light in the 1997 picture that wasn't in the original deep-field study. That blob turned out to be the supernova. The red background texture is an artifact of the process of isolating the supernova. Credits: NASA, Adam Riess (Space Telescope Science Institute, Baltimore, MD)

2002-01-01

36

"Ask Argonne" - Edwin Campos, Research Meteorologist, Part 2  

SciTech Connect

Argonne's Edwin Campos has for the last two decades studied weather, and in particular, clouds. His research can help make solar power a more viable option for the U.S. and the world. In this video, Dr. Campos answers questions that were submitted by the public in response to his introductory video: http://www.youtube.com/watch?v=pfdoHz.... We will be posting a new "Ask Argonne" video every other month, on various topics. Keep an eye out for your next opportunity to submit a question and see if it gets answered - and if you get a shout-out on camera.

Edwin Campos

2013-05-23

37

Edwin E. Moise Bibliography of the Vietnam War  

NSDL National Science Digital Library

Professor Edwin E. Moise of Clemson University has provided a vast bibliography of the Vietnam war. Containing mostly books, it is divided into three major sections: microfilmed document collections, general publications, and U.S. government publications. It is this organization, especially the latter two sections, that is the power of the site. General publications is divided into 45 sections (mostly chronological) and government publications is divided into 20 sections. Many entries are briefly annotated. Unfortunately, the site is not searchable, but the hundreds of citations and their categorization make this one of the more impressive bibliographies of its kind on the Internet.

Moise, Edwin E.

1996-01-01

38

HUBBLE PINPOINTS WHITE DWARFS IN GLOBULAR CLUSTER  

NASA Technical Reports Server (NTRS)

Peering deep inside a cluster of several hundred thousand stars, NASA's Hubble Space Telescope uncovered the oldest burned-out stars in our Milky Way Galaxy. Located in the globular cluster M4, these small, dying stars - called white dwarfs - are giving astronomers a fresh reading on one of the biggest questions in astronomy: How old is the universe? The ancient white dwarfs in M4 are about 12 to 13 billion years old. After accounting for the time it took the cluster to form after the big bang, astronomers found that the age of the white dwarfs agrees with previous estimates for the universe's age. In the top panel, a ground-based observatory snapped a panoramic view of the entire cluster, which contains several hundred thousand stars within a volume of 10 to 30 light-years across. The Kitt Peak National Observatory's 0.9-meter telescope took this picture in March 1995. The box at left indicates the region observed by the Hubble telescope. The Hubble telescope studied a small region of the cluster. A section of that region is seen in the picture at bottom left. A sampling of an even smaller region is shown at bottom right. This region is only about one light-year across. In this smaller region, Hubble pinpointed a number of faint white dwarfs. The blue circles pinpoint the dwarfs. It took nearly eight days of exposure time over a 67-day period to find these extremely faint stars. Globular clusters are among the oldest clusters of stars in the universe. The faintest and coolest white dwarfs within globular clusters can yield a globular cluster's age. Earlier Hubble observations showed that the first stars formed less than 1 billion years after the universe's birth in the big bang. So, finding the oldest stars puts astronomers within arm's reach of the universe's age. M4 is 7,000 light-years away in the constellation Scorpius. Hubble's Wide Field and Planetary Camera 2 made the observations from January through April 2001. These optical observations were combined to create the above images. Spectral data were also taken. Credit for Hubble telescope photos: NASA and H. Richer (University of British Columbia) Credit for ground-based photo: NOAO/AURA/NSF

2002-01-01

39

Hubble 2006: Science Year in Review  

NASA Technical Reports Server (NTRS)

The 10 science articles selected for this years annual science report exemplify the range of Hubble research from the Solar System, across our Milky Way, and on to distant galaxies. The objects of study include a new feature on Jupiter, binaries in the Kuiper Belt, Cepheid variable stars, the Orion Nebula, distant transiting planets, lensing galaxies, active galactic nuclei, red-and-dead galaxies, and galactic outflows and jets. Each narrative strives to construct the readers understanding of the topics and issues, and to place the latest research in historical, as well as scientific, context. These essays reveal trends in the practice of astronomy. More powerful computers are permitting astronomers to study ever larger data sets, enabling the discovery of subtle effects and rare objects. (Two investigations created mosaic images that are among the largest produced to date.) Multiwavelength data sets from ground-based telescopes, as well as other great observatories Spitzer and Chandraare increasingly important for holistic interpretations of Hubble results. This yearbook also presents profiles of 12 individuals who work with Hubble, or Hubble data, on a daily basis. They are representative of the many students, scientists, engineers, and other professions who are proudly associated with Hubble. Their stories collectively communicate the excitement and reward of careers related to space science and technology.

Brown, R.

2007-01-01

40

ASTRONOMICAL JOURNAL, American Astronomical Society. reserved. Printed  

E-print Network

Division of Geological Planetary Sciences, Mail 150­21, California Institute of Technology, PasadenaASTRONOMICAL JOURNAL, : 457�473, American Astronomical Society. reserved. Printed PROPERTIES DAVID JEWITT Institute Astronomy, 2680 Woodlawn Drive, Honolulu, HI =ifa.hawaii.edu, jewitt

Trujillo, Chad

41

Determination of the Hubble constant.  

PubMed

Establishing accurate extragalactic distances has provided an immense challenge to astronomers since the 1920s. The situation has improved dramatically as better detectors have become available, and as several new, promising techniques have been developed. For the first time in the history of this difficult field, relative distances to galaxies are being compared on a case-by-case basis, and their quantitative agreement is being established. New instrumentation, the development of new techniques for measuring distances, and recent measurements with the Hubble Space telescope all have resulted in new distances to galaxies with precision at the +/-5-20% level. The current statistical uncertainty in some methods for measuring H(0) is now only a few percent; with systematic errors, the total uncertainty is approaching +/-10%. Hence, the historical factor-of-two uncertainty in the value of the H(0) is now behind us. PMID:10500124

Freedman, W L; Feng, L L

1999-09-28

42

Determination of the Hubble constant  

PubMed Central

Establishing accurate extragalactic distances has provided an immense challenge to astronomers since the 1920s. The situation has improved dramatically as better detectors have become available, and as several new, promising techniques have been developed. For the first time in the history of this difficult field, relative distances to galaxies are being compared on a case-by-case basis, and their quantitative agreement is being established. New instrumentation, the development of new techniques for measuring distances, and recent measurements with the Hubble Space telescope all have resulted in new distances to galaxies with precision at the ±5–20% level. The current statistical uncertainty in some methods for measuring H0 is now only a few percent; with systematic errors, the total uncertainty is approaching ±10%. Hence, the historical factor-of-two uncertainty in the value of the H0 is now behind us. PMID:10500124

Freedman, Wendy L.; Feng, Long Long

1999-01-01

43

Spike: AI scheduling for NASA's Hubble Space Telescope  

Microsoft Academic Search

The Spike scheduling system, developed for scheduling astronomical observations for NASA's Hubble Space Telescope (HST), is described. Spike is an activity-based AI scheduler which incorporates innovative approaches to constraint representation and reasoning and scheduling search. Although developed for space telescope scheduling, the Spike system was designed around a general scheduling-constraint framework that can be applied to other domains. Techniques for

Mark D. Johnston

1990-01-01

44

The Scientific Impact of the Hubble Space Telescope  

Microsoft Academic Search

The Hubble Space Telescope (HST) is the flagship of a growing fleet of modern astronomical telescopes. The unique power of the HST derives from its combination of extremely sharp images, covering relatively wide angular fields in the sky, with a deep dynamic range, low background noise and sensitivity to wavelengths from the vacuum ultraviolet to the near-infrared. HST's greatest achievement

F. D. Macchetto

2002-01-01

45

STS-31: Hubble HST Science  

NASA Technical Reports Server (NTRS)

The primary objective of STS-31 was to deploy the Hubble Space Telescope(HST). This videotape presents a press briefing about the scientific goals of the HST program. The panel members were Dr. Weiler, HST program scientist; Dr. Boggess from NASA Goddard, the Center managing the HST Program; and Dr. Bahcall, President Elect of the American Astronomical Union. Dr. Weiler opened the panel discussion by introducing other HST scientists who were in the audience. Dr. Bahcall explained the four major areas that astronomers hope to better understand using the HST data: (1) The size and age of the universe; (2) quasars as flashlights to understanding other features of the universe; (3) planets around other stars; and (4) weather on the other planets of our Solar System. Other areas in which he hopes to have some understanding are galaxies under quasars, black holes, and missing matter. After his remarks, Dr. Bahcall presented a plaque to Charles Pellerin, who helped initiate the series of astrophysics telescopes. The HST is the first of these "Great Observatories". After the presentation, questions from the press were answered.

1990-01-01

46

HUBBLE: ON THE ASTEROID TRAIL  

NASA Technical Reports Server (NTRS)

Astronomers Karl Stapelfeldt and Robin Evans have tracked down about 100 small asteroids by hunting through more than 28,000 archival images taken by the Hubble Space Telescope's Wide Field and Planetary Camera 2. Here is a sample of what they have found: four archival images that show the curved trails left by asteroids. [Top left]: Hubble captured a bright asteroid, with a visual magnitude of 18.7, roaming in the constellation Centaurus. Background stars are shown in white, while the asteroid trail is depicted in blue at top center. The trail has a length of 19 arc seconds. This asteroid has a diameter of one and one-quarter miles (2 kilometers), and was located 87 million miles from Earth and 156 million miles from the sun. Numerous orange and blue specks in this image and the following two images were created by cosmic rays, energetic subatomic particles that struck the camera's detector. [Top right]: Here is an asteroid with a visual magnitude of 21.8 passing a galaxy in the constellation Leo. The trail is seen in two consecutive exposures, the first shown in blue and the second in red. This asteroid has a diameter of half a mile (0.8 kilometers), and was located 188 million miles from Earth and 233 million miles from the sun. [Lower left]: This asteroid in the constellation Taurus has a visual magnitude of 23, and is one of the faintest seen so far in the Hubble archive. It moves from upper right to lower left in two consecutive exposures; the first trail is shown in blue and the second in red. Because of the asteroid's relatively straight trail, astronomers could not accurately determine its distance. The estimated diameter is half a mile (0.8 kilometers) at an Earth distance of 205 million miles and a sun distance of 298 million miles. [Lower right]: This is a broken asteroid trail crossing the outer regions of galaxy NGC 4548 in Coma Berenices. Five trail segments (shown in white) were extracted from individual exposures and added to a cleaned color image of the galaxy. The asteroid enters the image at top center and moves down toward the lower left. Large gaps in the trail occur because the telescope is orbiting the Earth and cannot continuously observe the galaxy. This asteroid has a visual magnitude of 20.8, a diameter of one mile (1.6 kilometers), and was seen at a distance of 254 million miles from Earth and 292 million miles from the sun. Credit: R. Evans and K. Stapelfeldt (Jet Propulsion Laboratory) and NASA

2002-01-01

47

Hubble assists Rosetta comet mission  

NASA Astrophysics Data System (ADS)

Results from the NASA/ESA Hubble Space Telescope have played a major role in preparing ESA’s ambitious Rosetta mission for its new target, comet 67P/Churyumov-Gerasimenko. Hubble has been used to make precise measurements of the size, shape and rotational period of the comet. Information that is essential if Rosetta is to rendezvous with the comet and then drop down a probe, something never before attempted and yet a major step towards elucidating the origins of the solar system. Observations made by Hubble in March this year revealed that comet 67P/Churyumov-Gerasimenko (67P/C-G) is approximately five by three kilometres in size and shaped like a rugby ball. ESA mission scientists were concerned about the exact size of the solid nucleus, which is needed to adapt the mission to the comet’s gravity. "Although 67P/C-G is roughly three times larger than the original Rosetta target, its highly elongated shape should make landing on its nucleus feasible, now that measures are in place to adapt the lander package to the new scenario," says Dr Philippe Lamy of the Laboratoire d'Astronomie Spatiale in France, who is presenting the Hubble results on comet 67P/C-G today at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society in California, USA. Mission scientists began looking for an alternative target when the Rosetta mission's launch date was postponed. The delay meant that the original target comet, 46P/Wirtanen, was no longer easily reachable. But scientists did not have enough information on the back-up comet, 67P/C-G, and sought data from the largest telescopes. Using a technique developed over the past decade by Philippe Lamy, Imre Toth (Konkoly Observatory, Hungary), and Harold Weaver (Johns Hopkins University Applied Physics Laboratory, Laurel, USA), the team snapped 61 Hubble images of comet 67P/C-G over a period of 21 hours on 11 and 12 March. Hubble's Wide Field Planetary Camera 2 isolated the comet's nucleus from the coma, the diffuse gas surrounding the nucleus, quickly providing the figures required. The telescope showed that the nucleus is ellipsoidal and measured its rotation rate at approximately 12 hours. Rosetta's launch is currently planned for February 2004, with a rendezvous with the comet about 10 years later. # # # Notes for editors The team is made up of P. L. Lamy and L. Jorda (Laboratoire d'Astronomie Spatiale, France), I. Toth (Konkoly Observatory, Hungary), and H.A. Weaver (Johns Hopkins University Applied Physics Laboratory). The movie simulation of the Hubble results is provided by Mikko Kaasalainen (University of Helsinki, Finland) and Pedro Gutierrez (Laboratoire d'Astronomie Spatiale, France). The observations were made possible through a special programme approved by the Director of the Space Telescope Science Institute, S. Beckwith.

2003-09-01

48

Hubble Legacy Archive And The Public  

NASA Astrophysics Data System (ADS)

The Hubble Legacy Archive (HLA) at the Space Telescope Science Institute (STScI) hosts the Image of the Month (IOTM) Series. The HLA is a joint project of STScI, the Space Telescope European Coordinating Facility (ST-ECF), and the Canadian Astronomy Data Centre (CADC). The HLA is designed optimize science from the Hubble Space Telescope by providing online enhanced Hubble products and advanced browsing capabilities. The IOTM's are created for astronomers and the public to highlight various features within HLA, such as the "Interactive Display", "Footprint” and "Inventory” features to name a few. We have been working with the Office of Public Outreach (OPO) to create a standards based educational module for middle school to high school students of the IOTM: Rings and the Moons of Uranus. The set of Uranus activities are highlighted by a movie that displays the orbit of five of Uranus’ largest satellites. We made the movie based on eight visits of Uranus from 2000-06-16 to 2000-06-18, using the PC chip on the Wide Field Planetary Camera 2 (WFPC2) and filter F850LP (proposal ID: 8680). Students will be engaged in activities that will allow them to "discover” the rings and satellites around Uranus, calculate the orbit of the satellites, and introduces students to analyze real data from Hubble.

Harris, Jessica; Whitmore, B.; Eisenhamer, B.; Bishop, M.; Knisely, L.

2012-01-01

49

HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA  

NASA Technical Reports Server (NTRS)

A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This picture shows a Hubble Space Telescope image of the inner parts of the Crab. The pulsar itself is visible as the left of the pair of stars near the center of the frame. Surrounding the pulsar is a complex of sharp knots and wisp-like features. This image is one of a sequence of Hubble images taken over the course of several months. This sequence shows that the inner part of the Crab Nebula is far more dynamic than previously understood. The Crab literally 'changes it stripes' every few days as these wisps stream away from the pulsar at half the speed of light. The Hubble Space Telescope photo was taken Nov. 5, 1995 by the Wide Field and Planetary Camera 2 at a wavelength of around 550 nanometers, in the middle of the visible part of the electromagnetic spectrum. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

2002-01-01

50

Preparing Colorful Astronomical Images II  

NASA Astrophysics Data System (ADS)

We present additional techniques for using mainstream graphics software (Adobe Photoshop and Illustrator) to produce composite color images and illustrations from astronomical data. These techniques have been used on numerous images from the Hubble Space Telescope to produce photographic, print and web-based products for news, education and public presentation as well as illustrations for technical publication. We expand on a previous paper to present more detail and additional techniques, taking advantage of new or improved features available in the latest software versions. While Photoshop is not intended for quantitative analysis of full dynamic range data (as are IRAF or IDL, for example), we have had much success applying Photoshop's numerous, versatile tools to work with scaled images, masks, text and graphics in multiple semi-transparent layers and channels.

Levay, Z. G.; Frattare, L. M.

2002-12-01

51

The Hubble Space Telescope high speed photometer  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

52

BEAUTY IN THE EYE OF HUBBLE  

NASA Technical Reports Server (NTRS)

A dying star, IC 4406, dubbed the 'Retina Nebula' is revealed in this month's Hubble Heritage image. Like many other so-called planetary nebulae, IC 4406 exhibits a high degree of symmetry; the left and right halves of the Hubble image are nearly mirror images of the other. If we could fly around IC4406 in a starship, we would see that the gas and dust form a vast donut of material streaming outward from the dying star. From Earth, we are viewing the donut from the side. This side view allows us to see the intricate tendrils of dust that have been compared to the eye's retina. In other planetary nebulae, like the Ring Nebula (NGC 6720), we view the donut from the top. The donut of material confines the intense radiation coming from the remnant of the dying star. Gas on the inside of the donut is ionized by light from the central star and glows. Light from oxygen atoms is rendered blue in this image; hydrogen is shown as green, and nitrogen as red. The range of color in the final image shows the differences in concentration of these three gases in the nebula. Unseen in the Hubble image is a larger zone of neutral gas that is not emitting visible light, but which can be seen by radio telescopes. One of the most interesting features of IC 4406 is the irregular lattice of dark lanes that criss-cross the center of the nebula. These lanes are about 160 astronomical units wide (1 astronomical unit is the distance between the Earth and Sun). They are located right at the boundary between the hot glowing gas that produces the visual light imaged here and the neutral gas seen with radio telescopes. We see the lanes in silhouette because they have a density of dust and gas that is a thousand times higher than the rest of the nebula. The dust lanes are like a rather open mesh veil that has been wrapped around the bright donut. The fate of these dense knots of material is unknown. Will they survive the nebula's expansion and become dark denizens of the space between the stars or simply dissipate? This image is a composite of data taken by Hubble's Wide Field Planetary Camera 2 in June 2001 by Bob O'Dell (Vanderbilt University) and collaborators and in January 2002 by The Hubble Heritage Team (STScI). Filters used to create this color image show oxygen, hydrogen, and nitrogen gas glowing in this object. Image Credit: NASA and the Hubble Heritage Team (STScI/AURA) Acknowledgment: C.R. O'Dell (Vanderbilt University)

2002-01-01

53

HUBBLE SEES A VAST 'CITY' OF STARS  

NASA Technical Reports Server (NTRS)

In these pictures, a 'city' of a million stars glitters like a New York City skyline. The images capture the globular cluster 47 Tucanae, located 15,000 light-years from Earth in the southern constellation Tucana. Using NASA's Hubble Space Telescope, astronomers went hunting in this large city for planetary companions: bloated gaseous planets that snuggle close to their parent stars, completing an orbit in a quick three to five days. To their surprise, they found none. This finding suggests that the cluster's environment is too hostile for breeding planets or that it lacks the necessary elements for making them. The picture at left, taken by a terrestrial telescope, shows most of the cluster, a tightly packed group of middle-aged stars held together by mutual gravitational attraction. The box near the center represents the Hubble telescope's view. The image at right shows the Hubble telescope's close-up look at a swarm of 35,000 stars near the cluster's central region. The stars are tightly packed together: They're much closer together than our Sun and its closest stars. The picture, taken by the Wide Field and Planetary Camera 2, depicts the stars' natural colors and tells scientists about their composition and age. For example, the red stars denote bright red giants nearing the end of their lives; the more common yellow stars are similar to our middle-aged Sun. Most of the stars in the cluster are believed to have formed about 10 billion years ago. The bright, blue stars -- thought to be remnants of stellar collisions and mergers -- provide a few rejuvenated, energetic stars in an otherwise old system. The Hubble picture was taken in July 1999. Credits for Hubble image: NASA and Ron Gilliland (Space Telescope Science Institute) Credits for ground-based image: David Malin, c Anglo-Australian Observatory

2002-01-01

54

Hubble Space Telescope Image  

NASA Technical Reports Server (NTRS)

This photograph is a Hubble Space Telescope (HST) image of a sky full of glittering jewels. The HST peered into the Sagittarius star cloud, a narrow dust free region, providing this spectacular glimpse of a treasure chest full of stars.

1998-01-01

55

HUBBLE HERITAGE PROJECT'S FIRST ANNIVERSARY  

NASA Technical Reports Server (NTRS)

HH 32 is an excellent example of a 'Herbig-Haro object,' which is formed when young stars eject jets of material back into interstellar space. This object, about 1,000 light-years from Earth, is somewhat older than Hubble's variable nebula, and the wind from the bright central star has already cleared much of the dust out of the central region, thus exposing the star to direct view. Many young stars, like the central object in HH 32, are surrounded by disks of gas and dust that form as additional material is attracted gravitationally from the surrounding nebula. Material in the disk gradually spirals in toward the star and eventually some of it accretes onto the star, increasing its mass. A fraction of the gas, however, is ejected perpendicularly to the disk at speeds near 200 miles per second, and forms two oppositely directed jets. These jets plow into the surrounding nebula, producing strong shock waves that heat the gas and cause it to glow in the light of hydrogen atoms (green) and sulfur ions (blue), several other atoms and ions, and sometimes radiation from the exciting star that is reflected by the surrounding gas (red). This glow is called a Herbig-Haro object, in honor of astronomers George Herbig and Guillermo Haro, who did much of the early work in this area in the 1950's. The jet on the top side, whose furthest extent is about 0.2 light-year from the star, is pointed more nearly in our direction, while the opposite jet on the bottom lies on the far side of the star and is fainter either because it is partially obscured by dust surrounding the star or because there is much less material in front of the star. The Hubble Heritage team (NASA/AURA/STScI) made this image from observations of Herbig-Haro 32 acquired by Salvador Curiel, Jorge Canto, Alejandro Raga, (UNAM), Alberto Noriega-Crespo (IPAC), and collaborators. Image Credit: NASA/The Hubble Heritage Team (AURA/STScI).

2002-01-01

56

Edwin Grant Dexter: an early researcher in human behavioral biometeorology  

NASA Astrophysics Data System (ADS)

Edwin Grant Dexter (1868-1938) was one of the first researchers to study empirically the effects of specific weather conditions on human behavior. Dexter (1904) published his findings in a book, Weather influences. The author's purposes in this article were to (1) describe briefly Dexter's professional life and examine the historical contexts and motivations that led Dexter to conduct some of the first empirical behavioral biometeorological studies of the time, (2) describe the methods Dexter used to examine weather-behavior relationships and briefly characterize the results that he reported in Weather influences, and (3) provide a historical analysis of Dexter's work and assess its significance for human behavioral biometeorology. Dexter's Weather influences, while demonstrating an exemplary approach to weather, health, and behavior relationships, came at the end of a long era of such studies, as health, social, and meteorological sciences were turning to different paradigms to advance their fields. For these reasons, Dexter's approach and contributions may not have been fully recognized at the time and are, consequently, worthy of consideration by contemporary biometeorologists.

Stewart, Alan E.

2014-09-01

57

HUBBLE SHOOTS THE MOON  

NASA Technical Reports Server (NTRS)

In a change of venue from peering at the distant universe, NASA's Hubble Space Telescope has taken a look at Earth's closest neighbor in space, the Moon. Hubble was aimed at one of the Moon's most dramatic and photogenic targets, the 58 mile-wide (93 km) impact crater Copernicus. The image was taken while the Space Telescope Imaging Spectrograph (STIS) was aimed at a different part of the moon to measure the colors of sunlight reflected off the Moon. Hubble cannot look at the Sun directly and so must use reflected light to make measurements of the Sun's spectrum. Once calibrated by measuring the Sun's spectrum, the STIS can be used to study how the planets both absorb and reflect sunlight. (upper left) The Moon is so close to Earth that Hubble would need to take a mosaic of 130 pictures to cover the entire disk. This ground-based picture from Lick Observatory shows the area covered in Hubble's photomosaic with the Wide Field Planetary Camera 2.. (center) Hubble's crisp bird's-eye view clearly shows the ray pattern of bright dust ejected out of the crater over one billion years ago, when an asteroid larger than a mile across slammed into the Moon. Hubble can resolve features as small as 600 feet across in the terraced walls of the crater, and the hummock-like blanket of material blasted out by the meteor impact. (lower right) A close-up view of Copernicus' terraced walls. Hubble can resolve features as small as 280 feet across. Credit: John Caldwell (York University, Ontario), Alex Storrs (STScI), and NASA

2002-01-01

58

Footprints in the Hubble Legacy Archive  

NASA Astrophysics Data System (ADS)

Footprints are geometric outlines of observations. They are displayed against a background image. The observations of the Hubble Space Telescope are defined by a set of hierarchical geometric regions of instrument coverage: exposures, combined observations, high level science products, and mosaics. In the growing global community of networked applications, the science end-user has several use cases for visualizing and accessing footprint data including scientific proposal preparation, research and analysis of generated science products, and interoperability between archives for correlation of coverage. The Hubble Legacy Archive (HLA) at Space Telescope Science Institute, in coordination with ESO-ECF and CADC, has developed a web based science user interface built on a VO service oriented architecture system to enable varying levels of astronomical community access to science products derived from the HST archive. We describe new features and technologies for the HLA footprint component web browser visualization tool and the underyling footprint services utilized by the HST Astronomers Proposal Tool (APT) in compliance with an IVOA standard data access protocol. The service infrastructure is based on a high performance spherical geometric model developed by Johns Hopkins University (JHU) and database search algorithms co-developed by STScI and JHU.

Lubow, Stephen H.; Donaldson, T.; Gillies, K.; Greene, G.; Budavari, T.; Szalay, A.

2010-01-01

59

Hubble Space Telescope Solar Array  

NASA Technical Reports Server (NTRS)

This is a view of a solar cell blanket deployed on a water table during the Solar Array deployment test. The Hubble Space Telescope (HST) Solar Arrays provide power to the spacecraft. The arrays are mounted on opposite sides of the HST, on the forward shell of the Support Systems Module. Each array stands on a 4-foot mast that supports a retractable wing of solar panels 40-feet (12.1-meters) long and 8.2-feet (2.5-meters) wide, in full extension. The arrays rotate so that the solar cells face the Sun as much as possible to harness the Sun's energy. The Space Telescope Operations Control Center at the Goddard Space Center operates the array, extending the panels and maneuvering the spacecraft to focus maximum sunlight on the arrays. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST Solar Array was designed by the European Space Agency and built by British Aerospace. The Marshall Space Flight Center had overall responsibility for design, development, and construction of the HST.

1985-01-01

60

HUBBLE SPIES GLOBULAR CLUSTER IN NEIGHBORING GALAXY  

NASA Technical Reports Server (NTRS)

Hubble Space Telescope has captured a view of a globular cluster called G1, a large, bright ball of light in the center of the photograph consisting of at least 300,000 old stars. G1, also known as Mayall II, orbits the Andromeda galaxy (M31), the nearest major spiral galaxy to our Milky Way. Located 130,000 light-years from Andromeda's nucleus, G1 is the brightest globular cluster in the Local Group of galaxies. The Local Group consists of about 20 nearby galaxies, including the Milky Way. The crisp image is comparable to ground-based telescope views of similar clusters orbiting the Milky Way. The Andromeda cluster, however, is nearly 100 times farther away. A glimpse into the cluster's finer details allow astronomers to see its fainter helium-burning stars whose temperatures and brightnesses show that this cluster in Andromeda and the oldest Milky Way clusters have approximately the same age. These clusters probably were formed shortly after the beginning of the universe, providing astronomers with a record of the earliest era of galaxy formation. During the next two years, astronomers will use Hubble to study about 20 more globular clusters in Andromeda. The color picture was assembled from separate images taken in visible and near-infrared wavelengths taken in July of 1994. CREDIT: Michael Rich, Kenneth Mighell, and James D. Neill (Columbia University), and Wendy Freedman (Carnegie Observatories), and NASA Image files in GIF and JPEG format and captions may be accessed on Internet via anonymous ftp from oposite.stsci.edu in /pubinfo.

2002-01-01

61

Hubble Space Telescope image restoration in its fourth year  

Microsoft Academic Search

The NASA\\/ESA Hubble Space Telescope (HST), an astronomical observatory launched in 1990 into a low-altitude space orbit, was designed to deliver near-diffraction limited images, but its optics suffered from substantial spherical aberration. The HST image restoration problem is aggravated by insufficient image sampling, by a mixture of noise sources including spatially non-stationary, non-Gaussian noise, and by the desire to quantitatively

H.-M. Adorf

1995-01-01

62

The shrinking Hubble constant  

E-print Network

Hubble plots of the distance of stellar objects vs. recession velocity normally assume the red shift is wholly Doppler and ignore any gravitational contribution. This is unwarranted: gravity and Doppler velocity red shifts are found to be separable and contribute about equally. A recent data set, to Z=1.2, by Riess (1), was analyzed. Upon plotting distance vs. Doppler velocity, the slope of the Hubble plot increases. The Hubble plot is also curved, upwards, and this can be understood in terms of the relativistic metric changes of the space through which the light travels. On fitting the data to a simple model of a big bang of constant density, this finds the total mass of the big bang is M=21.1x10^52 kg. When present actual distance is plotted vs. Doppler velocity, the plot is linear and agrees with Hubble's concept, without acceleration. Time since the big bang is longer than the 14 billion years that had been thought, 23.5 billion years. The Hubble constant hence shrinks from Ho=71 to Ho=41.6. This is an independent affirmation of a recent CMB finding of a low Ho=35.

R. L. Collins

2006-01-03

63

Picture an Astronomer Activity  

NSDL National Science Digital Library

In this activity, which serves as an introduction to an astronomy unit or to a classroom visit by an astronomer or space scientist, students are asked to imagine an astronomer and then draw a picture. In the instructions, no clues are given about the astronomer's race, sex, or age. Students discuss why they drew the pictures they drew and why they have the mental images of scientists that they have.

Fraknoi, Andrew

1995-09-03

64

American Astronomical Society  

NSDL National Science Digital Library

The major organization of professional astronomers in North America, the American Astronomical Society's (AAS) main goal "is to promote the advancement of astronomy and closely related branches of science." The website presents the Society's three scholarly journals and its numerous publications. The Education link offers an abundance of educational resources for users of all levels, answers to many astronomical questions, and fascinating news articles. Researchers can find out about grants, prizes, employment, and membership opportunities.

65

HUBBLE UNVEILS A GALAXY IN LIVING COLOR  

NASA Technical Reports Server (NTRS)

In this view of the center of the magnificent barred spiral galaxy NGC 1512, NASA Hubble Space Telescope's broad spectral vision reveals the galaxy at all wavelengths from ultraviolet to infrared. The colors (which indicate differences in light intensity) map where newly born star clusters exist in both 'dusty' and 'clean' regions of the galaxy. This color-composite image was created from seven images taken with three different Hubble cameras: the Faint Object Camera (FOC), the Wide Field and Planetary Camera 2 (WFPC2), and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). NGC 1512 is a barred spiral galaxy in the southern constellation of Horologium. Located 30 million light-years away, relatively 'nearby' as galaxies go, it is bright enough to be seen with amateur telescopes. The galaxy spans 70,000 light-years, nearly as much as our own Milky Way galaxy. The galaxy's core is unique for its stunning 2,400 light-year-wide circle of infant star clusters, called a 'circumnuclear' starburst ring. Starbursts are episodes of vigorous formation of new stars and are found in a variety of galaxy environments. Taking advantage of Hubble's sharp vision, as well as its unique wavelength coverage, a team of Israeli and American astronomers performed one of the broadest and most detailed studies ever of such star-forming regions. The results, which will be published in the June issue of the Astronomical Journal, show that in NGC 1512 newly born star clusters exist in both dusty and clean environments. The clean clusters are readily seen in ultraviolet and visible light, appearing as bright, blue clumps in the image. However, the dusty clusters are revealed only by the glow of the gas clouds in which they are hidden, as detected in red and infrared wavelengths by the Hubble cameras. This glow can be seen as red light permeating the dark, dusty lanes in the ring. 'The dust obscuration of clusters appears to be an on-off phenomenon,' says Dan Maoz, who headed the collaboration. 'The clusters are either completely hidden, enshrouded in their birth clouds, or almost completely exposed.' The scientists believe that stellar winds and powerful radiation from the bright, newly born stars have cleared away the original natal dust cloud in a fast and efficient 'cleansing' process. Aaron Barth, a co-investigator on the team, adds: 'It is remarkable how similar the properties of this starburst are to those of other nearby starbursts that have been studied in detail with Hubble.' This similarity gives the astronomers the hope that, by understanding the processes occurring in nearby galaxies, they can better interpret observations of very distant and faint starburst galaxies. Such distant galaxies formed the first generations of stars, when the universe was a fraction of its current age. Circumstellar star-forming rings are common in the universe. Such rings within barred spiral galaxies may in fact comprise the most numerous class of nearby starburst regions. Astronomers generally believe that the giant bar funnels the gas to the inner ring, where stars are formed within numerous star clusters. Studies like this one emphasize the need to observe at many different wavelengths to get the full picture of the processes taking place.

2002-01-01

66

The hubble constant.  

PubMed

The Hubble constant is the constant of proportionality between recession velocity and distance in the expanding universe. It is a fundamental property of cosmology that sets both the scale and the expansion age of the universe. It is determined by measurement of galaxy The Hubble constant is the constant of proportionality between recession velocity and development of new techniques for the measurements of galaxy distances, both calibration uncertainties and debates over systematic errors remain. Current determinations still range over nearly a factor of 2; the higher values favored by most local measurements are not consistent with many theories of the origin of large-scale structure and stellar evolution. PMID:17743107

Huchra, J P

1992-04-17

67

Hubble News Archive  

NSDL National Science Digital Library

Hubble site this is a collection of all publicly released pictures from the Hubble Space Telescope. Accompanying each photograph is the official news release, an introduction to the object, fast facts, and related frequently asked questions. The news releases are sorted by category, year, and type. Some of these categories consist of: cosmology, exotic, galaxy, miscellaneous, nebula, solar system, star, star cluster, and survey. Image files in different sizes and formats are available for download. This is a nice resource for those interested in the more visual aspects of astronomy and space sciences.

2009-05-14

68

Astronomers meet in phoenix, recount a stellar year.  

PubMed

Despite a tightening of the National Aeronautics and Space Administration's budget and the trouble with the Hubble Space Telescope, astronomers were starry-eyed over their latest findings, presented at the major annual meeting of the American Astronomical Society, (AAS) January 3 to 7. New images and measurements of stars, galaxies, cosmic microwaves, and mysterious gamma rays, along with an exciting nova explosion, made it a bright year for those working with existing orbiting satellites and ground-based telescopes, though uncertain funding clouds the future. PMID:17734156

Flam, F

1993-01-22

69

Really Bad Astronomers  

Microsoft Academic Search

What happens when even Percival Lowell stops believing in your Mars observations? History can be troubling. This I learned while editing the Biographical Encyclopedia of Astronomers (Springer, 2007). There have been astronomers who do not fit our commonly held, and clung to, conceptual model: a sociological system that sifts out generally like-minded and sensible colleagues. I refer to those individuals

Thomas A. Hockey

2009-01-01

70

Astronomical Software Directory Service  

NASA Technical Reports Server (NTRS)

This is the final report on the development of the Astronomical Software Directory Service (ASDS), a distributable, searchable, WWW-based database of software packages and their related documentation. ASDS provides integrated access to 56 astronomical software packages, with more than 16,000 URL's indexed for full-text searching.

Hanisch, R. J.; Payne, H.; Hayes, J.

1998-01-01

71

Misconceptions about astronomical magnitudes  

Microsoft Academic Search

The present system of astronomical magnitudes was created as an inverse scale by Claudius Ptolemy in about 140 A.D. and was defined to be logarithmic in 1856 by Norman Pogson, who believed that human eyes respond logarithmically to the intensity of light. Although scientists have known for some time that the response is instead a power law, astronomers continue to

Eric Schulman; Caroline V. Cox

1997-01-01

72

HHuubbbbllee SSppaaccee TTeelleessccooppee Servicing Mission 4  

E-print Network

telescopes in history have had such a profound impact on astronomical research as the Hubble Space Telescope AAddmmiinniissttrraattiioonn #12;AAbboouutt tthhee CCoovveerrss he outside covers show the Hubble Space Telescope illuminated Bulletin 58 Edwin Hubble (1889­1953) at the 48-inch Schmidt telescope on Palomar Mountain The U.S. Postal

Colorado at Boulder, University of

73

Determining the Hubble Constant  

NSDL National Science Digital Library

Students will graph distance/velocity data of real galaxies to arrive at their own value of the Hubble constant (H). Once they have calculated their own value of H, they will use it to determine distances to real galaxies with known recessional velocities.

Copeland, Cush

2012-07-11

74

From Galileo to Hubble  

NSDL National Science Digital Library

This tutorial from the Space Telescope Science Institute covers the development of telescopes from Galileo to the Hubble Space Telescope, using images, animations, and text. Students must answer questions as they progress through the lesson. Telescopes covered include the Hooker, Hale, and Keck.

75

Space Telescope Programs Hubble Observatory  

E-print Network

Space Telescope Programs Hubble Observatory HST-COS FUV PER 11/8/00 HST COS FUV DETECTOR SYSTEM P.E.R. HST-COS FUV Detector Pre-Environmental Review November 8th 2000 #12;Space Telescope Programs Hubble Matrix FUV System Shipping Plan #12;Space Telescope Programs Hubble Observatory HST-COS FUV PER 11

Colorado at Boulder, University of

76

Calibration of Hubble Space Telescope  

E-print Network

Calibration of Hubble Space Telescope Guidance Sensors: Application of Seminal Ideas of Eichhorn's on solving important astrometric problem. Introduction Hubble Telescope Guidance Sensors (FGS) designed techniques. 1 #12; 14.0¢ #1 #2 Optical Subsystem Figure 1: showing location of the Hubble Telescope is 2

Jefferys, William

77

Space Telescope Programs Hubble Observatory  

E-print Network

Space Telescope Programs Hubble Observatory HST-COS FUV PER 11/8/00 FUV Detector System Materials;Space Telescope Programs Hubble Observatory HST-COS FUV PER 11/8/00 Materials and Processes · Materials based on Heritage of FUSE/ORFEUS Flight Systems #12;Space Telescope Programs Hubble Observatory HST

Colorado at Boulder, University of

78

The Astronomical League  

NASA Astrophysics Data System (ADS)

Founded over fifty years ago, the League is the largest general astronomy society in the world. It is a recognized non-profit, educational organization, promoting the science of astronomy. This includes astronomical education, research, individual observing of the heavens and coordination between the amateur and professional astronomy communities. The Astronomical League publishes a quarterly newsletter, the "Reflector", which details amateur activities and amateur collaboration with professional astronomers. The League's Observing Clubs hone the skills of the amateur astronomer in using their telescopes. These clubs provide awards to encourge observing and learning the sky. More general awards are presented to encourage amateur astronomy and the science of astronomy. These include the National Young Astronomer Award, amd the Horkheimer Planetary Imaging Award. They also sponsor conventions on both the National and Regional levels. This year's national is in Ventura, California, next year, near Washington, D.C.

Stevens, J. A.; Stevens, B. L.

2000-10-01

79

Hubble Tracks Jupiter Storms  

NASA Technical Reports Server (NTRS)

NASA's Hubble Space Telescope is following dramatic and rapid changes in Jupiter's turbulent atmosphere that will be critical for targeting observations made by the Galileo space probe when it arrives at the giant planet later this year.

This Hubble image provides a detailed look at a unique cluster of three white oval-shaped storms that lie southwest (below and to the left) of Jupiter's Great Red Spot. The appearance of the clouds, as imaged on February 13, 1995 is considerably different from their appearance only seven months earlier. Hubble shows these features moving closer together as the Great Red Spot is carried westward by the prevailing winds while the white ovals are swept eastward. (This change in appearance is not an effect of last July's comet Shoemaker-Levy 9 collisions with Jupiter.)

The outer two of the white storms formed in the late 1930s. In the centers of these cloud systems the air is rising, carrying fresh ammonia gas upward. New, white ice crystals form when the upwelling gas freezes as it reaches the chilly cloud top level where temperatures are -200 degrees Fahrenheit (- 130 degrees Centigrade).

The intervening white storm center, the ropy structure to the left of the ovals, and the small brown spot have formed in low pressure cells. The white clouds sit above locations where gas is descending to lower, warmer regions. The extent of melting of the white ice exposes varied amounts of Jupiter's ubiquitous brown haze. The stronger the down flow, the less ice, and the browner the region.

A scheduled series of Hubble observations will help target regions of interest for detailed scrutiny by the Galileo spacecraft, which will arrive at Jupiter in early December 1995. Hubble will provide a global view of Jupiter while Galileo will obtain close-up images of structure of the clouds that make up the large storm systems such as the Great Red Spot and white ovals that are seen in this picture.

This color picture is assembled from a series of images taken by the Wide Field Planetary Camera 2, in planetary camera mode, when Jupiter was at a distance of 519 million miles (961 million kilometers) from Earth. These images are part of a set of data obtained by a Hubble Space Telescope (HST) team headed by Reta Beebe of New Mexico State University.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1995-01-01

80

Characterizing History Independent Data Structures Jason D. Hartline # Edwin S. Hong + Alexander E. Mohr #  

E-print Network

Characterizing History Independent Data Structures Jason D. Hartline # Edwin S. Hong + Alexander E. Mohr # William R. Pentney § Emily C. Rocke § Abstract We consider history independent data structures as proposed for study by Naor and Teague [3]. In a history independent data structure, nothing can be learned

Bustamante, Fabián E.

81

Gold Medal Award for Life Achievement in the Application of Psychology: Edwin A. Fleishman  

ERIC Educational Resources Information Center

The 2004 Gold Medal Award for Life Achievement in the Application of Psychology was awarded to Edwin A. Fleishman, for his significant contributions to the science and applications of psychology, which he has sustained over his remarkable career. He is cited for his research, which has had a profound influence on our understanding of human…

American Psychologist, 2004

2004-01-01

82

A Field Computer for Animal Trackers Edwin H Blake, Lindsay Steventon, Jacqlyn Edge and Andrea Foster  

E-print Network

-literate trackers. User testing showed that trackers were easily able to master the interface. They benefit fromA Field Computer for Animal Trackers Edwin H Blake, Lindsay Steventon, Jacqlyn Edge and Andrea to gather complex data on animal behaviour that is observed by expert animal trackers. The system

Blake, Edwin

83

Cynthia J. Najdowski: Psi Chi/APA Edwin B. Newman Graduate Research Award  

ERIC Educational Resources Information Center

Presents a short biography of the winner of the American Psychological Association's Psi Chi/APA Edwin B. Newman Graduate Research Award. The 2012 winner is Cynthia J. Najdowski for an outstanding research paper that examines how jurors' judgments are influenced by a juvenile defendant's confession and status as intellectually disabled. Through…

American Psychologist, 2012

2012-01-01

84

Psi Chi/APA Edwin B. Newman Graduate Research Award: Joseph H. Hammer  

ERIC Educational Resources Information Center

Joseph H. Hammer, recipient of the Psi Chi/APA Edwin B. Newman Graduate Research Award, is cited for an outstanding research paper whose findings provide important evidence regarding the promise of a male-sensitive approach to mental health marketing and empirically support the inclusion of theory-driven enhancements in group-targeted mental…

American Psychologist, 2009

2009-01-01

85

Re-Taking a Test Online Gerd Kortemeyer, Wolfgang Bauer, Walter Benenson, and Edwin Kashy  

E-print Network

Re-Taking a Test Online Gerd Kortemeyer, Wolfgang Bauer, Walter Benenson, and Edwin Kashy Michigan.50K Testing Theory and Techniques Tests and midterms given during the running semester learners, however, these venues are purely summative ­ they "flunked" or "did well on" a test, but mostly

86

On the Zonal Structure of the North Atlantic Oscillation and Annular Modes EDWIN P. GERBER  

E-print Network

On the Zonal Structure of the North Atlantic Oscillation and Annular Modes EDWIN P. GERBER of intraseasonal variability in the extratropical atmosphere--namely, the North Atlantic Oscillation (NAO the zonal structure of the North Atlantic Oscillation (NAO) and the annular modes, the dominant patterns

Vallis, Geoff

87

Climate instability on tidally locked exoplanets1 Edwin S. Kite2  

E-print Network

Climate instability on tidally locked exoplanets1 Edwin S. Kite2 Department of Earth and Planetary-gas resupply by other processes. Detected small-radius exoplanets, and anticipated M-dwarf habitable-zone rocky Exoplanet research is driven in part by the hope of finding habitable planets beyond Earth (Ex-16 oplanet

Kite, Edwin

88

Lidar-Radar Measurements of Snowfall Edwin W. Eloranta--Univ. Of Wisconsin  

E-print Network

Lidar-Radar Measurements of Snowfall Edwin W. Eloranta--Univ. Of Wisconsin Aerodynamic flow around a lidar-radar based technique to measure the downward flux of snow at an altitude of ~100m. When particles the square of the mass of the average snowflake. For particles large compared to the wavelength, the lidar

Eloranta, Edwin W.

89

Lives and Deaths: Biographical Notes on Selections from the Works of Edwin S. Shneidman  

ERIC Educational Resources Information Center

Edwin S. Shneidman (DOB: 1918-05-13; DOD: 2009-05-15) is a father of contemporary suicidology. His work reflects the intensive study of lives lived and deaths, especially suicides, and is the mirror to his mind. His contributions can be represented by five categories: psychological assessment, logic, Melville and Murray, suicide, and death. His…

Leenaars, Antoon A.

2010-01-01

90

For Sale in London, Paris and Babylon: Edwin Long's The Babylonian Marriage Market  

E-print Network

in the season of the British `marriage market': the London 'season' was a period of social gathering in which1 For Sale in London, Paris and Babylon: Edwin Long's The Babylonian Marriage Market Sophie painting, The Babylonian Marriage Market was the `sensation picture' at the Royal Academy summer exhibition

Sheldon, Nathan D.

91

Astronaut Edwin Aldrin in EMU verifies fit of Portable Life Support System  

NASA Technical Reports Server (NTRS)

Astronaut Edwin E. Aldrin Jr., wearing an Extravehicular Mobility Unit (EMU), verifies fit of the Portable Life Support System (PLSS) strap length during lunar surface training at the Kennedy Space Center. Aldrin is the prime crew lunar module pilot of the Apollo 11 lunar landing mission. Aldrin's PLSS backpack is attached to a lunar weight simulator.

1969-01-01

92

The Link Collections A Register of Papers of Edwin A. Link, Marion Clayton Link, The  

E-print Network

Foundation, Hughes Training, Inc. Martha Clark and Marion Hanscom, rev. by Beth Turcy Kilmarx and Jeanne Eichelberger Binghamton University, State University of New York 1981, rev. 1999 Contact Information University, NY 139026012 (607) 7774844 Fax: (607) 7776500 Descriptive Summary Edwin A. Link 1904-1981 by Martha

Suzuki, Masatsugu

93

HUBBLE SNAPS PICTURE OF REMARKABLE DOUBLE CLUSTER  

NASA Technical Reports Server (NTRS)

The double cluster NGC 1850, found in one of our neighboring galaxies, the Large Magellanic Cloud, is an eye-catching object. It is a young, 'globular-like' star cluster -- a type of object unknown in our own Milky Way Galaxy. Moreover, NGC 1850 is surrounded by a filigree pattern of diffuse gas, which scientists believe was created by the explosion of massive stars. NGC 1850, imaged here with the NASA Hubble Space Telescope, is an unusual double cluster that lies in the bar of the Large Magellanic Cloud, a satellite galaxy of our own Milky Way. After the 30 Doradus complex, NGC 1850 is the brightest star cluster in the Large Magellanic Cloud. It is representative of a special class of objects -- young, globular-like star clusters -- that have no counterpart in our galaxy. The two components of the cluster are both relatively young and consist of a main, globular-like cluster in the center and an even younger, smaller cluster, seen below and to the right, composed of extremely hot, blue stars and, fainter red T-Tauri stars. The main cluster is about 50 million years old; the smaller cluster is only 4 million years old. One of Hubble's main contributions to the study of NGC 1850 is in the investigation of star formation at both ends of the stellar mass scale -- the low-mass T-Tauri stars and the high-mass OB stars. T-Tauri stars are young, solar-class stars that are still forming, so young that they may have not started converting hydrogen to helium, which is how our Sun produces its energy. Instead they radiate energy released by their own gravitational contraction. By investigating these stars astronomers learn about the births and lives of low-mass stars. T-Tauri stars tend to occur in crowded environments, but are themselves faint, making them difficult to distinguish with ground-based telescopes. However, Hubble's fine angular resolution can pick out these stars, even in galaxies other than our own. Hubble also has advantages when studying very massive stars. These stars emit large amounts of energetic ultraviolet radiation, which is absorbed by the Earth's atmosphere. From its position above the atmosphere, Hubble can detect ultraviolet light from these massive stars. The Hubble data can then be analyzed and used to characterize the stars' properties. This Hubble image is a good example of the interaction between gas, dust, and stars. Millions of years ago massive stars in the main cluster exploded as supernovas, forming the spectacular filigree pattern of diffuse gas visible in the image. It is believed that the birth of new stars can be triggered by the enormous forces in the shock fronts where the supernova blast waves hit and compress the gas. The nebulous gas is part of the N103 super bubble and looks similar to the well-known supernova remnant Cygnus Loop in our own Milky Way. NGC 1850 lies in the southern constellation of Dorado, the Goldfish, sometimes known as the Swordfish. This image was created from five archival exposures obtained with Hubble's Wide Field Planetary Camera 2 between April 3, 1994 and February 6, 1996. Image credits: NASA, ESA, and Martino Romaniello (European Southern Observatory, Germany) Acknowledgements: The image processing for this image was done by Martino Romaniello, Richard Hook, Bob Fosbury and the Hubble European Space Agency Information Center.

