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X-Rays From Sirius B
| Title |
X-Rays From Sirius B |
| Explanation |
In visible light Sirius A [ http://www.astro.uiuc.edu/~kaler/sow/sirius.html ] (Alpha Canis Majoris) is the brightest [ http://www.astro.wisc.edu/~dolan/constellations/extra/ brightest.html ] star in the night sky, a closely watched celestial beacon throughout recorded history [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query? bibcode=1999MNRAS.310..355W&db_key=AST&high=39d9fcfee514284 ]. Part of a binary star [ http://astrosun.tn.cornell.edu/courses/astro201/ binstar.htm ] system only 8 light-years away, it was known in modern times to have a small companion [ http://xxx.lanl.gov/abs/astro-ph/0010032 ] star, Sirius B. Sirius B is much dimmer and appears so close to the brilliant Sirius A that it was not actually sighted [ http://adsbit.harvard.edu/cgi-bin/ nph-iarticle_query?bibcode=1891AJ.....10..149H ] until 1862, during Alvan Clark's testing of a large, well made optical refracting telescope [ http://antwrp.gsfc.nasa.gov/apod/ap990114.html ]. For orbiting x-ray telescopes [ http://imagine.gsfc.nasa.gov/docs/science/ know_l2/history_xray.html ], the Sirius [ http://antwrp.gsfc.nasa.gov/apod/ap000611.html ] situation is exactly reversed, though. A smaller but hotter Sirius B appears as the overwhelmingly intense x-ray source in this Chandra Observatory x-ray image [ http://chandra.harvard.edu/photo/cycle1/0065/index.html ] (lines radiating from Sirius B are image artifacts). The fainter source seen at the position of Sirius A may be largely due to ultraviolet light from the star leaking into the x-ray detector. With a surface temperature of 25,000 kelvins [ http://www.its.bldrdoc.gov/fs-1037/dir-020/_2932.htm ], the mass of the Sun, and a radius just less than Earth's, Sirius B is the closest known white dwarf star [ http://hyperphysics.phy-astr.gsu.edu/hbase/astro/ whdwar.html#c1 ]. Can you guess what makes Sirius B [ http://hyperphysics.phy-astr.gsu.edu/hbase/astro/ whdwar.html#c2 ] like Neptune [ http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/ Neptune_and_Pluto.html ], the Sun's most distant gas giant planet? While still unseen, the presence of both celestial bodies was detected based on their gravitational influence alone ... making them early examples of dark matter [ http://www.astro.queensu.ca/~dursi/dm-tutorial/dm1.html ]. |
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Eclipse with Lighthouse
| Title |
Eclipse with Lighthouse |
| Explanation |
A red Moon rose [ http://www.abmedia.com/astro/current/ lunareclipse-030307.html ] over Cape Cod, Massachusetts, USA on March 3rd, immersed in Earth's shadow near the total phase [ http://antwrp.gsfc.nasa.gov/apod/ap070308.html ] of a lunar eclipse. This serene portrait [ http://www.liverpoolmuseums.org.uk/nof/portraits/ ] of the eclipsed Moon in a dark blue twilight sky also features the Highland Lighthouse [ http://www.nps.gov/archive/caco/places/ thehighlands.html ] (aka Cape Cod lighthouse), another more locally familiar beacon in the night. Now automated, the 66 foot tall structure in use today was built in 1857. How often has there been an eclipse within view of the Highland light? For locations on planet Earth there are about two eclipse seasons [ http://www.earthview.com/tutorial/patterns.htm ] each year. So, eclipses have actually had many chances [ http://www.eclipse.org.uk/eclbin/query_usno.cgi ] to be part of the pictorial history [ http://lighthouse.cc/highland/history.html ] of the Highland Lighthouse, including a total solar eclipse in 1932 [ http://www.eclipse.org.uk/eclipse/0311932/ ]. |
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Venus by the Lake
| Title |
Venus by the Lake |
| Explanation |
Finding Venus [ http://www.spitzer.caltech.edu/Media/releases/ssc2007-07/ ssc2007-07c.shtml ] in the night sky is not too hard these days. Now appearing as the evening star, Venus rules as the brightest celestial beacon in west just after sunset [ http://www.baltastro.org/AstroPoetry.html#Learned ]. And if you can find Venus tonight, you can also easily find the lovely Pleiades [ http://antwrp.gsfc.nasa.gov/apod/ap050111.html ] star cluster (aka M45) close by. In this serene skyview, recorded on Tuesday near Bolu, Turkey, Venus and [ http://antwrp.gsfc.nasa.gov/apod/ap040415.html ] the Pleiades are on the right, with brilliant Venus reflected in the calm waters of the small lake in the foreground. Left of Venus, the bright star Aldebaran anchors [ http://antwrp.gsfc.nasa.gov/apod/ap060720.html ] the V-shaped Hyades star cluster. Farther left are stars of the familiar constellation Orion with Rigel, at the foot of Orion, also reflected in the lake. Meanwhile, Sirius, in Canis Major, [ http://antwrp.gsfc.nasa.gov/apod/ap070203.html ] is the brightest star on the left side of the view. But the bright terrestrial light below Sirius is not a reflection, it's just a light near the lake shore. |