2002-01-01

94

The Astronomers' Data Manifesto  

NASA Astrophysics Data System (ADS)

A draft manifesto is presented for discussion. The manifesto sets out guidelines to which the astronomical community should aspire to maximise the rate and cost-effectiveness of scientific discovery. The challenges are not underestimated, but can still be overcome if astronomers, observatories, journals, data centres, and the Virtual Observatory Alliance work together to overcome the hurdles. The key points of the manifesto are: 1. All major tables, images, and spectra published in journals should appear in the astronomical data centres. 2. All data obtained with publicly-funded observatories should, after appropriate proprietary periods, be placed in the public domain. 3. In any new major astronomical construction project, the data processing, storage, migration, and management requirements should be built in at an early stage of the project plan, and costed along with other parts of the project. 4. Astronomers in all countries should have the same access to astronomical data and information. 5. Legacy astronomical data can be valuable, and high-priority legacy data should be preserved and stored in digital form in the data centres. 6. The IAU should work with other international organisations to achieve our common goals and learn from our colleagues in other fields.

Norris, R. P.

2006-08-01

95

Odessa Astronomical Calendar-2003  

NASA Astrophysics Data System (ADS)

The Odessa Astronomical Calendar is intended for a wide range of readers, who are interested in the problems of astronomy and in the applications of the astronomical data. The items, of information, assembled in the Calendar may be useful to professional workers requiring a definition of time of sets and rises of the Sun and the Moon and approach of twilights, as well as to the amateurs astronomers and other citizens. The Calendar may be used for astronomical education at schools, hymnasia, lycea, colleges and institutes. In this issue of the Calendar, besides a description of the main astronomical events of the year and the tables of the positions of celestial bodies and time of observations of astronomical events on the celestial sphere, there are also included sketches on interesting problems of astronomy and, as the appendix, the instruction on observations of comets. The Odessa Astronomical Calendar is published in Russian and is intended for the inhabitants of southern region of Ukraine. The Calendar is published every year with a constant part and series of articles, which change every year.

Karetnikov, V. G.; Mihalchuk, V. V.; Bazey, A. A.; Andronov, I. L.; Volyanskaya, M. Yu.; Garbuzov, G. A.; Komarov, N. S.; Koshkin, N. I.; Pozigun, V. A.; Ryabov, M. I.

2002-10-01

96

Hubble's Sharpest View Of Mars  

NASA Technical Reports Server (NTRS)

The sharpest view of Mars ever taken from Earth was obtained by the recently refurbished NASA Hubble Space Telescope (HST). This stunning portrait was taken with the HST Wide Field Planetary Camera-2 (WFPC2) on March 10, 1997, just before Mars opposition, when the red planet made one of its closest passes to the Earth (about 60 million miles or 100 million km).

At this distance, a single picture element (pixel) in WFPC2's Planetary Camera spans 13 miles (22 km) on the Martian surface.

The Martian north pole is at the top (near the center of the bright polar cap) and East is to the right. The center of the disk is at about 23 degrees north latitude, and the central longitude is near 305 degrees.

This view of Mars was taken on the last day of Martian spring in the northern hemisphere (just before summer solstice). It clearly shows familiar bright and dark markings known to astronomers for more than a century. The annual north polar carbon dioxide frost (dry ice) cap is rapidly sublimating (evaporating from solid to gas), revealing the much smaller permanent water ice cap, along with a few nearby detached regions of surface frost. The receding polar cap also reveals the dark, circular sea of sand dunes that surrounds the north pole (Olympia Planitia).

Other prominent features in this hemisphere include Syrtis Major Planitia, the large dark feature seen just below the center of the disk. The giant impact basin Hellas (near the bottom of the disk) is shrouded in bright water ice clouds. Water ice clouds also cover several great volcanos in the Elysium region near the eastern edge of the planet (right). A diffuse water ice haze covers much of the Martian equatorial region as well.

The WFPC2 was used to monitor dust storm activity to support the Mars Pathfinder and Mars Global Surveyor Orbiter Missions, which are currently en route to Mars. Airborne dust is most easily seen in WFPC2's red and near-infrared images. Hubble's 'weather report' from these images in invaluable for Mars Pathfinder, which is scheduled for a July 4 landing. Fortunately, these images show no evidence for large-scale dust storm activity, which plagued a previous Mars mission in the early 1970s.

The WFPC2 was used to observe Mars in nine different colors spanning the ultraviolet to the near infrared. The specific colors were chosen to clearly discriminate between airborne dust, ice clouds, and prominent Martian surface features. This picture was created by combining images taken in blue (433 nm), green (554 nm), and red (763 nm) colored filters.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1997-01-01

97

America's foremost early astronomer  

NASA Astrophysics Data System (ADS)

The life of 18th century astronomer, craftsman, and patriot David Rittenhouse is detailed. As a craftsman, he distinguished himself as one of the foremost builders of clocks. He also built magnetic compasses and surveying instruments. The finest examples of his craftsmanship are considered two orreries, mechanical solar systems. In terms of astronomical observations, his best-known contribution was his observation of the transit of Venus in 1769. Rittenhouse constructed the first diffraction grating. Working as Treasurer of Pennsylvania throughout the Revolution, he became the first director of the Mint in 1792. Astronomical observations in later life included charting the position of Uranus after its discovery.

Rubincam, David Parry; Rubincam, Milton, II

1995-05-01

98

Famous Astronomers and Astrophysicists  

NSDL National Science Digital Library

D. Mark Manley, a professor in the Physics Department at Kent State University, provides short introductions for almost one hundred famous astronomers and astrophysicists from the Classical Period to the present. By searching either chronologically or alphabetically, users can find out about a given astronomers major successes as well as birth years and places. A link is provided for each scientist listed, offering more in-depth information. Astronomers and historians can find inspiration by learning about the scientists' education and their important contribution to science. Most of the links also present a picture of the scientist and many interesting links.

Manley, D. M.

99

Setswana Astronomical Nomenclature  

NASA Astrophysics Data System (ADS)

Like many people across the globe, Africans have for many generations been awed by the night skies . Using their natural astronomical instrument, the eye, they have observed, commented on, and named celestial objects of interest to them. In anticipation of the inauguration of Southern African Large Telescope (SALT), and the very faint and distant objects it will observe, this paper revisits astronomical nomenclature of the Setswana language of Southern Africa (SA), focusing on the two brightest and nearest astronomical bodies from Earth after the Sun, the Moon and Venus.

Leeuw, L. L.

2007-07-01

100

Astronomical Video Suites  

NASA Astrophysics Data System (ADS)

Astronomer and visual artist Jose Francisco Salgado has directed two astronomical video suites to accompany live performances of classical music works. The suites feature awe-inspiring images, historical illustrations, and visualizations produced by NASA, ESA, and the Adler Planetarium. By the end of 2009, his video suites Gustav Holst's The Planets and Astronomical Pictures at an Exhibition will have been presented more than 40 times in over 10 countries. Lately Salgado, an avid photographer, has been experimenting with high dynamic range imaging, time-lapse, infrared, and fisheye photography, as well as with stereoscopic photography and video to enhance his multimedia works.

Francisco Salgado, Jose

2010-01-01

101

Astronomical photography, part T  

NASA Technical Reports Server (NTRS)

Photographic observations of astronomical interest conducted during the Apollo 15 mission are discussed. Procedures used in photographing the solar corona are described together with calibration and reduction methods. In addition, selected preliminary results obtained from the photography are presented.

Dunkelman, L.; Mercer, R. D.; Ross, C. L.; Worden, A. M.

1972-01-01

102

Type IA Supernovae and the Hubble Constant  

NASA Astrophysics Data System (ADS)

The focus of this review is the work that has been done during the 1990s on using Type Ia supernovae (SNe Ia) to measure the Hubble constant (H_0). SNe Ia are well suited for measuring (H_0). A straightforward maximum-light color criterion can weed out the minority of observed events that are either intrinsically subluminous or substantially extinguished by dust, leaving a majority subsample that has observational absolute-magnitude dispersions of less than ?_obs(M_B) ~= ?_obs(M_V) ~= 0.3 mag. Correlations between absolute magnitude and one or more distance-independent SN Ia or parent-galaxy observables can be used to further standardize the absolute magnitudes to better than 0.2 mag. The absolute magnitudes can be calibrated in two independent ways: empirically, using Cepheid-based distances to parent galaxies of SNe Ia, and physically, by light curve and spectrum fitting. At present the empirical and physical calibrations are in agreement at M_B ~= M_V ~= - 19.4 or - 19.5. Various ways that have been used to match Cepheid-calibrated SNe Ia or physical models to SNe Ia that have been observed out in the Hubble flow have given values of (H_0) distributed throughout the range of 54-67 km s^-1 Mpc^-1. Astronomers who want a consensus value of (H_0) from SNe Ia with conservative errors could, for now, use 60 +/- 10 km s^-1 Mpc^-1.

Branch, David

103

Astronomical Data Management  

E-print Network

We present a summary of the major contributions to the Special Session on Data Management held at the IAU General Assembly in Prague in 2006. While recent years have seen enormous improvements in access to astronomical data, and the Virtual Observatory aims to provide astronomers with seamless access to on-line resources, more attention needs to be paid to ensuring the quality and completeness of those resources. For example, data produced by telescopes are not always made available to the astronomical community, and new instruments are sometimes designed and built with insufficient planning for data management, while older but valuable legacy data often remain undigitised. Data and results published in journals do not always appear in the data centres, and astronomers in developing countries sometimes have inadequate access to on-line resources. To address these issues, an 'Astronomers Data Manifesto' has been formulated with the aim of initiating a discussion that will lead to the development of a 'code of best practice' in astronomical data management.

Ray Norris; Heinz Andernach; Guenther Eichhorn; Francoise Genova; Elizabeth Griffin; Robert Hanisch; Ajit Kembhavi; Robert Kennicutt; Anita Richards

2006-11-01

104

HUBBLE PEEKS INTO A STELLAR NURSERY IN A NEARBY GALAXY  

NASA Technical Reports Server (NTRS)

HUBBLE PEEKS INTO A STELLAR NURSERY IN A NEARBY GALAXY NASA's Hubble Space Telescope has peered deep into a neighboring galaxy to reveal details of the formation of new stars. Hubble's target was a newborn star cluster within the Small Magellanic Cloud, a small galaxy that is a satellite of our own Milky Way. The new images show young, brilliant stars cradled within a nebula, or glowing cloud of gas, cataloged as N 81. These massive, recently formed stars inside N 81 are losing material at a high rate, sending out strong stellar winds and shock waves and hollowing out a cocoon within the surrounding nebula. The two most luminous stars, seen in the Hubble image as a very close pair near the center of N 81, emit copious ultraviolet radiation, causing the nebula to glow through fluorescence. Outside the hot, glowing gas is cooler material consisting of hydrogen molecules and dust. Normally this material is invisible, but some of it can be seen in silhouette against the nebular background, as long dust lanes and a small, dark, elliptical-shaped knot. It is believed that the young stars have formed from this cold matter through gravitational contraction. Few features can be seen in N 81 from ground-based telescopes, earning it the informal nick-name 'The Blob.' Astronomers were not sure if just one or a few hot stars were embedded in the cloud, or if it was a stellar nursery containing a large number of less massive stars. Hubble's high-resolution imaging shows the latter to be the case, revealing that numerous young, white-hot stars---easily visible in the color picture---are contained within N 81. This crucial information bears strongly on theories of star formation, and N 81 offers a singular opportunity for a close-up look at the turbulent conditions accompanying the birth of massive stars. The brightest stars in the cluster have a luminosity equal to 300,000 stars like our own Sun. Astronomers are especially keen to study star formation in the Small Magellanic Cloud, because its chemical composition is different from that of the Milky Way. All of the chemical elements, other than hydrogen and helium, have only about one-tenth the abundances seen in our own galaxy. The study of N81 thus provides an excellent template for studying the star formation that occurred long ago in very distant galaxies, before nuclear reactions inside stars had synthesized the elements heavier than helium. The Small Magellanic Cloud, named after the explorer Ferdinand Magellan, lies 200,000 light-years away, and is visible only from the Earth's southern hemisphere. N 81 is the 81st nebula cataloged in a survey of the SMC carried out in the 1950's by astronomer Karl Henize, who later became an astronomer-astronaut who flew into space aboard NASA's space shuttle. The Hubble Heritage image of N 81 is a color representation of data taken in September, 1997, with Hubble's Wide Field Planetary Camera 2. Color filters were used to sample light emitted by oxygen ([O III]) and hydrogen (H-alpha, H-beta). N 81 is the target of investigations by European astronomers Mohammad Heydari-Malayeri from the Paris Observatory in France; Michael Rosa from the Space Telescope-European Coordinating Facility in Munich, Germany; Hans Zinnecker of the Astrophysical Institute in Potsdam, Germany; Lise Deharveng of Marseille Observatory, France; and Vassilis Charmadaris of Cornell University, USA (formerly at Paris Observatory). Members of this team are interested in understanding the formation of hot, massive stars, especially under conditions different from those in the Milky Way. Image Credit: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgement: Mohammad Heydari-Malayeri (Paris Observatory, France) EDITOR'S

2002-01-01

105

Hubble Space Telescope, Faint Object Camera  

NASA Technical Reports Server (NTRS)

This drawing illustrates Hubble Space Telescope's (HST's), Faint Object Camera (FOC). The FOC reflects light down one of two optical pathways. The light enters a detector after passing through filters or through devices that can block out light from bright objects. Light from bright objects is blocked out to enable the FOC to see background images. The detector intensifies the image, then records it much like a television camera. For faint objects, images can be built up over long exposure times. The total image is translated into digital data, transmitted to Earth, and then reconstructed. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

1981-01-01

106

Hubble Space Telescope Spies on 'Black Eye'  

NASA Technical Reports Server (NTRS)

Residing roughly 17 million light years from Earth, in the northern constellation Coma Berenices, is a merged star system known as Messier 64 (M64). First cataloged in the 18th century by the French astronomer Messier, M64 is a result of two colliding galaxies and has an unusual appearance as well as bizarre internal motions. It has a spectacular dark band of absorbing dust in front of its bright nucleus, lending to it the nickname of the 'Black Eye' or 'Evil Eye' galaxy. Fine details of the dark band can be seen in this image of the central portion of M64 obtained by the Wide Field Planetary Camera (WFPC2) of NASA's Hubble Space Telescope (HST). Appearing to be a fairly normal pinwheel-shaped galaxy, the M64 stars are rotating in the same direction, clockwise, as in the majority of galaxies. However, detailed studies in the 1990's led to the remarkable discovery that the interstellar gas in the outer regions of M64 rotates in the opposite direction from the gas and stars in the irner region. Astronomers believe that the oppositely rotating gas arose when M64 absorbed a satellite galaxy that collided with it, perhaps more than one billion years ago. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST.

2004-01-01

107

Zero CTE Glass in the Hubble Space Telescope  

NASA Technical Reports Server (NTRS)

Orbiting high above the turbulence of the Earth's atmosphere, the Hubble Space Telescope (HST) has provided breathtaking views of astronomical objects never before seen in such detail. The steady diffraction-limited images allow this medium-size telescope to reach faint galaxies fainter than 30th stellar magnitude. Some of these galaxies are seen as early as 2 billion years after the Big Bang in a 13.7 billion year old universe. Up until recently, astronomers assumed that all of the laws of physics and astronomy applied back then as they do today. Now, using the discovery that certain supernovae are "standard candles," astronomers have found that the universe is expanding faster today than it was back then: the universe is accelerating in its expansion. The Hubble Space Telescope is a two-mirror Ritchey-Chretien telescope of 2.4m aperture in low earth orbit. The mirrors are made of Ultra Low Expansion (ULE) glass by Corning Glass Works. This material allows rapid figuring and outstanding performance in space astronomy applications. The paper describes how the primary mirror was mis-figured in manufacturing and later corrected in orbit. Outstanding astronomical images taken over the last 17 years show how the application of this new technology has advanced our knowledge of the universe. Not only has the acceleration of the expansion been discovered, the excellent imaging capability of HST has allowed gravitational lensing to become a tool to study the distribution of dark matter and dark energy in distant clusters of galaxies. The HST has touched practically every field of astronomy enabling astronomers to solve many long-standing puzzles. It will be a long time until the end of the universe when the density is near zero and all of the stars have long since evaporated. It is remarkable that humankind has found the technology and developed the ability to interpret the measurements in order to understand this dramatic age we live in.

Wood, H. John

2008-01-01

108

Lives and deaths: Biographical notes on selections from the works of Edwin S. Shneidman.  

PubMed

Edwin S. Shneidman (DOB: 1918-05-13; DOD: 2009-05-15) is a father of contemporary suicidology. His work reflects the intensive study of lives lived and deaths, especially suicides, and is the mirror to his mind. His contributions can be represented by five categories: psychological assessment, logic, Melville and Murray, suicide, and death. His works on suicide can be further divided into five parts: definitional and theoretical, suicide notes, administrative and programmatic, clinical and community, and psychological autopsy and postvention. In this article, not only are the selected works explicated, but also Dr. Shneidman's rather personal biographical notes are shared to allow the reader to understand one more unique individual's life lived, and his death: Edwin S. Shneidman. PMID:21034210

Leenaars, Antoon A

2010-10-01

109

Hubble Space Telescope Image  

NASA Technical Reports Server (NTRS)

This color image from the Hubble Space Telescope (HST) shows a region in NGC 1365, a barred spiral galaxy located in a cluster of galaxies called Fornax. A barred spiral galaxy is characterized by a bar of stars, dust, and gas across its center. The black and white photograph from a ground-based telescope shows the entire galaxy, which is visible from the Southern Hemisphere. The galaxy is estimated to be 60-million light-years from Earth. This image was taken by the HST Wide Field/Planetary Camera 2 (WF/PC-2).

1996-01-01

110

HUBBLE SNAPSHOT CAPTURES LIFE CYCLE OF STARS  

NASA Technical Reports Server (NTRS)

NASA's Hubble Space Telescope has snapped a nearly face-on view of a swirling disk of dust and gas surrounding a developing star called AB Aurigae. The Hubble telescope image, taken in visible light by the Space Telescope Imaging Spectrograph, shows unprecedented detail in the disk, including clumps of dust and gas that may be the seeds of planet formation. Normally, a young star's bright light prevents astronomers from seeing material closer to it. That's why astronomers used a coronograph in these two images of AB Aurigae to block most of the light from the star. The rest of the disk material is illuminated by light reflected from the gas and dust surrounding the star. The image on the left represents the best ground-based coronographic observation of AB Aurigae. Paul Kalas of the Space Telescope Science Institute took the image with the University of Hawaii's 2.2-meter telescope. The telescope's coronograph eclipsed a 33.5-billion-mile (53.6-billion-kilometer) area centered on the star. This area is nine times larger than our solar system. The picture shows that the star resides in a region of dust clouds - the semicircular-shaped material to the left of the star. The Hubble telescope image on the right shows a windowpane-shaped occulting bar -- the dark bands running vertically through the middle of the image and horizontally across the upper part of it. The occulting bar covers the innermost part of the disk and star, about 7.1 billion miles (11.5 billion kilometers) or 1.4 times our solar system's diameter. The diagonal lines are the remnants of the diffraction spikes produced in Hubble telescope images of bright stars. The disk is extremely wide: its diameter is roughly 1,300 times Earth's distance from the Sun. The disk material seen in this image is at a distance equivalent to well beyond Pluto's orbit. One faint background star is visible at 5 o'clock. The star's disk shows a wealth of structure, with bright spiral-shaped bands from 9 o'clock to 6 o'clock and closer to the star from 12 o'clock to 3 o'clock. The outermost of these bands are seen in the ground-based image. The imaging spectrograph data show that these bands are themselves composed of numerous smaller bands. The smallest features include some bright knots of material to the left of the star. These knots are close in size to the resolution limit of the Hubble telescope and have diameters 1.3 to 3 billion miles (2 to 5 billion kilometers) wide or 14 to 32 times Earth's distance from the Sun. The brightest knot is at 9 o'clock. The image was taken Jan. 23 and 24, 1999. False colors were used to bring out details in AB Aurigae's disk. The wavelength range is 2,000 to 10,100 Angstroms. Credit: C.A. Grady (National Optical Astronomy Observatories, NASA Goddard Space Flight Center), B. Woodgate (NASA Goddard Space Flight Center), F. Bruhweiler and A. Boggess (Catholic University of America), P. Plait and D. Lindler (ACC, Inc., Goddard Space Flight Center), M. Clampin (Space Telescope Science Institute), and NASA.

2002-01-01

111

Amateur Astronomers' Excellent Adventures  

NASA Astrophysics Data System (ADS)

Last May, the Space Telescope Science Institute canceled the Hubble amateur program for lack of interest. It was a sad end to a program that gave citizen-scientists, brimming with fresh approaches, the means to study the universe. The benefits -- to them, to their communities, to science -- live on.

Cox, Nancy

1996-07-01

112

The Astronomical Journal  

NSDL National Science Digital Library

Based at the University of Wisconsin-Madison, the Astronomical Journal (AJ) publishes original astronomical research, with "an emphasis on significant scientific results derived from observations, including descriptions of data capture, surveys, analysis techniques, and astronomical interpretation." The publication was founded in 1849 in Cambridge, Massachusetts and since that time it has become highly regarded. Visitors to the site can read past issues for free and they can use the Most Read, Most Cited, and Latest Articles tabs to dive right in. Recent pieces in the AJ have addressed supernovae, infrared scientific measurement devices, and the numerical integration of rotational motion. On the site, visitors can contact the editorial board, learn about submission guidelines, and peruse the AJ's ethics policy. It is a rather wonderful way to learn about the latest research in this field and is a resource that users will want to bookmark for future consideration. [KMG

2013-01-01

113

The SIMBAD astronomical database  

E-print Network

Simbad is the reference database for identification and bibliography of astronomical objects. It contains identifications, `basic data', bibliography, and selected observational measurements for several million astronomical objects. Simbad is developed and maintained by CDS, Strasbourg. Building the database contents is achieved with the help of several contributing institutes. Scanning the bibliography is the result of the collaboration of CDS with bibliographers in Observatoire de Paris (DASGAL), Institut d'Astrophysique de Paris, and Observatoire de Bordeaux. When selecting catalogues and tables for inclusion, priority is given to optimal multi-wavelength coverage of the database, and to support of research developments linked to large projects. In parallel, the systematic scanning of the bibliography reflects the diversity and general trends of astronomical research. A WWW interface to Simbad is available at: http://simbad.u-strasbg.fr/Simbad

Marc Wenger; Francois Ochsenbein; Daniel Egret; Pascal Dubois; Francois Bonnarel; Suzanne Borde; Francoise Genova; Gerard Jasniewicz; Suzanne Laloe; Soizick Lesteven; Richard Monier

2000-02-04

114

Preparing Colorful Astronomical Images III: Cosmetic Cleaning  

NASA Astrophysics Data System (ADS)

We present cosmetic cleaning techniques for use with mainstream graphics software (Adobe Photoshop) to produce presentation-quality images and illustrations from astronomical data. These techniques have been used on numerous images from the Hubble Space Telescope when producing photographic, print and web-based products for news, education and public presentation as well as illustrations for technical publication. We expand on a previous paper to discuss the treatment of various detector-attributed artifacts such as cosmic rays, chip seams, gaps, optical ghosts, diffraction spikes and the like. While Photoshop is not intended for quantitative analysis of full dynamic range data (as are IRAF or IDL, for example), we have had much success applying Photoshop's numerous, versatile tools to final presentation images. Other pixel-to-pixel applications such as filter smoothing and global noise reduction will be discussed.

Frattare, L. M.; Levay, Z. G.

2003-12-01

115

Preparing Colorful Astronomical Images and Illustrations  

NASA Astrophysics Data System (ADS)

We present techniques for using mainstream graphics software, specifically Adobe Photoshop and Illustrator, for producing composite color images and illustrations from astronomical data. These techniques have been used with numerous images from the Hubble Space Telescope to produce printed and web-based news, education and public presentation products as well as illustrations for technical publication. While Photoshop is not intended for quantitative analysis of full dynamic range data (as are IRAF or IDL, for example), we have had much success applying Photoshop's numerous, versatile tools to work with scaled images, masks, text and graphics in multiple semi-transparent layers and channels. These features, along with its user-oriented, visual interface, provide convenient tools to produce high-quality, full-color images and graphics for printed and on-line publication and presentation.

Levay, Z. G.; Frattare, L. M.

2001-12-01

116

HUBBLE FINDS A BARE BLACK HOLE POURING OUT LIGHT  

NASA Technical Reports Server (NTRS)

NASA's Hubble Space Telescope has provided a never-before-seen view of a warped disk flooded with a torrent of ultraviolet light from hot gas trapped around a suspected massive black hole. [Right] This composite image of the core of the galaxy was constructed by combining a visible light image taken with Hubble's Wide Field Planetary Camera 2 (WFPC2), with a separate image taken in ultraviolet light with the Faint Object Camera (FOC). While the visible light image shows a dark dust disk, the ultraviolet image (color-coded blue) shows a bright feature along one side of the disk. Because Hubble sees ultraviolet light reflected from only one side of the disk, astronomers conclude the disk must be warped like the brim of a hat. The bright white spot at the image's center is light from the vicinity of the black hole which is illuminating the disk. [Left] A ground-based telescopic view of the core of the elliptical galaxy NGC 6251. The inset box shows Hubble Space Telescope's field of view. The galaxy is 300 million light-years away in the constellation Ursa Minor. Photo Credit: Philippe Crane (European Southern Observatory), and NASA

2002-01-01

117

HUBBLE OBSERVES THE LOST ANCESTORS TO OUR MILKY WAY GALAX  

NASA Technical Reports Server (NTRS)

This NASA Hubble Space Telescope (HST) image of the central portion of a remote cluster of galaxies (CL 0939+4713) as it looked when the universe was two-thirds of its present age. Hubble's high resolution allows astronomers to study, for the first time, the shapes of galaxies as they were long ago. The Space Telescope pictures are sharp enough to distinguish between various forms of spiral galaxies. Most of the spiral, or disk, galaxies have odd features, suggesting they were easily distorted within the environment of the rich cluster. Hubble reveals a number of mysterious 'fragments' of galaxies interspersed through the cluster. The HST picture confirms that billions of years ago, clusters of galaxies contained not only the types of galaxies dominating their descendant clusters today, but also several times as many spiral galaxies. These spiral galaxies have since disappeared through mergers and disruptions, as evident in the Hubble image. This visible light image was taken with HST's Wide Field Planetary Camera 2 in Wide Field Camera mode, on January 10 and 12, 1994. Credit: Alan Dressler (Carnegie Institution) and NASA

2002-01-01

118

Hubble's deepest view ever of the Universe unveils earliest galaxies  

NASA Astrophysics Data System (ADS)

Hubble sees galaxies galore hi-res Size hi-res: 446 kb Credits: NASA, ESA, and S. Beckwith (STScI) and the HUDF Team Hubble sees galaxies galore Galaxies, galaxies everywhere - as far as the NASA/ESA Hubble Space Telescope can see. This view of nearly 10,000 galaxies is the deepest visible-light image of the cosmos. Called the Hubble Ultra Deep Field, this galaxy-studded view represents a ‘deep’ core sample of the universe, cutting across billions of light-years. Hubble reveals galactic drama hi-res Size hi-res: 879 kb Credits: NASA, ESA, and S. Beckwith (STScI) and the HUDF Team Hubble reveals galactic drama A galactic brawl. A close encounter with a spiral galaxy. Blue wisps of galaxies. These close-up snapshots of galaxies in the Hubble Ultra Deep Field reveal the drama of galactic life. Here three galaxies just below centre are enmeshed in battle, their shapes distorted by the brutal encounter. Hubble reveals galactic drama hi-res Size hi-res: 886 kb Credits: NASA, ESA, and S. Beckwith (STScI) and the HUDF Team Hubble reveals galactic drama A galactic brawl. A close encounter with a spiral galaxy. Blue wisps of galaxies. These close-up snapshots of galaxies in the Hubble Ultra Deep Field reveal the drama of galactic life. Here three galaxies just below centre are enmeshed in battle, their shapes distorted by the brutal encounter. Hubble reveals galactic drama hi-res Size hi-res: 892 kb Credits: NASA, ESA, and S. Beckwith (STScI) and the HUDF Team Hubble reveals galactic drama A galactic brawl. A close encounter with a spiral galaxy. Blue wisps of galaxies. These close-up snapshots of galaxies in the Hubble Ultra Deep Field reveal the drama of galactic life. The galaxies in this panel were plucked from a harvest of nearly 10,000 galaxies in the Ultra Deep Field, the deepest visible-light image of the cosmos. This historic new view is actually made up by two separate images taken by Hubble's Advanced Camera for Surveys (ACS) and the Near Infrared Camera and Multi-object Spectrometer (NICMOS). Both images reveal some galaxies that are too faint to be seen by ground-based telescopes, or even in Hubble's previous faraway looks, called the Hubble Deep Fields (HDFs), taken in 1995 and 1998. The HUDF field contains an estimated 10,000 galaxies in a patch of sky just one-tenth the diameter of the full Moon. Besides the rich harvest of classic spiral and elliptical galaxies, there is a zoo of oddball galaxies littering the field. Some look like toothpicks; others like links on a bracelet. A few appear to be interacting. Their strange shapes are a far cry from the majestic spiral and elliptical galaxies we see today. These oddball galaxies chronicle a period when the Universe was more chaotic. Order and structure were just beginning to emerge. The combination of ACS and NICMOS images will be used to search for galaxies that existed between 400 and 800 million years after the Big Bang (in cosmological terms this corresponds to a 'redshift' range of 7 to 12). Astronomers around the world will use these data to understand whether in this very early stages the Universe appears to be the same as it did when the cosmos was between 1000 and 2000 million years old. Hubble's ACS allows astronomers to see galaxies two to four times fainter than Hubble could view previously, but the NICMOS sees even farther than the ACS. The NICMOS reveals the farthest galaxies ever seen because the expanding Universe has stretched their light into the near-infrared portion of the spectrum. The ACS uncovered galaxies that existed 800 million years after the Big Bang (at a redshift of 7). But the NICMOS might have spotted galaxies that lived just 400 million years after the birth of the cosmos (at a redshift of 12). Just like the previous HDFs, the new data are expected to galvanise the astronomical community and lead to dozens of research papers that will offer new insights into the birth and evolution of galaxies. This will hold the record as the deepest-ever view of the Universe until ESA together with NASA launches the James Webb Space Telescope in

2004-03-01

119

Anisotropy in the Hubble constant as modeled by density gradients  

E-print Network

The all-sky maps of the observed variation of the Hubble constant can be reproduced from a theoretical point of view by introducing an intergalactic plasma with a variable number density of electrons. The observed averaged value and variance of the Hubble constant are reproduced by adopting a rim model, an auto-gravitating model, and a Voronoi diagrams model as the backbone for an auto-gravitating medium. We also analyze an astronomer's model based on the 3D spatial distribution of galaxies as given by the 2MASS Redshift Survey and an auto-gravitating Lane--Emden ($n=5$) profile of the electrons. The simulation which involves the Voronoi diagrams is done in a cubic box with sides of 100 Mpc. The simulation which involves the 2MASS covers the range of redshift smaller than 0.05.

Zaninetti, L

2014-01-01

120

Calibration of the Hubble Space Telescope polarimetric modes  

NASA Technical Reports Server (NTRS)

Stellar and galactic polarimetry from space is an unexplored observational regime and one which holds exciting promise for answering many fundamental astrophysical questions. The Hubble Space Telescope will be the first space observatory to provide a variety of polarimetric modes to astronomers including spectral, imaging, and single-aperture UV polarimetry. As part of the calibration program for these modes, the Space Telescope Science Institute has initiated a ground-based program to define faint standard fields and solicited community support to establish a temporal baseline for these potential standard targets. In this paper, the polarimetric capabilities of the Hubble Space Telescope, the philosophy and complications of in-flight calibration, and the status and direction of the standard targets program are discussed.

Lupie, O. L.; Stockman, H. S.

1988-01-01

121

SIMBAD Astronomical Database  

NSDL National Science Digital Library

"The SIMBAD astronomical database provides basic data, cross-identifications, and bibliography for astronomical objects outside the solar system." Created by the Centre de Donn'es astronomiques de Strasbourg (CDS) in France, the website contains over three million objects, eight and a half million identifiers, one hundred thousand bibliographical references, and four million citations of objects in papers. The data can be searched by object name, coordinates, filters, and by a list of objects. Researchers can find help by visiting the user's guide and the regularly updated Dictionary of Nomenclature of Celestial Objects.

122

Astronomical hosting in Mongolia  

NASA Astrophysics Data System (ADS)

Networked projects such as gamma-ray burst follow-up optical observations with ground-based telescopes require worldwide coverage. In choosing places for new astronomical observatories one of the most important criteria is the number of clear-sky night hours. We are investigating potentially interesting sites in Mongolia and present results about the numbers of clear sky night hours (as well as some other parameters) at different sites in Mongolia, collected with weather stations and our own observations over several years. We also discuss the possibility of astronomical hosting at the sites and the future development of networked projects.

Volnova, Alina; Pozanenko, Alexei; Tungalag, N.; Davaakhuu, G.; Guziy, Sergey; Klunko, Evgeniy; Molotov, Igor

2014-09-01

123

The Edwin Smith Papyrus: the birth of analytical thinking in medicine and otolaryngology.  

PubMed

The Edwin Smith Papyrus, discovered in 1862 outside of Luxor, Egypt, is the oldest known surgical text in the history of civilization. The surviving scroll, a copy of an earlier text from around 3,000 B.C., gives us remarkable insight into the medical practice of ancient Egyptians in the Nile River bed during the dawn of civilization. The Papyrus is divided into 48 cases, most of which describe traumatic injuries. The text instructs the physician to examine the patient and look for revealing physical signs that may indicate the outcome of the injury. Although in modern medicine we take for granted that the use of physical examination and rational thinking lead to an accurate conclusion, 5,000 years ago, this was extraordinary. The Edwin Smith Papyrus cast aside the prevailing magic and mysticism of that time in favor of logic and deductive reasoning. As Egyptian civilization declined during the next millennium, the teachings of the Papyrus would be lost. It would not be until 300 B.C. when Hippocrates and his disciples in ancient Greece would once again revive logic in medical thinking and teaching. It is believed that the ancient Greeks had knowledge of the contents of the Edwin Smith Papyrus and its teachings and used them as the basis for their writings. As Europe entered the Dark Ages, so did medicine yet again, reverting to spells and prayers instead of judgment and reason. Although Hippocrates teachings were recognized by some scholars during the Middle Ages, they did not make up the basis for mainstream medical knowledge. With the dawn of the Renaissance, medicine would finally purge itself of its past supernatural foundation. Hippocratic teachings were used to form the basis of modern medicine, and medical pioneers in the 17 century studied the ancient Greek texts as the origin for their ideas. Many of the concepts physicians and patients today take as common knowledge originated in the Edwin Smith Papyrus. The authors attempt to uncover some of these fundamental ideas and trace them through time until their incorporation in our modern medical knowledge base. It is the rational, logical, and advanced thinking exhibited in the Edwin Smith Papyrus that mandates its respect from modern otolaryngologists and all physicians alike. PMID:16467701

Stiefel, Marc; Shaner, Arlene; Schaefer, Steven D

2006-02-01

124

18 years of science with the Hubble Space Telescope.  

PubMed

After several decades of planning, the Hubble Space Telescope (HST) was launched in 1990 as the first of NASA's Great Observatories. After a rocky start arising from an error in the fabrication of its main mirror, it went on to change forever many fields of astronomy, and to capture the public's imagination with its images. An ongoing programme of servicing missions has kept the telescope on the cutting edge of astronomical research. Here I review the advances made possible by the HST over the past 18 years. PMID:19122634

Dalcanton, Julianne J

2009-01-01

125

Obituary: Raymond Edwin White Jr., 1933-2004  

NASA Astrophysics Data System (ADS)

Raymond E. White, Jr., died unexpectedly at his home, in the early morning hours of October 12, 2004. Death appears to have been caused by severe diabetic shock. He retired from the Department of Astronomy/Steward Observatory in July 1999 with the title of University Distinguished Professor, after serving on the faculty of this institution for over 35 years. He was born in Freeport, Illinois, on 6 May 1933, to Beatrice and Raymond E, Sr. -the latter being a career soldier in the US Army. Ray's early schooling took place in Illinois, New Jersey, Germany and Switzerland, following his father's assignments. He obtained a bachelors degree from the University of Illinois in 1955. Next Ray enlisted in the US Army, but quickly was enrolled in Officer Candidate School. He then served as lst Lt. in the US Army Corps of Engineers. Although military affairs remained a lifelong interest, and he was a member of the Company of Military Historians, Ray decided after three years to return to academia. He entered the astronomy PhD program at the University of Illinois in 1958. His PhD dissertation was supervised by Ivan R. King. Ray accepted a faculty position at the University of Arizona in 1964. First and foremost, Ray White was known at Arizona as an excellent teacher, revered by a large number of former students. When the astronomy major program was begun in 1967, Ray was one of three, original, major advisors. Over the next three decades, he was a leader at the University level in reforming the undergraduate program and courses. He was selected Outstanding University Faculty Member in April 1989 and he served as one of a handful of professors who are Faculty Fellows. These Fellows devote untold hundreds of hours as part-time residents at student dormitories, to give students a friendly face to address their problems. In 1995, Ray was among the first group of faculty to be recognized as University Distinguished Professors. In the year of his retirement, 1999, University President Manuel Pachecho recognized Ray's extensive contributions by asking him to serve as Master of Ceremonies at the University commencement. Ray White's research career was not as extensive as his teaching activities, but it was creative. His original specialty was globular star clusters and classes of variable stars within them. He made several catalogs of star clusters and associations, measured the exact centers, the axial ratios and the orientations of around 100 Galactic globular clusters. Certainly, Ray's greatest love in research, especially in later years, was archaeoastronomy. He studied the evidence for astronomical observations of the Sun, Moon and stars from the mound sites of the prehistoric Hohokam inhabitants of the Salt River Valley of Arizona. He was best known for his studies of the Inkaic people of the pre-Columbian, Peruvian Andes. Most of this research involved the grand Machu Picchu site, where he showed (with David Dearborn) that the central tower (the "Torreon") certainly had been used as an Observatory. They also discovered a separate, solstice observatory and named it Intimachay. Characteristically, Ray combined much of his archaeoastronomy research interests with the involvement of undergraduate students and adults through the Earthwatch program in field trips to Machu Picchu. With a Professor in the humanities who was also well known at the University of Arizona, Donna Swaim, Ray introduced a group of undergraduates in summer classes to several archaeoastronomy sites in such countries as Ireland and the British isles. Of course they also gave on-site lectures at art museums, and sites of historical and cultural interest. Like many astronomers, Ray was well traveled. He had sabbaticals at the University of Cambridge in 1980, and at the Dublin Institute of Advanced Study (Dunsink Observatory), Ireland, in 1996-97. The latter was funded by his winning a Fulbright Fellowship, which enabled him to further his studies of the Celtic astronomical traditions. Earlier in 1971-72, Ray served as Program Officer for Stars and Stellar Evol

Liebert, James William

2004-12-01

126

NRAO Astronomer Honored by American Astronomical Society  

NASA Astrophysics Data System (ADS)

Dr. Scott Ransom, an astronomer at the National Radio Astronomy Observatory (NRAO), received the American Astronomical Society's (AAS) Helen B. Warner Prize on January 11, at the society's meeting in Seattle, Washington. The prize is awarded annually for "a significant contribution to observational or theoretical astronomy during the five years preceding the award." Presented by AAS President Debra Elmegreen, the prize recognized Ransom "for his astrophysical insight and innovative technical leadership enabling the discovery of exotic, millisecond and young pulsars and their application for tests of fundamental physics." "Scott has made landmark contributions to our understanding of pulsars and to using them as elegant tools for investigating important areas of fundamental physics. We are very proud that his scientific colleagues have recognized his efforts with this prize," said NRAO Director Fred K.Y. Lo. A staff astronomer at the NRAO since 2004, Ransom has led efforts using the National Science Foundation's Green Bank Telescope and other facilities to study pulsars and use them to make advances in areas of frontier astrophysics such as gravitational waves and particle physics. In 2010, he was on a team that discovered the most massive pulsar yet known, a finding that had implications for the composition of pulsars and details of nuclear physics, gravitational waves, and gamma-ray bursts. Ransom also is a leader in efforts to find and analyze rapidly-rotating millisecond pulsars to make the first direct detection of the gravitational waves predicted by Albert Einstein. In other work, he has advanced observational capabilities for finding millisecond pulsars in globular clusters of stars and investigated how millisecond pulsars are formed. A graduate of the United States Military Academy at West Point, NY, Ransom served as an artillery officer in the U.S. Army. After leaving the Army, he earned a Ph.D. at Harvard University in 2001, and was a postdoctoral fellow at McGill University before joining the NRAO in 2004. Ransom will deliver his Warner Prize Lecture, entitled "Millisecond Pulsars: The Gifts that Keep on Giving," at the AAS meeting on Tuesday, January 11, 2011, at 3:40 p.m., Pacific Time.

2011-01-01

127

Memphis Astronomical Society  

NSDL National Science Digital Library

Web site for amateur astronomers offering free "Getting Started with Your New Telescope" article (PDF), monthly newsletter, weblog ("MemphisAstro"), and information for ordering inexpensive out-of-print amateur's guides to finding Messier objects. The Society is a public-service organization promoting interest and education in astronomy and holding monthly meetings and offering lectures and demonstrations to local (Memphis, Tennessee) members.

2007-03-18

128

Astronomers as Amateurs  

NASA Astrophysics Data System (ADS)

The role of amateurs in astronomy is in need of redefinition. Such a redefinition would be consistent with recent sociological studies that distinguish avocation science from casual or recreational pursuits. While additional support and encouragement from professional astronomers will facilitate this development, the main initiative must come from amateurs.

Williams, Thomas R.

1983-06-01

129

Misconceptions of Astronomical Distances  

ERIC Educational Resources Information Center

Previous empirical studies using multiple-choice procedures have suggested that there are misconceptions about the scale of astronomical distances. The present study provides a quantitative estimate of the nature of this misconception among US university students by asking them, in an open-ended response format, to make estimates of the distances…

Miller, Brian W.; Brewer, William F.

2010-01-01

130

Astronomical Microdensitometry Conference  

NASA Technical Reports Server (NTRS)

The status of the current microdensitometers used for digitizing astronomical imagery is discussed. The tests and improvements that have and can be made to the Photometric Data System PDS microdensitometer are examined. The various types of microdensitometers that currently exist in the world are investigated. Papers are presented on the future needs and the data processing problems associated with digitizing large images.

Klinglesmith, D. A. (editor)

1984-01-01

131

Russian astronomical software  

NASA Astrophysics Data System (ADS)

Institute of Applied Astronomy of RAS has published “ The Astronomical Yearbook ” ( AY) with 1921, “ The Nautical Astronomical Yearbook ” (NAY) with 1930, “ The Nautical Astronomical Almanac ”’ biennial (NAA - 2) with 2001. The new IAU2006/2000 precession - nutation models, and the FK6/HIPPARCOS stellar catalogues were used in these editions. Ephemeris editions are based on the domestic EPM2004 (IAA RAS) theory of movement of planets, Sun and Moon. The electronic versions are developed for two editions. The important stage of work is creation of “The Personal Astronomical Yearbook ”’ (PersAY). The system gives ample opportunities to the user to put and to solve tasks of calculation of ephemerides for any moment in various time scales, and for any location of the observer on a terrestrial surface. Also in PersAY it is possible to calculate by means of DE405/LE405 theory to make comparison with others ephemeris editions. The time interval of validity of the system makes 2010 - 2015. Besides system of the removed access the "Navigator" was developed. It intended to solve some the navigating tasks describe d in NAA - 2. The system is accessible on a site http://shturman.ipa.nw.ru/ (in Russian). In electronic systems as in Y the same reduce theories and the theory of movement of planets, the Sun, the Moon are used. All calculations are work out on the basis of the multifunctional software system ERA.

Lukashova, Marina V.; Glebova, Nina I.; Netsvetaev, Ilja N.; Netsvetaeva, Galina A.; Parijskaja, Ekaterina Ju.; Pitieva, Elena V.; Sveshnikov, Michael L.; Skripnichenko, Vladimir I.

2012-08-01

132

The Hubble constant.  

PubMed Central

Five methods of estimating distances have demonstrated internal reproducibility at the level of 5-20% rms accuracy. The best of these are the cepheid (and RR Lyrae), planetary nebulae, and surface-brightness fluctuation techniques. Luminosity-line width and Dn-sigma methods are less accurate for an individual case but can be applied to large numbers of galaxies. The agreement is excellent between these five procedures. It is determined that Hubble constant H0 = 90 +/- 10 km.s-1.Mpc-1 [1 parsec (pc) = 3.09 x 10(16) m]. It is difficult to reconcile this value with the preferred world model even in the low-density case. The standard model with Omega = 1 may be excluded unless there is something totally misunderstood about the foundation of the distance scale or the ages of stars. PMID:11607391

Tully, R B

1993-01-01

133

Hubble Source Catalog  

NASA Astrophysics Data System (ADS)

We have created an initial catalog of objects observed by the WFPC2 and ACS instruments on the Hubble Space Telescope (HST). The catalog is based on observations taken on more than 6000 visits (telescope pointings) of ACS/WFC and more than 25000 visits of WFPC2. The catalog is obtained by cross matching by position in the sky all Hubble Legacy Archive (HLA) Source Extractor source lists for these instruments. The source lists describe properties of source detections within a visit. The calculations are performed on a SQL Server database system. First we collect overlapping images into groups, e.g., Eta Car, and determine nearby (approximately matching) pairs of sources from different images within each group. We then apply a novel algorithm for improving the cross matching of pairs of sources by adjusting the astrometry of the images. Next, we combine pairwise matches into maximal sets of possible multi-source matches. We apply a greedy Bayesian method to split the maximal matches into more reliable matches. We test the accuracy of the matches by comparing the fluxes of the matched sources. The result is a set of information that ties together multiple observations of the same object. A byproduct of the catalog is greatly improved relative astrometry for many of the HST images. We also provide information on nondetections that can be used to determine dropouts. With the catalog, for the first time, one can carry out time domain, multi-wavelength studies across a large set of HST data. The catalog is publicly available. Much more can be done to expand the catalog capabilities.

Lubow, S.; Budavári, T.

2013-10-01

134

The League of Astronomers  

NASA Astrophysics Data System (ADS)

The League of Astronomers is committed to engaging the University of Washington (UW) and the greater Seattle communities through outreach, research, and events. Since its re-founding two years ago, the LOA has provided a clear connection between the UW Astronomy Department, undergraduate students, and members of the public. Weekly outreach activities such as public star parties and planetarium talks in both the UW Planetarium and the Mobile Planetarium have connected enthusiastic LOA volunteers with hundreds of public observers. In addition, collaboration with organizations like the Seattle Astronomical Society and the UW Society of Physics Students has allowed the LOA to reach an even greater audience. The club also provides opportunities for undergraduate students to participate in research projects. The UW Student Radio Telescope (SRT) and the Manastash Ridge Observatory (MRO) both allow students to practice collecting their own data and turning it into a completed project. Students have presented many of these research projects at venues like the UW Undergraduate Research Symposium and meetings of the American Astronomical Society. For example, the LOA will be observing newly discovered globular clusters at the Dominion Astrophysical Observatory (DAO) in Victoria, B.C. and constructing color-magnitude diagrams. The LOA also helps engage students with the Astronomy major through a variety of events. Bimonthly seminars led by graduate students on their research and personal experiences in the field showcase the variety of options available for students in astronomy. Social events hosted by the club encourage peer mentoring and a sense of community among the Astronomy Department’s undergraduate and graduate students. As a part of one of the nation’s largest undergraduate astronomy programs, members of the League of Astronomers have a unique opportunity to connect and interact with not only the Seattle public but also the greater astronomical community.

Thomas, Nancy H.; Brandel, A.; Paat, A. M.; Schmitz, D.; Sharma, R.; Trujillo, J.; Laws, C. S.

2014-01-01

135

Type Ia Supernovae and the Hubble Constant  

E-print Network

The focus of this review is the work that has been done during the 1990s on using Type Ia supernovae (SNe Ia) to measure the Hubble constant ($H_0$). SNe Ia are well suited for measuring $H_0$. A straightforward maximum-light color criterion can weed out the minority of observed events that are either intrinsically subluminous or substantially extinguished by dust, leaving a majority subsample that has observational absolute-magnitude dispersions of less than $\\sigma_{obs}(M_B) \\simeq \\sigma_{obs}(M_V) \\simeq 0.3$ mag. Correlations between absolute magnitude and one or more distance-independent SN Ia or parent-galaxy observables can be used to further standardize the absolute magnitudes to better than 0.2 mag. The absolute magnitudes can be calibrated in two independent ways --- empirically, using Cepheid-based distances to parent galaxies of SNe Ia, and physically, by light curve and spectrum fitting. At present the empirical and physical calibrations are in agreement at $M_B \\simeq M_V \\simeq -19.4$ or -19.5. Various ways that have been used to match Cepheid-calibrated SNe Ia or physical models to SNe Ia that have been observed out in the Hubble flow have given values of $H_0$ distributed throughout the range 54 to 67 km/s Mpc$^{-1}$. Astronomers who want a consensus value of $H_0$ from SNe Ia with conservative errors could, for now, use $60 \\pm 10$ km/s Mpc^{-1}$.

D. Branch

1998-01-08

136

The Planetarium and the Astronomer (An Overview)  

NASA Astrophysics Data System (ADS)

The science of astronomy is one of the most accessible of the so-called "hard" sciences. Most people are familiar with some sky phenomena, and do not feel threatened at the prospect of learning more about the stars and planets. In the media, some of the best-known scientists are astronomers, and programs about astronomy tend to gather appreciatively large audiences. Planetarium facilities are a very special form of science media, with the fortunate task of presenting astronomy to the public. Like science writers, planetarium professionals take complex science information and make it accessible to the public with a variety of audio-visual techniques. Because many planetarium professionals have science backgrounds as well as educational training, they have an advantage over traditional media practitioners, who -- except for a few notable exceptions -- do not always have the luxury of a science background when it comes to writing about science. The unique background of the planetarian, however, builds a logical and natural link between astronomers and the public. This paper summarizes the wide variety of ways in which planetaria disseminate astronomy information -- ranging from live public lectures, to "astronomy updates", to hands-on activities for school children, and professionally-produced multi-media programs created especially for the needs of the domed theater. It ends with a few broad suggestions about possible roles for astronomers in any or all of these activities. Carolyn Collins Petersen has been a writer and producer of planetarium programs since 1980. Her programs have appeared in more than 500 facilities around the world. Her print work has appeared in the Denver Post, Sky and Telescope, Astronomy Magazine, and the Griffith Observer. She is the lead author of the upcoming book "Hubble Vision: Science With the Hubble Space Telescope" (due out from Cambridge University Press in Fall, 1995). Petersen has won several awards for her work. She is also a Graduate Research Assistant at the LASP at the University of Colorado, where she works on tasks for the GHRS team and the Ulysses Comet Watch. She has just completed work on a masters' thesis in science journalism.

Petersen, Carolyn Collins

1995-05-01

137

HUBBLE'S PLANETARY NEBULA GALLERY  

NASA Technical Reports Server (NTRS)

[Top left] - IC 3568 lies in the constellation Camelopardalis at a distance of about 9,000 light-years, and has a diameter of about 0.4 light-years (or about 800 times the diameter of our solar system). It is an example of a round planetary nebula. Note the bright inner shell and fainter, smooth, circular outer envelope. Credits: Howard Bond (Space Telescope Science Institute), Robin Ciardullo (Pennsylvania State University) and NASA [Top center] - NGC 6826's eye-like appearance is marred by two sets of blood-red 'fliers' that lie horizontally across the image. The surrounding faint green 'white' of the eye is believed to be gas that made up almost half of the star's mass for most of its life. The hot remnant star (in the center of the green oval) drives a fast wind into older material, forming a hot interior bubble which pushes the older gas ahead of it to form a bright rim. (The star is one of the brightest stars in any planetary.) NGC 6826 is 2,200 light- years away in the constellation Cygnus. The Hubble telescope observation was taken Jan. 27, 1996 with the Wide Field and Planetary Camera 2. Credits: Bruce Balick (University of Washington), Jason Alexander (University of Washington), Arsen Hajian (U.S. Naval Observatory), Yervant Terzian (Cornell University), Mario Perinotto (University of Florence, Italy), Patrizio Patriarchi (Arcetri Observatory, Italy) and NASA [Top right ] - NGC 3918 is in the constellation Centaurus and is about 3,000 light-years from us. Its diameter is about 0.3 light-year. It shows a roughly spherical outer envelope but an elongated inner balloon inflated by a fast wind from the hot central star, which is starting to break out of the spherical envelope at the top and bottom of the image. Credits: Howard Bond (Space Telescope Science Institute), Robin Ciardullo (Pennsylvania State University) and NASA [Bottom left] - Hubble 5 is a striking example of a 'butterfly' or bipolar (two-lobed) nebula. The heat generated by fast winds causes each of the lobes to expand, much like a pair of balloons with internal heaters. This observation was taken Sept. 9, 1997 by the Hubble telescope's Wide Field and Planetary Camera 2. Hubble 5 is 2,200 light-years away in the constellation Sagittarius. Credits: Bruce Balick (University of Washington), Vincent Icke (Leiden University, The Netherlands), Garrelt Mellema (Stockholm University), and NASA [Bottom center ] - Like NGC 6826, NGC 7009 has a bright central star at the center of a dark cavity bounded by a football-shaped rim of dense, blue and red gas. The cavity and its rim are trapped inside smoothly-distributed greenish material in the shape of a barrel and comprised of the star's former outer layers. At larger distances, and lying along the long axis of the nebula, a pair of red 'ansae', or 'handles' appears. Each ansa is joined to the tips of the cavity by a long greenish jet of material. The handles are clouds of low-density gas. NGC 7009 is 1,400 light-years away in the constellation Aquarius. The Hubble telescope observation was taken April 28, 1996 by the Wide Field and Planetary Camera 2. Credits: Bruce Balick (University of Washington), Jason Alexander (University of Washington), Arsen Hajian (U.S. Naval Observatory), Yervant Terzian (Cornell University), Mario Perinotto (University of Florence, Italy), Patrizio Patriarchi (Arcetri Observatory, Italy), NASA [Bottom right ] - NGC 5307 also lies in Centaurus but is about 10,000 light-years away and has a diameter of approximately 0.6 light-year. It is an example of a planetary nebula with a pinwheel or spiral structure; each blob of gas ejected from the central star has a counterpart on the opposite side of the star. Credits: Howard Bond (Space Telescope Science Institute), Robin Ciardullo (Pennsylvania State University) and NASA

2002-01-01

138

Astronomers without borders  

NASA Astrophysics Data System (ADS)

``Astronomers Without Borders'' is a new global organisational dedicated to furthering understanding and goodwill across national and cultural boundaries using the universal appeal of astronomy and space science. A growing network of affiliate organisations brings together clubs, magazines and other organizations involved in astronomy and space science. Forums, galleries, video conferences and other interactive technologies are used to connect participants around the world. Sharing of resources and direct connections through travel programs are also planned. One project, ``The World at Night'' (TWAN), has become an Special Project of IYA2009. TWAN creates wide-angle images of the night sky in important natural and historic settings around the world, dramatically demonstrating the universal nature and appeal of the night sky. ``Astronomers Without Borders'' is also a leader of the 100 Hours of Astronomy IYA2009 Global Cornerstone Project.

Simmons, Mike

2011-06-01

139

Misconceptions about astronomical magnitudes  

NASA Astrophysics Data System (ADS)

The present system of astronomical magnitudes was created as an inverse scale by Claudius Ptolemy in about 140 A.D. and was defined to be logarithmic in 1856 by Norman Pogson, who believed that human eyes respond logarithmically to the intensity of light. Although scientists have known for some time that the response is instead a power law, astronomers continue to use the Pogson magnitude scale. The peculiarities of this system make it easy for students to develop numerous misconceptions about how and why to use magnitudes. We present a useful exercise in the use of magnitudes to derive a cosmologically interesting quantity (the mass-to-light ratio for spiral galaxies), with potential pitfalls pointed out and explained.

Schulman, Eric; Cox, Caroline V.

1997-10-01

140

Astronomical Visualization for Education  

NASA Astrophysics Data System (ADS)

A plethora of diverse resources for astronomical research awaits scientists at their fingertips. Over the last 10 years many efforts have focussed on enhancing education and engaging the public in science using such astronomical data. Most of the materials created are centered on small data sets culled by scientists and developers. With the emergence of large data sets such as those available through the NVO, the SDSS, the DSS, WMAP, GOODS, and others as well as the promise of observatories such as the LSST, development of education activities utilizing such vast data stores has exciting potential. This kind of education has never been done before---offering Astronomy an opportunity to be a pathfinder for other sciences. In this paper, we remark upon visualization of large data sets and and best practices for integrating them into educational experiences.

Christian, C. A.; Conti, A.

2007-10-01

141

Celebrating 20 Years of Hubble  

NASA Video Gallery

NASA's Hubble Space Telescope began a remarkable journey of discovery on April 24, 1990. After 20 years in space, the observatory has shown humanity more of the universe than ever before. With the ...

142

Hubble View of Comet ISON  

NASA Video Gallery

This time-lapse sequence of images from the Hubble Space Telescope shows comet ISON as it appeared on May 8, 2013. At the time the images were taken, the comet was 403 million miles from the Earth,...

143

HUBBLE SNAPSHOT CAPTURES LIFE CYCLE OF STARS  

NASA Technical Reports Server (NTRS)

In this stunning picture of the giant galactic nebula NGC 3603, the crisp resolution of NASA's Hubble Space Telescope captures various stages of the life cycle of stars in one single view. To the upper right of center is the evolved blue supergiant called Sher 25. The star has a unique circumstellar ring of glowing gas that is a galactic twin to the famous ring around the supernova 1987A. The grayish-bluish color of the ring and the bipolar outflows (blobs to the upper right and lower left of the star) indicates the presence of processed (chemically enriched) material. Near the center of the view is a so-called starburst cluster dominated by young, hot Wolf-Rayet stars and early O-type stars. A torrent of ionizing radiation and fast stellar winds from these massive stars has blown a large cavity around the cluster. The most spectacular evidence for the interaction of ionizing radiation with cold molecular-hydrogen cloud material are the giant gaseous pillars to the right and lower left of the cluster. These pillars are sculptured by the same physical processes as the famous pillars Hubble photographed in the M16 Eagle Nebula. Dark clouds at the upper right are so-called Bok globules, which are probably in an earlier stage of star formation. To the lower left of the cluster are two compact, tadpole-shaped emission nebulae. Similar structures were found by Hubble in Orion, and have been interpreted as gas and dust evaporation from possibly protoplanetary disks (proplyds). The 'proplyds' in NGC 3603 are 5 to 10 times larger in size and correspondingly also more massive. This single view nicely illustrates the entire stellar life cycle of stars, starting with the Bok globules and giant gaseous pillars, followed by circumstellar disks, and progressing to evolved massive stars in the young starburst cluster. The blue supergiant with its ring and bipolar outflow marks the end of the life cycle. The color difference between the supergiant's bipolar outflow and the diffuse interstellar medium in the giant nebula dramatically visualizes the enrichment in heavy elements due to synthesis of heavier elements within stars. This true-color picture was taken on March 5, 1999 with the Wide Field Planetary Camera 2. This picture is being presented at the 194th Meeting of the American Astronomical Society in Chicago. Credit: Wolfgang Brandner (JPL/IPAC), Eva K. Grebel (Univ. Washington), You-Hua Chu (Univ. Illinois Urbana-Champaign), and NASA

2002-01-01

144

Lessons from a High-Impact Observatory: The Hubble Space Telescope's Science Productivity between 1998 and 2008  

Microsoft Academic Search

Almost two decades of continuous operation of the versatile and productive Hubble Space Telescope (HST) provide uniquely well-documented, robust statistics to study the scientific impact of a major astronomical observatory. We compiled a detailed database of refereed articles that use HST data for analysis and show it to be > 95 % complete. This HST Publication Database is publicly available

Dániel Apai; Jill Lagerstrom; Iain Neill Reid; Karen L. Levay; Elizabeth Fraser; Antonella Nota; Edwin Henneken

2010-01-01

145

HubbleSite: Video Archive  

NSDL National Science Digital Library

This index, part of the Hubble Space Telescope website, helps users find archived videos and image sets on every Hubble image released to the public. It is organized by topic: Cosmology, Dark Matter, Galaxies, Nebulae, Solar System, Stars, and Star Clusters. Example topics include black holes, neutron stars, distant galaxies, and supernovae. Users can search by subject or by keywords. All images and/or videos may be downloaded or embedded in classroom presentations.

2005-06-07

146

Astronomical Software Directory Service  

NASA Technical Reports Server (NTRS)

With the support of NASA's Astrophysics Data Program (NRA 92-OSSA-15), we have developed the Astronomical Software Directory Service (ASDS): a distributed, searchable, WWW-based database of software packages and their related documentation. ASDS provides integrated access to 56 astronomical software packages, with more than 16,000 URLs indexed for full-text searching. Users are performing about 400 searches per month. A new aspect of our service is the inclusion of telescope and instrumentation manuals, which prompted us to change the name to the Astronomical Software and Documentation Service. ASDS was originally conceived to serve two purposes: to provide a useful Internet service in an area of expertise of the investigators (astronomical software), and as a research project to investigate various architectures for searching through a set of documents distributed across the Internet. Two of the co-investigators were then installing and maintaining astronomical software as their primary job responsibility. We felt that a service which incorporated our experience in this area would be more useful than a straightforward listing of software packages. The original concept was for a service based on the client/server model, which would function as a directory/referral service rather than as an archive. For performing the searches, we began our investigation with a decision to evaluate the Isite software from the Center for Networked Information Discovery and Retrieval (CNIDR). This software was intended as a replacement for Wide-Area Information Service (WAIS), a client/server technology for performing full-text searches through a set of documents. Isite had some additional features that we considered attractive, and we enjoyed the cooperation of the Isite developers, who were happy to have ASDS as a demonstration project. We ended up staying with the software throughout the project, making modifications to take advantage of new features as they came along, as well as influencing the software development. The Web interface to the search engine is provided by a gateway program written in C++ by a consultant to the project (A. Warnock).

Hanisch, Robert J.; Payne, Harry; Hayes, Jeffrey

1997-01-01

147

HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA (color)  

NASA Technical Reports Server (NTRS)

A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This colorful photo shows a ground-based image of the entire Crab Nebula, the remnant of a supernova explosion witnessed over 900 years ago. The nebula, which is 10 light-years across, is located 7,000 light-years away in the constellation Taurus. The green, yellow and red filaments concentrated toward the edges of the nebula are remnants of the star that were ejected into space by the explosion. At the center of the Crab Nebula lies the Crab Pulsar -- the collapsed core of the exploded star. The Crab Pulsar is a rapidly rotating neutron star -- an object only about six miles across, but containing more mass than our Sun. As it rotates at a rate of 30 times per second the Crab Pulsar's powerful magnetic field sweeps around, accelerating particles, and whipping them out into the nebula at speeds close to that of light. The blue glow in the inner part of the nebula -- light emitted by energetic electrons as they spiral through the Crab's magnetic field -- is powered by the Crab Pulsar. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

2002-01-01

148

Astropix: Everyone's New Portal to the Universe of Astronomical Imagery  

NASA Astrophysics Data System (ADS)

Astropix is a new online repository for astronomical imagery that is now available for everyone to use. Currently in a beta development state, Astropix provides powerful ways to browse, search, and download images, diagrams, artwork, and photographs from many astronomical missions. The site is built around the Astronomical Visualization Metadata (AVM) standard developed by the Virtual Astronomy Multimedia Project (VAMP) that captures all the key descriptive information for a public image, including color representations and astronomical and sky coordinates. Existing image galleries containing AVM-tagged images can easily supply them to Astropix, which downloads them, extracts the metadata into its database, and generates versions of the images at a variety of common sizes. Visitors to Astropix can search the database using simple free-text queries, or use a structured search (similar to "Smart Playlists" found in iTunes, for example). The Astropix archive also features an Xquery-based method for posting http queries and retrieving XML lists of matching imagery, allowing for scripted access to the site. Current assets include imagery from Spitzer, Chandra, ESO, Galex, Herschel, Hubble, Spitzer, and WISE, with more on the way. Website: astropix.ipac.caltech.edu

Hurt, Robert L.; Squires, G. K.; Llamas, J.; Rosenthal, C.; Brinkworth, C. S.

2012-01-01

149

HUBBLE HUNTS DOWN BINARY OBJECTS AT FRINGE OF OUR SOLAR SYSTEM  

NASA Technical Reports Server (NTRS)

NASA's Hubble Space Telescope snapped pictures of a double system of icy bodies in the Kuiper Belt. This composite picture shows the apparent orbit of one member of the pair. In reality, the objects, called 1998 WW31, revolve around a common center of gravity, like a pair of waltzing skaters. This picture shows the motion of one member of the duo [the six faint blobs] relative to the other [the large white blob]. The blue oval represents the orbital path. Astronomers assembled this picture from six separate exposures, taken from July to September 2001, December 2001, and January to February 2002. Astronomers used the Hubble telescope to study the orbit of this binary system. They then used that information to determine other characteristics of the duo, such as their total mass, and their orbital period (the time it takes them to orbit each other). Credit: NASA and C. Veillet (Canada-France-Hawaii Telescope)

2002-01-01

150

ISO's Astronomical Harvest Continues  

NASA Astrophysics Data System (ADS)

Last autumn, nearly 400 astronomers gathered in Paris for a week - long discussion and review of ISO results, as presented in some 300 papers. This article presents a handful of ISO's many results, selected - mainly from the Proceedings (ESA SP-427)of the Paris meeting - both to show the breadth of the scientific fields being impacted by ISO and to complement results that have previously appeared in the 'In Brief' pages of the Bulletin. ISO has delivered a wealth of new results, spanning long-awaited confirmations of models to unexpected surprises and from our own Solar System out to the most distant extragalactic sources.

Kessler, M. F.; Heske, A.; Metcalfe, L.; Prusti, T.; Salama, A.

1999-09-01

151

Seeing Like an Astronomer  

NSDL National Science Digital Library

In this Digital Universe activity, students experiment with ways of looking (with the naked eye, under different circumstances and from different perspectives, and with aids such as binoculars or a digital model) to gain an understanding of how scientists use observation in their work. The nine-page printable PDF activity includes illustrated step-by-step instructions for the following hands-on and computer-assisted activities:Looking with the Naked Eye, Looking with Modified Observation Techniques, and How Astronomers Work.

152

Candidates of z ~= 5.5-7 Galaxies in the Hubble Space Telescope Ultra Deep Field  

Microsoft Academic Search

We report results from our z~=5.5-7 galaxy search in the Hubble Space Telescope Ultra Deep Field (UDF). Using the 400 orbit of Advanced Camera for Surveys data, we found 108 plausible 5.5<=z<=6.5 (or z~=6 for short) candidates to mAB(z850)=30.0 mag. The contamination to the sample, due to either image artifacts or known types of astronomical objects, is likely negligible. The

Haojing Yan; Rogier A. Windhorst

2004-01-01

153

Getting Astronomers Involved in the IYA: Astronomer in the Classroom  

NASA Astrophysics Data System (ADS)

The Astronomer in the Classroom program provides professional astronomers the opportunity to engage with 3rd-12th grade students across the nation in grade appropriate discussions of their recent research, and provides students with rich STEM content in a personalized forum, bringing greater access to scientific knowledge for underserved populations. 21st Century Learning and Interstellar Studios, the producer of the 400 Years of the Telescope documentary along with their educational partners, will provide the resources necessary to facilitate the Astronomer in the Classroom program, allowing students to interact with astronomers throughout the IYA2009. PROGRAM DESCRIPTION One of hundreds of astronomers will be available to interact with students via live webcast daily during Spring/Fall 2009. The astronomer for the day will conduct three 20-minute discussions (Grades 3-5 /6-8/9-12), beginning with a five-minute PowerPoint on their research or area of interest. The discussion will be followed by a question and answer period. The students will participate in real-time from their school computer(s) with the technology provided by 21st Century Learning. They will see and hear the astronomer on their screen, and pose questions from their keyboard. Teachers will choose from three daily sessions; 11:30 a.m., 12:00 p.m., 12:30 p.m. Eastern Time. This schedule overlaps all US time zones, and marginalizes bandwidth usage, preventing technological barriers to web access. The educational partners and astronomers will post materials online, providing easy access to information that will prepare teachers and students for the chosen discussion. The astronomers, invited to participate from the AAS and IAU, will receive a web cam shipment with instructions, a brief training and conductivity test, and prepaid postage for shipment of the web cam to the next astronomer on the list. The anticipated astronomer time required is 3-hours, not including the time to develop the PowerPoint.

Koenig, Kris

2008-05-01

154

Astronomers Sight An Asteroid's Moon  

NSF Publications Database

... information at media contacts. Astronomers Sight an Asteroid's Moon Photo Credit: Courtesy of ... Merline of the Southwest Research Institute sighted a moon orbiting the asteroid (45) Eugenia, in ...

155

The 1% Concordance Hubble Constant  

NASA Astrophysics Data System (ADS)

The determination of the Hubble constant has been a central goal in observational astrophysics for nearly a hundred years. Extraordinary progress has occurred in recent years on two fronts: the cosmic distance ladder measurements at low redshift and cosmic microwave background (CMB) measurements at high redshift. The CMB is used to predict the current expansion rate through a best-fit cosmological model. Complementary progress has been made with baryon acoustic oscillation (BAO) measurements at relatively low redshifts. While BAO data do not independently determine a Hubble constant, they are important for constraints on possible solutions and checks on cosmic consistency. A precise determination of the Hubble constant is of great value, but it is more important to compare the high and low redshift measurements to test our cosmological model. Significant tension would suggest either uncertainties not accounted for in the experimental estimates or the discovery of new physics beyond the standard model of cosmology. In this paper we examine in detail the tension between the CMB, BAO, and cosmic distance ladder data sets. We find that these measurements are consistent within reasonable statistical expectations and we combine them to determine a best-fit Hubble constant of 69.6 ± 0.7 km s–1 Mpc–1. This value is based upon WMAP9+SPT+ACT+6dFGS+BOSS/DR11+H 0/Riess; we explore alternate data combinations in the text. The combined data constrain the Hubble constant to 1%, with no compelling evidence for new physics.

Bennett, C. L.; Larson, D.; Weiland, J. L.; Hinshaw, G.

2014-10-01

156

Edwin Zaccai (d.), Sustainable consumption, ecology and fair trade, Londres, Routledge, 2007 Is large-scale fair trade possible?  

E-print Network

Edwin Zaccai (éd.), Sustainable consumption, ecology and fair trade, Londres, Routledge, 2007 1 Is large-scale fair trade possible? Ronan Le Velly Abstract The article presents the changes in the nature of the market relationship that are induced by the expansion of fair trade. It shows that the increase

Paris-Sud XI, Université de

157

MavHome: An AgentBased Smart Home Diane J. Cook, Michael Youngblood, Edwin O. Heierman, III,  

E-print Network

MavHome: An Agent­Based Smart Home Diane J. Cook, Michael Youngblood, Edwin O. Heierman, III­ habitant action prediction. We demonstrate the effective­ ness of these algorithms on smart home data. 1. Introduction The MavHome smart home project focuses on the cre­ ation of an environment that acts

Cook, Diane J.

158

Really Bad Astronomers  

NASA Astrophysics Data System (ADS)

What happens when even Percival Lowell stops believing in your Mars observations? History can be troubling. This I learned while editing the Biographical Encyclopedia of Astronomers (Springer, 2007). There have been astronomers who do not fit our commonly held, and clung to, conceptual model: a sociological system that sifts out generally like-minded and sensible colleagues. I refer to those individuals who (for at least a time) successfully entered the mainstream profession, but now disturb our worldview that says prosperity as a scientist usually is achieved by a rational being holding certain common values. My List of Shame includes examples from each of the last four centuries. Not "crack pot” cosmologists, these were hard-working observers for whom the end justified the means. And they all got away with it. Each person I discuss was vetted by the professional establishment of the day. Yet you will learn how to be fired from a major observatory, banned from prominent journals. But only after damage to the science is done. Be afraid.

Hockey, Thomas A.

2009-01-01

159

Professional Ethics for Astronomers  

NASA Astrophysics Data System (ADS)

There is a growing recognition that professional ethics is an important topic for all professional scientists, especially physical scientists. Situations at the National Laboratories have dramatically proven this point. Professional ethics is usually only considered important for the health sciences and the legal and medical professions. However, certain aspects of the day to day work of professional astronomers can be impacted by ethical issues. Examples include refereeing scientific papers, serving on grant panels or telescope allocation committees, submitting grant proposals, providing proper references in publications, proposals or talks and even writing recommendation letters for job candidates or serving on search committees. This session will feature several speakers on a variety of topics and provide time for questions and answers from the audience. Confirmed speakers include: Kate Kirby, Director Institute for Theoretical Atomic and Molecular Physics - Professional Ethics in the Physical Sciences: An Overview Rob Kennicutt, Astrophysical Journal Editor - Ethical Issues for Publishing Astronomers Peggy Fischer, Office of the NSF Inspector General - Professional Ethics from the NSF Inspector General's Point of View

Marvel, K. B.

2005-05-01

160

Hubble Takes First Image of a Possible Planet Around Another Star and Finds a Runaway World  

NSDL National Science Digital Library

The Hubble Space Telescope has returned an image of what is possibly the first planet outside our solar system. TMR-1C, about 450 light years away in the constellation Taurus, appears to have been "flung away from the vicinity of a newly forming pair of binary stars," as evidenced by a luminescent filament leading from the "planet" back to the stars. "Susan Terebey of the Extrasolar Research Corporation in Pasadena, California, and her team using Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS)," made the discovery. Hubble experts estimate the chance of the object being a background star instead of a planet at one to two percent. This Space Science Telescope Institute site contains the press release, captioned images in several formats and resolutions, and a space science update, a one hour RealPlayer press conference with Dr. Terebey and other astronomers.

1998-01-01

161

ASTRONOMICAL DATA ANALYSIS 1 Astronomical Data Analysis and Sparsity: from  

E-print Network

ten years. A quick search with ADS (NASA Astrophysics Data System, adswww.harvard.edu) showsASTRONOMICAL DATA ANALYSIS 1 Astronomical Data Analysis and Sparsity: from Wavelets to Compressed now in astronomy for many purposes, ranging from data filtering and deconvolution, to star and galaxy

Starck, Jean-Luc

162

HUBBLE'S ULTRAVIOLET VIEWS OF NEARBY GALAXIES YIELD CLUES TO EARLY UNIVERSE  

NASA Technical Reports Server (NTRS)

Astronomers are using these three NASA Hubble Space Telescope images to help tackle the question of why distant galaxies have such odd shapes, appearing markedly different from the typical elliptical and spiral galaxies seen in the nearby universe. Do faraway galaxies look weird because they are truly weird? Or, are they actually normal galaxies that look like oddballs, because astronomers are getting an incomplete picture of them, seeing only the brightest pieces? Light from these galaxies travels great distances (billions of light-years) to reach Earth. During its journey, the light is 'stretched' due to the expansion of space. As a result, the light is no longer visible, but has been shifted to the infrared where present instruments are less sensitive. About the only light astronomers can see comes from regions where hot, young stars reside. These stars emit mostly ultraviolet light. But this light is stretched, appearing as visible light by the time it reaches Earth. Studying these distant galaxies is like trying to put together a puzzle with some of the pieces missing. What, then, do distant galaxies really look like? Astronomers studied 37 nearby galaxies to find out. By viewing these galaxies in ultraviolet light, astronomers can compare their shapes with those of their distant relatives. These three Hubble telescope pictures, taken with the Wide Field and Planetary Camera 2, represent a sampling from that survey. Astronomers observed the galaxies in ultraviolet and visible light to study all the stars that make up these 'cities of stars.' The results of their survey support the idea that astronomers are detecting the 'tip of the iceberg' of very distant galaxies. Based on these Hubble ultraviolet images, not all the faraway galaxies necessarily possess intrinsically odd shapes. The results are being presented today at the 197th meeting of the American Astronomical Society in San Diego, CA. The central region of the 'star-burst' spiral galaxy at far left, NGC 3310, shows young and old stars evenly distributed. If this were the case with most galaxies, astronomers would be able to recognize faraway galaxies fairly easily. In most galaxies, however, the stars are segregated by age, making classifying the distant ones more difficult. NGC 3310 is 46 million light-years from Earth in the constellation Ursa Major. The image was taken Sept. 12-13, 2000. The middle image is an example of a tiny, youthful spiral galaxy. ESO 418-008 is representative of the myriad of dwarf galaxies astronomers have seen in deep surveys. These galaxies are much smaller than typical ones like our Milky Way. In this galaxy, the population of stars is more strongly segregated by age. The older stars [red] reside in the center; the younger [blue], in the developing spiral arms. These small, young galaxies may be the building blocks of galaxy formation. ESO 418-008 is 56 million light-years from Earth in the southern constellation Fornax. The image was taken Oct. 10, 2000. The picture at right shows a cosmic collision between two galaxies, UGC 06471 and UGC 06472. These collisions occurred frequently in the early universe, producing galaxies of unusual shapes. The Hubble telescope has spied many such galaxies in the deep field surveys. The ultraviolet images of this galaxy merger suggest the presence of large amounts of dust, which were produced by massive stars that formed before or during this dramatic collision. This dust reddens the starlight in many places, just like a dusty atmosphere reddens the sunset. Studying the effects of this nearby collision could help astronomers explain the peculiar shapes seen in some of the distant galaxies. UGC 06471 and UGC 06472 are 145 million light-years from Earth in the constellation Ursa Major. The image was taken July 11, 2000. Photo credits: NASA, Rogier Windhorst (Arizona State University, Tempe, AZ), and the Hubble mid-UV team

2002-01-01

163

HUBBLE REVEALS THE HEART OF THE WHIRLPOOL GALAXY  

NASA Technical Reports Server (NTRS)

New images from NASA's Hubble Space Telescope are helping researchers view in unprecedented detail the spiral arms and dust clouds of a nearby galaxy, which are the birth sites of massive and luminous stars. The Whirlpool galaxy, M51, has been one of the most photogenic galaxies in amateur and professional astronomy. Easily photographed and viewed by smaller telescopes, this celestial beauty is studied extensively in a range of wavelengths by large ground- and space-based observatories. This Hubble composite image shows visible starlight as well as light from the emission of glowing hydrogen, which is associated with the most luminous young stars in the spiral arms. M51, also known as NGC 5194, is having a close encounter with a nearby companion galaxy, NGC 5195, just off the upper edge of this image. The companion's gravitational pull is triggering star formation in the main galaxy, as seen in brilliant detail by numerous, luminous clusters of young and energetic stars. The bright clusters are highlighted in red by their associated emission from glowing hydrogen gas. This Wide Field Planetary Camera 2 image enables a research group, led by Nick Scoville (Caltech), to clearly define the structure of both the cold dust clouds and the hot hydrogen and link individual clusters to their parent dust clouds. Team members include M. Polletta (U. Geneva); S. Ewald and S. Stolovy (Caltech); R. Thompson and M. Rieke (U. of Arizona). Intricate structure is also seen for the first time in the dust clouds. Along the spiral arms, dust 'spurs' are seen branching out almost perpendicular to the main spiral arms. The regularity and large number of these features suggests to astronomers that previous models of 'two-arm' spiral galaxies may need to be revisited. The new images also reveal a dust disk in the nucleus, which may provide fuel for a nuclear black hole. The team is also studying this galaxy at near-infrared wavelengths with the NICMOS instrument onboard Hubble. At these wavelengths, the dusty clouds are more transparent and the true distribution of stars is more easily seen. In addition, regions of star formation that are obscured in the optical images are newly revealed in the near-infrared images. This image was composed by the Hubble Heritage Team from Hubble archival data of M51 and is superimposed onto ground-based data taken by Travis Rector (NOAO) at the 0.9-meter telescope at the National Science Foundation's Kitt Peak National Observatory (NOAO/AURA) in Tucson, AZ. Image Credit: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: N. Scoville (Caltech) and T. Rector (NOAO)

2002-01-01

164

The Astronomical Image Processing System  

E-print Network

The Astronomical Image Processing System Eric W. Greisen September 12, 1988 National Radio!egreisen Introduction The Astronomical Image Processing System, AIPS for short, is the National Radio and what they will find unnatural. And I cannot conceive some of the algorithms which will be invented

Groppi, Christopher

165

Hubble peers inside a celestial geode  

NASA Astrophysics Data System (ADS)

celestial geode hi-res Size hi-res: 148 Kb Credits: ESA/NASA, Yäel Nazé (University of Liège, Belgium) and You-Hua Chu (University of Illinois, Urbana, USA) Hubble peers inside a celestial geode In this unusual image, the NASA/ESA Hubble Space Telescope captures a rare view of the celestial equivalent of a geode - a gas cavity carved by the stellar wind and intense ultraviolet radiation from a young hot star. Real geodes are handball-sized, hollow rocks that start out as bubbles in volcanic or sedimentary rock. Only when these inconspicuous round rocks are split in half by a geologist, do we get a chance to appreciate the inside of the rock cavity that is lined with crystals. In the case of Hubble's 35 light-year diameter ‘celestial geode’ the transparency of its bubble-like cavity of interstellar gas and dust reveals the treasures of its interior. Low resolution version (JPG format) 148 Kb High resolution version (TIFF format) 1929 Kb Acknowledgment: This image was created with the help of the ESA/ESO/NASA Photoshop FITS Liberator. Real geodes are handball-sized, hollow rocks that start out as bubbles in volcanic or sedimentary rock. Only when these inconspicuous round rocks are split in half by a geologist, do we get a chance to appreciate the inside of the rock cavity that is lined with crystals. In the case of Hubble's 35 light-year diameter ‘celestial geode’ the transparency of its bubble-like cavity of interstellar gas and dust reveals the treasures of its interior. The object, called N44F, is being inflated by a torrent of fast-moving particles (what astronomers call a 'stellar wind') from an exceptionally hot star (the bright star just below the centre of the bubble) once buried inside a cold dense cloud. Compared with our Sun (which is losing mass through the so-called 'solar wind'), the central star in N44F is ejecting more than a 100 million times more mass per second and the hurricane of particles moves much faster at 7 million km per hour (as opposed to less than 1.5 million km per hour for our Sun). Because the bright central star does not exist in empty space but is surrounded by an envelope of gas, the stellar wind collides with this gas, pushing it out, like a snow plough. This forms a bubble, whose striking structure is clearly visible in the crisp Hubble image. The nebula N44F is one of a handful of known interstellar bubbles. Bubbles like these have been seen around evolved massive stars (called 'Wolf-Rayet stars'), and also around clusters of stars (where they are called 'super-bubbles'). But they have rarely been viewed around isolated stars, as is the case here. On closer inspection N44F harbours additional surprises. The interior wall of its gaseous cavity is lined with several four to eight light-year high finger-like columns of cool dust and gas. (The structure of these 'columns' is similar to the Eagle Nebula’s iconic 'Pillars of Creation' photographed by Hubble a decade ago, and is seen in a few other nebulae as well). The fingers are created by a blistering ultraviolet radiation from the central star. Like wind socks caught in a gale, they point in the direction of the energy flow. These pillars look small in this image only because they are much farther away from us then the Eagle Nebula’s pillars. N44F is located about 160 000 light-years in the neighbouring dwarf galaxy the Large Magellanic Cloud, in the direction of the southern constellation Dorado. N44F is part of the larger N44 complex, which contains a large super-bubble, blown out by the combined action of stellar winds and multiple supernova explosions. N44 itself is roughly 1000 light-years across. Several compact star-forming regions, including N44F, are found along the rim of the central super-bubble. This image was taken with Hubble's Wide Field Planetary Camera 2, using filters that isolate light emitted by sulphur (shown in blue, a 1200-second exposure) and hydrogen gas (shown in red, a 1000-second exposure).

2004-08-01

166

Hubble Sees Young Galaxies Bursting with Stars  

NASA Video Gallery

This video shows a zoom into the Hubble GOODS South Deep (GSD) field. Candidate extreme emission line galaxies are identified. This object was observed as part of the Hubble CANDELS Legacy Project....

167

Art concept of the Hubble Space Telescope  

NASA Technical Reports Server (NTRS)

Art concept of the Hubble Space Telescope in orbit above the earth with a Space Shuttle approaching and an astronaut performing an extravehicular activity (EVA) (30462); Art concept of the Hubble Space Telescope with the interior design exposed (30463).

1986-01-01

168

Immanuel Halton, the astronomer  

NASA Astrophysics Data System (ADS)

Immanuel Halton was born in Cumberland, studied at Grays Inn, London during the later stages of the English Civil War and, during the Commonwealth, entered the service of Henry Howard, later 6th Duke of Norfolk. He pursued his mathematical and astronomical interests while auditor to the Duke of Norfolk. He met with John Flamsteed, encouraged the latter's interest in mathematics and astronomy and became his first patron, as well as contributing observations to Flamsteed's published works. Immanuel ended his days at Wingfield Manor, Derbyshire. A short biographical piece on Immanuel Halton appeared in the Journal in the early 1950s, consisting mostly of quotations from Flamsteed's 'Self Inspections' and Baily's 'Life of Flamsteed'. 1996 is the 350th anniversary of Flamsteed's birth, and it is hoped that this fuller account will flesh out the bones of his first patron.

Barber, P. M.

1996-02-01

169

The Hubble diagram for supernovae  

Microsoft Academic Search

The distribution of 47 type I and 13 type II supernovae (SN) in the Hubble diagram is presented and evaluated. Values of the parameter Mpg(100) and the dispersion are determined by least-squares fits to various data subsets, and the results are compared with those of previous studies. Sources of scatter are considered, specifically inaccurate corrections for interstellar extinction in the

D. Branch; C. Bettis

1978-01-01

170

Hubble Discovers 100 New Planets  

NSDL National Science Digital Library

BBC News Online article published July 2, 2004 on the discovery by The Hubble Space Telescope of as many as 100 new planets orbiting stars in our galaxy, almosting doubling the number of planets known to be circling other stars to about 230.

Whitehouse, David

2005-05-17

171

Hubble Space Telescope Stability Assessment  

Microsoft Academic Search

The second Hubble Space Telescope shuttle servicing mission is scheduled for February, 1997. This paper will address two important topics: (1) First, the control system hardware that is presently scheduled for replacement will be discussed. The impact that the new hardware will have on the pointing stability will be examined. (2) Second, a two year study examining the origin of

A. Bradley; R. Chapman; J. Spuria

1995-01-01

172

Hubble Space Telescope Science Metrics  

Microsoft Academic Search

Since its launch in 1990 April, the Hubble Space Telescope (HST) has produced an increasing flow of scientific results. The large number of refereed publications based on HST data permits a detailed evaluation of the effectiveness of this observatory and its scientific programs. This paper presents the results of selected science metrics related to paper counts, citation counts, citation history,

Georges Meylan; Juan P. Madrid; Duccio Macchetto

2004-01-01

173

Hubble - 15 Years of Discovery  

NSDL National Science Digital Library

This web site is provided in celebration of the 15th anniversary of the Hubble Space Telescope. The site include a full-length DVD film (that can be downloaded in segments), a CD of the film soundtrack, a full-color book and additional educational material.

Agency, European S.

2008-08-02

174

Cosmic Origins Spectrograph Hubble Space Telescope  

E-print Network

Cosmic Origins Spectrograph Hubble Space Telescope COS November/December Monthly Status Review December 5, 1999 KSC #12;COS Monthly Status Review Cosmic Origins Spectrograph Hubble Space Telescope John Review Cosmic Origins Spectrograph Hubble Space Telescope John Andrews December 5, 1999 Progress Summary

Colorado at Boulder, University of

175

Cosmic Origins Spectrograph Hubble Space Telescope  

E-print Network

Cosmic Origins Spectrograph Hubble Space Telescope COS January Monthly Status Review February 1, 2000 GSFC #12;COS Monthly Status Review Cosmic Origins Spectrograph Hubble Space Telescope John Andrews Origins Spectrograph Hubble Space Telescope John Andrews February 1, 2000 Progress Summary Since Last

Colorado at Boulder, University of

176

On dying and dying well: Extracts from the Edwin Stevens lecture  

PubMed Central

The idea of a happy death is one that startles and disgusts modern man. However, although that phrase is not often used today, that is what the Archbishop of Canterbury, Dr Donald Coggan, is to some extent considering in his Edwin Stevens lecture given to the Royal Society of Medicine. We are publishing extracts from that lecture by kind permission of the President of the Royal Society of Medicine. We have chosen those passages in the lecture which discuss the limits of the doctor's responsibility to keep a patient alive, the erroneous idea that Christians believe in the artificial prolongation of life in all circumstances, and the most delicate question of the choice of patients who shall receive the costly benefits of modern medical technology. PMID:874979

Coggan, Donald

1977-01-01

177

VENUS CLOUD TOPS VIEWED BY HUBBLE  

NASA Technical Reports Server (NTRS)

This is a NASA Hubble Space Telescope ultraviolet-light image of the planet Venus, taken on January 24 1995, when Venus was at a distance of 70.6 million miles (113.6 million kilometers) from Earth. Venus is covered with clouds made of sulfuric acid, rather than the water-vapor clouds found on Earth. These clouds permanently shroud Venus' volcanic surface, which has been radar mapped by spacecraft and from Earth-based telescope. At ultraviolet wavelengths cloud patterns become distinctive. In particular, a horizontal 'Y'-shaped cloud feature is visible near the equator. Similar features were seen from Mariner 10, Pioneer Venus, and Galileo spacecrafts. This global feature might indicate atmospheric waves, analogous to high and low pressure cells on Earth. Bright clouds toward Venus' poles appear to follow latitude lines. The polar regions are bright, possibly showing a haze of small particles overlying the main clouds. The dark regions show the location of enhanced sulfur dioxide near the cloud tops. From previous missions, astronomers know that such features travel east to west along with the Venus' prevailing winds, to make a complete circuit around the planet in four days. Because Venus is closer to the Sun than Earth, the planet appears to go through phases, like the Moon. When Venus swings close to Earth the planet's disk appears to grow in size, but changes from a full disk to a crescent. The image was taken with the Wide Field Planetary Camera-2, in PC mode. False color has been used enhance cloud features. Credit: L. Esposito (University of Colorado, Boulder), and NASA

2002-01-01

178

Hubble Reveals Sombrero Galaxy (M104)  

NASA Technical Reports Server (NTRS)

In the 19th century, astronomer V. M. Slipher first discovered a hat-like object that appeared to be rushing away from us at 700 miles per second. This enormous velocity offered some of the earliest clues that it was really another galaxy, and that the universe was expanding in all directions. The trained razor sharp eye of the Hubble Space Telescope (HST) easily resolves this Sombrero galaxy, Messier 104 (M104). The galaxy is 50,000 light-years across and is located 28 million light-years from Earth at the southern edge of the rich Virgo cluster of galaxies. Equivalent to 800 billion suns, Sombrero is one of the most massive objects in that group. The hallmark of Sombrero is a brilliant white, bulbous core encircled by the thick dust lanes comprising the spiral structure of the galaxy. As seen from Earth, the galaxy is tilted nearly edge-on. We view it from just six degrees north of its equatorial plane. At a relatively bright magnitude of +8, M104 is just beyond the limit of naked-eye visibility and is easily seen through small telescopes. This rich system of globular clusters are estimated to be nearly 2,000 in number which is 10 times as many as in our Milky Way galaxy. The ages of the clusters are similar to the clusters in the Milky Way, ranging from 10-13 billion years old. Embedded in the bright core of M104 is a smaller disk, which is tilted relative to the large disk. X-ray emission suggests that there is material falling into the compact core, where a 1-billion-solar-mass black hole resides. The Marshall Space Flight Center (MSFC) had responsibility for design, development, and construction of the HST.

2006-01-01

179

The CAPRI Project: Coordinates for Astronomical Press Release Images  

NASA Astrophysics Data System (ADS)

The beauty and splendor of astronomical press release images has made an enormously positive impact with the media and public alike. As a leading provider of astronomical imagery and a major contributor of Hubble Space Telescope press release images, the outreach division of Space Telescope Science Institute (STScI) recognizes the importance of making press release images compliant with virtual observatory standards for inclusion in databases and repositories. Our goal is to make outreach images accessible by virtual observatory applications by calculating World Coordinate System (WCS) data for these images. We provide updated and improved software that allows observatories to easily and accurately transform coordinates on their astronomical press release images, using reference FITS files. The resultant metadata conforms to the Simple Image Access (SIA) protocol established by the International Virtual Observatory Alliance and has been used by popular end users such as Google Sky and World Wide Telescope. Several hundred images from the STScI Office of Public Outreach NewsCenter database have been processed, and their coordinates and other relevant metadata are accessible through an SIA-compliant web service.

Frattare, Lisa M.; Ferguson, B. A.; Summers, F.; Levay, Z. G.

2009-01-01

180

The ESA Hubble 15th Anniversary Campaign  

NASA Astrophysics Data System (ADS)

The 15th anniversary of the launch of the NASA/ESA Hubble Space Telescope occurred on 24th April 2005. As Hubble is one of the most successful scientific projects in the world, ESA decided to celebrate this anniversary, among other things, with the production of a Hubble 15th Anniversary movie and a book, both called "Hubble, 15 years of discovery". The movie covers all aspects of the Hubble Space Telescope project - a journey through the history, the problems and the scientific successes of Hubble. With more than 700,000 multi-lingual DVDs distributed to the public, media, educators, decision-makers and scientists, the Hubble 15th anniversary campaign has been one of the largest such projects in Europe.

Christensen, L. L.; Kornmesser, M.

2005-12-01

181

Coma Cluster Activity Using Hubble Space Telescope Data  

NSDL National Science Digital Library

This product uses a collection of Hubble Space Telescope (HST) images of galaxies in the Coma Cluster, and engages students in an inquiry-based learning activity studying the evolution of galaxies in dense clustered environments. Students learn the basics of galaxy classification by making use of the HST images to discover a "morphology-density effect," and will then make hypotheses about the cause of this effect. Along with this product are a series of StarDate Radio programs on the Coma Cluster and its related galaxies, and a brief YouTube video about research that is being conducted by astronomers and students at the University of Texas using HST data of the Coma Cluster.

Jogee, Shardha; Hemenway, Mary K.

2008-01-01

182

HUBBLE CAPTURES THE HEART OF STAR BIRTH  

NASA Technical Reports Server (NTRS)

NASA Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) has captured a flurry of star birth near the heart of the barred spiral galaxy NGC 1808. On the left are two images, one superimposed over the other. The black-and-white picture is a ground-based view of the entire galaxy. The color inset image, taken with the Hubble telescope's Wide Field and Planetary Camera 2 (WFPC2), provides a close-up view of the galaxy's center, the hotbed of vigorous star formation. The ground-based image shows that the galaxy has an unusual, warped shape. Most spiral galaxies are flat disks, but this one has curls of dust and gas at its outer spiral arms (upper right-hand corner and lower left-hand corner). This peculiar shape is evidence that NGC 1808 may have had a close interaction with another nearby galaxy, NGC 1792, which is not in the picture Such an interaction could have hurled gas towards the nucleus of NGC 1808, triggering the exceptionally high rate of star birth seen in the WFPC2 inset image. The WFPC2 inset picture is a composite of images using colored filters that isolate red and infrared light as well as light from glowing hydrogen. The red and infrared light (seen as yellow) highlight older stars, while hydrogen (seen as blue) reveals areas of star birth. Colors were assigned to this false-color image to emphasize the vigorous star formation taking place around the galaxy's center. NGC 1808 is called a barred spiral galaxy because of the straight lines of star formation on both sides of the bright nucleus. This star formation may have been triggered by the rotation of the bar, or by matter which is streaming along the bar towards the central region (and feeding the star burst). Filaments of dust are being ejected from the core into a faint halo of stars surrounding the galaxy's disk (towards the upper left corner) by massive stars that have exploded as supernovae in the star burst region. The portion of the galaxy seen in this 'wide-field' image is about 35,000 light-years across. The right-hand image, taken by WFPC2, provides a closer look at the flurry of star birth at the galaxy's core. The star clusters (blue) can be seen (and many more are likely obscured) amid thick lanes of gas and dust. This image shows that stars are often born in compact clusters within star bursts, and that dense gas and dust heavily obscures the star burst region. The brightest knot of star birth seen here is probably a giant cluster of stars, about 100 light-years in diameter, at the very center of the galaxy. The other star clusters are about 10 to 50 light-years in diameter. The entire star burst region shown here is about 3,000 light-years across. This galaxy is about 40 million light-years away in the southern constellation Columba. The observation was taken Aug. 14, 1997, and was the last of 13 Hubble Space Telescope amateur programs. Credits: Jim Flood, an amateur astronomer affiliated with Sperry Observatory at Union College in New Jersey, and Max Mutchler, a member of the Space Telescope Science Institute staff who volunteered to work with Jim.

2002-01-01

183

XEphem: Interactive Astronomical Ephemeris  

NASA Astrophysics Data System (ADS)

XEphem is a scientific-grade interactive astronomical ephemeris package for UNIX-like systems. Written in C, X11 and Motif, it is easily ported to systems. Among other things, XEphem: computes heliocentric, geocentric and topocentric information for all objects; has built-in support for all planets; the moons of Mars, Jupiter, Saturn, Uranus and Earth; central meridian longitude of Mars and Jupiter; Saturn's rings; and Jupiter's Great Red Spot; allows user-defined objects including stars, deepsky objects, asteroids, comets and Earth satellites; provides special efficient handling of large catalogs including Tycho, Hipparcos, GSC; displays data in configurable tabular formats in conjunction with several interactive graphical views; displays a night-at-a-glance 24 hour graphic showing when any selected objects are up; displays 3-D stereo Solar System views that are particularly well suited for visualizing comet trajectories; quickly finds all close pairs of objects in the sky; and sorts and prints all catalogs with very flexible criteria for creating custom observing lists. Its capabilities are listed more fully in the user manual introduction.

Downey, Elwood Charles

2011-12-01

184

Annotations of a Public Astronomer  

NASA Astrophysics Data System (ADS)

Angelo Adamo is an Italian astronomer and artist interested in inspiring people with scientifically-based tales. He has recently published two illustrated books exploring the relationships between mankind and cosmos through physics, art, literature, music, cartoons, and movies.

Adamo, A.

2011-06-01

185

Early results from the Infrared Astronomical Satellite  

Microsoft Academic Search

For 10 months the Infrared Astronomical Satellite (IRAS) provided astronomers with what might be termed their first view of the infrared sky on a clear, dark night. Without IRAS, atmospheric absorption and the thermal emission from both the atmosphere and Earthbound telescopes make the task of the infrared astronomer comparable to what an optical astronomer would face if required to

G. Neugebauer; C. A. Beichman; B. T. Soifer; H. H. Aumann; T. J. Chester; T. N. Gautier; F. C. Gillett; M. G. Hauser; J. R. Houck; C. J. Lonsdale; F. J. Low; E. T. Young

1984-01-01

186

Quasars and the Hubble Relation  

E-print Network

If active galaxies are defined as extragalactic objects with appreciably non thermal spectra then a continuity exists in redshift from the highest redshift quasars to low redshift Seyferts, AGNs and allied galaxies. Evidence is discussed for this sequence to be an evolutionary track with objects evolving from high to low intrinsic redshift with time. At the end of this evolution the objects are nearly the same age as our own galaxy and they come to rest on the traditional Hubble relation.