|
Messiers and Mars
| Title |
Messiers and Mars |
| Explanation |
A telescopic tour of the constellation Sagittarius [ http://www.seds.org/Maps/Stars_en/Fig/ sagittarius.html ] offers the many bright clusters and nebulae of dimensioned space [ http://antwrp.gsfc.nasa.gov/apod/ap010418.html ] in a starscape [ http://antwrp.gsfc.nasa.gov/apod/ap000629.html ] surrounding the galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap990911.html ]. This gorgeous color deep-sky photograph [ http://members.home.net/fct150/mars_visits_messier.htm ] visits two such lovely sights, cataloged by the 18th century cosmic tourist Charles Messier [ http://www.seds.org/messier/xtra/history/biograph.html ] as M8 and M20. M20 (upper left), the Trifid Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000328.html ], presents a striking contrast in red/blue colors and dark dust lanes. Just below and to the right is the expansive, alluring red glow of M8, the Lagoon Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap010103.html ]. Both nebulae are a few thousand light-years distant but at the far right, the dominant celestial beacon is a "local" source, the planet Mars [ http://www.seds.org/nineplanets/nineplanets/mars.html ]. Just passing through Sagittarius and strongly overexposed in this picture, the Red Planet [ http://mars.jpl.nasa.gov/ ] is a short 4 light-minutes away. Now near its closest approach [ http://www.skypub.com/sights/moonplanets/0105marsreturn.shtml ] to planet Earth since 1988, Mars rises around sunset and can be seen [ http://members.nbci.com/marsprev/mpenglish.htm ] for most of the night shining [ http://cfa-www.harvard.edu/iauc/07600/07642.html#Item1 ] brightly at about -2.3 magnitude [ http://csep10.phys.utk.edu/astr162/lect/stars/ magnitudes.html ]. Urban imager [ http://members.home.net/mrcolewa/cartoon.htm ] Michael Cole recorded this photograph at 3:00 AM on May 20th in clear skies over Camp Hancock, Oregon, USA. |
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Eclipse in African Skies
| Title |
Eclipse in African Skies |
| Explanation |
Yesterday, for a brief few minutes, a total eclipse of the Sun [ http://www.MrEclipse.com/MrEclipse.html#SE ] brought darkness to southern Africa's [ http://www.exploratorium.com/eclipse/zambia/index.html ] daytime skies. During this first total solar eclipse of the third millennium [ http://www.usno.navy.mil/millennium/ ] webcast sites were swamped, but sun-watchers along the eclipse path enjoyed clear weather [ http://www.eumetsat.de/en/index.html?area=left5.html &body=/en/area5/special/eclipse_21062001.html&a=500&b=0&c=0&d=0&e=0 ] and reported fantastic views [ http://www.skypub.com/sights/eclipses/solar/ 010621africa.html ]. Enthusiastic astrophotographer Olivier Staiger recorded these pictures [ http://eclipse.span.ch/210601.htm ] during the eclipse's total phase from Lusaka, Zambia. The large image above shows the Sun's tantalizing inner corona with telltale pinkish prominences around the solar limb, while the inset at the lower right reveals the spiky outer corona [ http://antwrp.gsfc.nasa.gov/apod/ap010408.html ]. But the inset also captures another celestial beacon [ http://antwrp.gsfc.nasa.gov/apod/ap010615.html ] sharing the eclipse-darkened heavens [ http://eclipse.span.ch/sky210601.htm ], the bright planet Jupiter shining at the lower left. The next total solar eclipse will be on 2002 December 4 [ http://sunearth.gsfc.nasa.gov/eclipse/SEplot/ SE2002Dec04T.gif ] ... again in southern African skies [ http://antwrp.gsfc.nasa.gov/apod/ap001116.html ]. |
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Moon Over Pigeon Point Light
…
| Title |
Moon Over Pigeon Point Lighthouse |
| Explanation |
This spectacular sky is mostly human-made. Once a year, the Light Station at Pigeon Point [ http://en.wikipedia.org/wiki/Pigeon_Point_Lighthouse ] near San Francisco [ http://en.wikipedia.org/wiki/San_Francisco%2C_California ], California [ http://en.wikipedia.org/wiki/California ], USA [ http://en.wikipedia.org/wiki/United_States ] is lit as it was over 100 years ago. During this time, light generated by five kerosene lamps [ http://en.wikipedia.org/wiki/Kerosene_lamp ] pours through 24 rotating Fresnel lenses [ http://science.howstuffworks.com/question244.htm ], warning approaching ships to stay away. Early last week, light emanating from the Pigeon Point Lighthouse was particularly picturesque [ http://www.flickr.com/photos/mumbleyjoe/2043508173/ ] because of a thin fog, also blurring the distant Moon. During the latter 1970s, the lighthouse [ http://www.rudyalicelighthouse.net/CalLts/PigeonPt/ PigeonPt.htm ] was guarded by an 800 pound pig named Lester. In modern times, the light house is still active but has been supplied with a more efficient [ http://en.wikipedia.org/wiki/Aerodrome_beacon ] flashing aerobeacon [ http://www.terrypepper.com/Lights/closeups/illumination/ aerobeacon/dcb224.htm ]. |