H. Arp

2007-11-16

187

Astronomical Parallax 2D  

NSDL National Science Digital Library

The Astronomical Parallax 2D Model illustrates the phenomenon of parallax in astronomy. Parallax is the apparent displacement of an object relative to the background that is caused by the motion of the observer (rather than the motion of the object itself, or of the background). This simulation illustrates the parallax of an object in space that results from the Earth's rotational or orbital motions. The simulation has two different modes. The default is an Earth Rotation Mode. In this mode the simulation illustrates the parallax caused by Earth's rotation on its axis. The top window shows an observer (indicated by a green dot) on the equator of Earth (blue disk). The green line shows that observer's line of sight to an object in space (indicated by a red dot). This line of sight extends to show where the object would appear against a more distant background. When the simulation is played the observer moves around the Earth as Earth rotates. Parallax causes the apparent position of the object to move back and forth between two extreme locations (indicated by open red circles). The bottom window shows the apparent motion of the object against the stars, as seen by the observer. [Note: to keep the simulation simple it is assumed that Earth's equator is aligned with the ecliptic plane (the plane of Earth's orbit). In actual fact they are tilted by 23.5 degrees, but this cannot be represented in a simple 2D simulation.] The other mode for the simulation is Earth Orbit Mode. In this mode the simulation illustrates the parallax caused by Earth's orbit around the Sun. Now the observer moves along Earth's orbital path (shown as a blue circle with the orange Sun in the center). The bottom window now shows the apparent motion of the Sun as well as that of the object being observed.

Timberlake, Todd

2011-05-18

188

Hubble Imaging of Jupiter after the 2009 Impact  

NASA Astrophysics Data System (ADS)

On 19 July 2009, amateur astronomer Anthony Wesley discovered an anomalous dark feature near Jupiter's south pole (planetographic latitude -58° system III west longitude 305°). Additional observations confirmed the new feature was an impact site created by an unknown object (the only other observed collision with Jupiter occurred 15 years earlier, when the shattered remains of Comet Shoemaker-Levy 9 created huge atmospheric disturbances). A world-wide observing campaign was initiated in response to this 2009 collision. We were awarded Directors Discretionary Time to use the newly-installed Wide-Field Camera 3 (WFC3) on Hubble Space Telescope. Observations were successfully obtained with WFC3 on July 23, August 3, and August 8, and with the Advanced Camera for Surveys' Solar Blind Channel in the UV on September 8. In this talk, we will present a summary of the HST images. The evolution of the impact debris field at UV, visible, near-IR wavelengths will be discussed, along with a comparison to Hubble observations of the Shoemaker-Levy 9 impact in 1994.

Hammel, Heidi B.; Clarke, J. T.; de Pater, I.; Fletcher, L. N.; Hueso, R.; Noll, K. S.; Orton, G. S.; Perez-Hoyos, S.; Sanchez-Lavega, A.; Simon-Miller, A. A.; Wong, M. H.; Yanamandra-Fisher, P. A.

2010-01-01

189

HUBBLE SURVEYS DYING STARS IN NEARBY GALAXY  

NASA Technical Reports Server (NTRS)

From ground-based telescopes, the glowing gaseous debris surrounding dying, sun-like stars in a nearby galaxy, called the Large Magellanic Cloud, appear as small, shapeless dots of light. But through the 'eyes' of NASA's Hubble Space Telescope, these bright dots take on a variety of shapes, from round- to pinwheel-shaped clouds of gas. Using Hubble's Space Telescope Imaging Spectrograph, scientists probed the glowing gas surrounding 27 dying stars, called planetary nebulae, in the Large Magellanic Cloud. The observations represent the most detailed study of planetary nebulae outside the Milky Way. The six objects in the picture illustrate the assortment of planetary nebulae identified in the galaxy. SMP 16, 30, and 93 are examples of a bipolar nebula, twin lobes of gas projecting away from a dying star. SMP 10 has a pinwheel shape and is known as a 'point-symmetric' nebula. SMP 4 has an elliptical appearance, and SMP 27, consisting of four lobes of gas, is called a 'quadrupolar' nebula. The lines point to the objects' locations in the Large Magellanic Cloud. A ground-based observatory snapped the picture of this galaxy. In the pictures of the planetary nebulae, color corresponds to temperature. Blue represents hotter regions of the nebulae and red, cooler. Scientists are probing these illuminated stellar relics in our neighboring galaxy because they are at relatively the same distance - about 168,000 light-years -- from Earth. Knowing the distance to these objects allows scientists to compare their shapes and sizes, and precisely determine the brightness of their central stars. For this reason, even though these glowing remains of dying stars are about 50 times farther away than the stunning planetary nebulae photographed in the Milky Way, they are of invaluable importance. By sampling this population, scientists noticed that the bipolar nebulae are richer in some heavier elements, such as neon, than those with a more spherical shape. At the dawn of the universe, only the lighter elements, such as hydrogen, filled the heavens. The heavier elements were produced later as stars died. Neon, in particular, is produced only when massive stars die in supernova explosions. Thus, a higher abundance of neon in 'bipolar' planetary nebulae indicates that the stars that sculpted these objects were born more recently (i.e., in an environment that had suffered more supernova explosions) than those that created the more symmetrically shaped clouds of gas. On the other hand, the stars that form planetary nebulae are great producers of carbon, the most important element for the origin of life, as we know it. The question of how life-forming atoms were made is at the heart of understanding how and why life evolved in our own solar system very shortly after the Sun itself had formed from clouds of carbon-enriched gas and dust 4.6 billion years ago. Scientists do not know for sure how the Milky Way behaved before the birth of the Sun. But they can look at regions in other galaxies where conditions may be very similar to the pre-solar days of the Milky Way. The Large Magellanic Cloud is an ideal laboratory for such an experiment, since its chemistry mimics a pre-solar environment. Astronomers are using the Hubble images of these planetary nebulae, together with spectroscopic information from ground-based observatories, to understand the important carbon-forming mechanisms in the Large Magellanic Cloud. The progenitor stars are expected to form some carbon and lock it deep in their interiors near the end of their lives. In the last few thousand years of their active lives, just before ejecting planetary nebulae, stars are able to dredge up the carbon locked deep in their cores. They undergo a phase as 'carbon stars,' then fling the carbon-rich gas into space as they form planetary nebulae, material for new generations of stars and planets. The Hubble images were taken between June and September 1999. Credits for the Hubble images: NASA; L. Stanghellini, R. Shaw, C. Blades, and M. Mutchler, Space Telescope Science Institute, Baltimore, Md.; an

2002-01-01

190

Two ESA astronauts named to early Hubble Space Telescope servicing mission  

NASA Astrophysics Data System (ADS)

Nicollier and three NASA astronauts, who had already been training for a Hubble servicing mission planned for June 2000, have been reassigned to this earlier mission (STS-103). Jean-Francois Clervoy and two other NASA astronauts will complete the STS-103 crew. The repairs and maintenance of the telescope will require many hours spent working outside the Shuttle and will make extensive use of the Shuttle's robotic arm Nicollier, of Swiss nationality and making his fourth flight, will be part of the team that will perform the "spacewalks". An astronomer by education, he took part in the first Hubble servicing mission (STS-61) in 1993, controlling the Shuttle's robotic arm while astronauts on the other end of the arm performed the delicate repairs to the telescope. He also served on STS-46 in 1992 using the robotic arm to deploy ESA's Eureca retrievable spacecraft from the Shuttle, and on STS-75 with the Italian Tethered Satellite System in 1996. Nicollier is currently the chief of the robotics branch in NASA's astronaut office and ESA's lead astronaut in Houston. Jean-Francois Clervoy, of French nationality and making his third flight, will have the lead role in the operation of the robotic arm for this mission. He previously served on STS-66 in 1994 using the robotic arm to deploy and later retrieve the German CRISTA-SPAS atmospheric research satellite, and on STS-84 in 1997, a Shuttle mission to the Russian Mir space station. The other STS-103 crewmembers are: Commander Curtis Brown, pilot Scott Kelly, and mission specialists Steven Smith, Michael Foale and John Grunsfeld. During the flight, the astronauts will replace Hubble's failing pointing system, which allows the telescope to aim at stars, planets and other targets, and install other equipment that will be ready for launch at that time. A second mission to complete the previously-scheduled Hubble refurbishment work is foreseen at a later date. The crew for that mission has not yet been assigned. The Hubble Space Telescope, launched in 1990, is one of the most powerful optical telescopes available to astronomers today, producing images and spectral observations at the forefront of astronomy. ESA contributed a 15 share to the development of Hubble and European astronomers receive in return a guaranteed 15 share of observing time (and 20 on average in practice).

1999-03-01

191

The Meaning of Color in Hubble Images  

NSDL National Science Digital Library

This resource describes how Hubble produces visible images. Taking color pictures with the Hubble Space Telescope is much more complex than taking color pictures with a traditional camera. For one thing, Hubble doesn't use color film in fact, it doesn't use film at all. Rather, its cameras record light from the universe with special electronic detectors. These detectors produce images of the cosmos not in color, but in shades of black and white.

2007-12-12

192

Astronomer and Educator: Friend or Foe?  

NASA Astrophysics Data System (ADS)

Warning: This presentation might offend some astronomers and science or planetarium educators. It is not intended to offend, but to provoke discussion, and it is based on real-life experiences of astronomers and planetarium educators working together for the first time. It will presented as a skit. Scene 1: An astronomer and a planetarium educator meet. The astronomer gives advice which the educator finds impractical and useless. The educator tells the astronomer what he teaches, and the astronomer finds it well-presented, irrelevent and misdirected. Scene 2: An astronomer and planetarium educator meet. The astronomer asks the educator what he could do to most help the planetarium. A surprising discussion ensues. The educator and astronomer agree on 3 basic ingredients which are usually required to create the best science programs.

Duncan, D. K.; Singel, A.

1995-05-01

193

ISO Results Presented at International Astronomical Union  

NASA Astrophysics Data System (ADS)

Some of the work being presented is collected in the attached ESA Information Note N 25-97, ISO illuminates our cosmic ancestry. A set of six colour images illustrating various aspects have also been released and are available at http://www.estec.esa.nl/spdwww/iso1808.htm or in hard copy from ESA Public Relations Paris (fax:+33.1.5369.7690). These pictures cover: 1. Distant but powerful infrared galaxies 2. A scan across the milky way 3. Helix nebula: the shroud of a dead star 4. Supernova remnant Cassiopeia A 5. Trifid nebula: a dusty birthplace of stars 6. Precursors of stars and planets The International Astronomical Union provides a forum where astronomers from all over the world can develop astronomy in all its aspects through international co-operation. General Assemblies are held every three years. It is expected that over 1600 astronomers will attend this year's meeting, which is being held in Kyoto, Japan from 18-30 August. Further information on the meeting can be found at: www.tenmon.or.jp/iau97/ . ISO illuminates our cosmic ancestry The European Space Agency's Infrared Space Observatory, ISO, is unmatched in its ability to explore and analyse many of the universal processes that made our existence possible. We are children of the stars. Every atom in our bodies was created in cosmic space and delivered to the Sun's vicinity in time for the Earth's formation, during a ceaseless cycle of birth, death and rebirth among the stars. The most creative places in the sky are cool and dusty, and opaque even to the Hubble Space Telescope. Infrared rays penetrating the dust reveal to ISO hidden objects, and the atoms and molecules of cosmic chemistry. "ISO is reading Nature's recipe book," says Roger Bonnet, ESA's director of science. "As the world's only telescope capable of observing the Universe over a wide range of infrared wavelengths, ISO plays an indispensable part in astronomical discoveries that help to explain how we came to exist." This Information Note describes several stages in our cosmic ancestry, revealed when ISO examines their counterparts still observable today. The evolving galaxies In the beginning was hydrogen, mixed with helium and minute traces of other light atoms. These were the atomic products of the Big Bang, the hypothetical cataclysm that created the Universe more than 10 billion years ago. The primeval gas was very dull. Nature could not make dust from it, never mind a living creature. But gravity gathered the hydrogen and helium into stars, and by nuclear reactions the stars glowed. As the first stars aged, the reactions made novel chemical elements like carbon, oxygen and silicon. Expelled into the stars' surroundings, these materials reacted with one another and with hydrogen to make the icy, tarry and stony grains of cosmic dust. The vast assemblies of stars called galaxies became crucibles where Nature could use physics and chemistry to make new materials and new stars. Rays from the most distant galaxies have taken so many billions of years to reach us that we see them as they were when they were young. The farthest galaxy observed so far by ISO is a quasar called BR 1202-0225, dating from a time when the Universe was less than one-tenth of its present age. Already it is dusty. ISO has also observed many galaxies at about half the age of the Universe, by staring long and hard through a window in the dust of our own Milky Way Galaxy, called the Lockman Hole. In those that glow most brightly in the infrared, astronomers suspect that frantic star-making is in progress, in episodes called starbursts. In nearer galaxies, ISO's astronomers can relate strong infrared emissions to collisions and to violent eruptions in the galactic cores, which have punctuated the evolution of the galaxies. "Having ISO in space brings special opportunities for the study of the history of the galaxies," says the Japanese astronomer Yoshiaki Taniguchi of Tohoku University. "By detecting infrared wavelengths that are hard to observe from the Earth, ISO picks out very clearly th

1997-08-01

194

Hubble Systems Optimize Hospital Schedules  

NASA Technical Reports Server (NTRS)

Don Rosenthal, a former Ames Research Center computer scientist who helped design the Hubble Space Telescope's scheduling software, co-founded Allocade Inc. of Menlo Park, California, in 2004. Allocade's OnCue software helps hospitals reclaim unused capacity and optimize constantly changing schedules for imaging procedures. After starting to use the software, one medical center soon reported noticeable improvements in efficiency, including a 12 percent increase in procedure volume, 35 percent reduction in staff overtime, and significant reductions in backlog and technician phone time. Allocade now offers versions for outpatient and inpatient magnetic resonance imaging (MRI), ultrasound, interventional radiology, nuclear medicine, Positron Emission Tomography (PET), radiography, radiography-fluoroscopy, and mammography.

2009-01-01

195

Friedmann equation and Hubble condition  

E-print Network

The note presents results on the solutions of the Friedmann equation, which satisfy the Hubble condition, where the radiation term is taken into account. For these solutions the equation $\\sigma=\\sigma_{cr}$, where $\\sigma$ is the radiation invariant of the Friedmann equation and $\\sigma_{cr}$ the "critical radiation parameter", introduced in [5], is an analytic relation between the matter density and the radiation density at the present time and the cosmological constant which can be represented by two function branches, expressing the cosmological constant as unique functions of the matter and radiation density. These functions are the "frontier lines" between regions of constant type.

Hellmut Baumgaertel

2014-05-02

196

Hubble Space Telescope Science Metrics  

E-print Network

Since its launch in April 1990, the Hubble Space Telescope (HST) has produced an increasing flow of scientific results. The large number of refereed publications based on HST data allows a detailed evaluation of the effectiveness of this observatory and of its scientific programs. This paper presents the results of selected science metrics related to paper counts, citation counts, citation history, high-impact papers, and the most productive programs and most cited papers, through the end of 2003. All these indicators point towards the high-quality scientific impact of HST.

Georges Meylan; Juan P. Madrid; Duccio Macchetto

2004-06-29

197

Modified Hubble law, the time-varying Hubble parameter and the problem of dark energy  

E-print Network

In the framework of the solvable model of cosmology constructed in the Earth-related coordinate system, we derive the modified Hubble law. This law carries the slowly time-varying Hubble parameter. The modified Hubble law eliminates the need for dark energy.

Jian-Miin Liu

2005-07-04

198

The Management of Astronomical Data  

NASA Astrophysics Data System (ADS)

Astronomy has a distinguished tradition of using technology to accelerate the quality and effectiveness of science. However, amongst the shining examples of excellent data management by major projects lie examples of projects and institutions where data management has not been properly resourced, or where hard-earned data remain inaccessible to most astronomers. We need to establish and agree on a set of guiding principles for the management of astronomical data. For example, all OECD governments, representing nearly all countries with major astronomical facilities, have committed to the principle that publicly-funded data should be placed in the public domain. The last IAU GA in Sydney passed a resolution that archive data from publicly funded observatories should be placed in the public domain. The HST archive, which quadruples the number of science publications resulting from HST data, has demonstrated the value to science of doing so. And yet many observatory archives are still inaccessible. Another example is the barrier between journals and data centres. The astronomical data centres are enormously successful, and provide powerful tools which have accelerated the advance of science, and some of our journals are forward-looking and receptive to new ideas. And yet most data published in those journals never appear in the data centres. These two examples show that we are not making most effective use of our data, and consequently are not extracting the maximum scientific value from our observatories and astronomers. The Virtual Observatory promises us tools to provide better access to data, but these tools lose their value if the data are not available. It is time for the astronomical community to adopt a professional approach to data management, to maximise the science that can be achieved with our new and existing facilities.

Norris, R. P.

2006-08-01

199

The astronomer - N. N. Donitch  

NASA Astrophysics Data System (ADS)

This paper describes a history of friendship and collaboration between the astronomers N. Donitch and A.A. Baikov. Information on other astronomers, L.V. Okulitch and E.A. Von der Pahlen, and meteorologists V.H. Dubinskii and Nina Gouma, can also be found. Details on the expeditions aimed at observing the total solar eclipses on 30 August 1905 (organized by the Imperial Academy of Sciences in Sankt-Petersburg) and 19 June 1936 (organized by the Romanian Royal Cultural foundation) are given. The main part represents the first English translation of the paper by Baikov, published earlier in Russian and Romanian, with a new preface, annotations, and comments.

Baikov, A. A.; Gaina, A.

200

HUBBLE PHOTOGRAPHS WARPED GALAXY AS CAMERA PASSES MILESTONE  

NASA Technical Reports Server (NTRS)

NASA's Hubble Space Telescope has captured an image of an unusual edge-on galaxy, revealing remarkable details of its warped dusty disk and showing how colliding galaxies spawn the formation of new generations of stars. The dust and spiral arms of normal spiral galaxies, like our own Milky Way, appear flat when viewed edge-on. This month's Hubble Heritage image of ESO 510-G13 shows a galaxy that, by contrast, has an unusual twisted disk structure, first seen in ground-based photographs obtained at the European Southern Observatory (ESO) in Chile. ESO 510-G13 lies in the southern constellation Hydra, roughly 150 million light-years from Earth. Details of the structure of ESO 510-G13 are visible because the interstellar dust clouds that trace its disk are silhouetted from behind by light from the galaxy's bright, smooth central bulge. The strong warping of the disk indicates that ESO 510-G13 has recently undergone a collision with a nearby galaxy and is in the process of swallowing it. Gravitational forces distort the structures of the galaxies as their stars, gas, and dust merge together in a process that takes millions of years. Eventually the disturbances will die out, and ESO 510-G13 will become a normal-appearing single galaxy. In the outer regions of ESO 510-G13, especially on the right-hand side of the image, we see that the twisted disk contains not only dark dust, but also bright clouds of blue stars. This shows that hot, young stars are being formed in the disk. Astronomers believe that the formation of new stars may be triggered by collisions between galaxies, as their interstellar clouds smash together and are compressed. The Heritage Team used Hubble's Wide Field Planetary Camera 2 (WFPC2) to observe ESO 510-G13 in April 2001. Pictures obtained through blue, green, and red filters were combined to make this color-composite image, which emphasizes the contrast between the dusty spiral arms, the bright bulge, and the blue star-forming regions. During the observations of ESO 510-G13, WFPC2 passed the milestone of taking its 100,000th image since its installation in the telescope by shuttle astronauts in 1993. Image Credit: NASA and the Hubble Heritage Team (STScI/AURA) Acknowledgment: C. Conselice (U. Wisconsin/STScI)

2002-01-01

201

The Hubble Ultra Deep Field  

E-print Network

This paper presents the Hubble Ultra Deep Field (HUDF), a one million second exposure of an 11 square minute-of-arc region in the southern sky with the Hubble Space Telescope. The exposure time was divided among four filters, F435W (B435), F606W (V606), F775W (i775), and F850LP (z850), to give approximately uniform limiting magnitudes mAB~29 for point sources. The image contains at least 10,000 objects presented here as a catalog. Few if any galaxies at redshifts greater than ~4 resemble present day spiral or elliptical galaxies. Using the Lyman break dropout method, we find 504 B-dropouts, 204 V-dropouts, and 54 i-dropouts. Using these samples that are at different redshifts but derived from the same data, we find no evidence for a change in the characteristic luminosity of galaxies but some evidence for a decrease in their number densities between redshifts of 4 and 7. The ultraviolet luminosity density of these samples is dominated by galaxies fainter than the characteristic luminosity, and the HUDF reveals considerably more luminosity than shallower surveys. The apparent ultraviolet luminosity density of galaxies appears to decrease from redshifts of a few to redshifts greater than 6. The highest redshift samples show that star formation was already vigorous at the earliest epochs that galaxies have been observed, less than one billion years after the Big Bang.

Steven V. W. Beckwith; Massimo Stiavelli; Anton M. Koekemoer; John A. R. Caldwell; Henry C. Ferguson; Richard Hook; Ray A. Lucas; Louis E. Bergeron; Michael Corbin; Shardha Jogee; Nino Panagia; Massimo Robberto; Patricia Royle; Rachel S. Somerville; Megan Sosey

2006-07-27

202

HUBBLE PROBES THE VIOLENT BIRTH OF STARS IN GALAXY NGC 253 [Left  

NASA Technical Reports Server (NTRS)

An image of the spiral galaxy NGC 253, taken with a ground-based telescope. The galaxy is located about 8 million light-years away in the constellation Sculptor. Credit: Jay Gallagher (University of Wisconsin-Madison), Alan Watson (Lowell Observatory, Flagstaff, AZ), and NASA [Right] This NASA Hubble Space Telescope image of the core of the nearest starburst spiral galaxy, NGC 253, reveals violent star formation within a region 1,000 light-years across. A starburst galaxy has an exceptionally high rate of star birth, first identified by its excess of infrared radiation from warm dust. Hubble's high resolution allows astronomers to quantify complex structures in the starburst core of the galaxy for the first time, including luminous star clusters, dust lanes which trace regions of dense gas and filaments of glowing gas. Hubble identifies several regions of intense star formation, which include a bright, super-compact star cluster. These observations confirm that stars are often born in dense clusters within starbursts, and that dense gas coexists with and obscures the starburst core. This image was taken with Hubble's Wide Field Planetary Camera 2 (in PC mode). Credit: Carnegie Institution of Washington

2002-01-01

203

Hubble 2008: Science Year in Review  

NASA Technical Reports Server (NTRS)

Hubbles remarkable mission has now spanned 18 years. During that time, it has been at the nexus of perhaps the most exciting period of discovery in the history of astronomy. Simultaneously, Hubble has offered up some of the most daunting engineering challenges to humans working in space, and success in meeting those challenges has been among NASAs greatest triumphs.

2009-01-01

204

Astronomers Discover Six-Image Gravitational Lens  

NASA Astrophysics Data System (ADS)

An international team of astronomers has used the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope and NASA's Hubble Space Telescope (HST) to discover the first gravitational lens in which the single image of a very distant galaxy has been split into six different images. The unique configuration is produced by the gravitational effect of three galaxies along the line of sight between the more-distant galaxy and Earth. Optical and Radio Images of Gravitational Lens "This is the first gravitational lens with more than four images of the background object that is produced by a small group of galaxies rather than a large cluster of galaxies," said David Rusin, who just received his Ph.D. from the University of Pennsylvania. "Such systems are expected to be extremely rare, so this discovery is an important stepping stone. Because this is an intermediate case between gravitational lenses produced by single galaxies and lenses produced by large clusters of galaxies, it will give us insights we can't get from other types of lenses," Rusin added. The gravitational lens, called CLASS B1359+154, consists of a galaxy more than 11 billion light-years away in the constellation Bootes, with a trio of galaxies more than 7 billion light-years away along the same line of sight. The more-distant galaxy shows signs that it contains a massive black hole at its core and also has regions in which new stars are forming. The gravitational effect of the intervening galaxies has caused the light and radio waves from the single, more-distant galaxy to be "bent" to form six images as seen from Earth. Four of these images appear outside the triangle formed by the three intermediate galaxies and two appear inside that triangle. "This lens system is a very interesting case to study because it is more complicated than lenses produced by single galaxies, and yet simpler than lenses produced by clusters of numerous galaxies," said Chris Kochanek of the Harvard-Smithsonian Center for Astrophysics (CfA). "When we understand this system, we will have a much clearer picture of how galaxies are changed by being part of a bigger cluster of galaxies," he added. B1359+154 was discovered in 1999 by the Cosmic Lens All-Sky Survey, an international collaboration of astronomers who use radio telescopes to search the sky for gravitational lenses. Images made by the NSF's Very Large Array in New Mexico and by Britain's MERLIN radio telescope showed six objects suspected of being gravitational-lens images, but the results were inconclusive. Rusin and his team used the VLBA and HST in 1999 and 2000 to make more-detailed studies of B1359+154. The combination of data from the VLBA and HST convinced the astronomers that B1359+154 actually consists of six lensed images of a single background galaxy. The VLBA images were made from data collected during observations at a radio frequency of 1.7 GHz. "This is a great example of modern, multi-wavelength astronomy," said Rusin. "We need the radio telescopes to detect the gravitational lenses in the first place, then we need the visible-light information from Hubble to show us additional detail about the structure of the system." Armed with the combined VLBA and HST data about the positions and brightnesses of the six images of the background galaxy as well as the positions of the three intermediate galaxies, the astronomers did computer simulations to show how the gravitation of the three galaxies could produce the lens effect. They were able to design a computer model of the system that, in fact, produces the six images seen in B1359+154. "Our computer model certainly is not perfect, and we need to do more observations of this system to refine it, but we have clearly demonstrated that the three galaxies we see can produce a six-image lens system," said Martin Norbury, a graduate student at Jodrell Bank Observatory in Britain. "We think this work will give us an excellent tool for studying much-denser clusters of gala

2001-08-01

205

Old Star's "Rebirth" Gives Astronomers Surprises  

NASA Astrophysics Data System (ADS)

Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope are taking advantage of a once-in-a-lifetime opportunity to watch an old star suddenly stir back into new activity after coming to the end of its normal life. Their surprising results have forced them to change their ideas of how such an old, white dwarf star can re-ignite its nuclear furnace for one final blast of energy. Sakurai's Object Radio/Optical Images of Sakurai's Object: Color image shows nebula ejected thousands of years ago. Contours indicate radio emission. Inset is Hubble Space Telescope image, with contours indicating radio emission; this inset shows just the central part of the region. CREDIT: Hajduk et al., NRAO/AUI/NSF, ESO, StSci, NASA Computer simulations had predicted a series of events that would follow such a re-ignition of fusion reactions, but the star didn't follow the script -- events moved 100 times more quickly than the simulations predicted. "We've now produced a new theoretical model of how this process works, and the VLA observations have provided the first evidence supporting our new model," said Albert Zijlstra, of the University of Manchester in the United Kingdom. Zijlstra and his colleagues presented their findings in the April 8 issue of the journal Science. The astronomers studied a star known as V4334 Sgr, in the constellation Sagittarius. It is better known as "Sakurai's Object," after Japanese amateur astronomer Yukio Sakurai, who discovered it on February 20, 1996, when it suddenly burst into new brightness. At first, astronomers thought the outburst was a common nova explosion, but further study showed that Sakurai's Object was anything but common. The star is an old white dwarf that had run out of hydrogen fuel for nuclear fusion reactions in its core. Astronomers believe that some such stars can undergo a final burst of fusion in a shell of helium that surrounds a core of heavier nuclei such as carbon and oxygen. However, the outburst of Sakurai's Object is the first such blast seen in modern times. Stellar outbursts observed in 1670 and 1918 may have been caused by the same phenomenon. Astronomers expect the Sun to become a white dwarf in about five billion years. A white dwarf is a dense core left after a star's normal, fusion-powered life has ended. A teaspoon of white dwarf material would weigh about 10 tons. White dwarfs can have masses up to 1.4 times that of the Sun; larger stars collapse at the end of their lives into even-denser neutron stars or black holes. Computer simulations indicated that heat-spurred convection (or "boiling") would bring hydrogen from the star's outer envelope down into the helium shell, driving a brief flash of new nuclear fusion. This would cause a sudden increase in brightness. The original computer models suggested a sequence of observable events that would occur over a few hundred years. "Sakurai's object went through the first phases of this sequence in just a few years -- 100 times faster than we expected -- so we had to revise our models," Zijlstra said. The revised models predicted that the star should rapidly reheat and begin to ionize gases in its surrounding region. "This is what we now see in our latest VLA observations," Zijlstra said. "It's important to understand this process. Sakurai's Object has ejected a large amount of the carbon from its inner core into space, both in the form of gas and dust grains. These will find their way into regions of space where new stars form, and the dust grains may become incorporated in new planets. Some carbon grains found in a meteorite show isotope ratios identical to those found in Sakurai's Object, and we think they may have come from such an event. Our results suggest this source for cosmic carbon may be far more important than we suspected before," Zijlstra added. The scientists continue to observe Sakurai's Object to take advantage of the rare opportunity to learn about the process of re-ignition. They are making new VLA observations just

2005-04-01

206

LGBT Workplace Issues for Astronomers  

Microsoft Academic Search

Federal Equal Employment Opportunity laws and regulations do not provide protection from discrimination on the basis of sexual orientation or gender identity or gender expression. Sexual minority astronomers (including lesbian, gay, bisexual and transgender people; LGBT) can face additional challenges at school and work. Studies show that LGBT students on many campuses report experiences of harassment. Cities, counties, and states

Laura E. Kay; R. Danner; K. Sellgren; V. Dixon; GLBTQastro

2011-01-01

207

astroplotlib: Astronomical library of plots  

NASA Astrophysics Data System (ADS)

Astropoltlib is a multi-language astronomical library of plots, a collection of templates useful for creating paper-quality figures. Most of the codes for producing the plots are written in IDL and/or Python; a very few are written in Mathematica. Any plot can be downloaded and customized to one's own needs.

Ubeda, Leonardo; Davis, Matt; Diaz, Rosa; Hammer, Derek; Philippe-Lajoie, Charles; Le Blanc, Tommy; Lim, Pey-Lian; Viana, Alex

2014-02-01

208

Historians and astronomers: same pursuits?  

NASA Astrophysics Data System (ADS)

It is a truism that historians looks to the past for justification of their existence, their raison d'être, and the astronomers are on the cutting edge of that which is new and exciting. But the reality is that historians provide (admittedly very imprecise) forecasts of the future. Astronomers plan trajectories for rockets to Mars and beyond the solar system, preparing us for the eventual life in space, sometime in the future, but every time they look through their telescopes or read their computer printouts of cosmic and radio waves, they are looking deep into the past. The nearest star's light took four years to arrive here; Deneb's took 1,600 years; the nearest large galaxy is 2.2 million lightyears away; light from quasars take 15 billion years to arrive. Clearly astronomers are looking deeply into the past, asking, "how did it all begin" and like historians, they speculate, "how will it all end". This and other relationships between astronomical scientists and humanistic historians are explored in this chapter.

Stein, Joshua B.

209

Astronomical Photography for the Classroom.  

ERIC Educational Resources Information Center

Describes class projects involving astronomical photography. Includes a description of how to make an astrocamera or convert a pocket camera into one suitable for astrophotography, film choices, and phenomena to photograph, such as star trails, meteors, the sun, and the moon. (DS)

Hulme, Kenneth S.

1981-01-01

210

Leslie Peltier: The World's Greatest Amateur Astronomer  

NASA Astrophysics Data System (ADS)

This paper is a brief account of the life of amateur astronomer Leslie C. Peltier, with reflections on how his astronomical accomplishments influenced the author's own involvement in variable star observing.

Simonsen, M.

2014-05-01

211

Engaging Students through Astronomically Inspired Music  

NASA Astrophysics Data System (ADS)

This paper describes a lesson outline in which astronomically inspired musical compositions are used to teach astronomical concepts via an introductory activity, close listening, and critical/creative reflection.

Whitehouse, M.

2011-09-01

212

Hubble Witnesses The Final Blaze Of Glory Of Sun-Like Stars  

NSDL National Science Digital Library

The Space Telescope Science Institute has released this stunning photograph from the Hubble Space Telescope, the "supersonic exhaust from [planetary] nebula M2-9." This is an example of a "bipolar planetary nebula" and is estimated to be ten times the diameter of Pluto's orbit. This picture, along with others, contributes to astronomers' understanding of the complex processes that can result from the death throes of Sun-like stars. The site contains the M2-9 photo in several resolutions and formats, an explanatory caption, a photo gallery of other planetary nebulas, a QuickTime movie illustrating the process, and other explanatory material.

1997-01-01

213

Hubble Space Telescope: High speed photometer instrument handbook. Version 2.0  

NASA Technical Reports Server (NTRS)

This manual is a guide for astronomers who intend to use the High Speed Photometer (HSP), one of the scientific instruments onboard the Hubble Space Telescope (HST). All the information needed for ordinary uses of the HSP is presented, including: (1) an overview of the instrument; (2) a detailed description of some details of the HSP-ST system that may be important for some observations; (3) tables and figures describing the sensitivity and limitations of the HSP; (4) how to go about planning an observation with the HSP; and (5) a description of the standard calibration to be applied to HSP data and the resulting data products.

White, Richard L. (editor)

1990-01-01

214

Hubble Gallery of Jupiter's Galilean Satellites  

NASA Technical Reports Server (NTRS)

This is a Hubble Space Telescope 'family portrait' of the four largest moons of Jupiter, first observed by the Italian scientist Galileo Galilei nearly four centuries ago. Located approximately one-half billion miles away, the moons are so small that, in visible light, they appear as fuzzy disks in the largest ground-based telescopes. Hubble can resolve surface details seen previously only by the Voyager spacecraft in the early 1980s. While the Voyagers provided close-up snapshots of the satellites, Hubble can now follow changes on the moons and reveal other characteristics at ultraviolet and near-infrared wavelengths.

Over the past year Hubble has charted new volcanic activity on Io's active surface, found a faint oxygen atmosphere on the moon Europa, and identified ozone on the surface of Ganymede. Hubble ultraviolet observations of Callisto show the presence of fresh ice on the surface that may indicate impacts from micrometeorites and charged particles from Jupiter's magnetosphere.

Hubble observations will play a complementary role when the Galileo spacecraft arrives at Jupiter in December of this year.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1995-01-01

215

Hubble Discovery Image of New Moon Orbiting Saturn  

NASA Technical Reports Server (NTRS)

This four-picture sequence (spanning 30 minutes) shows one of four new moons discovered by the Hubble Space Telescope, in images taken of Saturn on May 22, 1995, when Saturn's rings were tilted edge-on to Earth.

Identified as S/1995 S3, the moon appears as an elongated white spot near the center of each image. The new moon lies just outside Saturn's outermost 'F' ring and is no bigger than about 15 miles across. The brighter object to the left is the moon Epimetheus, which was discovered during the ring-plane crossing of 1966. Both moons change position from frame to frame because they are orbiting the planet.

Saturn appears as a bright white disk at far right, and the edge-on rings extend diagonally to the upper left. To the left of the vertical line, each image has been processed to remove residual light from the rings and accentuate any faint satellites orbiting near the rings. The long observing times necessary to detect the faint satellites have resulted in Saturn's bright, overexposed appearance.

Saturn ring plane crossings happen only once every 15 years, and historically have given astronomers an opportunity to discover new satellites that are normally lost in the glare of the planet's bright ring system.

The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1995-01-01

216

ALMA array element astronomical verification  

NASA Astrophysics Data System (ADS)

The Atacama Large Millimeter/submillimeter Array (ALMA) will consist of at least 54 twelve-meter antennas and 12 seven-meter antennas operating as an aperture synthesis array in the (sub)millimeter wavelength range. The ALMA System Integration Science Team (SIST) is a group of scientists and data analysts whose primary task is to verify and characterize the astronomical performance of array elements as single dish and interferometric systems. The full set of tasks is required for the initial construction phase verification of every array element, and these can be divided roughly into fundamental antenna performance tests (verification of antenna surface accuracy, basic tracking, switching, and on-the-fly rastering) and astronomical radio verification tasks (radio pointing, focus, basic interferometry, and end-to-end spectroscopic verification). These activities occur both at the Operations Support Facility (just below 3000 m elevation) and at the Array Operations Site at 5000 m.

Asayama, S.; Knee, L. B. G.; Calisse, P. G.; Cortés, P. C.; Jager, R.; López, B.; López, C.; Nakos, T.; Phillips, N.; Radiszcz, M.; Simon, R.; Toledo, I.; Whyborn, N.; Yatagai, H.; McMullin, J. P.; Planesas, P.

2012-09-01

217

The Quito Astronomical Instruments Heritage  

NASA Astrophysics Data System (ADS)

The Quito Astronomical Observatory was build in the 1873s thanks to the generous sponsoring of the president of the Republic of Ecuador Dr. Gabriel García Moreno who desire was to build a long-lasting monument to Ecuadorian science . Thanks to the collaboration of father J. B. Menten one of the leading german astronomer the President' s dream came true. The Observatory with its splendid buildings was in fact equipped with a series of very important instruments such as the 30-cm Mertz refractor a large Molteni meridian instrument and a Bamber of 10 cm. Other instruments were subsequently added in the course of the 20th century. Recently we have performed a detailed inventory of all the historical instruments still preserved at the Observatory. This paper is dedicated to briefly trace the history of the Quito Observatory and describe its most characteristic instruments. Moreover it is presented the work done for preserving this important scientific heritage and discuss some of the typical problems that the researchers the students amateur astronomers and the public find in a still active scientific institution in a developing country.

Lopez, Ericsson

218

Hubble Space Telescope Servicing begins.  

NASA Astrophysics Data System (ADS)

The day's work began when astronauts Story Musgrave and Jeff Hoffman stepped out into the cargo bay at 9h41 pm CST, Saturday (4h41 am CET, Sunday). They immediately set to work replacing two gyroscope assemblies, known as the Rate Sensor Units, two associated electronics boxes, called Electronic Control Units, and eight electrical fuse plugs. The work was completed ahead of schedule, but the astronauts had trouble closing the doors of the compartment housing the gyros and took over an hour to get them shut. The astronauts also prepared equipment for the replacement of the solar arrays. "The feeling down here is one of great satisfaction for a tremendous job today" said spacecraft communicator Greg Harbaugh in mission control. "We are very proud of the work that you all did and we are very confident in the continued success of the mission. Everything is going great and tomorrow is going to be another great day". ESA astronaut Claude Nicollier played a vital role during the spacewalk moving the astronauts and their equipment around the cargo bay with the shuttle's robot arm. The Hubble Space Telescope servicing mission features more robot arm operations than any other shuttle flight. The telescope's left-hand solar array was rolled up successfully at 6h24 am CST (1h24 pm CET). The 11-tonne observatory was rotated 180 degrees on its turntable before commands were sent to retract the second array at 8h23 am CST (3h23 pm CET). The crew stopped the retraction when it appeared the system may have jammed. Mission control instructed the crew to jettison the array, a procedure that they have trained for. Tomorrow astronauts Kathy Thornton and Tom Akers will make a six-hour spacewalk to jettison the troublesome wing, store the other in the cargo bay, and install two new panels supplied by ESA. The second set of arrays feature thermal shields and a modified thermal compensation system to prevent the flexing that affected the first pair. The Hubble Space Telescope was plucked from orbit this Saturday by ESA astronaut Claude Nicollier, operating the shuttle's robot arm. The Swiss-born astronaut gripped the 11- tonne observatory with the shuttle's 15-metre long robot arm at 2h34 am CST (9h34 am CET) after a two-day chase through space as the two spacecraft flew over the South Pacific Ocean. "Endeavour has a firm handshake with Mr. Hubble's telescope" said mission commander Dick Covey. "It's quite a sight". About half an hour later Nicollier had the telescope berthed on a special turntable in the back of the Shuttle's cargo bay. Later he used the camera at the end of the arm to surveyed the telescope for any damage. As the shuttle approached the telescope the astronauts first reported that one of the twin solar arrays appeared to be bowed and twisted. ESA officials said the problem was caused by the failure in early 1992 of the tensioning system on one side of the right-hand array. The system is designed to allow the blanket-like array to expand and contract in orbit. That failure placed stress on one of the supporting bi-stem booms resulting in its bent condition. Endeavour's mission began Thursday 2 December and will end 13 December. A total of five spacewalks are planned to service the telescope.

1993-12-01

219

THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY  

SciTech Connect

The Panchromatic Hubble Andromeda Treasury is an ongoing Hubble Space Telescope Multi-Cycle Treasury program to image {approx}1/3 of M31's star-forming disk in six filters, spanning from the ultraviolet (UV) to the near-infrared (NIR). We use the Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) to resolve the galaxy into millions of individual stars with projected radii from 0 to 20 kpc. The full survey will cover a contiguous 0.5 deg{sup 2}area in 828 orbits. Imaging is being obtained in the F275W and F336W filters on the WFC3/UVIS camera, F475W and F814W on ACS/WFC, and F110W and F160W on WFC3/IR. The resulting wavelength coverage gives excellent constraints on stellar temperature, bolometric luminosity, and extinction for most spectral types. The data produce photometry with a signal-to-noise ratio of 4 at m{sub F275W} = 25.1, m{sub F336W} = 24.9, m{sub F475W} = 27.9, m{sub F814W} = 27.1, m{sub F110W} = 25.5, and m{sub F160W} = 24.6 for single pointings in the uncrowded outer disk; in the inner disk, however, the optical and NIR data are crowding limited, and the deepest reliable magnitudes are up to 5 mag brighter. Observations are carried out in two orbits per pointing, split between WFC3/UVIS and WFC3/IR cameras in primary mode, with ACS/WFC run in parallel. All pointings are dithered to produce Nyquist-sampled images in F475W, F814W, and F160W. We describe the observing strategy, photometry, astrometry, and data products available for the survey, along with extensive testing of photometric stability, crowding errors, spatially dependent photometric biases, and telescope pointing control. We also report on initial fits to the structure of M31's disk, derived from the density of red giant branch stars, in a way that is independent of assumed mass-to-light ratios and is robust to variations in dust extinction. These fits also show that the 10 kpc ring is not just a region of enhanced recent star formation, but is instead a dynamical structure containing a significant overdensity of stars with ages >1 Gyr.

Dalcanton, Julianne J.; Williams, Benjamin F.; Rosenfield, Philip; Weisz, Daniel R.; Gilbert, Karoline M.; Gogarten, Stephanie M. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Lang, Dustin [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Lauer, Tod R.; Dong Hui [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Kalirai, Jason S.; Boyer, Martha L.; Gordon, Karl D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Seth, Anil C. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Dolphin, Andrew [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States); Bianchi, Luciana C. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Dorman, Claire E.; Guhathakurta, Puragra [University of California Observatories/Lick Observatory, University of California, 1156 High St., Santa Cruz, CA 95064 (United States); Girardi, Leo [Osservatorio Astronomico di Padova-INAF, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy); and others

2012-06-01

220

The Challenge of Astronomical Visualisation  

NASA Astrophysics Data System (ADS)

Current astronomical instruments now routinely produce such large volumes of data that it becomes difficult for an astronomer to obtain the information he wants from the data. While the machines get faster and cheaper, and are certainly able to handle the load, and the astronomer's brain is certainly capable of interpreting the data, the interface between machine and brain prevents the astronomer from assembling the data in a coherent fashion in his mind, and so prevents him from being able to extract all the useful information which resides in his data. This is particularly true of large spectral-line data cubes. There are three aspects to overcoming this bottleneck between man and machine: Make the data analysis tools more user friendly, so that they cease to be a hindrance to most users. In particular, users need to be able to easily extract quantitative information from the images presented to them. Devise better ways of handling large multi-dimensional images so that the astronomer can hold in his mind some representation of the entire data set. For example, spectral-line data cubes can be viewed interactively as three-dimensional cubes, or even walked through in a virtual reality system. Such techniques enable the user to make use of the powerful image recognition capabilities of his brain. For example, a weak spiral arm may be only just above the noise in each plane of an HI data cube, and yet is obvious to the human brain (and is indeed physically significant) when the whole cube is viewed at once. When each of these two goals has been achieved, we need to combine them to devise better ways of obtaining quantitative data from large data sets. For example, a user needs to be able to obtain the mean and rms amplitude over a region immersed in the depths of a large data cube. In each of these three aspects, the challenge is to accomplish this while keeping the user in touch with the data, so that he will remain alert to problems or unexpected features in the data. In this talk I will demonstrate some of the efforts being made to overcome this man-machine bottleneck at the Australia Telescope.

Norris, Ray P.

221

Applying artificial intelligence to astronomical databases - A survey of applicable technology  

NASA Technical Reports Server (NTRS)

AI technologies which are relevant to astronomical data bases are reviewed, including intelligent interfaces, internal representations, and data analysis. The natural language query system developed for the Hubble Space Telescope and the technique of goal directed queries are considered. Two technologies which might lead to the development of pictorial interfaces are presented: one based on Bayesian probabilities, the other on associative memories. The development of a data analysis system which can discover classes of data within a data base without any information other than the data itself is examined. A prototype data analysis assistant to automatically develop and implement plans for data reduction is described.

Rosenthal, Donald A.

1988-01-01

222

West uses Hubble to study `cannibal  

E-print Network

West uses Hubble to study `cannibal galaxies' Dr. Michael West, UH Hilo professor of astrono- my that are believed to have "cannibalized" JANUARY, 2001 Ka Lono Hanakahi 18 Ka Lono Hanakahi DECEMBER, 1997 Hanakahi

Wiegner, Tracy N.

223

Hubble Finds Many Bright Clouds on Uranus  

NASA Technical Reports Server (NTRS)

A recent Hubble Space Telescope view reveals Uranus surrounded by its four major rings and by 10 of its 17 known satellites. This false-color image was generated by Erich Karkoschka using data taken on August 8, 1998, with Hubble's Near Infrared Camera and Multi-Object Spectrometer. Hubble recently found about 20 clouds - nearly as many clouds on Uranus as the previous total in the history of modern observations.

The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1998-01-01

224

Hubble 2007: Science Year in Review  

NASA Technical Reports Server (NTRS)

This book epitomizes Hubbles continuing years of glorious accomplishments, presenting a sample of the activities, operations and observations, and scientific findings from 2007. Here is our observatory. Here are a few of our talented people. Here is what we have done. NASA plans a final servicing mission to Hubble in 2008. Two powerful new instruments are to be installed, and repairs made. After the astronauts do their wonderful work, Hubble will be more capable than at any time since launch. The science community eagerly anticipates the new opportunities for research offered by a refurbished observatory. While we do not know exactly what new science stories will appear in future editions of this book, we are certain that the frontiers of science will continue to be pushed outward by the forces of human curiosity and cleverness, channeled by the Hubble Space Telescope.

2008-01-01

225

HUBBLE PROBES THE COMPLEX HISTORY OF A DYING STAR  

NASA Technical Reports Server (NTRS)

This NASA Hubble Space Telescope image shows one of the most complex planetary nebulae ever seen, NGC 6543, nicknamed the 'Cat's Eye Nebula.' Hubble reveals surprisingly intricate structures including concentric gas shells, jets of high-speed gas and unusual shock-induced knots of gas. Estimated to be 1,000 years old, the nebula is a visual 'fossil record' of the dynamics and late evolution of a dying star. A preliminary interpretation suggests that the star might be a double-star system. The dynamical effects of two stars orbiting one another most easily explains the intricate structures, which are much more complicated than features seen in most planetary nebulae. (The two stars are too close together to be individually resolved by Hubble, and instead, appear as a single point of light at the center of the nebula.) According to this model, a fast 'stellar wind' of gas blown off the central star created the elongated shell of dense, glowing gas. This structure is embedded inside two larger lobes of gas blown off the star at an earlier phase. These lobes are 'pinched' by a ring of denser gas, presumably ejected along the orbital plane of the binary companion. The suspected companion star also might be responsible for a pair of high-speed jets of gas that lie at right angles to this equatorial ring. If the companion were pulling in material from a neighboring star, jets escaping along the companion's rotation axis could be produced. These jets would explain several puzzling features along the periphery of the gas lobes. Like a stream of water hitting a sand pile, the jets compress gas ahead of them, creating the 'curlicue' features and bright arcs near the outer edge of the lobes. The twin jets are now pointing in different directions than these features. This suggests the jets are wobbling, or precessing, and turning on and off episodically. The image was taken with the Wide Field Planetary Camera-2 on September 18, 1994. NGC 6543 is 3,000 light-years away in the northern constellation Draco. The term planetary nebula is a misnomer; dying stars create these cocoons when they lose outer layers of gas. The process has nothing to do with planet formation, which is predicted to happen early in a star's life. This material was presented at the 185th meeting of the American Astronomical Society in Tucson, AZ on January 11, 1995. Credit: J.P. Harrington and K.J. Borkowski (University of Maryland), and NASA

2002-01-01

226

HUBBLE IDENTIFIES SOURCE OF ULTRAVIOLET LIGHT IN AN OLD GALAXY  

NASA Technical Reports Server (NTRS)

Hubble Space Telescope's exquisite resolution has allowed astronomers to resolve, for the first time, hot blue stars deep inside an elliptical galaxy. The swarm of nearly 8,000 blue stars resembles a blizzard of snowflakes near the core (lower right) of the neighboring galaxy M32, located 2.5 million light-years away in the constellation Andromeda. Hubble confirms that the ultraviolet light comes from a population of extremely hot helium-burning stars at a late stage in their lives. Unlike the Sun, which burns hydrogen into helium, these old stars exhausted their central hydrogen long ago, and now burn helium into heavier elements. The observations, taken in October 1998, were made with the camera mode of the Space Telescope Imaging Spectrograph (STIS) in ultraviolet light. The STIS field of view is only a small portion of the entire galaxy, which is 20 times wider on the sky. For reference, the full moon is 70 times wider than the STIS field-of-view. The bright center of the galaxy was placed on the right side of the image, allowing fainter stars to be seen on the left side of the image. These results are to be published in the March 1, 2000 issue of The Astrophysical Journal. Thirty years ago, the first ultraviolet observations of elliptical galaxies showed that they were surprisingly bright when viewed in ultraviolet light. Before those pioneering UV observations, old groups of stars were assumed to be relatively cool and thus extremely faint in the ultraviolet. Over the years since the initial discovery of this unexpected ultraviolet light, indirect evidence has accumulated that it originates in a population of old, but hot, helium-burning stars. Now Hubble provides the first direct visual evidence. Nearby elliptical galaxies are thought to be relatively simple galaxies comprised of old stars. Because they are among the brightest objects in the Universe, this simplicity makes them useful for tracing the evolution of stars and galaxies. Credits: NASA and Thomas M. Brown, Charles W. Bowers, Randy A. Kimble, Allen V. Sweigart (NASA Goddard Space Flight Center) and Henry C. Ferguson (Space Telescope Science Institute).

2002-01-01

227

Algorithm and Hardware Support for Branch Anticipation Ted Zhihong Yu Edwin H.-M. Sha Nelson Passos Roy Dz-ching Ju  

E-print Network

Multi-Dimensional Branch Anticipation Scheduling, is able to achieve near- optimal schedule length in the presence of pipelined ar- chitectures. An optimization method, called MD branch anticipationAlgorithm and Hardware Support for Branch Anticipation Ted Zhihong Yu¡ Edwin H.-M. Sha¡ Nelson

Sha, Edwin

228

A brief history of hair cell regeneration research and speculations on Edwin W Rubel a,b,*, Stephanie A. Furrer a  

E-print Network

Review A brief history of hair cell regeneration research and speculations on the future Edwin W this to be false. Adult birds were shown to regenerate lost hair cells in the auditory sensory epithelium after noise- and ototoxic drug-induced damage. Since then, the field of hair cell regeneration has continued

Rubel, Edwin

229

A brief history of hair cell regeneration research and speculations on Edwin W. Rubel a,b,*, Stephanie A. Furrer a  

E-print Network

Review A brief history of hair cell regeneration research and speculations on the future Edwin W this to be false. Adult birds were shown to regenerate lost hair cells in the auditory sensory epithelium after noise- and ototoxic drug-induced damage. Since then, the field of hair cell regeneration has continued

Rubel, Edwin

230

ABUNDANCES OF MOLECULAR SPECIES IN BARNARD 68 James Di Francesco 1;2 , Michiel R. Hogerheijde 1;3 , William J. Welch 1 , and Edwin A. Bergin 4  

E-print Network

1 ABUNDANCES OF MOLECULAR SPECIES IN BARNARD 68 James Di Francesco 1;2 , Michiel R. Hogerheijde 1;3 , William J. Welch 1 , and Edwin A. Bergin 4 1 Radio Astronomy Laboratory, 601 Campbell Hall, University of Waterloo, Canada, 21-23 August 2002 (C. L. Curry & M. Fich eds.). #12; 2 Di Francesco, Hogerheijde, Welch

Hogerheijde, Michiel

231

23Satellite Drag and the Hubble Space Telescope The Hubble Space Telescope was never designed to operate forever. What  

E-print Network

23Satellite Drag and the Hubble Space Telescope The Hubble Space Telescope was never designed. The answer should be about 50 weeks. "NASA's 23-year-old Hubble Space Telescope is still going strong out, potentially for another six years at least. After its final overhaul in 2009, the Hubble

232

No Hubble Bubble in the Local Universe  

E-print Network

Zehavi et al. (1998) have suggested that the Hubble flow within 70/h Mpc may be accelerated by the existence of a void centered on the Local Group. Its underdensity would be ~20 %, which would result in a local Hubble distortion of about 6.5 %. We have combined the peculiar velocity data of two samples of clusters of galaxies, SCI and SCII, to investigate the amplitude of Hubble distortions to 200/h Mpc. Our results are not supportive of that conclusion. The amplitude of a possible distortion in the Hubble flow within 70/h Mpc in the SCI+SCII merged data is 0.010\\pm0.022. The largest, and still quite marginal, geocentric deviation from smooth Hubble flow consistent with that data set is a shell with (Delta H)/H =0.027\\pm0.023, centered at hd = 101 Mpc and extending over some 30/h Mpc. Our results are thus consistent with a Hubble flow that, on distances in excess of about 50/h Mpc, is remarkably smooth.

R. Giovanelli; Daniel Dale; Martha Haynes; Eduardo Hardy; Luis Campusano

1999-06-23

233

THE SPIRAL GALAXY M100 AS SEEN WITH THE HUBBLE'S IMPROVED VISION  

NASA Technical Reports Server (NTRS)

An image of the grand design spiral galaxy M100 obtained with the second generation Wide Field and Planetary Camera (WFPC-2), newly installed in the Hubble Space Telescope. Though the galaxy lies several tens of millions of light-years away, modified optics incorporated within the WFPC-2 allow Hubble to view M100 with a level of clarity and sensitivity previously possible only for the very few nearby galaxies that compose our ``Local Group.'' Just as one does not learn about the diversity of mankind by conversing only with your next door neighbor, astronomers must study many galaxies in a host of different environments if they are to come to understand how our own galaxy, our star, and our earth came to be. By expanding the region of the universe that can be studied in such detail a thousand fold, the WFPC-2 will help the Hubble Space Telescope to fulfill this mission. One of the greatest gains of the high resolution provided by Hubble is the ability to resolve individual stars in other galaxies. The new camera not only allows astronomers to separate stars which would have been blurred together at the resolution available from the ground, but also allows astronomers to accurately measure the light from very faint stars. The quantitative study of compositions, ages, temperatures, and other properties of stars and gas in other galaxies will provide important clues about how galaxies form and evolve. In addition, the WFPC-2 will allow the Hubble Space Telescope to be used to attack one of the most fundamental questions in science: the age and scale of the universe. Astronomers have many ``yardsticks'' for measuring the scale of the universe, but lack a good knowledge of how long these yardsticks really are. M100 is a member of the Virgo Cluster of galaxies. By allowing astronomers to resolve and measure individual stars in the Virgo Cluster -- in particular a special type of star called Cepheid variables, which have well known absolute brightnesses -- HST observations are expected to provide a crucial measurement of this much needed scale. (Only Space Telescope can make these types of observations. Cepheids are too faint and the resolution too poor, as seen from ground-based telescopes, to separate the images in such a crowded region of a distant galaxy.) The picture is chevron-shaped because it is a mosaic of the three wide field cameras and the planetary camera which make up the WFPC-2. The three wide field detectors in the camera reveal individual stars and filamentary dust lanes in the outer arms of the majestic spiral galaxy. The instrument's planetary camera image (upper right) resolves complex structure in the core of the galaxy, which is the site of vigorous star formation. The image was taken on December 31, 1993. The field of view is about two and a half arc minutes across. PHOTO RELEASE NO.: STScI-PR94-02

2002-01-01

234

Hubble Tracks Clouds on Uranus  

NASA Technical Reports Server (NTRS)

Taking its first peek at Uranus, NASA Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has detected six distinct clouds in images taken July 28,1997.

The image on the right, taken 90 minutes after the left-hand image, shows the planet's rotation. Each image is a composite of three near-infrared images. They are called false-color images because the human eye cannot detect infrared light. Therefore, colors corresponding to visible light were assigned to the images. (The wavelengths for the 'blue,' 'green,' and 'red' exposures are 1.1, 1.6, and 1.9 micrometers, respectively.)

At visible and near-infrared light, sunlight is reflected from hazes and clouds in the atmosphere of Uranus. However, at near-infrared light, absorption by gases in the Uranian atmosphere limits the view to different altitudes, causing intense contrasts and colors.

In these images, the blue exposure probes the deepest atmospheric levels. A blue color indicates clear atmospheric conditions, prevalent at mid-latitudes near the center of the disk. The green exposure is sensitive to absorption by methane gas, indicating a clear atmosphere; but in hazy atmospheric regions, the green color is seen because sunlight is reflected back before it is absorbed. The green color around the south pole (marked by '+') shows a strong local haze. The red exposure reveals absorption by hydrogen, the most abundant gas in the atmosphere of Uranus. Most sunlight shows patches of haze high in the atmosphere. A red color near the limb (edge) of the disk indicates the presence of a high-altitude haze. The purple color to the right of the equator also suggests haze high in the atmosphere with a clear atmosphere below.

The five clouds visible near the right limb rotated counterclockwise during the time between both images. They reach high into the atmosphere, as indicated by their red color. Features of such high contrast have never been seen before on Uranus. The clouds are almost as large as continents on Earth, such as Europe. Another cloud (which barely can be seen) rotated along the path shown by the black arrow. It is located at lower altitudes, as indicated by its green color.

The rings of Uranus are extremely faint in visible light but quite prominent in the near infrared. The brightest ring, the epsilon ring, has a variable width around its circumference. Its widest and thus brightest part is at the top in this image. Two fainter, inner rings are visible next to the epsilon ring.

Eight of the 10 small Uranian satellites, discovered by Voyager 2, can be seen in both images. Their sizes range from about 25 miles (40 kilometers) for Bianca to 100 miles (150 kilometers) for Puck. The smallest of these satellites have not been detected since the departure of Voyager 2 from Uranus in 1986. These eight satellites revolve around Uranus in less than a day. The inner ones are faster than the outer ones. Their motion in the 90 minutes between both images is marked in the right panel. The area outside the rings was slightly enhanced in brightness to improve the visibility of these faint satellites.

The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1997-01-01

235

Visualizing Astronomical Data with Blender  

NASA Astrophysics Data System (ADS)

We present methods for using the 3D graphics program Blender in the visualization of astronomical data. The software's forte for animating 3D data lends itself well to use in astronomy. The Blender graphical user interface and Python scripting capabilities can be utilized in the generation of models for data cubes, catalogs, simulations, and surface maps. We review methods for data import, 2D and 3D voxel texture applications, animations, camera movement, and composite renders. Rendering times can be improved by using graphic processing units (GPUs). A number of examples are shown using the software features most applicable to various kinds of data paradigms in astronomy.

Kent, Brian R.

2014-01-01

236

Hubble Identifies What May Be the Most Luminous Star Known  

NSDL National Science Digital Library

The Space Telescope Science Institute and National Aeronautics and Space Administration's Jet Propulsion Laboratory contain sites of current interest related to the stars and planets this week. A UCLA-led team using cameras recently installed aboard the Hubble Space Telescope has identified a massive star approximately 25,000 light-years from Earth. Named the "Pistol Star" for the pistol-shaped nebula surrounding it, it is believed to be one of the largest ever discovered, releasing up to ten million times the energy of our sun and spanning the diameter of the Earth's orbit. Astronomers claim that the Pistol Star "unleashes as much energy in six seconds as our sun does in one year." This site offers the official press release and a caption for photos of the star, which are available in five resolutions and three formats (JPEG, GIF, .pdf). The Cassini flight system, containing a launch vehicle and the Huygens probe orbiter which will explore Saturn's moon Titan in the year 2004, is set to launch October 13, 1997. At this JPL site, interested users can follow launch activity. It features a large section explaining the mission, and includes a section on the controversial nuclear safety issues involved. Users can read both the Cassini Final and Supplemental Environmental Impact Statements issued by NASA (in 1995 and 1997 respectively). There is also an image section and a kids page, among other features.

1997-01-01

237

HUBBLE UNCOVERS MYSTERY OBJECTS IN THE DENSE CORE OF A NEARBY STAR CLUSTER  

NASA Technical Reports Server (NTRS)

Piercing the heart of a glittering swarm of stars, NASA's sharp-eyed Hubble Space Telescope unveils the central region of the globular cluster M22, a 12- to 14-billion-year-old grouping of stars in the constellation Sagittarius. The telescope's view of the cluster's core measures 3.3 light-years across. The stars near the cluster's core are 100,000 times more numerous than those in the Sun's neighborhood. Buried in the glow of starlight are about six 'mystery objects,' which astronomers estimate are no larger than one quarter the mass of the giant planet Jupiter, the solar system's heftiest planet. The mystery objects are too far and dim for Hubble to see directly. Instead, the orbiting observatory detected these unseen celestial bodies by looking for their gravitational effects on the light from far distant stars. In this case, the stars are far beyond the cluster in the galactic bulge, about 30,000 light-years from Earth at the center of the Milky Way Galaxy. M22 is 8,500 light-years away. The invisible objects betrayed their presence by bending the starlight gravitationally and amplifying it, a phenomenon known as microlensing. From February 22 to June 15, 1999, Hubble's Wide Field and Planetary Camera 2 looked through this central region and monitored 83,000 stars. During that time the orbiting observatory recorded six unexpectedly brief microlensing events. In each case a background star jumped in brightness for less than 20 hours before dropping back to normal. These transitory spikes in brightness mean that the object passing in front of the star must have been much smaller than a normal star. Hubble also detected one clear microlensing event. In that observation a star appeared about 10 times brighter over an 18-day span before returning to normal. Astronomers traced the leap in brightness to a dwarf star in the cluster floating in front of the background star. The inset photo shows the entire globular cluster of about 10 million stars. M22 is about 60 light-years wide. The image was taken in June 1995 by the Burrell Schmidt telescope at the Case Western Reserve University's Warner and Swasey Observatory on Kitt Peak in Arizona. This release is issued jointly by NASA and ESA. Credits for Hubble image: NASA, Kailash Sahu, Stefano Casertano, Mario Livio, Ron Gilliland (Space Telescope Science Institute), Nino Panagia (European Space Agency/Space Telescope Science Institute), Michael Albrow and Mike Potter (Space Telescope Science Institute) Credits for ground-based image: Nigel A.Sharp, REU program/AURA/NOAO/NSF

2002-01-01

238

HUBBLE'S CLOSE-UP VIEW OF A SHOCKWAVE FROM A STELLAR EXPLOSION  

NASA Technical Reports Server (NTRS)

This image shows a small portion of a nebula called the 'Cygnus Loop.' Covering a region on the sky six times the diameter of the full Moon, the Cygnus Loop is actually the expanding blastwave from a stellar cataclysm - a supernova explosion - which occurred about 15,000 years ago. In this image the supernova blast wave, which is moving from left to right across the field of view, has recently hit a cloud of denser than average interstellar gas. This collision drives shock waves into the cloud that heats interstellar gas, causing it to glow. Just as the microscope revolutionized the study of the human body by revealing the workings of cells, the Hubble Space Telescope is offering astronomers an unprecedented look at fine structure within these shock fronts. Astronomers have been performing calculations of what should go on behind shock fronts for about the last 20 years, but detailed observations have not been possible until Hubble. This image was taken with Hubble's Wide Field and Planetary Camera 2 (WFPC2). The color is produced by composite of three different images. Blue shows emission from 'doubly ionized' oxygen atoms (atoms that have had two electrons stripped away) produced by the heat behind the shock front. Red shows light given off by 'singly ionized' sulfur atoms (sulfur atoms that are missing a single electron). This sulfur emission arises well behind the shock front, in gas that has had a chance to cool since the passage of the shock. Green shows light emitted by hydrogen atoms. Much of the hydrogen emission comes from an extremely thin zone (only several times the distance between the Sun and Earth) immediately behind the shock front itself. These thin regions appear as sharp, green, filaments in the image. This supernova remnant lies 2,500 light-years away in the constellation Cygnus the Swan. Credit: Jeff Hester (Arizona State University) and NASA

2002-01-01

239

CATALOG MATCHING WITH ASTROMETRIC CORRECTION AND ITS APPLICATION TO THE HUBBLE LEGACY ARCHIVE  

SciTech Connect

Object cross-identification in multiple observations is often complicated by the uncertainties in their astrometric calibration. Due to the lack of standard reference objects, an image with a small field of view can have significantly larger errors in its absolute positioning than the relative precision of the detected sources within. We present a new general solution for the relative astrometry that quickly refines the World Coordinate System of overlapping fields. The efficiency is obtained through the use of infinitesimal three-dimensional rotations on the celestial sphere, which do not involve trigonometric functions. They also enable an analytic solution to an important step in making the astrometric corrections. In cases with many overlapping images, the correct identification of detections that match together across different images is difficult to determine. We describe a new greedy Bayesian approach for selecting the best object matches across a large number of overlapping images. The methods are developed and demonstrated on the Hubble Legacy Archive, one of the most challenging data sets today. We describe a novel catalog compiled from many Hubble Space Telescope observations, where the detections are combined into a searchable collection of matches that link the individual detections. The matches provide descriptions of astronomical objects involving multiple wavelengths and epochs. High relative positional accuracy of objects is achieved across the Hubble images, often sub-pixel precision in the order of just a few milliarcseconds. The result is a reliable set of high-quality associations that are publicly available online.

Budavari, Tamas [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218 (United States); Lubow, Stephen H., E-mail: budavari@jhu.edu, E-mail: lubow@stsci.edu [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States)

2012-12-20

240

Radio Astronomers Set New Standard for Accurate Cosmic Distance Measurement  

NASA Astrophysics Data System (ADS)

A team of radio astronomers has used the National Science Foundation's Very Long Baseline Array (VLBA) to make the most accurate measurement ever made of the distance to a faraway galaxy. Their direct measurement calls into question the precision of distance determinations made by other techniques, including those announced last week by a team using the Hubble Space Telescope. The radio astronomers measured a distance of 23.5 million light-years to a galaxy called NGC 4258 in Ursa Major. "Ours is a direct measurement, using geometry, and is independent of all other methods of determining cosmic distances," said Jim Herrnstein, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. The team says their measurement is accurate to within less than a million light-years, or four percent. The galaxy is also known as Messier 106 and is visible with amateur telescopes. Herrnstein, along with James Moran and Lincoln Greenhill of the Harvard- Smithsonian Center for Astrophysics; Phillip Diamond, of the Merlin radio telescope facility at Jodrell Bank and the University of Manchester in England; Makato Inoue and Naomasa Nakai of Japan's Nobeyama Radio Observatory; Mikato Miyoshi of Japan's National Astronomical Observatory; Christian Henkel of Germany's Max Planck Institute for Radio Astronomy; and Adam Riess of the University of California at Berkeley, announced their findings at the American Astronomical Society's meeting in Chicago. "This is an incredible achievement to measure the distance to another galaxy with this precision," said Miller Goss, NRAO's Director of VLA/VLBA Operations. "This is the first time such a great distance has been measured this accurately. It took painstaking work on the part of the observing team, and it took a radio telescope the size of the Earth -- the VLBA -- to make it possible," Goss said. "Astronomers have sought to determine the Hubble Constant, the rate of expansion of the universe, for decades. This will in turn lead to an estimate of the age of the universe. In order to do this, you need an unambiguous, absolute distance to another galaxy. We are pleased that the NSF's VLBA has for the first time determined such a distance, and thus provided the calibration standard astronomers have always sought in their quest for accurate distances beyond the Milky Way," said Morris Aizenman, Executive Officer of the National Science Foundation's (NSF) Division of Astronomical Sciences. "For astronomers, this measurement is the golden meter stick in the glass case," Aizenman added. The international team of astronomers used the VLBA to measure directly the motion of gas orbiting what is generally agreed to be a supermassive black hole at the heart of NGC 4258. The orbiting gas forms a warped disk, nearly two light-years in diameter, surrounding the black hole. The gas in the disk includes water vapor, which, in parts of the disk, acts as a natural amplifier of microwave radio emission. The regions that amplify radio emission are called masers, and work in a manner similar to the way a laser amplifies light emission. Determining the distance to NGC 4258 required measuring motions of extremely small shifts in position of these masers as they rotate around the black hole. This is equivalent to measuring an angle one ten-thousandth the width of a human hair held at arm's length. "The VLBA is the only instrument in the world that could do this," said Moran. "This work is the culmination of a 20-year effort at the Harvard Smithsonian Center for Astrophysics to measure distances to cosmic masers," said Irwin Shapiro, Director of that institution. Collection of the data for the NGC 4258 project was begun in 1994 and was part of Herrnstein's Ph.D dissertation at Harvard University. Previous observations with the VLBA allowed the scientists to measure the speed at which the gas is orbiting the black hole, some 39 million times more massive than the Sun. They did this by observing the amount of change in the wavelength of the radio wave

1999-06-01

241

The many faces of Hubble; measuring the public impact of the Hubble Space Telescope  

Microsoft Academic Search

The Office of Public Outreach (OPO) at the STScI was created to share the amazing discoveries of the Hubble Space Telescope with the American public. During the last five years we have developed a multitude of products and that have capitalized on the intense interest in Hubble to inform and inspire millions of Americans and many others around the globe.

I. Griffin; B. Eisenhammer; J. Stoke; S. Kakadelis; T. Teays; R. Villard; G. Voit

2002-01-01

242

The Infrared Astronomical Mission AKARI  

NASA Astrophysics Data System (ADS)

AKARI, the first Japanese satellite dedicated to infrared astronomy, was launched on 2006 February 21, and started observations in May of the same year. AKARI has a 68.5 cm cooled telescope, together with two focal-plane instruments, which survey the sky in six wavelength bands from mid- to far-infrared. The instruments also have a capability for imaging and spectroscopy in the wavelength range 2-180?m in the pointed observation mode, occasionally inserted into a continuous survey operation. The in-orbit cryogen lifetime is expected to be one and a half years. The All-Sky Survey will cover more than 90% of the whole sky with a higher spatial resolution and a wider wavelength coverage than that of the previous IRAS all-sky survey. Point-source catalogues of the All-Sky Survey will be released to the astronomical community. Pointed observations will be used for deep surveys of selected sky areas and systematic observations of important astronomical targets. These will become an additional future heritage of this mission.

Murakami, H.; Baba, H.; Barthel, P.; Clements, D. L.; Cohen, M.; Doi, Y.; Enya, K.; Figueredo, E.; Fujishiro, N.; Fujiwara, H.; Fujiwara, M.; Garcia-Lario, P.; Goto, T.; Hasegawa, S.; Hibi, Y.; Hirao, T.; Hiromoto, N.; Hong, S. S.; Imai, K.; Ishigaki, M.; Ishiguro, M.; Ishihara, D.; Ita, Y.; Jeong, W.-S.; Jeong, K. S.; Kaneda, H.; Kataza, H.; Kawada, M.; Kawai, T.; Kawamura, A.; Kessler, M. F.; Kester, D.; Kii, T.; Kim, D. Chan; Kim, W.; Kobayashi, H.; Koo, B. C.; Kwon, S. M.; Lee, H. M.; Lorente, R.; Makiuti, S.; Matsuhara, H.; Matsumoto, T.; Matsuo, H.; Matsuura, S.; Müller, T. G.; Murakami, N.; Nagata, H.; Nakagawa, T.; Naoi, T.; Narita, M.; Noda, M.; Oh, S. H.; Ohnishi, A.; Ohyama, Y.; Okada, Y.; Okuda, H.; Oliver, S.; Onaka, T.; Ootsubo, T.; Oyabu, S.; Pak, S.; Park, Y.-S.; Pearson, C. P.; Rowan-Robinson, M.; Saito, T.; Sakon, I.; Salama, A.; Sato, S.; Savage, R. S.; Serjeant, S.; Shibai, H.; Shirahata, M.; Sohn, J.; Suzuki, T.; Takagi, T.; Takahashi, H.; Tanabé, T.; Takeuchi, T. T.; Takita, S.; Thomson, M.; Uemizu, K.; Ueno, M.; Usui, F.; Verdugo, E.; Wada, T.; Wang, L.; Watabe, T.; Watarai, H.; White, G. J.; Yamamura, I.; Yamauchi, C.; Yasuda, A.

2007-10-01

243

The XML Astronomical Data Center  

NASA Astrophysics Data System (ADS)

The eXtensible Markup Language (XML) is a document markup language for the creation of hierarchical information structures. The document designer specifies (in a DTD) requirements on the document's content and provides choices for attributes of the contents. XML is supported by most major commercial software developers world-wide. A rich array of tools are already available to process and display XML documents. The Astronomical Data Center (ADC, http://adc.gsfc.nasa.gov) is involved in a research project to define an XML format for the metadata of an astronomical repository and for large data tables. In the process, an XML tool box is being developed for importation, enhancement, and distribution of tabled data and their metadata documents. There is now a working draft Document Type Definition (DTD, at http://tarantella.gsfc.nasa.gov/xml/dataset.dtd) which specifies the required elements of content and their attributes. The ADC is actively creating designs for the flow of data through automated pipelines from authors and journal presses into the ADC's XML archive, as well as data retrieval through the web via the eXtensible Query Language (XQL) (see accompanying poster by B. Holmes).

Shaya, E. J.; Blackwell, J.; Gass, J.; Holmes, B.; Odegard, N.; Schneider, G. L.; Thomas, Brian; Sodroski, T.; Cheung, C. Y.

1999-12-01

244

Astronomical Methods in Aerial Navigation  

NASA Technical Reports Server (NTRS)

The astronomical method of determining position is universally used in marine navigation and may also be of service in aerial navigation. The practical application of the method, however, must be modified and adapted to conform to the requirements of aviation. Much of this work of adaptation has already been accomplished, but being scattered through various technical journals in a number of languages, is not readily available. This report is for the purpose of collecting under one cover such previous work as appears to be of value to the aerial navigator, comparing instruments and methods, indicating the best practice, and suggesting future developments. The various methods of determining position and their application and value are outlined, and a brief resume of the theory of the astronomical method is given. Observation instruments are described in detail. A complete discussion of the reduction of observations follows, including a rapid method of finding position from the altitudes of two stars. Maps and map cases are briefly considered. A bibliography of the subject is appended.

Beij, K Hilding

1925-01-01

245

Effect upon universal order of Hubble expansion  

NASA Astrophysics Data System (ADS)

The level of order R in a spherical system of radius r0 with a probability amplitude function ?(x),x=r,?,? obeys R=(1/2)r02I, where I=4?dx| is its Fisher information level. We show that a flat space universe obeying the Robertson-Walker metric has an invariant value of the order as it undergoes either uniform Hubble expansion or contraction. This means that Hubble expansion per se does not cause a loss of universal order as time progresses. Instead, coarse graining processes characterizing decoherence and friction might cause a loss of order. Alternatively, looking backward in time, i.e. under Hubble contraction, as the big bang is approached and the Hubble radius r0 approaches small values, the structure in the amplitude function ?(x) becomes ever more densely packed, increasing all local slopes ?? and causing the Fisher information I to approach unboundedly large values. As a speculation, this ever-well locates the initial position of the universe in a larger, multiverse. We define a measure of order or complexity proportional to the Fisher information. The measure is applied to our flat-space, dust and gas dominated, universe. Despite the universe’s relentless, ever-accelerating Hubble expansion, its level of order is found to remain constant.

Frieden, B. R.; Plastino, A.; Plastino, A. R.

2012-01-01

246

Astronomers Reveal Extinct Extra-Terrestrial Fusion Reactor  

NASA Astrophysics Data System (ADS)

An international team of astronomers, studying the left-over remnants of stars like our own Sun, have found a remarkable object where the nuclear reactor that once powered it has only just shut down. This star, the hottest known white dwarf, H1504+65, seems to have been stripped of its entire outer regions during its death throes leaving behind the core that formed its power plant. Scientists from the United Kingdom, Germany and the USA focused two of NASA's space telescopes, the Chandra X-ray Observatory and the Far Ultraviolet Spectroscopic Explorer (FUSE), onto H1504+65 to probe its composition and measure its temperature. The data revealed that the stellar surface is extremely hot, 200,000 degrees, and is virtually free of hydrogen and helium, something never before observed in any star. Instead, the surface is composed mainly of carbon and oxygen, the 'ashes' of the fusion of helium in a nuclear reactor. An important question we must answer is why has this unique star lost the hydrogen and helium, which usually hide the stellar interior from our view? Professor Martin Barstow (University of Leicester) said. 'Studying the nature of the ashes of dead stars give us important clues as to how stars like the Sun live their lives and eventually die. The nuclear waste of carbon and oxygen produced in the process are essential elements for life and are eventually recycled into interstellar space to form new stars, planets and, possibly, living beings.' Professor Klaus Werner (University of Tübingen) said. 'We realized that this star has, on astronomical time scales, only very recently shut down nuclear fusion (about a hundred years ago). We clearly see the bare, now extinct reactor that once powered a bright giant star.' Dr Jeffrey Kruk (Johns Hopkins University) said: 'Astronomers have long predicted that many stars would have carbon-oxygen cores near the end of their lives, but I never expected we would actually be able to see one. This is a wonderful opportunity to improve our understanding of the life-cycle of stars.' The Chandra X-ray data also reveal the signatures of neon, an expected by-product of helium fusion. However, a big surprise was the presence of magnesium in similar quantities. This result may provide a key to the unique composition of H1504+65 and validate theoretical predictions that, if massive enough, some stars can extend their lives by tapping yet another energy source: the fusion of carbon into magnesium. However, as magnesium can also be produced by helium fusion, proof of the theory is not yet ironclad. The final link in the puzzle would be the detection of sodium, which will require data from yet another observatory: the Hubble Space Telescope. The team has already been awarded time on the Hubble Space Telescope to search for sodium in H1504+65 next year, and will, hopefully, discover the final answer as to the origin of this unique star. This work will be published in July in the 'Astronomy & Astrophysics' journal. The Chandra X-ray Observatory and the Far Ultraviolet Spectroscopic Explorer (FUSE) were both launched into orbit by NASA in 1999. Their instruments make use of a technique called spectroscopy, which spreads the light obtained from astronomical objects into its constituent X-ray and ultraviolet 'colours', in the same way visible light is dispersed into a rainbow naturally, by water droplets in the atmosphere, or artificially, by a prism. When studied in fine detail each spectrum is a unique 'fingerprint' which tells us what elements are present and reveals the physical conditions in the object being studied. Related Internet Address http://www.ras.org.uk/index.php?option=com_content&task=view&id=673&Itemid=2

2004-06-01

247

HUBBLE SENDS SEASON'S GREETINGS FROM THE COSMOS TO EARTH  

NASA Technical Reports Server (NTRS)

Looking like a colorful holiday card, this image from NASA's Hubble Space Telescope reveals a vibrant green and red nebula far from Earth, where nature seems to have put on the traditional colors of the season. These colors, produced by the light emitted by oxygen and hydrogen, help astronomers investigate the star-forming processes in nebulas such as NGC 2080. NGC 2080, nicknamed 'The Ghost Head Nebula,' is one of a chain of star-forming regions lying south of the 30 Doradus nebula in the Large Magellanic Cloud that have attracted special attention. These regions have been studied in detail with Hubble and have long been identified as unique star-forming sites. 30 Doradus is the largest star-forming complex in the whole local group of galaxies. The light from the nebula captured in this image is emitted by two elements, hydrogen and oxygen. The red and the blue light are from regions of hydrogen gas heated by nearby stars. The green light on the left comes from glowing oxygen. The energy to illuminate the green light is supplied by a powerful stellar wind (a stream of high-speed particles) coming from a massive star just outside the image. The white region in the center is a combination of all three emissions and indicates a core of hot, massive stars in this star-formation region. The intense emission from these stars has carved a bowl-shaped cavity in the surrounding gas. In the white region, the two bright areas (the 'eyes of the ghost') - named A1 (left) and A2 (right) - are very hot, glowing 'blobs' of hydrogen and oxygen. The bubble in A1 is produced by the hot, intense radiation and powerful stellar wind from a single massive star. A2 has a more complex appearance due to the presence of more dust, and it contains several hidden, massive stars. The massive stars in A1 and A2 must have formed within the last 10,000 years, since their natal gas shrouds are not yet disrupted by the powerful radiation of the newly born stars. The research team noted that Hubble's superb resolution is essential to see the various features in the nebula and to better understand the formation of massive stars in this interesting region. This 'enhanced color' picture is composed of three narrow-band-filter images obtained March 28, 2000, with Hubble's Wide Field Planetary Camera 2. The colors are red (ionized hydrogen, H-alpha, 1040 seconds), green (ionized oxygen, 1200 seconds) and blue (ionized hydrogen, H-beta, 1040 seconds). The image spans 67 x 67 arc-seconds, corresponding to 55 x 55 light-years at the distance of the Large Magellanic Cloud (168,000 light-years). Credit: NASA, ESA and Mohammad Heydari-Malayeri (Observatoire de Paris, France)

2002-01-01

248

Astronomical observatory for shuttle. Phase A study  

NASA Technical Reports Server (NTRS)

The design, development, and configuration of the astronomical observatory for shuttle are discussed. The characteristics of the one meter telescope in the spaceborne observatory are described. A variety of basic spectroscopic and image recording instruments and detectors which will permit a large variety of astronomical observations are reported. The stDC 37485elines which defined the components of the observatory are outlined.

Guthals, D. L.

1973-01-01

249

Astronomical Society of Australia Annual Scientific Meeting  

E-print Network

Astronomical Society of Australia Annual Scientific Meeting University of Adelaide (4 ­ 8 July 2011 would like to welcome you to Adelaide for the 2011 ASA Annual Scientific Meeting. The meeting in the Australian astronomical community. Evidence of this is the fact that just over 200 (talk+poster) abstracts

Adelaide, University of

250

ASTRONOMICAL THEORY of PALEOCLIMATES September 1425, 2011  

E-print Network

ASTRONOMICAL THEORY of PALEOCLIMATES September 1425, 2011 Berger A., Yin Q.Z. TABLE OF CONTENTS 1. Why paleoclimates and Global warming? What do we learn from paleoclimates and the astronomical theory? 2. The last 1 million years, proxy records and paleoclimates reconstructions 3

251

Conceptual Astronomy Knowledge among Amateur Astronomers  

ERIC Educational Resources Information Center

Amateur astronomers regularly serve as informal astronomy educators for their communities. This research inquires into the level of knowledge of basic astronomy concepts among amateur astronomers and examines factors related to amateur astronomy that affect that knowledge. Using the concept questions from the Astronomy Diagnostic Test Version 2,…

Berendsen, Margaret L.

2005-01-01

252

Nicephoros Gregoras: the greatest Byzantine astronomer  

Microsoft Academic Search

In the whole of Greece, no eminent astronomers appeared after the great Claudius Ptolemy (second century AD). For ten centuries after Ptolemy we can distinguish only one astronomer: Nicephoros Gregoras (1295 1360). The monk Nicephoros Gregoras is discussed together with his teacher, Theodoros Metochites, one of the most significant scholars of Byzantium. The literary work of Gregoras is especially important,

Efstratios Th. Theodossiou; Vassilios N. Manimanis; Milan S. Dimitrijevic; Emmanuel Danezis

2006-01-01

253

Nicephoros Gregoras: the greatest Byzantine astronomer  

Microsoft Academic Search

In the whole of Greece, no eminent astronomers appeared after the great Claudius Ptolemy (second century AD). For ten centuries after Ptolemy we can distinguish only one astronomer: Nicephoros Gregoras (1295–1360). The monk Nicephoros Gregoras is discussed together with his teacher, Theodoros Metochites, one of the most significant scholars of Byzantium. The literary work of Gregoras is especially important, while

Efstratios T. H. Theodossiou; Vassilios N. Manimanis; Milan S. Dimitrijevi?; Emmanuel Danezis

2006-01-01

254

Exploration and Fulfilment of Astronomical Literature  

NASA Astrophysics Data System (ADS)

The characteristic of the fulltext database and the database technique are analyzed in this paper. Development of the astronomical full text search system on the basis of Lucene search engine is also introduced. The system deals with astronomical literature without the background database. The system works well on the internet.

Sun, Yong-Bo; Guo, Hong-Feng

2007-09-01

255

HUBBLE'S NEW IMPROVED OPTICS PROBE THE CORE OF A DISTANT GALAXY  

NASA Technical Reports Server (NTRS)

This comparison image of the core of the galaxy M100 shows the dramatic improvement in Hubble Space Telescope's view of the universe. The new image was taken with the second generation Wide Field and Planetary Camera (WFPC-2) which was installed during the STS-61 Hubble Servicing Mission. The picture beautifully demonstrates that the corrective optics incorporated within the WFPC-2 compensate fully for optical aberration in Hubble's primary mirror. The new camera will allow Hubble to probe the universe with unprecedented clarity and sensitivity, and to fulfill many of the most important scientific objectives for which the telescope was originally built. [ Right ] The core of the grand design spiral galaxy M100, as imaged by Hubble Space Telescope's Wide Field Planetary Camera 2 in its high resolution channel. The WFPC-2 contains modified optics that correct for Hubble's previously blurry vision, allowing the telescope for the first time to cleanly resolve faint structure as small as 30 light-years across in a galaxy which is tens of millions of light years away. The image was taken on December 31, 1993. [Left ] For comparison, a picture taken with the WFPC-1 camera in wide field mode, on November 27, 1993, just a few days prior to the STS-61 servicing mission. The effects of optical aberration in HST's 2.4-meter primary mirror blur starlight, smear out fine detail, and limit the telescope's ability to see faint structure. Both Hubble images are 'raw;' they have not been subject to computer image reconstruction techniques commonly used in aberrated images made before the servicing mission. TARGET INFORMATION: M100 The galaxy M100 (100th object in the Messier Catalog of non-stellar objects) is one of the brightest members of the Virgo Cluster of galaxies. The galaxy is in the spring constellation Coma Berenices and can be seen through a moderate-sized amateur telescope. M100 is spiral shaped, like our Milky Way, and tilted nearly face-on as seen from earth. The galaxy has two prominent arms of bright stars and several fainter arms. Though the galaxy is estimated to be tens of millions of light-years away, Hubble reveals the sort of detail only seen previously (with ground based telescopes) in neighboring galaxies that are ten times closer. Before HST, astronomers could only see such a level of detail in roughly a dozen galaxies in our Local Group. Now, with Hubble's improved vision, the portion of the universe which can be studied with such clarity has grown a thousand fold. Only the future will tell what revelations await as Hubble's spectacular vision is applied to a host of fascinating and important questions about the universe and our place in it. PHOTO RELEASE NO.: STScI-PR94-01

2002-01-01

256

Local gravitational physics of the Hubble expansion  

E-print Network

We study physical consequences of the Hubble expansion of FLRW manifold on measurement of space, time and light propagation in the local inertial frame. We analyse the solar system radar ranging and Doppler tracking experiments, and time synchronization. FLRW manifold is covered by global coordinates (t,y^i), where t is the cosmic time coinciding with the proper time of the Hubble observers. We introduce local inertial coordinates x^a=(x^0,x^i) in the vicinity of a world line of a Hubble observer with the help of a special conformal transformation. The local inertial metric is Minkowski flat and is materialized by the congruence of time-like geodesics of static observers being at rest with respect to the local spatial coordinates x^i. We consider geodesic motion of test particles and notice that the local coordinate time x^0=x^0(t) taken as a parameter along the world line of particle, is a function of the Hubble's observer time t. This function changes smoothly from x^0=t for a particle at rest (observer's clock), to x^0=t+1/2 Ht^2 for photons, where H is the Hubble constant. Thus, motion of a test particle is non-uniform when its world line is parametrized by time t. NASA JPL Orbit Determination Program presumes that motion of light (after the Shapiro delay is excluded) is uniform with respect to the time t but it does not comply with the non-uniform motion of light on cosmological manifold. For this reason, the motion of light in the solar system analysed with the Orbit Determination Program appears as having a systematic blue shift of frequency, of radio waves circulating in the Earth-spacecraft radio link. The magnitude of the anomalous blue shift of frequency is proportional to the Hubble constant H that may open an access to the measurement of this fundamental cosmological parameter in the solar system radiowave experiments.

Sergei Kopeikin

2014-07-24

257

Developing an astronomical observatory in Paraguay  

NASA Astrophysics Data System (ADS)

Background: Paraguay has some heritage from the astronomy of the Guarani Indians. Buenaventura Suarez S.J. was a pioneer astronomer in the country in the XVIII century. He built various astronomical instruments and imported others from England. He observed eclipses of Jupiter's satellites and of the Sun and Moon. He published his data in a book and through letters. The Japanese O.D.A. has collaborated in obtaining equipment and advised their government to assist Paraguay in building an astronomical observatory, constructing a moving-roof observatory and training astronomers as observatory operators. Future: An astronomical center is on the horizon and some possible fields of research are being considered. Goal: To improve education at all possible levels by not only observing sky wonders, but also showing how instruments work and teaching about data and image processing, saving data and building a data base. Students must learn how a modern scientist works.

Troche-Boggino, Alexis E.

258

Astronomical Photographic Plate Collections: Treasure or Trash?  

NASA Astrophysics Data System (ADS)

Our efforts over the past three years to establish a national archive for astronomical plates will be described. This work has led to the following major conclusions regarding the preservation of astronomical photographic plates: (1) a significant number of observatories, as well as retiring astronomers, wish to dispose of the plates they hold; (2) most astronomers feel direct and spectroscopic plates of potential scientific value should be preserved; (3) there is little interest in providing support for preservation efforts on a broad scale. We offer that the astronomical community must quickly decide to preserve plate collections or they will soon be lost, either consciously discarded or through benign neglect. If a systematic effort to preserve these archival data is indeed to be made, priorities need to be established. Not only is archiving (and eventually digitizing) all existing plates impracticable, many plates have little or no potential value. We will present our ideas on priorities and seek the input of the community.

Osborn, W. H.; Castelaz, M. W.; Cline, J. D.

2005-12-01

259

Astronomical interferometry on the Moon  

NASA Technical Reports Server (NTRS)

Optical interferometric arrays are particularly attractive candidates for a manned lunar base. A permanent lunar can provide support for a variety of astronomical investigations. An optical interferometric array, perhaps of the general form of the VLA but designed for optical instead of radio wavelengths, would lead to a qualitative advance in the understanding of the universe. A wide variety of scientific problems could be addressed by such an instrument. The stellar analogs of the solar cycle, the behavior of sunspots on other stars, the magnetic field configurations of other stars, and the behavior of dynamic plasma phenomena such as flares and winds are examples of star related problems that ultimately would lead to both increased understanding of our Sun and fundamental knowledge of the manner in which stars form and evolve.

Burke, Bernard F.

1988-01-01

260

Hubble Heritage Observations of LBN 67  

NASA Astrophysics Data System (ADS)

We are proposing new observations for the Hubble Heritage project in cycle 22. We have identified a new target that will be used to produce high-quality, high-impact images that ensure continued public support for the Hubble mission. This proposal is submitted to the cycle 22 DD program to provide new images that will be obtained and released over the coming year. Our continuing ability to do science with HST and our hopes for JWST depend crucially on public support generated by our continuing commitment to sharing new images with the public.

Levay, Zolt

2014-10-01

261

Hubble Space Telescope Primer for Cycle 21  

NASA Astrophysics Data System (ADS)

The Hubble Space Telescope Primer for Cycle 21 is a companion document to the HST Call for Proposals1. It provides an overview of the Hubble Space Telescope (HST), with basic information about telescope operations, instrument capabilities, and technical aspects of the proposal preparation process. A thorough understanding of the material in this document is essential for the preparation of a competitive proposal. This document is available as an online HTML document and a PDF file. The HTML version, optimized for online browsing, contains many links to additional information. The PDF version is optimized for printing, but online PDF readers have search capabilities for quick retrieval of specific information.

Gonzaga, S.; et al.

2012-12-01

262

Astronomical Image Processing with Hadoop  

NASA Astrophysics Data System (ADS)

In the coming decade astronomical surveys of the sky will generate tens of terabytes of images and detect hundreds of millions of sources every night. With a requirement that these images be analyzed in real time to identify moving sources such as potentially hazardous asteroids or transient objects such as supernovae, these data streams present many computational challenges. In the commercial world, new techniques that utilize cloud computing have been developed to handle massive data streams. In this paper we describe how cloud computing, and in particular the map-reduce paradigm, can be used in astronomical data processing. We will focus on our experience implementing a scalable image-processing pipeline for the SDSS database using Hadoop (http://hadoop.apache.org). This multi-terabyte imaging dataset approximates future surveys such as those which will be conducted with the LSST. Our pipeline performs image coaddition in which multiple partially overlapping images are registered, integrated and stitched into a single overarching image. We will first present our initial implementation, then describe several critical optimizations that have enabled us to achieve high performance, and finally describe how we are incorporating a large in-house existing image processing library into our Hadoop system. The optimizations involve prefiltering of the input to remove irrelevant images from consideration, grouping individual FITS files into larger, more efficient indexed files, and a hybrid system in which a relational database is used to determine the input images relevant to the task. The incorporation of an existing image processing library, written in C++, presented difficult challenges since Hadoop is programmed primarily in Java. We will describe how we achieved this integration and the sophisticated image processing routines that were made feasible as a result. We will end by briefly describing the longer term goals of our work, namely detection and classification of transient objects and automated object classification.

Wiley, K.; Connolly, A.; Krughoff, S.; Gardner, J.; Balazinska, M.; Howe, B.; Kwon, Y.; Bu, Y.

2011-07-01

263

HUBBLE TRACKS CLOUDS ON URANUS  

NASA Technical Reports Server (NTRS)

Taking its first peek at Uranus, NASA Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has detected six distinct clouds in images taken July 28,1997. The image on the right, taken 90 minutes after the left-hand image, shows the planet's rotation. Each image is a composite of three near-infrared images. They are called false-color images because the human eye cannot detect infrared light. Therefore, colors corresponding to visible light were assigned to the images. (The wavelengths for the 'blue,' 'green,' and 'red' exposures are 1.1, 1.6, and 1.9 micrometers, respectively.) At visible and near-infrared light, sunlight is reflected from hazes and clouds in the atmosphere of Uranus. However, at near-infrared light, absorption by gases in the Uranian atmosphere limits the view to different altitudes, causing intense contrasts and colors. In these images, the blue exposure probes the deepest atmospheric levels. A blue color indicates clear atmospheric conditions, prevalent at mid-latitudes near the center of the disk. The green exposure is sensitive to absorption by methane gas, indicating a clear atmosphere; but in hazy atmospheric regions, the green color is seen because sunlight is reflected back before it is absorbed. The green color around the south pole (marked by '+') shows a strong local haze. The red exposure reveals absorption by hydrogen, the most abundant gas in the atmosphere of Uranus. Most sunlight shows patches of haze high in the atmosphere. A red color near the limb (edge) of the disk indicates the presence of a high-altitude haze. The purple color to the right of the equator also suggests haze high in the atmosphere with a clear atmosphere below. The five clouds visible near the right limb rotated counterclockwise during the time between both images. They reach high into the atmosphere, as indicated by their red color. Features of such high contrast have never been seen before on Uranus. The clouds are almost as large as continents on Earth, such as Europe. Another cloud (which barely can be seen) rotated along the path shown by the black arrow. It is located at lower altitudes, as indicated by its green color. The rings of Uranus are extremely faint in visible light but quite prominent in the near infrared. The brightest ring, the epsilon ring, has a variable width around its circumference. Its widest and thus brightest part is at the top in this image. Two fainter, inner rings are visible next to the epsilon ring. Eight of the 10 small Uranian satellites, discovered by Voyager 2, can be seen in both images. Their sizes range from about 25 miles (40 kilometers) for Bianca to 100 miles (150 kilometers) for Puck. The smallest of these satellites have not been detected since the departure of Voyager 2 from Uranus in 1986. These eight satellites revolve around Uranus in less than a day. The inner ones are faster than the outer ones. Their motion in the 90 minutes between both images is marked in the right panel. The area outside the rings was slightly enhanced in brightness to improve the visibility of these faint satellites. Credits: Erich Karkoschka (University of Arizona), and NASA.

2002-01-01

264

Local gravitational physics of the Hubble expansion  

E-print Network

We study physical consequences of the Hubble expansion of FLRW manifold on measurement of space, time and light propagation in the local inertial frame. We analyse the solar system radar ranging and Doppler tracking experiments, and time synchronization. FLRW manifold is covered by global coordinates (t,y^i), where t is the cosmic time coinciding with the proper time of the Hubble observers. We introduce local inertial coordinates x^a=(x^0,x^i) in the vicinity of a world line of a Hubble observer with the help of a special conformal transformation. The local inertial metric is Minkowski flat and is materialized by the congruence of time-like geodesics of static observers being at rest with respect to the local spatial coordinates x^i. We consider geodesic motion of test particles and notice that the local coordinate time x^0=x^0(t) taken as a parameter along the world line of particle, is a function of the Hubble's observer time t. This function changes smoothly from x^0=t for a particle at rest (observer's c...

Kopeikin, Sergei

2014-01-01

265

Hubble Space Telescope: now and then  

Microsoft Academic Search

The Hubble Space Telescope started out on its mission of infamy and is now providing unparalleled information on the universe. Shortly after its launch in April 1990, the HST was found to have a problem with the primary mirror. After extensive analysis, it was concluded that serious spherical aberration was present caused by an improper manufacturing process and measurement of

Lincoln L. Endelman

1997-01-01

266

Hubble Space Telescope Observations of Isolated Pulsars  

Microsoft Academic Search

Using the COSTAR corrected Faint Object Camera on the Hubble Space Telescope, we have obtained deep ultraviolet and optical images of the fields containing three nearby radio pulsars spanning a range in age between ˜1 × 105 and 2 × 107 yr. Deep 7\\

G. G. Pavlov; G. S. Stringfellow; F. A. Cordova

1996-01-01

267

The Infrared Surface Brightness Fluctuation Hubble Constant  

E-print Network

We measured infrared surface brightness fluctuation (SBF) distances to an isotropically-distributed sample of 16 distant galaxies with redshifts reaching 10,000 km/s using the near-IR camera and multi-object spectrometer (NICMOS) on the Hubble Space Telescope (HST). The excellent spatial resolution, very low background, and brightness of the IR fluctuations yielded the most distant SBF measurements to date. Twelve nearby galaxies were also observed and used to calibrate the F160W (1.6 micron) SBF distance scale. Of these, three have Cepheid variable star distances measured with HST and eleven have optical I-band SBF distance measurements. A distance modulus of 18.5 mag to the Large Magellanic Cloud was adopted for this calibration. We present the F160W SBF Hubble diagram and find a Hubble constant Ho=76 +/- 1.3 (1-sigma statistical) +/- 6 (systematic) km/s/Mpc. This result is insensitive to the velocity model used to correct for local bulk motions. Restricting the fit to the six most distant galaxies yields the smallest value of Ho=72 +/- 2.3 km/s/Mpc consistent with the data. This 6% decrease in the Hubble constant is consistent with the hypothesis that the Local Group inhabits an under-dense region of the universe, but is also consistent with the best-fit value of Ho=76 km/s/Mpc at the 1.5-sigma level.

Joseph B. Jensen; John L. Tonry; Rodger I. Thompson; Edward A. Ajhar; Tod R. Lauer; Marcia J. Rieke; Marc Postman; Michael C. Liu

2000-11-15

268

Dark Energy and the Hubble Law  

NASA Astrophysics Data System (ADS)

The Big Bang predicted by Friedmann could not be empirically discovered in the 1920th, since global cosmological distances (more than 300-1000 Mpc) were not available for observations at that time. Lemaitre and Hubble studied receding motions of galaxies at local distances of less than 20-30 Mpc and found that the motions followed the (nearly) linear velocity-distance relation, known now as Hubble's law. For decades, the real nature of this phenomenon has remained a mystery, in Sandage's words. After the discovery of dark energy, it was suggested that the dynamics of local expansion flows is dominated by omnipresent dark energy, and it is the dark energy antigravity that is able to introduce the linear velocity-distance relation to the flows. It implies that Hubble's law observed at local distances was in fact the first observational manifestation of dark energy. If this is the case, the commonly accepted criteria of scientific discovery lead to the conclusion: In 1927, Lemaitre discovered dark energy and Hubble confirmed this in 1929.

Chernin, A. D.; Dolgachev, V. P.; Domozhilova, L. M.

269

Testing for monotonicity in the Hubble diagram  

E-print Network

General relativistic kinematics and the cosmological principle alone imply a monotonicity constraint in the Hubble diagram, which we confront to present-day supernova data. We use the running gradient method of statistical inference by Hall & Heckman (2000). We find no significant departure from monotonicity. The method seems well adapted and we recommend its use with future data.

Nicolai Meinshausen; John Rice; Thomas Schücker

2006-12-19

270

Cosmic Origins Spectrograph Hubble Space Telescope  

E-print Network

? How were the chemical elements for life created in massive stars and supernovae? How do stars sightlines, 26 T Tauri stars) · 555 GTO orbits (not all will be executed by the end of Cycle 18) · Solar inference." #12;Cosmic Origins Spectrograph Hubble Space Telescope Cycle 17/18 Observations · ~25% of prime

Colorado at Boulder, University of

271

FGS Astrometry with the Hubble Space Telescope  

E-print Network

This article describes astrometric science that can be done with the Hubble Space Telescope Fine Guidance Sensors and presents some recent science results. We outline how these data are modeled, acquired, and calibrated. We next show how the astrometer, FGS 3, works as an interferometer. Finally, we present a guide to the literature that provides additional detail for each item discussed in the article.

G. Fritz Benedict

2000-07-05

272

Results from the corrected Hubble Space Telescope  

Microsoft Academic Search

Findings from the refurbished Hubble Space Telescope are presented, including imaging of asymmetrical circumstellar material around pre-main sequence stars in the Orion Nebula, discovery of a triple ring system in the supernova remnant 1987a, and the measurement of high velocity in the central region of the nucleus of the active galaxy M87 which provides evidence of the presence of a

A. L. Kinney

1995-01-01

273

The Hubble Space Telescope attitude observer anomaly  

Microsoft Academic Search

In mid-2004, the Hubble Space Telescope (HST) began experiencing occasional losses of lock during Fine Guidance Sensor (FGS) guide star acquisitions, threatening a potential loss of science. These failures were associated with an increasing disparity between the FGS-derived estimates of gyro bias calculated in orbit day and those calculated in orbit night. Early efforts to mitigate the operational effects of

Morgan M. Van Arsdall; Patrick R. Ramsey; Scott R. Swain

2006-01-01

274

Is Hubble's Expansion due to Dark Energy  

E-print Network

{\\it The universe is expanding} is known (through Galaxy observations) since 1929 through Hubble's discovery ($V = H D$). Recently in 1999, it is found (through Supernovae observations) that the universe is not simply expanding but is accelerating too. We, however, hardly know only $4\\%$ of the universe. The Wilkinson Microwave Anisotropy Probe (WMAP) satellite observational data suggest $73\\%$ content of the universe in the form of dark-energy, $23\\%$ in the form of non-baryonic dark-matter and the rest $4\\%$ in the form of the usual baryonic matter. The acceleration of the universe is ascribed to this dark-energy with bizarre properties (repulsive-gravity). The question is that whether Hubble's expansion is just due to the shock of big-bang & inflation or it is due to the repulsive-gravity of dark-energy? Now, it is believed to be due to dark-energy, say, by re-introducing the once-discarded cosmological-constant $\\Lambda$. In the present paper, it is shown that `the formula for acceleration due to dark-energy' is (almost) exactly of same-form as `the acceleration formula from the Hubble's law'. Hence, it is concluded that: yes, `indeed it is the dark-energy responsible for the Hubble's expansion too, in-addition to the current on-going acceleration of the universe'.

R. C. Gupta; Anirudh Pradhan

2010-10-19

275

A SURVEY OF ASTRONOMICAL RESEARCH: A BASELINE FOR ASTRONOMICAL DEVELOPMENT  

SciTech Connect

Measuring scientific development is a difficult task. Different metrics have been put forward to evaluate scientific development; in this paper we explore a metric that uses the number of peer-reviewed, and when available non-peer-reviewed, research articles as an indicator of development in the field of astronomy. We analyzed the available publication record, using the Smithsonian Astrophysical Observatory/NASA Astrophysics Database System, by country affiliation in the time span between 1950 and 2011 for countries with a gross national income of less than 14,365 USD in 2010. This represents 149 countries. We propose that this metric identifies countries in ''astronomical development'' with a culture of research publishing. We also propose that for a country to develop in astronomy, it should invest in outside expert visits, send its staff abroad to study, and establish a culture of scientific publishing. Furthermore, we propose that this paper may be used as a baseline to measure the success of major international projects, such as the International Year of Astronomy 2009.

Ribeiro, V. A. R. M. [Astrophysics, Cosmology and Gravity Centre, Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Russo, P. [EU Universe Awareness, Leiden Observatory, Leiden University, PO 9513 Leiden, 2300 RA (Netherlands); Cárdenas-Avendaño, A., E-mail: vribeiro@ast.uct.ac.za, E-mail: russo@strw.leidenuniv.nl [Departamento de Física, Universidad Nacional de Colombia, Carrera 45 No 26-85, Edificio Gutierréz, Bogotá, DC (Colombia)

2013-12-01

276

A Survey of Astronomical Research: A Baseline for Astronomical Development  

NASA Astrophysics Data System (ADS)

Measuring scientific development is a difficult task. Different metrics have been put forward to evaluate scientific development; in this paper we explore a metric that uses the number of peer-reviewed, and when available non-peer-reviewed, research articles as an indicator of development in the field of astronomy. We analyzed the available publication record, using the Smithsonian Astrophysical Observatory/NASA Astrophysics Database System, by country affiliation in the time span between 1950 and 2011 for countries with a gross national income of less than 14,365 USD in 2010. This represents 149 countries. We propose that this metric identifies countries in "astronomical development" with a culture of research publishing. We also propose that for a country to develop in astronomy, it should invest in outside expert visits, send its staff abroad to study, and establish a culture of scientific publishing. Furthermore, we propose that this paper may be used as a baseline to measure the success of major international projects, such as the International Year of Astronomy 2009.

Ribeiro, V. A. R. M.; Russo, P.; Cárdenas-Avendaño, A.

2013-12-01

277

NASA's Spitzer and Hubble Space Telescopes have teamed up  

E-print Network

NASA's Spitzer and Hubble Space Telescopes have teamed up to expose the chaos that baby stars image from the Hubble Space Telescope with an infrared image from the Spitzer Space Telescope. National be identified as the yellow smudge near the center of the image. Swirls of green in Hubble's ultraviolet

278

Calibration of the Hubble Space Telescope Fine Guidance Sensors  

E-print Network

Calibration of the Hubble Space Telescope Fine Guidance Sensors: An Application of Seminal Ideas, showing the location of the FGS The Hubble Space Telescope is a 2.4-meter, f-24 instrument of Ritchey- Chr of H.K. Eichhorn William H. Jefferys May 11, 1998 Abstract The calibration of the Hubble Space

Jefferys, William

279

Franklin Edward Kameny (1925-2011, Astronomer)  

NASA Astrophysics Data System (ADS)

Dr. Frank Kameny is best known today as one of the most important members of the gay rights movement in the United States, but he was also a PhD astronomer. In fact, it was his firing from his civil service position as astronomer for the US Army Map Service on the grounds of homosexuality that sparked his lifelong career of activism. Here, I explore some aspects of his short but interesting astronomical career and the role of the AAS in his life.

Wright, Jason

2012-01-01

280

Treasure-Hunting in Astronomical Plate Archives  

NASA Astrophysics Data System (ADS)

In our days astronomical research shows two trends - anong others: On the one hand traditional astronomical plate archives are in danger of falling into oblivion while science is losing their information content. On the other hand, there is an ever-growing need for long-term monitoring of large quantities of objects - the very information contained in the archives. On thes background the workshop ``Treasure-Hunting in Astronomical Plate Archives'' was convened in order to discuss the scientific potential of the world's photometric and astrometric plate archives, ways of making them fully available to scientific research, as well as technical problems connected with this.

Kroll, Peter; La Dous, Constanze; Bräuer, Hans-Jürgen

281

HUBBLE SPACE TELESCOPE ON TRACK FOR MEASURING THE EXPANSION RATE OF THE UNIVERSE  

NASA Technical Reports Server (NTRS)

Two international teams of astronomers, using NASA's Hubble Space Telescope, are reporting major progress in converging on an accurate measurement of the Universe's rate of expansion -- a value which has been debated for over half a century. These new results yield ranges for the age of the Universe from 9-12 billion years, and 11-14 billion years, respectively. The goal of the project is to measure the Hubble Constant to ten percent accuracy. The Hubble Space Telescope Key Project team, an international group of over 20 astronomers, is led by Wendy Freedman of Carnegie Observatories, Pasadena, CA, Robert Kennicutt, University of Arizona, Tucson, AZ, and Jeremy Mould, Mount Stromlo and Siding Springs Observatory, Australia. The group's interim results, announced at a meeting held at the Space Telescope Science Institute (STScI) in Baltimore, Maryland, are consistent with their preliminary result, announced in 1994, of 80 kilometers per second per megaparsec (km/sec/Mpc), based on observations of a galaxy in the Virgo cluster. 'We have five different ways of measuring the Hubble Constant with HST,' said Dr. Freedman. 'The results are coming in between 68 and 78 km/sec/Mpc.' (For example, at an expansion rate of 75 km/sec/Mpc, galaxies appear to be receding from us at a rate of 162,000 miles per hour for every 3.26 million light-years farther out we look). Two months ago, a second team, led by Allan Sandage, also of the Carnegie Observatories, Abhijit Saha, STScI, Gustav Tammann and Lukas Labhardt, Astronomical Institute, University of Basel, Duccio Macchetto and Nino Panagia, STScI/European Space Agency, reported a slower expansion rate of 57 km/sec/Mpc. The value of the Hubble Constant allows astronomers to calculate the expansion age of the Universe, the time elapsed since the Big Bang. Astronomers have been arguing recently whether the time since the Big Bang is consistent with the ages of the oldest stars. The ages are calculated from combining the expansion rate with an estimate of how much matter is in space. The younger age values from each team assume the Universe is at a critical density where it contains just enough matter to expand indefinitely. The higher age estimates are calculated based on a low density of matter in space. (See 'Science Background' for more information on the expanding Universe.) 'A point of great interest is whether the age of the Universe arrived at this way is really older than the independently derived ages of the oldest stars,' said Saha, an investigator on both Hubble teams. 'The numbers lean on the side that the stellar ages are a little lower, or that the hypothesis that we live in a critical density universe needs to be questioned,' said Saha. 'As further results accumulate over the next few years, we hope to tighten the constraints on these issues.' THE OBSERVATIONS The Key Project team is midway along in their three-year program to derive the expansion rate of the Universe based on precise distance measurements to galaxies. They have now measured Cepheid distances to a dozen galaxies, and are about halfway through their overall program. The Key Project team also presented a preliminary estimate of the distance to the Fornax cluster of galaxies. The estimate was obtained through the detection and measurement with the Hubble Space Telescope of pulsating stars known as Cepheid variables found in the Fornax cluster. The Fornax cluster is measured to be approximately as far away as the Virgo cluster of galaxies -- about 60 million light-years. The Key Project team member who led this effort, Caltech astronomer Barry Madore said, 'This cluster allows us to make independent estimates of the expansion rate of the Universe using a number of different techniques. All of these methods are now in excellent agreement. With Fornax we are now at turning point in this field.' The team is measuring Cepheid distances to the Virgo and Fornax clusters of galaxies as a complementary test. Their strategy is to compare and contrast expansion numbers from a variety of distance indicators. The Key Projec

2002-01-01

282

99Counting Craters On the Hubble Space Telescope! The STS-125 Atlantis astronauts retrieved the Hubble Space Telescope Wide-  

E-print Network

99Counting Craters On the Hubble Space Telescope! The STS-125 Atlantis astronauts retrieved the Hubble Space Telescope Wide- field Planetary Camera 2 (WFPC2) during a very successful and final on the average. The images below show some close-up images of impact craters on the Hubble Space Telescope

283

Image enhancement for astronomical scenes  

NASA Astrophysics Data System (ADS)

Telescope images of astronomical objects and man-made satellites are frequently characterized by high dynamic range and low SNR. We consider the problem of how to enhance these images, with the aim of making them visually useful rather than radiometrically accurate. Standard contrast and histogram adjustment tends to strongly amplify noise in dark regions of the image. Sophisticated techniques have been developed to address this problem in the context of natural scenes. However, these techniques often misbehave when confronted with low-SNR scenes that are also mostly empty space. We compare two classes of algorithms: contrast-limited adaptive histogram equalization, which achieves spatial localization via a tiling of the image, and gradient-domain techniques, which perform localized contrast adjustment by non-linearly remapping the gradient of the image in a content-dependent manner. We extend these to include a priori knowledge of SNR and the processing (e.g. deconvolution) that was applied in the preparation of the image. The methods will be illustrated with images of satellites from a ground-based telescope.

Lucas, Jacob; Calef, Brandoch; Knox, Keith

2013-09-01

284

A Future Astronomical Software Environment  

NASA Astrophysics Data System (ADS)

Analyzing data sets in astronomy has become more and more complex and has driven the development of specific tools, functions and tasks. In order to integrate these tools in a global environment and thereby preserving them, the OPTICON Network 9.2 in coordination with US-VAO has outlined requirements, defined an architectural concept and developed a prototype of a Future Astronomical Software Environment (FASE). Important features are support for user scripting (e.g. Python), access to legacy applications (e.g. IRAF, MIDAS), integration with the Virtual Observatory (VO) for access to remote data and computation, and scalability supporting desktops to distributed cluster systems. A first prototype has been implemented and demonstrates the feasibility by offering access to numerous applications (e.g. ds9, ESO CPL pipelines, MIDAS, topcat) from a Python or Unix shell using VO-SAMP as a software bus. A simple packaging system is also provided to allow easy definition and sharing of applications at a Web portal.

Grosböl, P.; Tody, D.; Paioro, L.; Granet, Y.; Garilli, B.; Surace, C.; Opticon Fase Network

2012-09-01

285

HUBBLE DISCOVERS POWERFUL LASER BEAMED FROM CHAOTIC STAR  

NASA Technical Reports Server (NTRS)

This is an artist's concept of a gas cloud (left) that acts as a natural ultraviolet laser, near the huge, unstable star Eta Carinae (right) -- one of most massive and energetic stars in our Milky Way Galaxy. The super-laser was identified by a team led by Kris Davidson of the University of Minnesota, and including nine other collaborators in the U.S. and Sweden during spectroscpic observations made with the Goddard High Resolution spectrograph aboard NASA's Hubble Space Telescope. Since it's unlikely that a single beam from the cloud would happen to be precisely aimed in earth's driection, the astronomers conclude that numerous beams must be radiating from the cloud in all directions - beams from a dance hall mirror-ball. The interstellar laser may result from Eta Carinae's violently chaotic eruptions, illustrated here as a reddish (due to light scattering by dust) outflow from the bright star. A laser, (an acronym for Light Amplification by Stimulated Emission of Radiation) creates an intense coherent beam of light when atoms or molecules in a gas, liquid or solid medium, force an incoming mix of wavelengths (or colors) of light to work in phase, or, at the same wavelength. Though a natural infrared laser was identified in space in 1995, lasers are very rare in space and nothing like the UV laser has ever been seen before. Eta Carinae is several million times brighter than the Sun, and one hundred times as massive. The superstar, located 8,000 light-years away in the souther constellation Carina, underwent a colossal outburst 150 years ago. Illustration courtesy James Gitlin/STScI

2002-01-01

286

Astronomers Discover Six Planets Orbiting Nearby Stars  

NSF Publications Database

... astronomers have discovered outside our solar system, to a total of 28 planets. All 28 have been ... circular orbits such as we see in our own solar system are relatively rare," said Vogt. The presence ...

287

Astronomical education in Tajikistan. Project TAJASTRO  

NASA Astrophysics Data System (ADS)

The centre of astronomy in Tajikistan is the Institute of Astrophysics of the Academy of Sciences of Tajikistan. This institute carries out scientific research and contributes to the preparation of the astronomical staff and to astronomical education. The reform of education in Tajikistan continues and now astronomy is studied in schools (together with physics) and at universities. The Tajik State Pedagogical University resumed in 2007 the training of teachers in physics and astronomy. Since 1999 the Tajik National University (TNU) offers a a specialty in astronomy. In 2006 is restored the Small Academy of Sciences (SAS) of Tajikistan. There is a planetarium in Khujand and in 2006 the Institute of Astrophysics, TNU and the Astronomical Society of Tajikistan, along with the support IBSP/UNESCO, organised the Training Methodical Center (TMC) ``TAJASTRO'' at the Hisar astronomical observatory for students, graduate students, young scientists, and teachers at secondary schools.

Ibadinov, Khursandkul I.; Rahmonov, A. A.

2011-06-01

288

Future Directions for Astronomical Image Display  

NASA Astrophysics Data System (ADS)

In the "Future Directions for Astronomical Image Displav" project, the Smithsonian Astrophysical Observatory (SAO) and the National Optical Astronomy Observatories (NOAO) evolved our existing image display program into fully extensible. cross-platform image display software. We also devised messaging software to support integration of image display into astronomical analysis systems. Finally, we migrated our software from reliance on Unix and the X Window System to a platform-independent architecture that utilizes the cross-platform Tcl/Tk technology.

Mandel, Eric

2000-03-01

289

Charge transfer inefficiency in the Hubble Space Telescope since Servicing Mission 4  

NASA Astrophysics Data System (ADS)

We update a physically motivated model of radiation damage in the Hubble Space Telescope Advanced Camera for Surveys/Wide Field Channel, using data up to mid-2010. We find that charge transfer inefficiency increased dramatically before shuttle Servicing Mission 4, with ~1.3 charge traps now present per pixel. During detector readout, charge traps spuriously drag electrons behind all astronomical sources, degrading image quality in a way that affects object photometry, astrometry and morphology. Our detector readout model is robust to changes in operating temperature and background level, and can be used to iteratively remove the trailing by pushing electrons back to where they belong. The result is data taken in mid-2010 that recovers the quality of imaging obtained within the first six months of orbital operations.

Massey, Richard

2010-11-01

290

HUBBLE CAPTURES AN EXTRAORDINARY AND POWERFUL ACTIVE GALAXY  

NASA Technical Reports Server (NTRS)

Resembling a swirling witch's cauldron of glowing vapors, the black hole-powered core of a nearby active galaxy appears in this colorful NASA Hubble Space Telescope image. The galaxy lies 13 million light-years away in the southern constellation Circinus. This galaxy is designated a type 2 Seyfert, a class of mostly spiral galaxies that have compact centers and are believed to contain massive black holes. Seyfert galaxies are themselves part of a larger class of objects called Active Galactic Nuclei or AGN. AGN have the ability to remove gas from the centers of their galaxies by blowing it out into space at phenomenal speeds. Astronomers studying the Circinus galaxy are seeing evidence of a powerful AGN at the center of this galaxy as well. Much of the gas in the disk of the Circinus spiral is concentrated in two specific rings -- a larger one of diameter 1,300 light-years, which has already been observed by ground-based telescopes, and a previously unseen ring of diameter 260 light-years. In the Hubble image, the smaller inner ring is located on the inside of the green disk. The larger outer ring extends off the image and is in the plane of the galaxy's disk. Both rings are home to large amounts of gas and dust as well as areas of major 'starburst' activity, where new stars are rapidly forming on timescales of 40 - 150 million years, much shorter than the age of the entire galaxy. At the center of the starburst rings is the Seyfert nucleus, the believed signature of a supermassive black hole that is accreting surrounding gas and dust. The black hole and its accretion disk are expelling gas out of the galaxy's disk and into its halo (the region above and below the disk). The detailed structure of this gas is seen as magenta-colored streamers extending towards the top of the image. In the center of the galaxy and within the inner starburst ring is a V-shaped structure of gas. The structure appears whitish-pink in this composite image, made up of four filters. Two filters capture the narrow lines from atomic transitions in oxygen and hydrogen; two wider filters detect green and near-infrared light. In the narrow-band filters, the V-shaped structure is very pronounced. This region, which is the projection of a three-dimensional cone extending from the nucleus to the galaxy's halo, contains gas that has been heated by radiation emitted by the accreting black hole. A 'counter-cone,' believed to be present, is obscured from view by dust in the galaxy's disk. Ultraviolet radiation emerging from the central source excites nearby gas causing it to glow. The excited gas is beamed into the oppositely directed cones like two giant searchlights. Located near the plane of our own Milky Way Galaxy, the Circinus galaxy is partially hidden by intervening dust along our line of sight. As a result, the galaxy went unnoticed until about 25 years ago. This Hubble image was taken on April 10, 1999 with the Wide Field Planetary Camera 2. The research team, led by Andrew S. Wilson of the University of Maryland, is using these visible light images along with near-infrared data to further understand the dynamics of this powerful galaxy. Credits: NASA, Andrew S. Wilson (University of Maryland); Patrick L. Shopbell (Caltech); Chris Simpson (Subaru Telescope); Thaisa Storchi-Bergmann and F. K. B. Barbosa (UFRGS, Brazil); and Martin J. Ward (University of Leicester, U.K.)

2002-01-01

291

HUBBLE FINDS THOUSANDS OF GASEOUS FRAGMENTS SURROUNDING DYING STAR  

NASA Technical Reports Server (NTRS)

Resembling a bizarre setting from a science fiction movie, dramatic images sent back by NASA's Hubble Space Telescope have surprised astronomers by uncovering thousands of gigantic tadpole-shaped objects surrounding a dying star. Dubbed 'cometary knots' because their glowing heads and gossamer tails superficially resemble comets, they are probably the result of a dying star's final outbursts. Though ground-based telescopic observations have hinted at such objects, they have not previously been seen in such abundance, say researchers. The knots were detected by Hubble astronomer C. Robert O'Dell and graduate student Kerry P. Handron of Rice University in Houston, Texas, while exploring the Helix nebula, a ring of glowing gases blown off the surface of a sunlike star late in its life. O'Dell expects the gaseous knots, which are each several billion miles across, will eventually dissipate and vanish into the cold emptiness of interstellar space. However, he speculates that if the objects contract to form permanent solid bodies, they may contribute to a fraction (less than ten percent) of the missing mass of our galaxy, simply because of their sheer abundance around a typical dying star. (This so-called dark matter is a known source of gravity that affects the motions of stars in the galaxy). The mysterious 'space pods' came into view as O'Dell used Hubble's Wide Field Planetary Camera 2 to survey the Helix nebula, located 450 light-years away in the constellation Aquarius and the closest planetary nebula to Earth -- so close that its angular size is almost half that of the full Moon. The most visible cometary knots all lie along the inner edge of the ring, at a distance of trillions of miles from the central star. Their comet-like tails, each stretching a hundred billion miles, form a radial pattern around the star like the spokes on a wagon wheel. Though previous ground-based observations show a spoke pattern in the Helix, and some structure, O'Dell emphasizes that the Hubble images reveal an underlying population of many more smaller objects. O'Dell made the observation because he was curious if these objects were the result of the star's final outburst which would bring comets out of 'cold storage' by boiling off the icy, solid comet nuclei. This is how comets behave as they swing near our Sun. The knots have just the right appearance and are at just the right distance from the dying star to be a long-sought comet cloud -- much like the hypothesized Oort cloud encircling our solar system. However, each gaseous cometary 'head' is at least twice the diameter of our solar system -- far too large for the gaseous shell, called a coma, that surrounds an active comet as we know it. The most likely explanation is the objects have been formed during the final years of a star's life when it ejects shells of gas into space. This 'planetary nebula' formation happens in stages where, toward the end of the process, a faster moving shell of gas ejected off the doomed star collides with slower moving gas released ten thousand years before. This collision of hot, lower density gas with cooler, higher density gas forms an unstable condition where the two gases intermix and fragment the previously smooth cloud. This process, called a Rayleigh-Taylor instability, breaks the cloud into smaller and denser finger-like droplets, like dripping paint. Standard models predict that the knots should expand and dissipate within a few hundred thousand years. However, dust particles inside each gas ball might collide and stick together, snowballing to planet- sized bodies over time. The resulting objects would be like Earth- sized copies of the frigid, icy planet Pluto. These icy worlds would escape the dead star and presumably roam interstellar space forever. If this phenomena is common among stars, then our galaxy could be littered with trillions of these objects, O'Dell concludes. 'Planetary nebulae have been formed in our galaxy for billions of years and about one new one is created every year since this is the usual ending for the billions of sunl

2002-01-01

292

Dark Energy and the Hubble Constant  

E-print Network

Dark energy is inferred from a Hubble expansion which is slower at epochs which are earlier than ours. But evidence reviewed here shows $H_0$ for nearby galaxies is actually less than currently adopted and would instead require {\\it deceleration} to reach the current value. Distances of Cepheid variables in galaxies in the Local Supercluster have been measured by the Hubble Space Telescope and it is argued here that they require a low value of $H_0$ along with redshifts which are at least partly intrinsic. The intrinsic component is hypothesized to be a result of the particle masses increasing with time. The same considerations apply to Dark Matter. But with particle masses growing with time, the condensation from plasmoid to proto galaxy not only does away with the need for unseen ``dark matter'' but also explains the intrinsic (non-velocity) redshifts of younger matter.

H. Arp

2007-12-19

293

Hubble space telescope onboard battery performance  

NASA Technical Reports Server (NTRS)

The performance of six 88 Ah Nickel-Hydrogen (Ni-H2) batteries that are used onboard in the Hubble Space Telescope (Flight Spare Module (FSM) and Flight Module 2 (FM2)) is discussed. These batteries have 22 series cells per battery and a common bus that would enable them to operate at a common voltage. It is launched on April 24, 1990. This paper reviews: the cell design, battery specification, system constraints, operating parameters, onboard battery management, and battery performance.

Rao, Gopalakrishna M.; Wajsgras, Harry; Vaidyanathan, Hari; Armontrout, Jon D.

1996-01-01

294

Hubble Space Telescope: Battery Capacity Trend Studies  

NASA Technical Reports Server (NTRS)

Battery cell wear out mechanisms and signatures are examined and compared to orbital data from the six on-orbit Hubble Space Telescope (HST) batteries, and the Flight Spare Battery (FSB) Test Bed at Marshall Space Flight Center (MSFC), which is instrumented with individual cell voltage monitoring. Capacity trend data is presented which suggests HST battery replacement is required in 2005-2007 or sooner.

Rao, M. Gopalakrishna; Hollandsworth, Roger; Armantrout, Jon

2004-01-01

295

Type IA Supernovae and the Hubble Constant  

Microsoft Academic Search

The focus of this review is the work that has been done during the 1990s on using Type Ia supernovae (SNe Ia) to measure the Hubble constant (H_0). SNe Ia are well suited for measuring (H_0). A straightforward maximum-light color criterion can weed out the minority of observed events that are either intrinsically subluminous or substantially extinguished by dust, leaving

David Branch

1998-01-01

296

The Infrared Surface Brightness Fluctuation Hubble Constant  

Microsoft Academic Search

We measured infrared surface brightness fluctuation (SBF) distances to an isotropically distributed sample of 16 distant galaxies with redshifts reaching 10,000 km s-1 using the near-IR camera and multiobject spectrometer (NICMOS) on the Hubble Space Telescope (HST). The excellent spatial resolution, very low background, and brightness of the IR fluctuations yielded the most distant SBF measurements to date. Twelve nearby

Joseph B. Jensen; John L. Tonry; Rodger I. Thompson; Edward A. Ajhar; Tod R. Lauer; Marcia J. Rieke; Marc Postman; Michael C. Liu

2001-01-01

297

Hubble Deep Field surface photometry (Fasano+ 1998)  

Microsoft Academic Search

The detailed surface photometry of a sample of early-type galaxies in the Hubble Deep Field is presented as part of a long-term project aimed to settle strong observational constraints to the theories modelling the evolution of elliptical galaxies from the early stages. The sample has been extracted, in the V606 band, from the database provided by the ESO-STECF-HDF Group (Couch,

G. Fasano; M. Filippi; F. Bertola

1997-01-01

298

The Infrared Surface Brightness Fluctuation Hubble Constant  

E-print Network

We measured infrared surface brightness fluctuation (SBF) distances to an isotropically-distributed sample of 16 distant galaxies with redshifts reaching 10,000 km/s using the near-IR camera and multi-object spectrometer (NICMOS) on the Hubble Space Telescope (HST). The excellent spatial resolution, very low background, and brightness of the IR fluctuations yielded the most distant SBF measurements to date. Twelve nearby galaxies were also observed and used to calibrate the F160W (1.6 micron) SBF distance scale. Of these, three have Cepheid variable star distances measured with HST and eleven have optical I-band SBF distance measurements. A distance modulus of 18.5 mag to the Large Magellanic Cloud was adopted for this calibration. We present the F160W SBF Hubble diagram and find a Hubble constant Ho=76 +/- 1.3 (1-sigma statistical) +/- 6 (systematic) km/s/Mpc. This result is insensitive to the velocity model used to correct for local bulk motions. Restricting the fit to the six most distant galaxies yields t...

Jensen, J B; Thompson, R I; Ajhar, E A; Lauer, T R; Rieke, M J; Postman, M; Liu, M C; Jensen, Joseph B.; Tonry, John L.; Thompson, Rodger I.; Ajhar, Edward A.; Lauer, Tod R.; Rieke, Marcia J.; Postman, Marc; Liu, Michael C.

2000-01-01

299

Hubble Images of Comet Hale-Bopp  

NASA Technical Reports Server (NTRS)

This is a series of Hubble Space Telescope observations of the region around the nucleus of Hale-Bopp, taken on eight different dates since September 1995. They chronicle changes in the evolution of the nucleus as it moves ever closer to, and is warmed by, the sun.

The first picture in the sequence, seen at upper left shows a strong dust outburst on the comet that occurred when it was beyond the orbit of Jupiter. Images in the Fall of 1996 show multiple jets that are presumably connected to the activation of multiple vents on the surface of the nucleus.

In these false color images, taken with the Wide Field and Planetary Camera 2, the faintest regions are black, the brightest regions are white, and intermediate intensities are represented by different levels of red. All images are processed at the same spatial scale of 280 miles per pixel (470 kilometers), so the solid nucleus, no larger than 25 miles across, is far below Hubble's resolution.

The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1998-01-01

300

Artist's Concept of Hubble-Discovered Ancient Gas-Giant Planet  

NASA Technical Reports Server (NTRS)

NASA's Hubble Space Telescope (HST) precisely measured the mass of the oldest known planet in our Milky Way Galaxy bringing closure to a decade of speculation. Scientists weren't sure if the object was a planet or a brown dwarf. Hubble's analysis shows that the object is 2.5 times the mass of Jupiter, confirming that it is indeed a planet. At an estimated age of 13 billion years, the planet is more than twice the age of Earth's 4.5 billion years. It formed around a young, sun-like star barely 1 million years after our universe's birth in the Big Bang. The ancient planet resides in an unlikely, rough neighborhood. It orbits a peculiar pair of burned-out stars in the crowded core cluster of more than 100,000 stars. Its very existence provides evidence that the first planets formed rapidly, within a billion years of the Big Bang, and leads astronomers to conclude that planets may be very abundant in our galaxy. This artist's concept depicts the planet with a view of a rich star filled sky.

2003-01-01

301

New Horizons: Long-Range Kuiper Belt Targets Observed by the Hubble Space Telescope  

NASA Astrophysics Data System (ADS)

We will report on Hubble Space Telescope (HST) observations of three Kuiper Belt Objects (KBOs), discovered in our dedicated ground-based search campaign, that are candidates for long-range observations from the New Horizons spacecraft: 2011 JY31, 2011 HZ102, and 2013 LU35. Astrometry with HST enables both current and future critical accuracy improvements for orbit precision, required for possible New Horizons observations, beyond what can be obtained from the ground. Photometric colors of all three objects are red, typical of the Cold Classical dynamical population within which they reside; they are also the faintest KBOs to have had their colors measured. None are observed to be binary with HST above separations of ~0.02 arcsec 700 km at 44 AU) and ?m ? 0.5. This research is based in part on ground-based data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan, and on data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile. Space-based observations were made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Benecchi, Susan D.; Noll, Keith; Weaver, Harold; Spencer, John; Stern, S. A.; Buie, Marc; Parker, Alex

2014-11-01

302

Scalable Machine Learning for Massive Astronomical Datasets  

NASA Astrophysics Data System (ADS)

We present the ability to perform data mining and machine learning operations on a catalog of half a billion astronomical objects. This is the result of the combination of robust, highly accurate machine learning algorithms with linear scalability that renders the applications of these algorithms to massive astronomical data tractable. We demonstrate the core algorithms kernel density estimation, K-means clustering, linear regression, nearest neighbors, random forest and gradient-boosted decision tree, singular value decomposition, support vector machine, and two-point correlation function. Each of these is relevant for astronomical applications such as finding novel astrophysical objects, characterizing artifacts in data, object classification (including for rare objects), object distances, finding the important features describing objects, density estimation of distributions, probabilistic quantities, and exploring the unknown structure of new data. The software, Skytree Server, runs on any UNIX-based machine, a virtual machine, or cloud-based and distributed systems including Hadoop. We have integrated it on the cloud computing system of the Canadian Astronomical Data Centre, the Canadian Advanced Network for Astronomical Research (CANFAR), creating the world's first cloud computing data mining system for astronomy. We demonstrate results showing the scaling of each of our major algorithms on large astronomical datasets, including the full 470,992,970 objects of the 2 Micron All-Sky Survey (2MASS) Point Source Catalog. We demonstrate the ability to find outliers in the full 2MASS dataset utilizing multiple methods, e.g., nearest neighbors. This is likely of particular interest to the radio astronomy community given, for example, that survey projects contain groups dedicated to this topic. 2MASS is used as a proof-of-concept dataset due to its convenience and availability. These results are of interest to any astronomical project with large and/or complex datasets that wishes to extract the full scientific value from its data.

Ball, Nicholas M.; Gray, A.

2014-04-01

303

Scalable Machine Learning for Massive Astronomical Datasets  

NASA Astrophysics Data System (ADS)

We present the ability to perform data mining and machine learning operations on a catalog of half a billion astronomical objects. This is the result of the combination of robust, highly accurate machine learning algorithms with linear scalability that renders the applications of these algorithms to massive astronomical data tractable. We demonstrate the core algorithms kernel density estimation, K-means clustering, linear regression, nearest neighbors, random forest and gradient-boosted decision tree, singular value decomposition, support vector machine, and two-point correlation function. Each of these is relevant for astronomical applications such as finding novel astrophysical objects, characterizing artifacts in data, object classification (including for rare objects), object distances, finding the important features describing objects, density estimation of distributions, probabilistic quantities, and exploring the unknown structure of new data. The software, Skytree Server, runs on any UNIX-based machine, a virtual machine, or cloud-based and distributed systems including Hadoop. We have integrated it on the cloud computing system of the Canadian Astronomical Data Centre, the Canadian Advanced Network for Astronomical Research (CANFAR), creating the world's first cloud computing data mining system for astronomy. We demonstrate results showing the scaling of each of our major algorithms on large astronomical datasets, including the full 470,992,970 objects of the 2 Micron All-Sky Survey (2MASS) Point Source Catalog. We demonstrate the ability to find outliers in the full 2MASS dataset utilizing multiple methods, e.g., nearest neighbors, and the local outlier factor. 2MASS is used as a proof-of-concept dataset due to its convenience and availability. These results are of interest to any astronomical project with large and/or complex datasets that wishes to extract the full scientific value from its data.

Ball, Nicholas M.; Astronomy Data Centre, Canadian

2014-01-01

304

Hubble tracks down a galaxy cluster's dark matter  

NASA Astrophysics Data System (ADS)

Unique mass map hi-res Size hi-res: 495 kb Credits: European Space Agency, NASA and Jean-Paul Kneib (Observatoire Midi-Pyrénées, France/Caltech, USA) Unique mass map This is a mass map of galaxy cluster Cl0024+1654 derived from an extensive Hubble Space Telescope campaign. The colour image is made from two images: a dark-matter map (the blue part of the image) and a 'luminous-matter' map determined from the galaxies in the cluster (the red part of the image). They were constructed by feeding Hubble and ground-based observations into advanced mathematical mass-mapping models. The map shows that dark matter is present where the galaxies clump together. The mass of the galaxies is shown in red, the mass of the dark matter in blue. The dark matter behaves like a 'glue', holding the cluster together. The dark-matter distribution in the cluster is not spherical. A secondary concentration of dark-matter mass is shown in blue to the upper right of the main concentration. Sky around galaxy cluster Cl0024+1654 hi-res Size hi-res: 3742 kb Credits: European Space Agency, NASA and Jean-Paul Kneib (Observatoire Midi-Pyrénées, France/Caltech, USA) Sky around galaxy cluster Cl0024+1654 This is a 2.5-degree field around galaxy cluster Cl0024+1654. The cluster galaxies are visible in the centre of the image in yellow. The image is a colour composite constructed from three Digitized Sky Survey 2 images: Blue (shown in blue), Red (shown in green), and Infrared (shown in red). HST observes shapes of more than 7000 faint background galaxies hi-res Size hi-res: 5593 kb Credits: European Space Agency, NASA and Jean-Paul Kneib (Observatoire Midi-Pyrénées, France/Caltech, USA) Hubble observes shapes of more than 7000 faint background galaxies Five days of observations produced the altogether 39 Hubble Wide Field and Planetary Camera 2 (WFPC2) images required to map the mass of the galaxy cluster Cl0024+1654. Each WFPC2 image has a size of about 1/150 the diameter of the full Moon. In total, the image measures 27 arc-minutes across, slightly smaller than the diameter of the Moon. The observed warped shapes of more than 7000 faint background galaxies have been converted into a unique map of the dark matter in the cluster. The images were taken through a red filter and have been reduced a factor of two in size. Ground-based image of the galaxy cluster C10024+1654 hi-res Size hi-res: 4699 kb Credits: European Space Agency, NASA and Jean-Paul Kneib (Observatoire Midi-Pyrénées, France/Caltech, USA) Ground-based image of the galaxy cluster C10024+1654 This is a colour image of the galaxy cluster C10024+1654 obtained with the CFHT12k camera at the Canada France Hawaii Telescope on Mauna Kea (Hawaii). The cluster clearly appears as a concentration of yellow galaxies in the centre of this image although cluster galaxies actually extend at least to the edge of this image. This image measures 21 x 21 arc-minutes. Clusters of galaxies are the largest stable systems in the Universe. They are like laboratories for studying the relationship between the distributions of dark and visible matter. In 1937, Fritz Zwicky realised that the visible component of a cluster (the thousands of millions of stars in each of the thousands of galaxies) represents only a tiny fraction of the total mass. About 80-85% of the matter is invisible, the so-called 'dark matter'. Although astronomers have known about the presence of dark matter for many decades, finding a technique to view its distribution is a much more recent development. Led by Drs Jean-Paul Kneib (from the Observatoire Midi-Pyrénées, France/Caltech, United States), Richard Ellis and Tommaso Treu (both Caltech, United States), the team used the NASA/ESA Hubble Space Telescope to reconstruct a unique 'mass map' of the galaxy cluster CL0024+1654. It enabled them to see for the first time on such large scales how mysterious dark matter is distributed with respect to galaxies. This comparison gives new clues on how such large clusters assemble and which role dark matter plays in cosmic evolution. Tracing dark ma

2003-07-01

305

Finding possibility of dynamical dark energy with Hubble parameters  

NASA Astrophysics Data System (ADS)

The Hubble parameter is a critical measurement in cosmology, which contains the most direct information of the cosmic expansion history. Since discrepancy is found between low redshift and high redshift estimations of Hubble constant, we are interested in whether that tension indicates dynamical dark energy. In this paper, we emphasize that the observed Hubble parameters at various redshifts, along with observed Hubble constant, can help us in probing the evolutional behavior of the mysterious dark energy. Null hypothesis tests are carried out with two diagnostic approaches. We find out that, according to the present measurements of Hubble parameters, rejection of constant dark energy is captured at 1? level from null tests with and without the observed value of Hubble constant.

Wang, Jiaxin; Meng, Xinhe

2014-10-01

306

Eight Physicists and Astronomers: Biographical Portraits  

E-print Network

This essay provides concise biographical information about eight physicists, astronomers, astrophysicists, and cosmologists from the twentieth century. The portrayed scientists are Hermann Bondi (1919-2005), Charles L. Critchfield (1910-1994), Arthur E. Haas (1884-1941), Chushiro Hayashi (1920-2010, Gustave Le Bon (1841-1931), Wilhelm Lenz (1888-1957), Franz Selety (1893-1933?), and S. Elis Str\\"omgren (1870-1947). Because the entries were written for a biographical dictionary of astronomers, the emphasis is on the astronomical and astrophysical contributions of the scientists rather than their work in physics. While some of them are well known, others (such as Selety, Haas and Le Bon) will probably be unknown to most physicists.

Kragh, Helge

2012-01-01

307

Airglow measurements with astronomical data  

NASA Astrophysics Data System (ADS)

The highly elusive airglow lines and continuum probe the atmosphere at a height of roughly 80 to several 100 km. Since the emission originates from different atoms (O, Na) as well as different molecules as line emission (OH,O2) or in continuum emission (NO+O/O3) one needs to span a broad wavelength range to cover them all (near-UV to near-IR). Most spectrographs used by the community cover only a very narrow wavelength range with medium to high resolution. The European Southern Observatory (ESO) has the necessary instruments to provide spectra from near-UV to near-IR with moderate to high spectral resolution. ESO's main site is the Very Large Telescope (VLT), which is located in the Atacama desert in Chile at an altitude of 2635 m. It consists of four 8 m class telescopes and several smaller ones. The X-Shooter instrument is mounted on one of the 8 m class telescopes and covers a wavelength range of 300-2500 nm simultaneously. Thus, it is one of the most sensitive and versatile spectrographs at hand today and has a resolution of 3000-18000 depending on the observation mode. Observations started in October 2009 and continue until today. Our current dataset includes all observations taken between October 2009 and March 2013. The temporal coverage of this period is good since X-Shooter is frequently used. Due to its wide wavelength range, X-Shooter provides almost all OH bands, most of the O2 bands, and the atomic lines NI[520.0 nm], OI[557.7 nm], NaID[589.0 nm], and OI[630.0,636.4 nm]. This gives us the opportunity to do a detailed study on airglow lines and continuum depending on different parameters such as solar activity, night time, and seasonal variation. In addition, we are able to derive mesopause temperatures depending on the same parameters. All the above mentioned studies are a valuable asset to the understanding of the dynamics and chemical processes in the upper atmosphere. To illustrate the capabilities of astronomical data, we investigated intensity measurements of FeO*, which was recently discovered to contribute to the airglow continuum. Until now mainly its existence was proven but studies on its properties based on large datasets are missing. To obtain reasonable results on the FeO* emission between 500-720 nm, one has to disentangle several continuum contributions. Nevertheless, the two main peaks are clearly visible in our X-Shooter spectra. Furthermore, we will compare FeO* to NaID intensities since they are expected to be linked in two ways: they are both replenished by meteors and their intensities should vary in union as both of them have ozone as a common reactant. We present a longterm study on the intensity measurements for FeO* and NaID to probe their variations.

Unterguggenberger, Stefanie; Noll, Stefan; Kausch, Wolfgang; Kimeswenger, Stefan; Jones, Amy

2014-05-01

308

Hubble Observes a New Saturn Storm  

NASA Technical Reports Server (NTRS)

This NASA Hubble Space Telescope image of the ringed planet Saturn shows a rare storm that appears as a white arrowhead-shaped feature near the planet's equator. The storm is generated by an upwelling of warmer air, similar to a terrestrial thunderhead. The east-west extent of this storm is equal to the diameter of the Earth (about 7,900 miles). Hubble provides new details about the effects of Saturn's prevailing winds on the storm. The new image shows that the storm's motion and size have changed little since its discovery in September, 1994.

The storm was imaged with Hubble's Wide Field Planetary Camera 2 (WFPC2) in the wide field mode on December 1, 1994, when Saturn was 904 million miles from the Earth. The picture is a composite of images taken through different color filters within a 6 minute interval to create a 'true-color' rendition of the planet. The blue fringe on the right limb of the planet is an artifact of image processing used to compensate for the rotation of the planet between exposures.

The Hubble images are sharp enough to reveal that Saturn's prevailing winds shape a dark 'wedge' that eats into the western (left) side of the bright central cloud. The planet's strongest eastward winds (clocked at 1,000 miles per hour from analysis of Voyager spacecraft images taken in 1980-81) are at the latitude of the wedge.

To the north of this arrowhead-shaped feature, the winds decrease so that the storm center is moving eastward relative to the local flow. The clouds expanding north of the storm are swept westward by the winds at higher latitudes. The strong winds near the latitude of the dark wedge blow over the northern part of the storm, creating a secondary disturbance that generates the faint white clouds to the east (right) of the storm center.

The storm's white clouds are ammonia ice crystals that form when an upward flow of warmer gases shoves its way through Saturn's frigid cloud tops. This current storm is larger than the white clouds associated with minor storms that have been reported more frequently as bright cloud features.

Hubble observed a similar, though larger, storm in September 1990, which was one of three major Saturn storms seen over the past two centuries. Although these events were separated by about 57 years (approximately 2 Saturnian years) there is yet no explanation why they apparently follow a cycle -- occurring when it is summer in Saturn's northern hemisphere.

The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1994-01-01

309

Hubble Provides Clear Images of Saturn's Aurora  

NASA Technical Reports Server (NTRS)

This is the first image of Saturn's ultraviolet aurora taken by the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope in October 1997, when Saturn was a distance of 810 million miles (1.3 billion kilometers) from Earth. The new instrument, used as a camera, provides more than ten times the sensitivity of previous Hubble instruments in the ultraviolet. STIS images reveal exquisite detail never before seen in the spectacular auroral curtains of light that encircle Saturn's north and south poles and rise more than a thousand miles above the cloud tops.

Saturn's auroral displays are caused by an energetic wind from the Sun that sweeps over the planet, much like the Earths aurora that is occasionally seen in the nighttime sky and similar to the phenomenon that causes fluorescent lamps to glow. But unlike the Earth, Saturn's aurora is only seen in ultraviolet light that is invisible from the Earths surface, hence the aurora can only be observed from space. New Hubble images reveal ripples and overall patterns that evolve slowly, appearing generally fixed in our view and independent of planet rotation. At the same time, the curtains show local brightening that often follow the rotation of the planet and exhibit rapid variations on time scales of minutes. These variations and regularities indicate that the aurora is primarily shaped and powered by a continual tug-of-war between Saturn's magnetic field and the flow of charged particles from the Sun.

Study of the aurora on Saturn had its beginnings just seventeen years ago. The Pioneer 11 spacecraft observed a far-ultraviolet brightening on Saturn's poles in 1979. The Saturn flybys of the Voyager 1 and 2 spacecraft in the early 1980s provided a basic description of the aurora and mapped for the first time planets enormous magnetic field that guides energetic electrons into the atmosphere near the north and south poles.

The first images of Saturn's aurora were provided in 1994-5 by the Hubble Space Telescopes Wide Field and Planetary Camera (WFPC2). Much greater ultraviolet sensitivity of the new STIS instrument allows the workings of Saturn's magnetosphere and upper atmosphere to be studied in much greater detail. These Hubble aurora investigations provide a framework that will ultimately complement the in situ measurements of Saturn's magnetic field and charged particles by NASA/ ESA's Cassini spacecraft, now en route to its rendezvous with Saturn early in the next decade.

Two STIS imaging modes have been used to discriminate between ultraviolet emissions predominantly from hydrogen atoms (shown in red) and emissions due to molecular hydrogen (shown in blue). Hence the bright red aurora features are dominated by atomic hydrogen, while the white traces within them map the more tightly confined regions of molecular hydrogen emissions. The southern aurora is seen at lower right, the northern at upper left.

The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1998-01-01

310

Cosmic Supernova Rates and the Hubble Sequence  

E-print Network

We compute the type Ia, Ib/c and II supernova (SN) rates as functions of the cosmic time for galaxies of different morphological types. We use four different chemical evolution models, each one reproducing the features of a particular morphological type: E/S0, S0a/b, Sbc/d and Irr galaxies. We essentially describe the Hubble sequence by means of decreasing efficiency of star formation and increasing infall timescale. These models are used to study the evolution of the SN rates per unit luminosity and per unit mass as functions of cosmic time and as functions of the Hubble type. Our results indicate that: (i) the observed increase of the SN rate per unit luminosity and unit mass from early to late galaxy types is accounted for by our models. Our explanation of this effect is related to the fact that the latest Hubble types have the highest star formation rate per unit mass; (ii) By adopting a Scalo (1986) initial mass function in spiral disks, we find that massive single stars ending their lives as Wolf-Rayet objects are not sufficient to account for the observed type Ib/c SN rate per unit mass. Less massive stars in close binary systems can give instead a significant contribution to the local Ib/c SN rates. On the other hand, with the assumption of a Salpeter (1955) IMF for all galaxy types, single massive WR stars are sufficient to account for the observed type Ib/c SN rate. (iii) Our models allow us to reproduce the observed type Ia SN rate density up to redshift z~1. We predict an increasing type Ia SN rate density with redshift, reaching a peak at redshift z >= 3, because of the contribution of massive spheroids.

F. Calura; F. Matteucci

2006-07-31

311

Coronagraph for astronomical imaging and spectrophotometry  

NASA Technical Reports Server (NTRS)

A coronagraph designed to minimize scattered light in astronomical observations caused by the structure of the primary mirror, secondary mirror, and secondary support structure of a Cassegrainian telescope is described. Direct (1:1) and reducing (2.7:1) imaging of astronomical fields are possible. High-quality images are produced. The coronagraph can be used with either a two-dimensional charge-coupled device or photographic film camera. The addition of transmission dispersing optics converts the coronagraph into a low-resolution spectrograph. The instrument is modular and portable for transport to different observatories.

Vilas, Faith; Smith, Bradford A.

1987-01-01

312

Book Review: Scientific Writing for Young Astronomers  

NASA Astrophysics Data System (ADS)

Part 1, 165 pp., hardcover, EAS Publication Series Volume 49, ISBN 978-2-7598-0506-8. Price 36 Euro, including VAT (http://www.edition-sciences.com/scientific-writing-for-young-astronomers-part-1.htm). Part 2, 298 pp., hardcover, EAS Publication Series Volume 50, ISBN 987-2-7598-0639-3. Price 61 Euro, including VAT (http://www.edition-sciences.com/scientific-writing-for-young-astronomers-part-2.htm). Both parts include subject and name index and list of acronyms. Published by EAS, EDP Sciences, Les Ulis, France.

Broens, E.

2013-06-01

313

Johann and Elizabeth Hevelius, astronomers of Danzig.  

PubMed

Elizabeth Hevelius (1647-1693) was the second wife of Johann Hevelius, the renowned astronomer of Danzig, and assisted with his observations from the first years of her marriage. Hevelius wrote of her in his books as an able collaborator and she is portrayed in one of them observing with him. She brought out his final, posthumous work. With Johann, she received many notable visitors (including Edmond Halley) and observed with some of them at Danzig. She is the first woman astronomer of whom we have any record. PMID:10824438

Cook, A

2000-01-01

314

Large scale deviations from the Hubble flow.  

NASA Astrophysics Data System (ADS)

All standard Big Bang cosmologies have one thing in common. The initial state from which the Universe has developed, was homogeneous and isotropic to a "very high degree". Indeed we now observe that the distribution of galaxies is very homogeneous and isotropic when smoothed over a suitable large area of the sky. Also we observe that galaxies recede from one another in a universal manner described by the Hubble law, and this law is considered as valid on sufficiently "Iarge scales". There is additional observational evidence in the "very high degree" of isotropy of the microwave background radition, neglecting the very weil understood dipole anisotropy for the moment.

Hesselbjerg Christensen, J.

1988-06-01

315

The Infrared Surface Brightness Fluctuation Hubble Constant  

Microsoft Academic Search

We measured infrared surface brightness fluctuation (SBF) distances to an\\u000aisotropically-distributed sample of 16 distant galaxies with redshifts reaching\\u000a10,000 km\\/s using the near-IR camera and multi-object spectrometer (NICMOS) on\\u000athe Hubble Space Telescope (HST). The excellent spatial resolution, very low\\u000abackground, and brightness of the IR fluctuations yielded the most distant SBF\\u000ameasurements to date. Twelve nearby galaxies were

Joseph B. Jensen; John L. Tonry; Rodger I. Thompson; Edward A. Ajhar; Tod R. Lauer; Marcia J. Rieke; Marc Postman; Michael C. Liu

2000-01-01

316

Inverse Hubble Flows in Molecular Clouds  

E-print Network

Motivated by recent numerical simulations of molecular cloud (MC)evolution, in which the clouds engage in global gravitational contraction, and local collapse events culminate significantly earlier than the global collapse, we investigate the growth of density perturbations embedded in a collapsing background, to which we refer as an Inverse Hubble Flow (IHF). We use the standard procedure for the growth of perturbations in a universe that first expands (the usual Hubble Flow) and then recollapses (the IHF). We find that linear density perturbations immersed in an IHF grow faster than perturbations evolving in a static background (the standard Jeans analysis). A fundamental distinction between the two regimes is that, in the Jeans case, the time $\\tau_\\mathrm{nl}$ for a density fluctuation to become nonlinear increases without limit as its initial value approaches zero, while in the IHF case $\\tau_\\mathrm{nl} \\le \\tau_\\mathrm{ff}$ always, where $\\tau_\\mathrm{ff}$ is the free-fall time of the background densit...

Toalá, Jesús A; Colín, Pedro; Gómez, Gilberto C

2014-01-01

317

HUBBLE REVEALS STELLAR FIREWORKS ACCOMPANYING GALAXY COLLISION  

NASA Technical Reports Server (NTRS)

This Hubble Space Telescope image provides a detailed look at a brilliant 'fireworks show' at the center of a collision between two galaxies. Hubble has uncovered over 1,000 bright, young star clusters bursting to life as a result of the head-on wreck. [Left] A ground-based telescopic view of the Antennae galaxies (known formally as NGC 4038/4039) - so named because a pair of long tails of luminous matter, formed by the gravitational tidal forces of their encounter, resembles an insect's antennae. The galaxies are located 63 million light-years away in the southern constellation Corvus. [Right] The respective cores of the twin galaxies are the orange blobs, left and right of image center, crisscrossed by filaments of dark dust. A wide band of chaotic dust, called the overlap region, stretches between the cores of the two galaxies. The sweeping spiral- like patterns, traced by bright blue star clusters, shows the result of a firestorm of star birth activity which was triggered by the collision. This natural-color image is a composite of four separately filtered images taken with the Wide Field Planetary Camera 2 (WFPC2), on January 20, 1996. Resolution is 15 light-years per pixel (picture element). Credit: Brad Whitmore (STScI), and NASA

2002-01-01

318

The Hubble flow around the Local Group  

NASA Astrophysics Data System (ADS)

We use updated data on distances and velocities of galaxies in the proximity of the Local Group (LG) in order to establish properties of the local Hubble flow. For 30 neighbouring galaxies with distances 0.7 < DLG < 3.0 Mpc, the local flow is characterized by the Hubble parameter Hloc = (78 +/- 2)kms-1 Mpc-1, the mean-square peculiar velocity ?v = 25kms-1, corrected for errors of radial velocity measurements (~4kms-1) and distance measurements (~10kms-1), as well as the radius of the zero-velocity surface R0 = (0.96 +/- 0.03) Mpc. The minimum value for ?v is achieved when the barycentre of the LG is located at the distance Dc = (0.55 +/- 0.05) DM31 towards Andromeda galaxy (M31) corresponding to the Milky Way (MW)-to-M31 mass ratio MMW/MM31 ~= 4/5. In the reference frame of the 30 galaxies at 0.7-3.0 Mpc, the LG barycentre has a small peculiar velocity ~(24 +/- 4)kms-1 towards the Sculptor constellation. The derived value of R0 corresponds to the total mass MT(LG) = (1.9 +/- 0.2) 1012 Msolar with ?m = 0.24 and a topologically flat universe, a value in good agreement with the sum of virial mass estimates for the MW and M31.

Karachentsev, I. D.; Kashibadze, O. G.; Makarov, D. I.; Tully, R. B.

2009-03-01

319

HUBBLE CAPTURES MERGER BETWEEN QUASAR AND GALAXY  

NASA Technical Reports Server (NTRS)

This NASA Hubble Space Telescope image shows evidence fo r a merger between a quasar and a companion galaxy. This surprising result might require theorists to rethink their explanations for the nature of quasars, the most energetic objects in the universe. The bright central object is the quasar itself, located several billion light-years away. The two wisps on the (left) of the bright central object are remnants of a bright galaxy that have been disrupted by the mutual gravitational attraction between the quasar and the companion galaxy. This provides clear evidence for a merger between the two objects. Since their discovery in 1963, quasars (quasi-stellar objects) have been enigmatic because they emit prodigious amounts of energy from a very compact source. The most widely accepted model is that a quasar is powered by a supermassive black hole in the core of a galaxy. These new observations proved a challenge for theorists as no current models predict the complex quasar interactions unveiled by Hubble. The image was taken with the Wide Field Planetary Camera-2. Credit: John Bahcall, Institute for Advanced Study, NASA.

2002-01-01

320

14Counting Galaxies with the Hubble Space Telescope In 2004, the Hubble Space Telescope took a million-second exposure of a  

E-print Network

14Counting Galaxies with the Hubble Space Telescope In 2004, the Hubble Space Telescope took in counting these galaxies? Problem 2 ­ One square degree equals 3,600 square arcminutes. If Hubble Ultra Deep as faint as the faintest galaxy that Hubble detected in the Deep Field image? Space Math http

321

42Planetary Conjunctions Since 1995, astronomers have  

E-print Network

42Planetary Conjunctions Since 1995, astronomers have detected over 350 planets orbiting distant above, draw a series of new diagrams that show where will the planets be in their orbits after: A) 1 year? B) 2 years? C) 3 years? D) 4 years? Problem 2 - Suppose the three planets, A, B and C, orbited

322

Is astronomical research appropriate for developing countries?  

Microsoft Academic Search

An unproductive 45-cm astronomical telescope, given by JICA (Japan) to Sri Lanka, raises general questions as to the reasons for unproductive pure science in developing countries. Before installation, site, maintenance, and scientific objectives were discussed. The facility was launched with a conference organised by the UN Office for Outer Space Affairs. Unfortunately, no research or significant education has resulted after

Michael S. Snowden

2001-01-01

323

Invited Paper Exploring ultraviolet astronomical polarimetry  

E-print Network

.5m Cassegram telescope coupled to a Monk-Gileson spectrometer with a magnesium fluoride polarizing beamsplitter preceded by magnesium fluoride halfwave retarders. Two spectra from 135 to 330 nm with orthogonal is currently scheduled for 1994. 1. INTRODUCTION The technique of astronomical polarimetry extracts information

Sirianni, Marco

324

BISHOP'S UNIVERSITY ASTRONOMICAL OBERVATORY SAFETY INSTRUCTIONS  

E-print Network

BISHOP'S UNIVERSITY ASTRONOMICAL OBERVATORY SAFETY INSTRUCTIONS It is the Observatory Guide's responsibility to ensure the safety of all of the guests in the group visiting the Observatory. Do NOT assume that the individuals who act as chaperones for children will ensure their safety or follow all of your instructions

325

An Astronomer's View of Optical Turbulence  

NASA Astrophysics Data System (ADS)

Optical turbulence is a key determinant of an astronomical telescope science performance. Forecasting optical turbulence at altitude is thus of paramount importance for astronomy. And so are the understanding and management of ground layer and locally induced turbulence. This paper presents an astronomer's view of both the futility and the utility of various site characterization activities, of the challenges they pose and of dreams one has about understanding and forecasting site qualities. It is pointed out that, for likely suitable sites, the average integrated optical turbulence can be calculated to good accuracy by a simple model and that turbulence profiles differ less between sites that between nights or times at a given site. The challenges therefore stem from the temporal and spatial variability of the turbulence. This variability is illustrated and briefly discussed. Collaboration between astronomers and atmospheric physicists must hold the key to the astronomers' dream of knowing in detail what the optical turbulence at the site will be tomorrow night, or next week, and which science program will then make best use of the facility.

Racine, René

2009-09-01

326

Applications of transputers to astronomical instruments  

Microsoft Academic Search

The application of parallel processing techniques based on transputers to astronomical instruments under development at the Royal Observatory Edinburgh is discussed. On the COSMOS photographic plate measuring machine, a data farm of transputers allows backgrounds to be determined in real time instead of requiring 1.5 h of offline VAX processing per plate. Transputers have been adopted as the embedded processors

J. M. Stewart; S. M. Beard; B. D. Kelly; M. J. Paterson

1990-01-01

327

Applications of transputers to astronomical instruments  

Microsoft Academic Search

The application of parallel processing techniques based on transputers to astronomical instruments under development at the Royal Observatory Edinburgh is discussed. On the Cosmos plate-measuring machine, a data farm of transputers allows backgrounds to be determined in real time instead of requiring 1.5 h of offline VAX processing per plate. Transputers have been adopted as the embedded processors in a

J. M. Stewart; S. M. Beard; B. D. Kelly; M. J. Paterson

1990-01-01

328

Contamination control of the Infrared Astronomical Satellite  

Microsoft Academic Search

The Infrared Astronomical Satellite, to be launched in August 1981, will perform an all-sky survey in the 8-120 micron wavelength region. High sensitivity to thermal radiation and the low operating temperature of optics and thermal control surfaces make the IRAS telescope extremely vulnerable to contamination. Four special topics of importance are discussed in this paper: (1) deposition of atmospheric gases;

L. C. Andreozzi; W. R. Irace; C. R. Maag

1980-01-01

329

The Infrared Astronomical Satellite (IRAS) mission  

Microsoft Academic Search

The Infrared Astronomical Satellite (IRAS) consists of a spacecraft and a liquid helium cryostat that contains a cooled IR telescope. The telescope's focal plane assembly is cooled to less than 3 K, and contains 62 IR detectors in the survey array which are arranged so that every source crossing the field of view can be seen by at least two

G. Neugebauer; H. J. Habing; R. van Duinen; H. H. Aumann; B. Baud; C. A. Beichman; D. A. Beintema; N. Boggess; P. E. Clegg; T. de Jong; J. P. Emerson; T. N. Gautier; F. C. Gillett; S. Harris; M. G. Hauser; J. R. Houck; R. E. Jennings; F. J. Low; P. L. Marsden; G. K. Miley; F. M. Olnon; S. R. Pottasch; E. Raimond; M. Rowan-Robinson; B. T. Soifer; R. G. Walker; P. R. Wesselius; E. Young

1984-01-01

330

The origins of Ptolemy's astronomical tables  

Microsoft Academic Search

Following the line set by his earlier book 'The crime of Claudius Ptolemy' the author discusses here the numerous astronomical tables in Ptolemy's work that have been calculated with the aid of trigonometric tables, as well as a few that are nonlinear but that do not involve trigonometry. The purpose in this study is to determine, if possible, whether Ptolemy

R. R. Newton

1985-01-01

331

Harvard astronomers discover new molecule in space  

Microsoft Academic Search

A team of scientists from Harvard College Observatory in Cambridge, Massachusetts, has reported discovery of sulfur monoxide molecules in space.The discovery of the molecules, not previously known to exist in interstellar space, is important, the scientists said, because astronomers may be able to make inferences, through complicated theoretical interpretations, about the abundance of oxygen in space and about the processes

Anonymous

1973-01-01

332

The Virtual Astronomical Observatory Users Forum  

NASA Astrophysics Data System (ADS)

We present the online forum astrobabel.com, which has the goal of being a gathering place for the collective community intelligence about astronomical computing. The audience for this forum is anyone engaged in the analysis of astronomical or planetary data, whether that data be observational or theoretical. It is a free, community driven site where discussions are formulated primarily around the "question and answer" format. Current topics on the forum range from “Is there a photometry package in Python?” to “Where are the support forums for astronomy software packages?” and “Why is my SDSS SkyQuery query missing galaxies?” The poster will detail the full scope of discussions in the forum, and provide some basic guidelines for ensuring high quality forum posts. We will highlight the ways astronomers can discover and participate in discussions. Further, we view this as an excellent opportunity to gather feedback and feature requests from AAS221 attendees. Acknowledgement: The Virtual Astronomical Observatory (VAO) is managed by the VAO, LLC, a non-profit company established as a partnership of the Associated Universities, Inc. and the Association of Universities for Research in Astronomy, Inc. The VAO is sponsored by the National Science Foundation and the National Aeronautics and Space Administration.

Muench, August A.; Emery Bunn, S.; Astronomical Observatory, Virtual

2013-01-01

333

Galileo: the first* astronomer to use a  

E-print Network

Galileo: the first* astronomer to use a telescope Bob Joseph Institute for Astronomy University of Padua (Republic of Venice). · Remained at Padua for the next 18 years. Padua · Galileo produced three children with his common-law wife, a Venetian woman named Marina Gamba. · At Padua Galileo did much

Joseph, Robert D.

334

Metrology and pointing for astronomical interferometers  

Microsoft Academic Search

Metrology and pointing will be enabling technologies for a new generation of astronomical missions having large and distributed apertures and delivering unprecedented performance. The UV interferometer Stellar Imager would study stellar dynamos by imaging magnetic activity on the disks of stars in our Galaxy. The X-ray interferometer Black Hole Imager would study strong gravity physics and the formation of jets

James D. Phillips; Kenneth G. Carpenter; Keith C. Gendreau; Margarita Karovska; Philip E. Kaaret; Robert D. Reasenberg

2004-01-01

335

Nathaniel Bowditch, Early American Amateur Astronomer  

NASA Astrophysics Data System (ADS)

Nathaniel Bowditch had very successful careers as a seaman/ship's master and as an actuary/insurance executive. In addition he managed to make very substantial contributions to mathematics and astronomy. Bowditch is therefore important as one of the earliest significant amateur astronomers in the United States.

Williams, Thomas R.

1984-10-01

336

Space Place: How Astronomers "Detwinkle" the Stars  

NSDL National Science Digital Library

This article contains a series of kinesthetic activities, explaining and demonstrating why stars twinkle and what astronomers can do to minimize it. The activities can be used to demonstrate how Earth's atmosphere distorts starlight and how advanced telescope technology (adaptive optics) is used to compensate for this distortion.

337

Satellite laser ranging observation at Shanghai Astronomical Observatory in 1997  

Microsoft Academic Search

This is a report of satellite laser ranging observations at Shanghai Astronomical Observatory in 1997. The total 1118 passes and 477661 observations for 18 satellites are obtained. The acievement of daylight laser ranging at Shanghai Astronomical Observatory is presented.

Fumin Yang; Wanzhen Chen; Juping Chen; Zhongping Zhang; Huang Li; Yongping Xu; Xiaohai Xia; Chikun Xiao

1999-01-01

338

HUBBLE SEES AURORAL EMISSION ARCS FOLLOWING THE K IMPACT  

NASA Technical Reports Server (NTRS)

This far-ultraviolet image of Jupiter taken with NASA's Hubble Space Telescope (HST) shows narrow auroral 'arcs' that appeared at northern mid-latitudes following the impact of the K nucleus fragment of comet P/Shoemaker-Levy 9. (The dark K impact region is on the left limb, followed, from left to right, by the C, A, and E comet impact regions.) The image was taken on 19 July 1994, 45 minutes after the K nucleus slammed into the gas giant planet. The image shows arc-like auroral emissions near the western (left) limb at mid-latitudes in the north, and fainter but remarkably similar emissions near the K impact site in the south. The 'arcs' are being produced by energetic charged particles, like the other auroral emissions, except that they appear to last less than one hour and they are at a location where Jupiter normally does not have aurora. They were apparently produced by the K impact, even though they appear bright in the northern hemisphere nearly 70,000 miles away from the impact site. The overlay of magnetic field lines shows the path of the charged particles near Jupiter (from a model based on Pioneer and Voyager spacecraft data), starting at the northern 'arcs' and tracing the magnetic field back to the impact site in the southern atmosphere. (There is an overlay of a longitude/latitude grid to indicate locations on Jupiter). Aurorae, also known as the northern and southern lights, are produced by high energy charged particles, trapped in Jupiter's magnetic field, that cause atmosphereic gasses to glow. Based on comparison with ROSAT satellite X-ray images of Jupiter also taken at time of the K impact, astronomers know that the northern disturbance was brightest near the time of the K impact, and then faded. If HST images had been taken during the K impact, they would likely have shown far brighter arcs than those observed 45 min. later. The image was taken with the Wide Field Planetary Camera-2 at UV wavelengths (1300-2100 Angstroms), where the polar regions normally appear dark and the northern and southern lights are clearly visible. Credit: John T. Clarke (U. of Michigan), and NASA

2002-01-01

339

Hubble Space Telescope characterized by using phase-retrieval algorithms  

E-print Network

Hubble Space Telescope characterized by using phase-retrieval algorithms J. R. Fienup, J. C. Marron, T. J. Schulz, and J. H. Seldin We describe several results characterizing the Hubble Space Telescope of the optical axis of a camera relay telescope relative to the main telescope. After we accounted for measured

Fienup, James R.

340

THE ADVANCED CAMERA FOR THE HUBBLE SPACE TELESCOPE  

E-print Network

THE ADVANCED CAMERA FOR THE HUBBLE SPACE TELESCOPE G.D. ILLINGWORTH UCO/Lick Observatory), will be a high throughput (45% at 700 nm, including the HST optical telescope assembly (OTA)), wide eld (20000 for the Advanced Camera The ACS team is building an Advanced Camera for the Hubble Space Tele- scope which

Johns Hopkins University, Department of Physics and Astonomy, Advanced Camera for Surveys Team

341

The Hubble constant and dark energy from cosmological distance measures  

SciTech Connect

We study how the determination of the Hubble constant from cosmological distance measures is affected by models of dark energy and vice versa. For this purpose, constraints on the Hubble constant and dark energy are investigated using the cosmological observations of cosmic microwave background, baryon acoustic oscillations and type Ia supernovae. When one investigates dark energy, the Hubble constant is often a nuisance parameter; thus it is usually marginalized over. On the other hand, when one focuses on the Hubble constant, simple dark energy models such as a cosmological constant and a constant equation of state are usually assumed. Since we do not know the nature of dark energy yet, it is interesting to investigate the Hubble constant assuming some types of dark energy and see to what extent the constraint on the Hubble constant is affected by the assumption concerning dark energy. We show that the constraint on the Hubble constant is not affected much by the assumption for dark energy. We furthermore show that this holds true even if we remove the assumption that the universe is flat. We also discuss how the prior on the Hubble constant affects the constraints on dark energy and/or the curvature of the universe.

Ichikawa, Kazuhide [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan); Takahashi, Tomo, E-mail: kazuhide@icrr.u-tokyo.ac.jp, E-mail: tomot@cc.saga-u.ac.jp [Department of Physics, Saga University, Saga 840-8502 (Japan)

2008-04-15

342

International Ultraviolet Explorer (IUE) ultraviolet spectral atlas of selected astronomical objects  

NASA Technical Reports Server (NTRS)

The IUE Ultraviolet Spectral Atlas of Selected Astronomical Objects (or 'the Atlas'), is based on the data that were available in the IUE archive in 1986, and is intended to be a quick reference for the ultraviolet spectra of many categories of astronomical objects. It shows reflected sunlight from the Moon, planets, and asteroids, and also shows emission from comets. Comprehensive compilations of UV spectra for main sequence, subgiant, giant, bright giant, and supergiant stars are published elsewhere. This Atlas contains the spectra for objects occupying other areas of the Hertzsprung-Russell diagram: pre-main sequence stars, chemically peculiar stars, pulsating variables, subluminous stars, and Wolf-Rayet stars. This Atlas also presents phenomena such as the chromospheric and transition region emissions from late-type stars; composite spectra of stars, gas streams, accretion disks and gas envelopes of binary systems; the behavior of gas ejecta shortly after the outburst of novac and supernovac; and the H II regions, planetary nebulae, and supernova remnants. Population 2 stars, globular clusters, and luminous stars in the Magellanic Clouds, M31, and M33, are also included in this publication. Finally, the Atlas gives the ultraviolet spectra of galaxies of different Hubble types and of active galaxies.

Wu, Chi-Chao; Reichert, Gail A.; Ake, Thomas B.; Boggess, Albert; Holm, Albert V.; Imhoff, Catherine L.; Kondo, Yoji; Mead, Jaylee M.; Shore, Steven N.

1992-01-01

343

International Ultraviolet Explorer (IUE) ultraviolet spectral atlas of selected astronomical objects  

NASA Astrophysics Data System (ADS)

The IUE Ultraviolet Spectral Atlas of Selected Astronomical Objects (or 'the Atlas'), is based on the data that were available in the IUE archive in 1986, and is intended to be a quick reference for the ultraviolet spectra of many categories of astronomical objects. It shows reflected sunlight from the Moon, planets, and asteroids, and also shows emission from comets. Comprehensive compilations of UV spectra for main sequence, subgiant, giant, bright giant, and supergiant stars are published elsewhere. This Atlas contains the spectra for objects occupying other areas of the Hertzsprung-Russell diagram: pre-main sequence stars, chemically peculiar stars, pulsating variables, subluminous stars, and Wolf-Rayet stars. This Atlas also presents phenomena such as the chromospheric and transition region emissions from late-type stars; composite spectra of stars, gas streams, accretion disks and gas envelopes of binary systems; the behavior of gas ejecta shortly after the outburst of novac and supernovac; and the H II regions, planetary nebulae, and supernova remnants. Population 2 stars, globular clusters, and luminous stars in the Magellanic Clouds, M31, and M33, are also included in this publication. Finally, the Atlas gives the ultraviolet spectra of galaxies of different Hubble types and of active galaxies.

Wu, Chi-Chao; Reichert, Gail A.; Ake, Thomas B.; Boggess, Albert; Holm, Albert V.; Imhoff, Catherine L.; Kondo, Yoji; Mead, Jaylee M.; Shore, Steven N.

1992-11-01

344

Novel optical designs for consumer astronomical telescopes and their application to professional imaging  

NASA Astrophysics Data System (ADS)

Since the launch of the Hubble Space Telescope there has been widespread popular interest in astronomy. A further series of events, most notably the recent Deep Impact mission and Mars oppositions have served to fuel further interest. As a result more and more amateurs are coming into astronomy as a practical hobby. At the same time more sophisticated optical equipment is becoming available as the price to performance ratio become more favourable. As a result larger and better optical telescopes are now in use by amateurs. We also have the explosive growth in digital imaging technologies. In addition to displacing photographic film as the preferred image capture modality it has made the capture of high quality astronomical imagery more accessible to a wider segment of the astronomy community. However, this customer requirement has also had an impact on telescope design. There has become a greater imperative for wide flat image fields in these telescopes to take advantage of the ongoing advances in CCD imaging technology. As a result of these market drivers designers of consumer astronomical telescopes are now producing state of the art designs that result in wide, flat fields with optimal spatial and chromatic aberrations. Whilst some of these designs are not scalable to the larger apertures required for professional ground and airborne telescope use there are some that are eminently suited to make this transition.

Wise, Peter; Hodgson, Alan

2006-06-01

345

Public perception of astronomers Revered, reviled and ridiculed  

NASA Astrophysics Data System (ADS)

Society's view of astronomers has changed over time and from culture to culture. This review discusses some of the many ways that astronomers have been perceived by their societies and suggests ways that astronomers can influence public perception of ourselves and our profession in the future.

West, Michael J.

2011-06-01

346

Artificial intelligence approaches to astronomical observation scheduling  

NASA Technical Reports Server (NTRS)

Automated scheduling will play an increasing role in future ground- and space-based observatory operations. Due to the complexity of the problem, artificial intelligence technology currently offers the greatest potential for the development of scheduling tools with sufficient power and flexibility to handle realistic scheduling situations. Summarized here are the main features of the observatory scheduling problem, how artificial intelligence (AI) techniques can be applied, and recent progress in AI scheduling for Hubble Space Telescope.

Johnston, Mark D.; Miller, Glenn

1988-01-01

347

American Astronomical Society Honors NRAO Scientist  

NASA Astrophysics Data System (ADS)

The American Astronomical Society (AAS) has awarded its prestigious George Van Biesbroeck Prize to Dr. Eric Greisen of the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico. The society cited Greisen's quarter-century as "principal architect and tireless custodian" of the Astronomical Image Processing System (AIPS), a massive software package used by astronomers around the world, as "an invaluable service to astronomy." Dr. Eric Greisen Dr. Eric Greisen CREDIT: NRAO/AUI/NSF (Click on image for larger version) The Van Biesbroeck Prize "honors a living individual for long-term extraordinary or unselfish service to astronomy, often beyond the requirements of his or her paid position." The AAS, with about 7,000 members, is the major organization of professional astronomers in North America. " The Very Large Array (VLA) is the most productive ground-based telescope in the history of astronomy, and most of the more than 10,000 observing projects on the VLA have depended upon the AIPS software to produce their scientific results," said Dr. James Ulvestad, NRAO's Director of New Mexico Operations. "This same software package also has been the principal tool for scientists using the Very Long Baseline Array and numerous other radio telescopes around the world," Ulvestad added. Greisen, who received a Ph.D in astronomy from the California Institute of Technology, joined the NRAO in 1972. He moved from the observatory's headquarters in Charlottesville, Virginia, to its Array Operations Center in Socorro in 2000. Greisen, who learned of the award in a telephone call from the AAS President, Dr. Robert Kirschner of Harvard University, said, "I'm pleased for the recognition of AIPS and also for the recognition of the contributions of radio astronomy to astronomy as a whole." He added that "it wasn't just me who did AIPS. There were many others." The AIPS software package grew out of the need for an efficient tool for producing images with the VLA, which was being built in the late 1970s. Work on the package began in 1978 in Charlottesville. Now including nearly a million lines of program code and almost a half-million lines of documentation, AIPS is used at more than 500 sites around the world. The package is a mainstay and a daily tool for most of the world's radio astronomers, and also has been used by scientists in such other fields as fluid-dynamics simulation and medical imaging. Over the years, Greisen and his colleagues at NRAO have revised the AIPS package numerous times and expanded its capabilities as new astronomical and computing hardware was developed. The software has been kept independent of specific computing hardware and operating systems, and so has been successfully used on a wide variety of computing equipment. "We are extremely proud of Eric's work and congratulate him on receiving this award," said NRAO Director Dr. Fred K.Y. Lo. "He has shown extraordinary dedication to making AIPS a valuable and effective tool for the world astronomical community, and this award is well-deserved recognition." The AAS citation reads, "The 2005 Van Biesbroeck Prize is awarded to Dr. Eric Greisen of NRAO for the initiation, development, and maintenance for twenty-five years of the Astronomical Image Processing System (AIPS). Virtually every VLA and VLBA program relies on AIPS for calibration and image reconstruction, and it has been exported to more than 500 sites worldwide. Greisen, as its principal architect and tireless custodian, has provided an invaluable service to astronomy. Moreover, AIPS represented a new paradigm for the processing of massive astronomical datasets, i.e., a comprehensive software package that was rigorously independent of particular operating systems, which supported portability and adaptability to evolving hardware designs. Beyond the call of duty, Greisen has generously responded to individual queries about the code from users at all levels, sometimes in real time at odd hours to support observ

2005-01-01

348

Disc heating agents across the Hubble sequence  

NASA Astrophysics Data System (ADS)

We measure the shape of the velocity ellipsoid in two late-type spiral galaxies (Hubble types Sc and Scd) and combine these results with our previous analyses of six early-type spirals (Sa to Sbc) to probe the relation between galaxy morphology and the ratio of the vertical and radial dispersions. We confirm at much higher significance (99.9 per cent) our prior detection of a tight correlation between these quantities. We explore the trends of the magnitude and shape of the velocity ellipsoid axes with galaxy properties (colour, gas surface mass density and spiral arm structure). The observed relationships allow for an observational identification of the radial and vertical disc heating agents in external disc galaxies. Based on observations made with ESO Telescopes at the La Silla Observatory under programmes 074.B-0550(A) and 078.B-0152(A).

Gerssen, J.; Shapiro Griffin, K.

2012-07-01

349

Hubble Space Telescope electrical power system  

NASA Technical Reports Server (NTRS)

The Hubble Space Telescope (HST) electrical power system (EPS) is supplying between 2000 and 2400 W of continuous power to the electrical loads. The major components of the EPS are the 5000-W back surface field reflector solar array, the six nickel-hydrogen (NiH2) 22-cell 88-Ah batteries, and the charge current controllers, which, in conjunction with the flight computer, control battery charging. The operation of the HST EPS and the results of the HST NiH2 six-battery test are discussed, and preliminary flight data are reviewed. The HST NiH2 six-battery test is a breadboard of the HST EPS on test at Marshall Space Flight Center.

Whitt, Thomas H.; Bush, John R., Jr.

1990-01-01

350

Bianchi I meets the Hubble diagram  

E-print Network

We improve existing fits of the Bianchi I metric to the Hubble diagram of supernovae and find an intriguing yet non-significant signal for anisotropy that should be verified or falsified in the near future by the Large Synoptic Survey Telescope. Since the literature contains two different formulas for the apparent luminosity as a function of time of flight in Bianchi I metrics, we present an independent derivation confirming the result by Saunders (1969). The present fit differs from earlier ones by Koivisto & Mota and by Campanelli et al. in that we use Saunders' formula, a larger sample of supernovae, Union 2 and JLA, and we use the general Bianchi I metric with three distinct eigenvalues.

Schucker, Thomas; Valent, Galliano

2014-01-01

351

Bianchi I meets the Hubble diagram  

NASA Astrophysics Data System (ADS)

We improve existing fits of the Bianchi I metric to the Hubble diagram of supernovae and find an intriguing yet non-significant signal for anisotropy that should be verified or falsified in the near future by the Large Synoptic Survey Telescope. Since the literature contains two different formulas for the apparent luminosity as a function of time of flight in Bianchi I metrics, we present an independent derivation confirming the result by Saunders. The present fit differs from earlier ones by Koivisto & Mota and by Campanelli et al. in that we use Saunders' formula, a larger sample of supernovae, Union 2 and Joint Light curve Analysis, and we use the general Bianchi I metric with three distinct eigenvalues.

Schücker, Thomas; Tilquin, André; Valent, Galliano

2014-11-01

352

Hubble Space Telescope observations of globular cluster systems along the Hubble sequence of spiral galaxies  

E-print Network

We have studied the globular cluster (GC) systems of 7 giant, edge-on spiral galaxies using Hubble Space Telescope imaging in V and I. The galaxy sample covers the Hubble types Sa to Sc, allowing us to study the variation of the properties of GC systems along the Hubble sequence. The photometry reaches ~1.5 mag beyond the turn-over magnitude of the GC luminosity function for each galaxy. Specific frequencies (S_N values) of GCs were evaluated by comparing the numbers of GCs found in our WFPC2 pointings with those in the Milky Way which would be detected in the same metric area. The S_N values of spirals with B/T Hubble type later than about Sb) are consistent with a value of S_N = 0.55 +- 0.25. We suggest that this population of GCs represents a `universal', old halo population that is present around each galaxy. Most galaxies in our sample have S_N values that are consistent with a scenario in which GC systems are made up of (i) the aforementioned halo population plus (ii) a population that is associated with bulges, which grows linearly with the mass of the bulge. Such scenarios include the `merger scenario' for the formation of elliptical galaxies as well as the `multi-phase collapse' scenario, but it seems inconsistent with the `secular evolution' scenario of Pfenniger & Norman (1990), in which bulges are formed from disc stars by means of the redistribution of angular momentum through bar instabilities and/or minor perturbations. However, there is one bulge-dominated spiral galaxy in our sample (NGC 7814) with a low S_N value that is consistent with those of the latest-type spirals. Thus, our results suggest that the formation histories of galaxy bulges of early-type spirals can be significantly different from one galaxy to another. (abridged)

Paul Goudfrooij; Jay Strader; Laura Brenneman; Markus Kissler-Patig; Dante Minniti; Edwin Huizinga

2003-04-10

353

Hubble Clicks Images of Io Sweeping Across Jupiter  

NASA Technical Reports Server (NTRS)

While hunting for volcanic plumes on Io, NASA's Hubble Space Telescope captured these images of the volatile moon sweeping across the giant face of Jupiter. Only a few weeks before these dramatic images were taken, the orbiting telescope snapped a portrait of one of Io's volcanoes spewing sulfur dioxide 'snow.'

These stunning images of the planetary duo are being released to commemorate the ninth anniversary of the Hubble telescope's launch on April 24, 1990. All of these images were taken with the Wide Field and Planetary Camera 2.

The three overlapping snapshots show in crisp detail Io passing above Jupiter's turbulent clouds. The close-up picture of Io (bottom right) reveal a 120-mile-high (200-kilometer) plume of sulfur dioxide 'snow' emanating from Pillan, one of the moon's active volcanoes.

'Other observations have inferred sulfur dioxide 'snow' in Io's plumes, but this image offers direct observational evidence for sulfur dioxide 'snow' in an Io plume,' explains John R. Spencer of Lowell Observatory in Flagstaff, Ariz.

A Trip Around Jupiter

The three snapshots of the volcanic moon rounding Jupiter were taken over a 1.8-hour time span. Io is roughly the size of Earth's moon but 2,000 times farther away. In two of the images, Io appears to be skimming Jupiter's cloud tops, but it's actually 310,000 miles (500,000 kilometers) away. Io zips around Jupiter in 1.8 days, whereas the moon circles Earth every 28 days.

The conspicuous black spot on Jupiter is Io's shadow and is about the size of the moon itself (2,262 miles or 3,640 kilometers across). This shadow sails across the face of Jupiter at 38,000 mph (17 kilometers per second). The smallest details visible on Io and Jupiter measure 93 miles (150 kilometers) across, or about the size of Connecticut.

These images were further sharpened through image reconstruction techniques. The view is so crisp that one would have to stand on Io to see this much detail on Jupiter with the naked eye.

The bright patches on Io are regions of sulfur dioxide frost. On Jupiter, the white and brown regions distinguish areas of high-altitude haze and clouds; the blue regions depict relatively clear skies at high altitudes.

These images were taken July 22, 1997, in two wavelengths: 3400 Angstroms (ultraviolet) and 4100 Angstroms (violet). The colors do not correspond closely to what the human eye would see because ultraviolet light is invisible to the eye.

Io: Jupiter's Volcanic Moon

In the close-up picture of Io (bottom right), the mound rising from Io's surface is actually an eruption from Pillan, a volcano that had previously been dormant.

Measurements at two ultraviolet wavelengths indicate that the ejecta consist of sulfur dioxide 'snow,' making the plume appear green in this false-color image. Astronomers increased the color contrast and added false colors to the image to make the faint plume visible.

Pillan's plume is very hot and its ejecta is moving extremely fast. Based on information from the Galileo spacecraft, Pillan's outburst is at least 2,240 degrees Fahrenheit (1,500 degrees Kelvin). The late bloomer is spewing material at speeds of 1,800 mph (2,880 kilometers per hour). The hot sulfur dioxide gas expelled from the volcano cools rapidly as it expands into space, freezing into snow.

Io is well known for its active volcanoes, many of which blast huge plumes of volcanic debris into space. Astronomers discovered Pillan's volcanic explosion while looking for similar activity from a known active volcano, Pele, about 300 miles (500 kilometers) away from Pillan. But Pele turned out to be peaceful. Io has hundreds of active volcanoes, but only a few, typically eight or nine, have visible plumes at any given time.

Scientists will get a closer look at Io later this year during a pair of close flybys to be performed by NASA's Galileo spacecraft, which has been orbiting Jupiter and its moons for nearly 3-1/2 years.&

1999-01-01

354

HUBBLE CLICKS IMAGES OF IO SWEEPING ACROSS JUPITER  

NASA Technical Reports Server (NTRS)

While hunting for volcanic plumes on Io, NASA's Hubble Space Telescope captured these images of the volatile moon sweeping across the giant face of Jupiter. Only a few weeks before these dramatic images were taken, the orbiting telescope snapped a portrait of one of Io's volcanoes spewing sulfur dioxide 'snow.' These stunning images of the planetary duo are being released to commemorate the ninth anniversary of the Hubble telescope's launch on April 24, 1990. All of these images were taken with the Wide Field and Planetary Camera 2. The three overlapping snapshots show in crisp detail Io passing above Jupiter's turbulent clouds. The close-up picture of Io (bottom right) reveal a 120-mile-high (200-kilometer) plume of sulfur dioxide 'snow' emanating from Pillan, one of the moon's active volcanoes. 'Other observations have inferred sulfur dioxide 'snow' in Io's plumes, but this image offers direct observational evidence for sulfur dioxide 'snow' in an Io plume,' explains John R. Spencer of Lowell Observatory in Flagstaff, Ariz. A Trip Around Jupiter The three snapshots of the volcanic moon rounding Jupiter were taken over a 1.8-hour time span. Io is roughly the size of Earth's moon but 2,000 times farther away. In two of the images, Io appears to be skimming Jupiter's cloud tops, but it's actually 310,000 miles (500,000 kilometers) away. Io zips around Jupiter in 1.8 days, whereas the moon circles Earth every 28 days. The conspicuous black spot on Jupiter is Io's shadow and is about the size of the moon itself (2,262 miles or 3,640 kilometers across). This shadow sails across the face of Jupiter at 38,000 mph (17 kilometers per second). The smallest details visible on Io and Jupiter measure 93 miles (150 kilometers) across, or about the size of Connecticut. These images were further sharpened through image reconstruction techniques. The view is so crisp that one would have to stand on Io to see this much detail on Jupiter with the naked eye. The bright patches on Io are regions of sulfur dioxide frost. On Jupiter, the white and brown regions distinguish areas of high-altitude haze and clouds; the blue regions depict relatively clear skies at high altitudes. These images were taken July 22, 1997, in two wavelengths: 3400 Angstroms (ultraviolet) and 4100 Angstroms (violet). The colors do not correspond closely to what the human eye would see because ultraviolet light is invisible to the eye. Io: Jupiter's Volcanic Moon In the close-up picture of Io (bottom right), the mound rising from Io's surface is actually an eruption from Pillan, a volcano that had previously been dormant. Measurements at two ultraviolet wavelengths indicate that the ejecta consist of sulfur dioxide 'snow,' making the plume appear green in this false-color image. Astronomers increased the color contrast and added false colors to the image to make the faint plume visible. Pillan's plume is very hot and its ejecta is moving extremely fast. Based on information from the Galileo spacecraft, Pillan's outburst is at least 2,240 degrees Fahrenheit (1,500 degrees Kelvin). The late bloomer is spewing material at speeds of 1,800 mph (2,880 kilometers per hour). The hot sulfur dioxide gas expelled from the volcano cools rapidly as it expands into space, freezing into snow. Io is well known for its active volcanoes, many of which blast huge plumes of volcanic debris into space. Astronomers discovered Pillan's volcanic explosion while looking for similar activity from a known active volcano, Pele, about 300 miles (500 kilometers) away from Pillan. But Pele turned out to be peaceful. Io has hundreds of active volcanoes, but only a few, typically eight or nine, have visible plumes at any given time. Scientists will get a closer look at Io later this year during a pair of close flybys to be performed by NASA's Galileo spacecraft, which has been orbiting Jupiter and its moons for nearly 3-1/2 years. The first Galileo flyby is scheduled for Oct. 10 at an altitude of 379 miles (610 kilometers), and the other will occur on Nov. 25, when the spacecraft will fly only 186 mil

2002-01-01

355

Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant  

E-print Network

We present here the final results of the Hubble Space Telescope Key Project to measure the Hubble constant. We summarize our method, the results and the uncertainties, tabulate our revised distances, and give the implications of these results for cosmology. The analysis presented here benefits from a number of recent improvements and refinements, including (1) a larger LMC Cepheid sample to define the fiducial period-luminosity (PL) relations, (2) a more recent HST Wide Field and Planetary Camera 2 (WFPC2) photometric calibration, (3) a correction for Cepheid metallicity, and (4) a correction for incompleteness bias in the observed Cepheid PL samples. New, revised distances are given for the 18 spiral galaxies for which Cepheids have been discovered as part of the Key Project, as well as for 13 additional galaxies with published Cepheid data. The new calibration results in a Cepheid distance to NGC 4258 in better agreement with the maser distance to this galaxy. Based on these revised Cepheid distances, we find values (in km/sec/Mpc) of H0 = 71 +/- 2 (random) +/- 6 (systematic) (type Ia supernovae), 71 +/- 2 +/- 7 (Tully-Fisher relation), 70 +/- 5 +/- 6 (surface brightness fluctuations), 72 +/- 9 +/- 7 (type II supernovae), and 82 +/- 6 +/- 9 (fundamental plane). We combine these results for the different methods with 3 different weighting schemes, and find good agreement and consistency with H0 = 72 +/- 8. Finally, we compare these results with other, global methods for measuring the Hubble constant.

W. L. Freedman; B. F. Madore; B. K. Gibson; L. Ferrarese; D. D. Kelson; S. Sakai; J. R. Mould; R. C. Kennicutt, Jr.; H. C. Ford; J. A. Graham; J. P. Huchra; S. M. G. Hughes; G. D. Illingworth; L. M. Macri; P. B. Stetson

2000-12-18

356

110th Anniversary of the Engelhardt Astronomical Observatory  

NASA Astrophysics Data System (ADS)

The Engelhardt Astronomical Observatory (EAO) was founded in September 21, 1901. The history of creation of the Engelhard Astronomical Observatory was begun in 1897 with transfer a complimentary to the Kazan University of the unique astronomical equipment of the private observatory in Dresden by known astronomer Vasily Pavlovichem Engelgardt. Having stopped astronomical activity owing to advanced years and illnesses Engelgardt has decided to offer all tools and library of the Astronomical observatory of the Kazan University. Vasily Pavlovich has put the first condition of the donation that his tools have been established as soon as possible and on them supervision are started. In 1898 the decree of Emperor had been allocated means and the ground for construction of the Astronomical observatory is allocated. There is the main historical telescope of the Engelhard Astronomical Observatory the 12-inch refractor which was constructed by English master Grubbom in 1875. The unique tool of the Engelhard Astronomical Observatory is unique in the world now a working telescope heliometer. It's one of the first heliometers, left workshops Repsolda. It has been made in 1874 and established in Engelgardt observatory in 1908 in especially for him the constructed round pavilion in diameter of 3.6 m. Today the Engelhard Astronomical Observatory is the only thing scientifically - educational and cultural - the cognitive astronomical center, located on territory from Moscow up to the most east border of Russia. Currently, the observatory is preparing to enter the protected UNESCO World Heritage List.

Nefedyev, Y.

2012-09-01

357

Astronomical Society of the Pacific: Educational Resources  

NSDL National Science Digital Library

The Astronomical Society of the Pacific (ASP) has created this website to share key educational resources in the field of astronomy with educators, students, and members of the general public. First-time visitors should take a look at "The Universe in the Classroom," the ASP's newsletter for teachers. Visitors can peruse their archive of past editions, and they will find titles such as "A Silent Cry for Dark Skies" and "A Flag for Mars." Moving along, the Selected Resource Guides area features background reading from a number of annotated astronomical bibliographies. The subjects covered here include the moon, Galileo, and black holes. The site also includes a catalog of helpful astronomy apps for smartphones and tablets, along with some fine suggestions for teaching introductory astronomy to college non-science majors.

2012-03-09

358

Recruitment and Retention of LGBTIQ Astronomers  

NASA Astrophysics Data System (ADS)

While lesbian, gay, bisexual, transgender, intersex, or questioning (LGBTIQ) astronomers face many of the same workplace challenges as women and racial/ethnic minorities, from implicit bias to overt discrimination, other challenges are unique to this group. An obvious example is the absence at many institutions of health insurance and other benefits for the same-sex domestic partners of their employees. More subtle is the psychological toll paid by LGBTIQ astronomers who remain "in the closet," self-censoring every statement about their personal lives. Paradoxically, the culture of the physical sciences, in which sexuality, gender identity, and gender expression are considered irrelevant, can discourage their discussion, further isolating LGBTIQ researchers. Addressing these challenges is not just a matter of fairness; it is an essential tool in the recruitment and retention of the brightest researchers and in assuring their productivity. We will discuss these issues and what individuals and departments can to make their institutions more welcoming to their LGBTIQ colleagues.

Dixon, William Van Dyke

2012-01-01

359

Isaac Newton and the astronomical refraction.  

PubMed

In a short interval toward the end of 1694, Isaac Newton developed two mathematical models for the theory of the astronomical refraction and calculated two refraction tables, but did not publish his theory. Much effort has been expended, starting with Biot in 1836, in the attempt to identify the methods and equations that Newton used. In contrast to previous work, a closed form solution is identified for the refraction integral that reproduces the table for his first model (in which density decays linearly with elevation). The parameters of his second model, which includes the exponential variation of pressure in an isothermal atmosphere, have also been identified by reproducing his results. The implication is clear that in each case Newton had derived exactly the correct equations for the astronomical refraction; furthermore, he was the first to do so. PMID:19037356

Lehn, Waldemar H

2008-12-01

360

Lunar orbital photography of astronomical phenomena.  

NASA Technical Reports Server (NTRS)

This paper reports further progress on photography of faint astronomical and geophysical phenomena accomplished during the recent Apollo missions. Command module pilots have been able to photograph such astronomical objects as the solar corona, zodiacal light-corona transition region, lunar libration region, and portions of the Milky Way. The methods utilized for calibration of the film by adaptation of the High Altitude Observatory sensitometer are discussed. Kodak 2485 high-speed recording film was used in both 35-mm and 70-mm formats. The cameras used were Nikon f/1.2 55-mm focal length and Hasselblad f/2.8 80-mm focal length. Preflight and postflight calibration exposures were included on both the flight and control films, corresponding to luminances extending from the inner solar corona to as faint as 1/10 of the luminance of the light of the night sky. The photographs obtained from unique vantage points available during lunar orbit are discussed.

Mercer, R. D.; Dunkelman, L.; Ross, C. L.; Worden, A.

1972-01-01

361

Laser frequency combs for astronomical observations  

E-print Network

A direct measurement of the universe's expansion history could be made by observing in real time the evolution of the cosmological redshift of distant objects. However, this would require measurements of Doppler velocity drifts of about 1 centimeter per second per year, and astronomical spectrographs have not yet been calibrated to this tolerance. We demonstrate the first use of a laser frequency comb for wavelength calibration of an astronomical telescope. Even with a simple analysis, absolute calibration is achieved with an equivalent Doppler precision of approximately 9 meters per second at about 1.5 micrometers - beyond state-of-the-art accuracy. We show that tracking complex, time-varying systematic effects in the spectrograph and detector system is a particular advantage of laser frequency comb calibration. This technique promises an effective means for modeling and removal of such systematic effects to the accuracy required by future experiments to see direct evidence of the universe's putative acceleration.

Tilo Steinmetz; Tobias Wilken; Constanza Araujo-Hauck; Ronald Holzwarth; Theodor W. Hänsch; Luca Pasquini; Antonio Manescau; Sandro D'Odorico; Michael T. Murphy; Thomas Kentischer; Wolfgang Schmidt; Thomas Udem

2008-09-09

362

Astronomical dating in the 19th century  

NASA Astrophysics Data System (ADS)

Today astronomical tuning is widely accepted as numerical dating method after having revolutionised the age calibration of the geological archive and time scale over the last decades. However, its origin is not well known and tracing its roots is important especially from a science historic perspective. Astronomical tuning developed in consequence of the astronomical theory of the ice ages and was repeatedly used in the second half of the 19th century before the invention of radio-isotopic dating. Building upon earlier ideas of Joseph Adhémar, James Croll started to formulate his astronomical theory of the ice ages in 1864 according to which precession controlled ice ages occur alternatingly on both hemispheres at times of maximum eccentricity of the Earth's orbit. The publication of these ideas compelled Charles Lyell to revise his Principles of Geology and add Croll's theory, thus providing an alternative to his own geographical cause of the ice ages. Both Croll and Lyell initially tuned the last glacial epoch to the prominent eccentricity maximum 850,000 yr ago. This age was used as starting point by Lyell to calculate an age of 240 million years for the beginning of the Cambrium. But Croll soon revised the tuning to a much younger less prominent eccentricity maximum between 240,000 and 80,000 yr ago. In addition he tuned older glacial deposits of late Miocene and Eocene ages to eccentricity maxima around 800,000 and 2,800,000 yr ago. Archibald and James Geikie were the first to recognize interglacials during the last glacial epoch, as predicted by Croll's theory, and attempted to tune them to precession. Soon after Frank Taylor linked a series of 15 end-moraines left behind by the retreating ice sheet to precession to arrive at a possible age of 300,000 yr for the maximum glaciation. In a classic paper, Axel Blytt (1876) explained the scattered distribution of plant groups in Norway to precession induced alternating rainy and dry periods as recorded by the layering in Holocene peat bogs. He specifically linked the exceptionally wet Atlantic period to the prolonged precession minimum at 33,300 yr ago and further related basic stratigraphic alternations to precession induced climate change in general. Such a linkage was also proposed by Grove Karl Gilbert for cyclic alternations in the marine Cretaceous of North America. Extrapolating sedimentation rates, he arrived at an astronomical duration for part of the Cretaceous that was roughly as long as the final estimate of William Thomson for the age of the Earth. Assuming that orbital parameters directly affect sea level, Karl Mayer-Eymar and Blytt correlated the well known succession of Tertiary stages to precession and eccentricity, respectively. Remarkably, Blytt, like Croll before him, used very long-period cycles in eccentricity to establish and validate his tuning. Understandably these studies in the second half of the 19th century were largely deductive in nature and proved partly incorrect later. Nevertheless, this fascinating period marks a crucial phase in the development of the astronomical theory of the ice ages and climate, and in astronomical dating. It preceded the final inductive phase, which started with the recovery of deep-sea cores in 1947 and led to a spectacular revival of the astronomical theory, by a century. The first half of the 20th century can best be regarded as an intermediate phase, despite the significant progress made in both theoretical aspects and tuning.

Hilgen, Frederik J.

2010-01-01

363

Astrophotonics: a new era for astronomical instruments.  

PubMed

Astrophotonics lies at the interface of astronomy and photonics. This burgeoning field has emerged over the past decade in response to the increasing demands of astronomical instrumentation. Early successes include: (i) planar waveguides to combine signals from widely spaced telescopes in stellar interferometry; (ii) frequency combs for ultra-high precision spectroscopy to detect planets around nearby stars; (iii) ultra-broadband fibre Bragg gratings to suppress unwanted background; (iv) photonic lanterns that allow single-mode behaviour within a multimode fibre; (v) planar waveguides to miniaturize astronomical spectrographs; (vi) large mode area fibres to generate artificial stars in the upper atmosphere for adaptive optics correction; (vii) liquid crystal polymers in optical vortex coronographs and adaptive optics systems. Astrophotonics, a field that has already created new photonic capabilities, is now extending its reach down to the Rayleigh scattering limit at ultraviolet wavelengths, and out to mid infrared wavelengths beyond 2500 nm. PMID:19189019

Bland-Hawthorn, Joss; Kern, Pierre

2009-02-01

364

Nicephoros Gregoras: the greatest Byzantine astronomer  

NASA Astrophysics Data System (ADS)

In the whole of Greece, no eminent astronomers appeared after the great Claudius Ptolemy (second century AD). For ten centuries after Ptolemy we can distinguish only one astronomer: Nicephoros Gregoras (1295 1360). The monk Nicephoros Gregoras is discussed together with his teacher, Theodoros Metochites, one of the most significant scholars of Byzantium. The literary work of Gregoras is especially important, while Byzantine astronomy owes indisputable progress to him. Gregoras was the first to propose, in 1324, a correction to the calculation of the date of Easter, and to the Julian calendar similar to that adopted later, in 1582, by Pope Gregory XIII. This proposition and, more obviously, his dispute with St Gregory Palamas created problems in the relationship between Gregoras and the Church, leading to the desecration of his corpse by a fanatical crowd.

Theodossiou, Efstratios Th.; Manimanis, Vassilios N.; Dimitrijevi?, Milan S.; Danezis, Emmanuel

2006-02-01

365

The origins of Ptolemy's astronomical tables.  

NASA Astrophysics Data System (ADS)

Following the line set by his earlier book 'The crime of Claudius Ptolemy' the author discusses here the numerous astronomical tables in Ptolemy's work that have been calculated with the aid of trigonometric tables, as well as a few that are nonlinear but that do not involve trigonometry. The purpose in this study is to determine, if possible, whether Ptolemy calculated these tables or whether he copied them from now-lost original works. The conclusion isthat Ptolemy made few if any original contributions to astronomy, either observational or computational.Contents: 1. Introduction; thetable of chords. 2. The tables of the latitude and of gnomon shadows.3. Tables of the Sun. 4. Astronomical geography. 5. The tables of theMoon. 6. Eclipse tables. 7. Tables of the planets. 8. The empirical basis for Hipparchus's mean motions of the Moon. 9. Summary and conclusions.

Newton, R. R.

366

The la Plata Astronomical Data Center  

NASA Astrophysics Data System (ADS)

RESUMEN. El Centro de Datos Astron6micos tiene su sede en la Facuitad de Ciencias Astron6micas y Geofisicas d la Universidad Nacional de La Plata y funciona por convenio entre esta facultad y el Centre des Stellaires de la Universite' Louis Pasteur en Estrasburgo (CDS), Francia. La finalidad de este centro es la de proveer a los astr6nomos del area con copias de los alrededor de 500 acumulados y/o preparados por el CDS a la vez que promover la producci6n y/o acumulaci6n de en el rea. Para la realizaci6n de esta tarea se cuenta con el apoyo del Centro Superior para el Procesamiento de la Informaci6n (CESPI) de la UNLP cuyos equipos se describen. Las tareas que se estan realizando incluyen la distribuci6n de SIMBAD a los astr6nomos argentinos y se efectuan ensayos de distribuci6n en linea de CD-ROM TEST DISK del Astronomical Data Center (ADC) de la NASA que contiene los 31 mas solicitados por los astr6nomos de todo el mundo. ABSTRACl The La Plata Astronomical Data Center operates by an agreement between the Facultad de Ciencias Astron6micas y Geofisicas at La Plata University and the Centre des Donnees Stellaires of Louis Pasteur University at Strasbourg (CDS), France. The purpose of the Center is to provide to the area astronomers with copies of the catalogs they need amongst those stored and/or prepared at CDS. At the same time the center will act of the astronomical data produced within its area. K words: DATA ANALYSIS

Marraco, H. G.

1990-11-01

367

Complex study of astronomical data arrays  

NASA Astrophysics Data System (ADS)

Some questions concerning of complex analysis of all available information about observations of stars with prismatic astrolabe are discussed. This analysis is indispensable for enhancing the validity of long series of station coordinates, which was derived in the past. We suppose that application of new information technologies to arrays of astronomical data should improve the accuracy of ground-based astrometry, which is restricted by atmosphere influences.

Khalyavina, L.

2005-06-01

368

Astronomical image denoising using dictionary learning  

NASA Astrophysics Data System (ADS)

Astronomical images suffer a constant presence of multiple defects that are consequences of the atmospheric conditions and of the intrinsic properties of the acquisition equipment. One of the most frequent defects in astronomical imaging is the presence of additive noise which makes a denoising step mandatory before processing data. During the last decade, a particular modeling scheme, based on sparse representations, has drawn the attention of an ever growing community of researchers. Sparse representations offer a promising framework to many image and signal processing tasks, especially denoising and restoration applications. At first, the harmonics, wavelets and similar bases, and overcomplete representations have been considered as candidate domains to seek the sparsest representation. A new generation of algorithms, based on data-driven dictionaries, evolved rapidly and compete now with the off-the-shelf fixed dictionaries. Although designing a dictionary relies on guessing the representative elementary forms and functions, the framework of dictionary learning offers the possibility of constructing the dictionary using the data themselves, which provides us with a more flexible setup to sparse modeling and allows us to build more sophisticated dictionaries. In this paper, we introduce the centered dictionary learning (CDL) method and we study its performance for astronomical image denoising. We show how CDL outperforms wavelet or classic dictionary learning denoising techniques on astronomical images, and we give a comparison of the effects of these different algorithms on the photometry of the denoised images. The current version of the code is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/556/A132

Beckouche, S.; Starck, J. L.; Fadili, J.

2013-08-01

369

Software Helps Extract Information From Astronomical Images  

NASA Technical Reports Server (NTRS)

PAC Skyview 2.0 is interactive program for display and analysis of astronomical images. Includes large set of functions for display, analysis and manipulation of images. "Man" pages with descriptions of functions and examples of usage included. Skyview used interactively or in "server" mode, in which another program calls Skyview and executes commands itself. Skyview capable of reading image data files of four types, including those in FITS, S, IRAF, and Z formats. Written in C.

Hartley, Booth; Ebert, Rick; Laughlin, Gaylin

1995-01-01

370

Towards Good Statistical Practices in Astronomical Studies  

NASA Astrophysics Data System (ADS)

Astronomers do not receive strong training in statistical methodology and are therefore sometimes prone to analyze data in ways that are discouraged by modern statisticians. A number of such cases are reviewed involving the Kolmogorov-Smirnov test, histograms and other binned statistics, various issues with regression, model selection with the likelihood ratio test, over-reliance on `3-sigma' criteria, under-use of multivariate clustering algorithms, and other issues.

Feigelson, Eric

2014-06-01

371

Publication Costs of Astronomical Research: Economic Considerations  

NASA Astrophysics Data System (ADS)

We examine the ways of covering the costs of dissemination of new knowledge in astronomy. We analyse the costs to researchers and research users of the self-publishing made possible by new electronic information systems. We explore whether costs of publication in the astronomical community will in the future be met by the originators of new knowledge (researchers), consumers (libraries and their users) or institutions which provide electronic databases.

Mitton, Simon; Mitton, Lavinia

372

Planar Integrated Optics and astronomical interferometry  

E-print Network

Integrated optics (IO) is an optical technology that allows to reproduce optical circuits on a planar substrate. Since 1996, we have investigated the potentiality of IO in the framework of astronomical single mode interferometry. We review in this paper the principles of IO, the requirements for interferometry and the corresponding solutions offered by IO, the results of component characterization and the possible fields of application.

Pierre Kern; Jean-Philippe Berger; Pierre Haguenauer; Fabien Malbet; Karine Perraut

2005-08-01

373

An Astronomer's View of Climate Change  

E-print Network

This paper describes some of the astronomical effects that could be important for understanding the ice ages, historic climate changes and the recent temperature increase. These include changes in the sun's luminosity, periodic changes in the earth's orbital parameters, the sun's orbit around our galaxy, the variability of solar activity and the anticorrelation of cosmic ray flux with that activity. Finally recent trends in solar activity and global temperatures are compared with the predictions of climate models.

Morton, Donald C

2014-01-01

374

Astronomers Find Planet with Similarities to Earth  

NSDL National Science Digital Library

Astronomers have found a new planet that is more like Earth than the other extrasolar planets found before, which were large and gaseous. This radio broadcast reports on this newly discovered planet, which appears to be small and rocky. The new terrestrial planet is extremely hot as it orbits very close to its star, Gliese 876. The clip is 1 minute and 58 seconds in length.

375

Elizabeth Brown (1830-1899), solar astronomer  

NASA Astrophysics Data System (ADS)

Were it not for the fact that she was a woman, Elizabeth Brown might well be thought of as a fairly typical nineteenth-century British amateur astronomer. She has a place, although a relatively modest one, in the distinguished group of people who, with their own fortunes, carried out much of the astronomical research being done in the country at a time before extensive government support was forthcoming for the work.1 Her career in fact follows a pattern common to several of the nineteenth-century men astronomers in that her full productive period came only after she was freed from her primary responsibilities; she did not have to amass the necessary financial resources as did many of the men,2 but she had the time-consuming responsibility, not unusual for a Victorian woman, of caring for a parent through a lengthy old age. Only after her father died at the age of ninety-one, did Elizabeth, then in her early fifties, begin her sixteen years of remarkable public activity in astronomy.

Creese, M.

1998-08-01

376

New Asteroid Ephemerides for the Astronomical Almanac  

NASA Astrophysics Data System (ADS)

Since the 2000 edition of the Astronomical Almanac , the ephemerides for the first four asteroids, Ceres, Pallas, Juno, and Vesta, have been based on the USNO/AE98 (Hilton, J.L. 1999, Astron. J ., 117 , 1077-1086). Beginning with the 2003 edition, the Astronomical Almanac will replace the current bi-daily ephemerides of the first four asteroids with daily ephemerides for 60 days either side of opposition of these asteroids and the other 11 asteroids included in USNO/AE98. In addition to the ephemerides of these asteroids, the Astronomical Almanac will print the elements, date of opposition, and approximate declination at opposition of a total of 93 asteroids. These asteroids were chosen because they are particularly bright (m < 11 at mean opposition or m < 12 if d > 200 km) and, generally, large. The asteroids in this selection include the 15 in USNO/AE98 and an additional 78 whose ephemerides, tentatively titled USNO/AE2001, are currently under development. Analysis of the residuals of the preliminary ephemerides show significant systematic errors for at least four and, perhaps, as many as 13 of the 78 asteroids. The most likely source of these systematic errors is perturbation by asteroids unmodeled in the preliminary ephemerides. Thus, if the perturbing asteroids can be identified, it may be possible to add to the number of large asteroids for which masses have been determined.

Hilton, J. L.

2001-11-01

377

GalileoMobile: Astronomical activities in schools  

NASA Astrophysics Data System (ADS)

GalileoMobile is an itinerant science education initiative run on a voluntary basis by an international team of astronomers, educators, and science communicators. Our team's main goal is to make astronomy accessible to schools and communities around the globe that have little or no access to outreach actions. We do this by performing teacher workshops, activities with students, and donating educational material. Since the creation of GalileoMobile in 2008, we have travelled to Chile, Bolivia, Peru, India, and Uganda, and worked with 56 schools in total. Our activities are centred on the GalileoMobile Handbook of Activities that comprises around 20 astronomical activities which we adapted from many different sources, and translated into 4 languages. The experience we gained in Chile, Bolivia, Peru, India, and Uganda taught us that (1) bringing experts from other countries was very stimulating for children as they are naturally curious about other cultures and encourages a collaboration beyond borders; (2) high-school students who were already interested in science were always very eager to interact with real astronomers doing research to ask for career advice; (3) inquiry-based methods are important to make the learning process more effective and we have therefore, re-adapted the activities in our Handbook according to these; (4) local teachers and university students involved in our activities have the potential to carry out follow-up activities, and examples are those from Uganda and India.

Dasi Espuig, Maria; Vasquez, Mayte; Kobel, Philippe

378

Recent Astronomical Development in Asia Pacific Rim  

NASA Astrophysics Data System (ADS)

For over two decades The Pacific Rim Conference on Stellar Astrophysics series has been held exclusively at the Asian Rim. The primary reason is that the majority of nations in Asia are less developed in Astronomy than many countries on the American Rim. At time same time, many nations in Asia are less able to afford the costs of long distance travel for astronomical conferences. As a result Asia has had a hold on the Pacific Rim Conferences. Over the last few years new research institutes have been coming on board. The ones that have most visibly emerged are; National Astronomical Research Institute of Thailand, NARIT, The Astrophysical Research Center for the Structure and Evolution of the Cosmos, ARCSEC, and Kavli Institute of Astronomy and Astrophysics at Peking University, KIAA-PKU. It is interesting to note the development and structure of each is very different. So far they all appear to be working well. Hopefully they will provide a variety of models for astronomical institutes in developing nations of the region and perhaps beyond.

Leung, K.-C.

2009-08-01

379

International Schools for Young Astronomers Teaching for Astronomy Development: two programmes of the International Astronomical Union  

NASA Astrophysics Data System (ADS)

This text outlines the main features of two educational programmes of the International Astronomical Union (IAU): the International Schools for Young Astronomers (ISYA) and the Teaching for Astronomy Development programme (TAD), developed since 1967. The main goal of the International Schools for Young Astronomers (ISYA) is to support astronomy (education and research) in developing countries in organizing a 3-week School for students with typically M.Sc. degrees. The context in which the ISYA were developed changed drastically during the last decade. From a time when access to large telescopes was difficult and mainly organized on a nation-basis, nowadays the archives of astronomical data have accumulated at the same time that many major telescope become accessible, and they are accessible from everywhere, the concept of virtual observatory reinforcing this access. A second programme of the IAU, Teaching for Astronomy Development (TAD), partially based on a School, but also of shorter duration (typically one week) has a complementary objective. It is dedicated to assist countries that have little or no astronomical activity, but that wish to enhance their astronomy education. The fast development of the TAD programme over the past years is emphasized.

Gerbaldi, Michèle; DeGreve, Jean-Pierre; Guinan, Edward

2011-06-01

380

PLANCK and WMAP constraints on generalised Hubble flow inflationary trajectories  

NASA Astrophysics Data System (ADS)

We use the Hamilton-Jacobi formalism to constrain the space of possible single field, inflationary Hubble flow trajectories when compared to the WMAP and PLANK satellites Cosmic Microwave Background (CMB) results. This method yields posteriors on the space of Hubble Slow Roll (HSR) parameters that uniquely determine the history of the Hubble parameter during the inflating epoch. The trajectories are used to numerically determine the observable primordial power spectrum and bispectra that can then be compared to observations. Our analysis is used to infer the most likely shape of the inflaton potential V(phi) and also yields a prediction for, Script B, the dimensionless amplitude of the non-Gaussian bispectrum.

Contaldi, Carlo R.; Horner, Jonathan S.

2014-08-01

381

HUBBLE PROVIDES COMPLETE VIEW OF JUPITER'S AURORAS  

NASA Technical Reports Server (NTRS)

NASA's Hubble Space Telescope has captured a complete view of Jupiter's northern and southern auroras. Images taken in ultraviolet light by the Space Telescope Imaging Spectrograph (STIS) show both auroras, the oval- shaped objects in the inset photos. While the Hubble telescope has obtained images of Jupiter's northern and southern lights since 1990, the new STIS instrument is 10 times more sensitive than earlier cameras. This allows for short exposures, reducing the blurring of the image caused by Jupiter's rotation and providing two to five times higher resolution than earlier cameras. The resolution in these images is sufficient to show the 'curtain' of auroral light extending several hundred miles above Jupiter's limb (edge). Images of Earth's auroral curtains, taken from the space shuttle, have a similar appearance. Jupiter's auroral images are superimposed on a Wide Field and Planetary Camera 2 image of the entire planet. The auroras are brilliant curtains of light in Jupiter's upper atmosphere. Jovian auroral storms, like Earth's, develop when electrically charged particles trapped in the magnetic field surrounding the planet spiral inward at high energies toward the north and south magnetic poles. When these particles hit the upper atmosphere, they excite atoms and molecules there, causing them to glow (the same process acting in street lights). The electrons that strike Earth's atmosphere come from the sun, and the auroral lights remain concentrated above the night sky in response to the 'solar wind,' as Earth rotates underneath. Earth's auroras exhibit storms that extend to lower latitudes in response to solar activity, which can be easily seen from the northern U. S. But Jupiter's auroras are caused by particles spewed out by volcanoes on Io, one of Jupiter's moons. These charged particles are then magnetically trapped and begin to rotate with Jupiter, producing ovals of auroral light centered on Jupiter's magnetic poles in both the day and night skies. Scientists are comparing the Hubble telescope images with measurements taken by NASA's Galileo spacecraft of Jupiter's magnetic field and co-rotating charged particles. They believe the data will help them understand the production of Jupiter's auroras. Both auroras clearly show vapor trails of light left by Io. These vapor trails are the white, comet-shaped streaks just outside both auroral ovals. These streaks are not part of the auroral ovals. They are caused when an invisible electrical current of charged particles (equal to about 1 million amperes), ejected from Io, flow along Jupiter's magnetic field lines to the planets north and south magnetic poles. This enormous current produces a bright but localized aurora where it enters Jupiter's atmosphere at both magnetic poles. The brightest part of both emissions (on the left in both images) pinpoints where Io's magnetic field lines leave its footprint on the planet. The trail of light following both emissions extends to the right all the way to Jupiter's edge and represents the most sensitive detection of ultraviolet emissions from Jupiter to date. These emissions are related to magnetically trapped ions and electrons that are carried by Jupiter's magnetic field along Io's orbital path, and some of these charged particles continue to be driven down into Jupiter's atmosphere for several hours after Io has passed by. The images were taken Sept. 20, 1997. The artificial colors used here have been constructed by combining images taken in two different ultraviolet band passes, with one ultraviolet color presented as blue and the other as red. In this color representation, the planet's reflected sunlight appears brown, while the auroral emissions appear white or shades of blue or red. Credits: John Clarke (University of Michigan), and NASA Co-investigators: Joe Ajello, Kent Tobiska, and John Trauger (NASA's Jet Propulsion Laboratory) Gilda Ballester (University of Michigan) Lotfi Ben jaffel (IAP Paris) Jack Connerney (NASA's Goddard Space Flight Center) Jean-Claude Gerard (University of Liege, Belgium) Randy Glads

2002-01-01

382

HUBBLE VIEWS OF THREE STELLAR JETS  

NASA Technical Reports Server (NTRS)

These NASA Hubble Space Telescope views of gaseous jets from three newly forming stars show a new level of detail in the star formation process, and are helping to solve decade-old questions about the secrets of star birth. Jets are a common 'exhaust product' of the dynamics of star formation. They are blasted away from a disk of gas and dust falling onto an embryonic star. [upper left] - This view of a protostellar object called HH-30 reveals an edge-on disk of dust encircling a newly forming star. Light from the forming star illuminates the top and bottom surfaces of the disk, making them visible, while the star itself is hidden behind the densest parts of the disk. The reddish jet emanates from the inner region of the disk, and possibly directly from the star itself. Hubble's detailed view shows, for the first time, that the jet expands for several billion miles from the star, but then stays confined to a narrow beam. The protostar is 450 light-years away in the constellation Taurus. Credit: C. Burrows (STScI and ESA), the WFPC 2 Investigation Definition Team, and NASA [upper right] - This view of a different and more distant jet in object HH-34 shows a remarkable beaded structure. Once thought to be a hydrodynamic effect (similar to shock diamonds in a jet aircraft exhaust), this structure is actually produced by a machine-gun-like blast of 'bullets' of dense gas ejected from the star at speeds of one-half million miles per hour. This structure suggests the star goes through episodic 'fits' of construction where chunks of material fall onto the star from a surrounding disk. The protostar is 1,500 light- years away and in the vicinity of the Orion Nebula, a nearby star birth region. Credit: J. Hester (Arizona State University), the WFPC 2 Investigation Definition Team, and NASA [bottom] - This view of a three trillion mile-long jet called HH-47 reveals a very complicated jet pattern that indicates the star (hidden inside a dust cloud near the left edge of the image) might be wobbling, possibly caused by the gravitational pull of a companion star. Hubble's detailed view shows that the jet has burrowed a cavity through the dense gas cloud and now travels at high speed into interstellar space. Shock waves form when the jet collides with interstellar gas, causing the jet to glow. The white filaments on the left reflect light from the obscured newborn star. The HH-47 system is 1,500 light-years away, and lies at the edge of the Gum Nebula, possibly an ancient supernova remnant which can be seen from Earth's southern hemisphere. Credit: J. Morse/STScI, and NASA The scale in the bottom left corner of each picture represents 93 billion miles, or 1,000 times the distance between Earth and the Sun. All images were taken with the Wide Field Planetary Camera 2 in visible light. The HH designation stands for 'Herbig-Haro' object -- the name for bright patches of nebulosity which appear to be moving away from associated protostars.

2002-01-01

383

The Hubble Diagram of Type IA Supernovae in Non-Uniform Pressure Universes  

NASA Astrophysics Data System (ADS)

We use the redshift-magnitude relation, as derived by D?browski, for the two exact non-uniform pressure spherically symmetric Stephani universes with the observer positioned at the center of symmetry in order to test the agreement of these models with recent observations of high-redshift Type Ia supernovae (SN Ia's). By a particular choice of model parameters, we show that these models can give an excellent fit to the observed redshifts and (corrected) B-band apparent magnitudes of the data, but for an age of the universe that is typically about 2 Gyr--and may be more than 3 Gyr--greater than in the corresponding Friedmann model, for which nonnegative values of the deceleration parameter appear to be favored by the data. We show that this age increase is obtained for a wide range of the non-uniform pressure parameters of the Stephani models. We claim that this paper is the first attempt to compare inhomogeneous models of the universe with real astronomical data. Several recent calibrations of the Hubble parameter from the Hubble diagram of SN Ia's and other distance indicators indicate a value of H0 ~= 65 and a Hubble time of ~15 Gyr. Based on this value for H0 and assuming ? >= 0, the data would imply a Friedmann age of at most 13 Gyr and in fact a best-fit (for q0 = 0.5) age of only 10 Gyr. Our Stephani models, on the other hand, can give a good fit to the data with an age of up to 15 Gyr. The Stephani models considered here could, therefore, significantly alleviate the conflict between recent cosmological and astrophysical age predictions. The choice of model parameters is quite robust: in order to obtain a good fit to the current data, one requires only that the non-uniform pressure parameter a in one of the models be negative and satisfy |a| <~ 3 km2 s-2 Mpc-1. This limit gives a value for the acceleration scalar u? of order |u?|<~0.66×10-10r Mpc-1, where r is the radial coordinate in the model. Thus, although the pressure is not zero at the center of symmetry, r = 0, the effect of acceleration is nondetectable at the center, since the acceleration scalar vanishes there. However, the effect of the nonuniform pressure on the redshift-magnitude relation is clearly seen, since neighboring galaxies are not situated at the center, and they necessarily experience acceleration. By allowing slightly larger negative values of a one may fine-tune the model to give an even better fit to the data.

D?browski, Mariusz P.; Hendry, Martin A.

1998-05-01

384

Theistic Arguments Edwin Chong  

E-print Network

it is impossible to please God, because anyone who comes to him must believe that he exists and that he rewards't believe that God exists. Nobody knows if God exists. I don't need the concept of God. The idea of God, recognized that the whether God exists makes a tremendous difference! #12;3 February 2005 5 Quote from Norman

Chong, Edwin K. P.

385

A Hubble diagram of distant type IA supernovae  

Microsoft Academic Search

We have constructed Hubble diagrams in B and V for 13 Type Ia supernovae (SNe Ia) found in the course of the Calan\\/Tololo survey covering an unprecedented range in redshift (0.01 less than Z less than 0.1). As opposed to other published Hubble diagrams, these are solely based on light curves obtained with CCDs, which have been carefully reduced in

Mario Hamuy; M. M. Phillips; Jose Maza; Nicholas B. Suntzeff; R. A. Schommer; R. Aviles

1995-01-01

386

Star Formation in Galaxies Along the Hubble Sequence  

Microsoft Academic Search

Observations of star formation rates (SFRs) in galaxies provide vital clues\\u000ato the physical nature of the Hubble sequence, and are key probes of the\\u000aevolutionary properties of galaxies. The focus of this review is on the broad\\u000apatterns in the star formation properties of galaxies along the Hubble\\u000asequence, and their implications for understanding galaxy evolution and the\\u000aphysical

Robert C. Kennicutt

1998-01-01

387

Building the Pipeline for Hubble Legacy Archive Grism data  

Microsoft Academic Search

The Pipeline for Hubble Legacy Archive Grism data (PHLAG) is currently being developed as an end-to-end pipeline for the Hubble Legacy Archive (HLA). The inputs to PHLAG are slitless spectroscopic HST data with only the basic calibrations from standard HST pipelines applied; the outputs are fully calibrated, Virtuall Observatory-compatible spectra, which will be made available through a static HLA-archive. We

M. Kümmel; R. Albrecht; R. Fosbury; W. Freudling; J. Haase; R. N. Hook; H. Kuntschner; M. Lombardi; A. Micol; M. Rosa; F. Stoehr; J. R. Walsh

2008-01-01

388

Hubble Space Telescope Crew Rescue Analysis  

NASA Technical Reports Server (NTRS)

In the aftermath of the 2003 Columbia accident, NASA removed the Hubble Space Telescope (HST) Servicing Mission 4 (SM4) from the Space Shuttle manifest. Reasons cited included concerns that the risk of flying the mission would be too high. The HST SM4 was subsequently reinstated and flown as Space Transportation System (STS)-125 because of improvements in the ascent debris environment, the development of techniques for astronauts to perform on orbit repairs to damaged thermal protection, and the development of a strategy to provide a viable crew rescue capability. However, leading up to the launch of STS-125, the viability of the HST crew rescue capability was a recurring topic. For STS-125, there was a limited amount of time available to perform a crew rescue due to limited consumables (power, oxygen, etc.) available on the Orbiter. The success of crew rescue depended upon several factors, including when a problem was identified; when and what actions, such as powering down, were begun to conserve consumables; and where the Launch on Need (LON) vehicle was in its ground processing cycle. Crew rescue success also needed to be weighed against preserving the Orbiter s ability to have a landing option in case there was a problem with the LON vehicle. This paper focuses on quantifying the HST mission loss of crew rescue capability using Shuttle historical data and various power down strategies. Results from this effort supported NASA s decision to proceed with STS-125, which was successfully completed on May 24th 2009.

Hamlin, Teri L.; Canga, Michael A.; Cates, Grant R.

2010-01-01

389

Type Ia Supernovae and the Hubble Constant  

E-print Network

The focus of this review is the work that has been done during the 1990s on using Type Ia supernovae (SNe Ia) to measure the Hubble constant ($H_0$). SNe Ia are well suited for measuring $H_0$. A straightforward maximum-light color criterion can weed out the minority of observed events that are either intrinsically subluminous or substantially extinguished by dust, leaving a majority subsample that has observational absolute-magnitude dispersions of less than $\\sigma_{obs}(M_B) \\simeq \\sigma_{obs}(M_V) \\simeq 0.3$ mag. Correlations between absolute magnitude and one or more distance-independent SN Ia or parent-galaxy observables can be used to further standardize the absolute magnitudes to better than 0.2 mag. The absolute magnitudes can be calibrated in two independent ways --- empirically, using Cepheid-based distances to parent galaxies of SNe Ia, and physically, by light curve and spectrum fitting. At present the empirical and physical calibrations are in agreement at $M_B \\simeq M_V \\simeq -19.4$ or -19....

Branch, D

1998-01-01

390

Hubble Space Telescope imaging of Eta Carinae  

SciTech Connect

New high spatial resolution observations of the material around Eta Carinae, obtained with the Hubble Space Telescope Wide Field/Planetary Camera, are presented. The star Eta Carinae is one of the most massive and luminous stars in the Galaxy, and has been episodically expelling significant quantities of gas over the last few centuries. The morphology of the bright central nebulosity (the homunculus) indicates that it is a thin shell with very well defined edges, and is clumpy on 0.2 arcsec (about 10 to the 16th cm) scales. An extension to the northeast of the star (NN/NS using Walborn's 1976 nomenclature) appears to be a stellar jet and its associated bow shock. The bow shock is notable for an intriguing series of parallel linear features across its face. The S ridge and the W arc appear to be part of a 'cap' of emission located to the SW and behind the star. Together, the NE jet and the SW cap suggest that the symmetry axis for the system runs NE-SW rather than SE-NW, as previously supposed. Overall, the data indicate that the material around the star may represent an oblate shell with polar blowouts, rather than a bipolar flow. 26 refs.

Hester, J.J.; Westphal, J.A.; Light, R.M.; Currie, D.G.; Groth, E.J. (California Inst. of Tech., Pasadena (United States) Lick Observatory, Santa Cruz, CA (United States) Maryland Univ., College Park (United States) Princeton Univ., NJ (United States))

1991-08-01

391

Keeping the Hubble Space Telescope in focus  

NASA Astrophysics Data System (ADS)

The Hubble Space Telescope is a Ritchie-Chrétien optical design with a main primary concave mirror followed by a convex secondary. The focus is determined by the position of each of these two mirrors. The truss containing them is made of graphite epoxy which has very low thermal expansion. Nevertheless, temperature variations do cause the mirror separation to vary by several microns within an orbit. Additionally, outgassing of water vapor causes a long-term shrinkage which soon after launch in 1990 varied by more than 2 microns per month. This necessitated adjusting the position of the secondary mirror every few months. Currently this rate is greatly reduced and adjustments are needed less than once per year. The focus is monitored monthly to continually assess the need for such adjustments. The measurements have been used to develop models to predict the focus at times between measurements to assist in the analysis of observations. Detailed focus knowledge is of value in photometry, coronagraphy and image deconvolution. The various focus models that have been applied so far are described with an evaluation of their performance. Continuing attempts to refine the model will be discussed.

Cox, Colin; Lallo, Matthew

2012-09-01

392

HUBBLE PARAMETER MEASUREMENT CONSTRAINTS ON DARK ENERGY  

SciTech Connect

We use 21 Hubble parameter versus redshift data points from Simon et al., Gaztanaga et al., Stern et al., and Moresco et al. to place constraints on model parameters of constant and time-evolving dark energy cosmologies. The inclusion of the eight new measurements results in H(z) constraints more restrictive than those derived by Chen and Ratra. These constraints are now almost as restrictive as those that follow from current Type Ia supernova (SNIa) apparent magnitude versus redshift data, which now more carefully account for systematic uncertainties. This is a remarkable result. We emphasize, however, that SNIa data have been studied for a longer time than the H(z) data, possibly resulting in a better estimate of potential systematic errors in the SNIa case. A joint analysis of the H(z), baryon acoustic oscillation peak length scale, and SNIa data favors a spatially flat cosmological model currently dominated by a time-independent cosmological constant but does not exclude slowly evolving dark energy.

Farooq, Omer; Mania, Data; Ratra, Bharat, E-mail: omer@phys.ksu.edu, E-mail: mania@phys.ksu.edu, E-mail: ratra@phys.ksu.edu [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States)] [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States)

2013-02-20

393

Hubble Space Telescope imaging of Eta Carinae  

NASA Technical Reports Server (NTRS)

New high spatial resolution observations of the material around Eta Carinae, obtained with the Hubble Space Telescope Wide Field/Planetary Camera, are presented. The star Eta Carinae is one of the most massive and luminous stars in the Galaxy, and has been episodically expelling significant quantities of gas over the last few centuries. The morphology of the bright central nebulosity (the homunculus) indicates that it is a thin shell with very well defined edges, and is clumpy on 0.2 arcsec (about 10 to the 16th cm) scales. An extension to the northeast of the star (NN/NS using Walborn's 1976 nomenclature) appears to be a stellar jet and its associated bow shock. The bow shock is notable for an intriguing series of parallel linear features across its face. The S ridge and the W arc appear to be part of a 'cap' of emission located to the SW and behind the star. Together, the NE jet and the SW cap suggest that the symmetry axis for the system runs NE-SW rather than SE-NW, as previously supposed. Overall, the data indicate that the material around the star may represent an oblate shell with polar blowouts, rather than a bipolar flow.

Hester, J. J.; Westphal, James A.; Light, Robert M.; Currie, Douglas G.; Groth, Edward J.

1991-01-01

394

US Gateway to SIMBAD Astronomical Database  

NASA Technical Reports Server (NTRS)

During the last year the US SIMBAD Gateway Project continued to provide services like user registration to the US users of the SIMBAD database in France. User registration is required by the SIMBAD project in France. Currently, there are almost 3000 US users registered. We also provide user support by answering questions from users and handling requests for lost passwords. We have worked with the CDS SIMBAD project to provide access to the SIMBAD database to US users on an Internet address basis. This will allow most US users to access SIMBAD without having to enter passwords. This new system was installed in August, 1998. The SIMBAD mirror database at SAO is fully operational. We worked with the CDS to adapt it to our computer system. We implemented automatic updating procedures that update the database and password files daily. This mirror database provides much better access to the US astronomical community. We also supported a demonstration of the SIMBAD database at the meeting of the American Astronomical Society in January. We shipped computer equipment to the meeting and provided support for the demonstration activities at the SIMBAD booth. We continued to improve the cross-linking between the SIMBAD project and the Astro- physics Data System. This cross-linking between these systems is very much appreciated by the users of both the SIMBAD database and the ADS Abstract Service. The mirror of the SIMBAD database at SAO makes this connection faster for the US astronomers. The close cooperation between the CDS in Strasbourg and SAO, facilitated by this project, is an important part of the astronomy-wide digital library initiative called Urania. It has proven to be a model in how different data centers can collaborate and enhance the value of their products by linking with other data centers.

Eichhorn, G.

1998-01-01

395

Expansion of The Astronomical Almanac Online Website  

NASA Astrophysics Data System (ADS)

The Astronomical Almanac (AsA) Online website (http://asa.usno.navy.mil/ and http://asa.hmnao.com/), a joint project between the Nautical Almanac Office (NAO) at the US Naval Observatory and Her Majesty's Nautical Almanac Office (HMNAO) at the UK Hydrographic Office, began as a supplement to the printed Astronomical Almanac. The original intent of the AsA Online was to provide data in text form for machine parsing, datasets no longer published in the book but still needed by some users, a list of errata as they become known, and a means for user feedback. For the past few years we have looked at how to improve the AsA Online by presenting additional data with methods not available in a printed book. Starting with the proof-of-concept observatory search--designed to add a dynamic element to the data from the observatory section while still maintaining the look of printed pages in the AsA--we have added: maps for lunar occultations of the planets, many minor planets, and bright stars (supplementing the Phenomena section); a table on the main page of the website that presents entries from the Diary of Phenomena for two weeks into the future; a utility for finding the geocentric coordinates of the planets (supplementing Section E); searches for some tables found in Section H (Stars), allowing users to filter the data and print a subset of the entries for ease-of-use; and a Delta T: Past, Present and Future feature updated multiple times per year. In the future, we plan to increase the amount of information on the AsA Online by adding more filterable datasets from the book, new ways of visualizing information, and options to download data in machine-friendly XML, while still maintaining the website as a complement to the printed Astronomical Almanac.

Barron, Eric G.; Bell, S. A.; Hohenkerk, C. Y.; Stewart, S. G.; Urban, S. E.

2010-01-01

396

Astronomical Beliefs in Medieval Georgia: Innovative Approaches  

NASA Astrophysics Data System (ADS)

Written sources from medieval Georgia show, among other things, how astronomical ideas were adapted on the periphery of the Byzantine and Islamic worlds. In this paper, we investigate a number of Georgian beliefs about the heavens from a calendrical work and a celestial prognostication text, but also from less expected sources including the medieval life of a saint and an epic poem. For the most part, these sources were derived from Byzantine or Persian models. We show the extent to which the sources nevertheless conform to a specifically Georgian view of the cosmos. We argue that, in so doing, medieval Georgian authors employed several innovative approaches hitherto unnoticed by modern scholars.

Sauter, Jefferson; Orchiston, W.; Stephenson, F.

2014-01-01

397

The Astronomical Orientation of Ancient Greek Temples  

PubMed Central

Despite its appearing to be a simple question to answer, there has been no consensus as to whether or not the alignments of ancient Greek temples reflect astronomical intentions. Here I present the results of a survey of archaic and classical Greek temples in Sicily and compare them with temples in Greece. Using a binomial test I show strong evidence that there is a preference for solar orientations. I then speculate that differences in alignment patterns between Sicily and Greece reflect differing pressures in the expression of ethnic identity. PMID:19936239

Salt, Alun M.

2009-01-01

398

Applications of transputers to astronomical instruments  

SciTech Connect

Parallel processing techniques based on transputers are being applied to astronomical instruments under development. On the COSMOS photographic plate measuring machine, a data farm of transputers allows backgrounds to be determined in realtime instead of requiring 1.5 hours of offline VAX processing per plate. Transputers have been adopted as the embedded processors in a submillimetre bolometer array instrument and their use is planned in demanding future applications such as thermal infrared array instruments and data compression applied to remote observing. The techniques of interfacing transputers to external hardware and to VAX/VMS computers are discussed.

Stewart, J.M.; Beard, S,M.; Kelly, B.D.; Paterson, M.J. (Royal Observatory, Edinburgh (UK))

1990-04-01

399

An astronomical survey conducted in Belgium  

NASA Astrophysics Data System (ADS)

This paper presents the results of the first survey conducted in Belgium about the interest in and knowledge of astronomy. Two samples were studied, the public at large (667 questionnaires) and students (2589 questionnaires), but the results are generally similar in both samples. We evaluated people’s interest, main information source and attitudes towards astronomy, as well as their supposed and actual knowledge of the subject. The main conclusion is that, despite poor self-confidence, people do know the basic astronomical concepts. However, that knowledge is not deeply rooted, as reasoning questions show widespread misconceptions and/or misunderstandings.

Nazé, Yaël; Fontaine, Sébastien

2014-03-01

400

Anglo-Australian Observatory Astronomical Images  

NSDL National Science Digital Library

David Malin, Adjunct Professor of Scientific Photography at Royal Melbourne Institute of Technology (RMIT), has created this "gateway to a unique collection of wide-field astronomical photographs." These awe-striking photographs were mostly taken with the telescopes of the Anglo-Australian Observatory and include photos of galaxies, emission and reflection nebulae, supernovae, star clusters, messier objects, and more. Underneath each picture is a brief description, along with links to other related images. Users may scan the images by object type, by telescope type, or by the portfolio pages of thumbnail pictures (a slightly slower process).

Malin, David.

401

Contamination control of the Infrared Astronomical Satellite  

NASA Astrophysics Data System (ADS)

The Infrared Astronomical Satellite, to be launched in August 1981, will perform an all-sky survey in the 8-120 micron wavelength region. High sensitivity to thermal radiation and the low operating temperature of optics and thermal control surfaces make the IRAS telescope extremely vulnerable to contamination. Four special topics of importance are discussed in this paper: (1) deposition of atmospheric gases; (2) sighting of particles released from the satellite; (3) functions of a deployable aperture cover; and (4) degradation of a radiatively cooled sunshade from spacecraft outgassing. These topics demonstrate how mission strategy, ground cleaning and handling, and hardware design are used to avoid contamination which would degrade telescope performance.

Andreozzi, L. C.; Irace, W. R.; Maag, C. R.

402

Contamination control of the Infrared Astronomical Satellite  

NASA Technical Reports Server (NTRS)

The Infrared Astronomical Satellite, to be launched in August 1981, will perform an all-sky survey in the 8-120 micron wavelength region. High sensitivity to thermal radiation and the low operating temperature of optics and thermal control surfaces make the IRAS telescope extremely vulnerable to contamination. Four special topics of importance are discussed in this paper: (1) deposition of atmospheric gases; (2) sighting of particles released from the satellite; (3) functions of a deployable aperture cover; and (4) degradation of a radiatively cooled sunshade from spacecraft outgassing. These topics demonstrate how mission strategy, ground cleaning and handling, and hardware design are used to avoid contamination which would degrade telescope performance.

Andreozzi, L. C.; Irace, W. R.; Maag, C. R.

1980-01-01

403

ASPRO 2: Astronomical Software to PRepare Observations  

NASA Astrophysics Data System (ADS)

ASPRO 2 (Astronomical Software to PRepare Observations) is an observation preparation tool for interferometric observations with the VLTI or other interferometers such as CHARA and SUSI. It is a Java standalone program that provides a dynamic graphical interface to simulate the projected baseline evolution during observations (super-synthesis) and derive visibilities for targets (i.e., single star, binaries, user defined FITS image). It offers other useful functions such as the ability to load and save your observation settings and generate Observing Blocks.

Bourgès, Laurent; Mella, Guillaume; Lafrasse, Sylvain; Duvert, Gilles

2013-10-01

404

ANSEF Support to Astronomical Research in Armenia  

NASA Astrophysics Data System (ADS)

To promote scientific and scholarly research in Armenia, in 1999 the Armenian National Science and Education Fund (ANSEF) was formed in New York, USA. Since 2000, ANSEF has issued an annual request for proposals from scientists and scholars working in Armenia. In the last seven years we have received 200 to 300 proposals each year. These proposals are peer reviewed and grants issued to the top 10% to 15% annually. Proposals in the astronomical sciences have primarily been submitted from scientists from the Byurakan Astrophysical Observatory, and the Yerevan State University, and they have been very successful. These competitive awards have produced significant new research published in many international journals.

Terzian, Yervant

2007-08-01

405

Software design for panoramic astronomical pipeline processing  

E-print Network

We describe the software requirement and design specifications for all-sky panoramic astronomical pipelines. The described software aims to meet the specific needs of super-wide angle optics, and includes cosmic-ray hit rejection, image compression, star recognition, sky opacity analysis, transient detection and a web server allowing access to real-time and archived data. The presented software is being regularly used for the pipeline processing of 11 all-sky cameras located in some of the world's premier observatories. We encourage all-sky camera operators to use our software and/or our hosting services and become part of the global Night Sky Live network.

Lior Shamir; Robert J. Nemiroff; David O. Torrey; Wellesley E. Pereira

2005-11-23

406

Building up a European astronomical community  

NASA Astrophysics Data System (ADS)

Astronomy is arguably the science that brought most economical benefits throughout mankind history. Keeping time allowed for agriculture, navigation and most human activities. Intellectual pursuit came along the way. In the last century our activity has turned almost exclusively towards the physical study of our far environment. From local our pursuit turned global. Our research context has, however, not yet followed that route, most of the efforts are nationally funded. Looking at a world political map, one sees that Europe is in a rather poor position, being fractionated in very small national entities. The EAS works towards overcoming this by building a European astronomical community extending from the Azores to Russia.

Courvoisier, T.

2013-09-01

407

Publications of the Astronomical Society of the Pacific  

NSDL National Science Digital Library

The University of Chicago Press has announced unrestricted access to an online journal until mid-1998. Full text articles, announcements, and editorials are all available. Publications of the Astronomical Society of the Pacific (PASP) begin with Volume 110 (1998). This journal "provides an outlet for astronomical results of a scientific nature and serves to keep readers in touch with current astronomical research. PASP contains refereed research and instrumentation papers, invited reviews, and dissertation summaries." The publication is available in various formats.

1998-01-01

408

Amateur and professional astronomers meet at Mill Hill  

NASA Astrophysics Data System (ADS)

Nearly forty professional and amateur astronomers from around the UK converged on the Mill Hill Observatory of University College, London, on Saturday September 16, for a meeting set up by the Royal Astronomical Society and The Astronomer to promote and exchange ideas on professional?amateur collaboration in astronomy. Fields discussed included variable star research, gamma ray bursters, supernova searching, spectroscopy and minor planet and meteor work.

Poyner, G.

2000-12-01

409

Using Fuzzy Logic for Automatic Analysis of Astronomical Pipelines  

E-print Network

Fundamental astronomical questions on the composition of the universe, the abundance of Earth-like planets, and the cause of the brightest explosions in the universe are being attacked by robotic telescopes costing billions of dollars and returning vast pipelines of data. The success of these programs depends on the accuracy of automated real time processing of the astronomical images. In this paper the needs of modern astronomical pipelines are discussed in the light of fuzzy-logic based decision-making. Several specific fuzzy-logic algorithms have been develop for the first time for astronomical purposes, and tested with excellent results on data from the existing Night Sky Live sky survey.

Lior Shamir; Robert J. Nemiroff

2005-06-27

410

Canadian Astronomy Education: A Project by the Canadian Astronomical Society  

NSDL National Science Digital Library

The Canadian Astronomical Society offers educational astronomy materials for teachers, students, youth organizations, and professional and amateur astronomers. Educators can find astronomy curriculum expectations for Canada, a list of science centers and observatories, activity ideas, lesson plans, star charts, and much more. The website features an informative biography of the astronomer of the month. Students can find an interactive tour of the universe and great tips to help them learn astronomy as well as information about astronomy careers, clubs, and science fairs. Novice astronomers can obtain guides about buying telescopes and observing. This high-quality site is sure to have appealing materials for all individuals interested in astronomy.

411

Providing Legacy Access to Astronomical Data Analysis Software  

NASA Astrophysics Data System (ADS)

Astronomical data analysis systems, especially in space projects, usually have a very long expected lifetime after the relatively short operational project phase when developer resources are available. Therefore these software projects need to take measures to make sure astronomers can continue to run the necessary mission-specific data analysis tools. Computing hardware available to astronomers tends to evolve substantially over timescales of about 10 years. Data access and data reduction of raw data are usually highly dependent on the availability of a data product archive and of the processing software. There are a number of issues that might jeopardize the legacy availability of astronomical software systems.

Huygen, R.; Vandenbussche, B.; De Meester, W.; De Jong, J.; Wieprecht, E.; Wetzstein, M.

2012-09-01