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Mars and Orion Over Monument
…
| Title |
Mars and Orion Over Monument Valley |
| Explanation |
Welcome to The World At Night. [ http://www.twanight.org/ ] Sharing the night sky seen around the world, this view from Monument Valley [ http://en.wikipedia.org/wiki/Monument_valley ], USA includes a picturesque foreground of famous buttes. Buttes [ http://www.britannica.com/eb/article-9018335 ] are composed of hard rock left behind after water eroded away the surrounding soft rock. The two buttes on the image left are known as the Mittens, while Merrick Butte [ http://thalmann.com/images/96043.htm ] is on the right. Recorded just last week, planet Mars [ http://antwrp.gsfc.nasa.gov/apod/ap060730.html ] is at the left of the skyscape, a glowing beacon of orange that is the brightest object in the frame. To the right of Mars lies the constellation of Orion [ http://stardate.org/nightsky/constellations/ orion.html ]. Betelgeuse [ http://antwrp.gsfc.nasa.gov/apod/ap990605.html ] is the reddish star near the center and the Belt of Orion [ http://antwrp.gsfc.nasa.gov/apod/ap061229.html ] and the Orion Nebula [ http://vis.sdsc.edu/research/orion.html ] are farther right. Finally, the bright blue star Rigel [ http://www.astro.uiuc.edu/~kaler/sow/rigel.html ] appears above Merrick Butte in this stunning view of The World At Night [ http://www.twanight.org/ ]. |
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Quadrantid Meteors and Auror
…
| Title |
Quadrantid Meteors and Aurora from the Air |
| Explanation |
Where do meteor showers originate? To help answer this question, astronomers studied in some detail the Quadrantid meteor shower [ http://en.wikipedia.org/wiki/Quadrantid ] that occurred over this past weekend. In particular, astronomers with specialized cameras flew as part of the Quadrantid's Multi-Instrument Aircraft Campaign (MAC) aboard a Gulfstream V aircraft [ http://en.wikipedia.org/wiki/Gulfstream_V ] above northern Canada over the past few days and studied the Quadrantid meteor shower [ http://www.spaceweather.com/meteors/quadrantids/quadrantids.html ] in unprecedented detail. Pictured above [ http://quadrantid.seti.org/ ] is a composite image combining many short exposures. Visible in the image are the wingtip of the airplane reflecting a red beacon on the left, green aurora most prominent on the image right, and numerous meteor streaks [ http://www.allthesky.com/atmosphere/quadrantid.html ] throughout. Preliminary indications [ http://quadrantid.seti.org/ ] are that the meteor stream is quite stable in time but variable in meteor abundance. Over 100 meteors per hour were visible at the peak from the MAC aircraft. Meteor data from around the world will continue to be analyzed to try to verify Peter Jenniskens [ http://leonid.arc.nasa.gov/pjenniskens.html ]'s recent hypothesis [ http://adsabs.harvard.edu/abs/2004AJ....127.3018J ] that minor planet [ http://en.wikipedia.org/wiki/Minor_planet ] 2003 EH1 [ http://ephemeris.sjaa.net/0401/e.html ] is an intermittently active comet and the parent body of the annual Quadrantid meteor shower [ http://meteorshowersonline.com/quadrantids.html ]. |
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PKS 1127-145: Quasar View
| Title |
PKS 1127-145: Quasar View |
| Explanation |
The quasar [ http://antwrp.gsfc.nasa.gov/apod/ap971206.html ] known as PKS 1127-145 [ http://chandra.harvard.edu/photo/2002/1127/ index.html ] lies ten "billion" light-years [ http://www.nationalacademies.org/bpa/reports/aanm/web/ tier2html/telescope.htm ] from our fair planet. A Hubble Space Telescope [ http://hubble.gsfc.nasa.gov/servicing-missions/ sm3b.html ] view in the left panel shows this quasar along with other galaxies as they appear in optical light. The quasar [ http://chandra.harvard.edu/photo/2002/1127/more.html ] itself is the brightest object in the lower right corner. In the right panel is a Chandra Observatory [ http://chandra.harvard.edu/resources/misc/ chandra2001.html ] x-ray picture, exactly corresponding to the Hubble field. While the more ordinary galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap010427.html ] are not seen in the Chandra image, a striking jet, nearly a million light-years long, emerges from the quasar to dominate the x-ray view. Bright in both optical and x-ray light, the quasar is thought to harbor a supermassive black hole which powers [ http://chandra.harvard.edu/xray_sources/ quasars2.html ] the jet and makes PKS 1127-145 [ http://xxx.lanl.gov/abs/astro-ph/0201116 ] visible across the spectrum [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/ emspectrum.html ] -- a beacon from the distant cosmos [ http://www.anzwers.org/free/universe/universe.html ]. |
|
Stereo Saturn
| Title |
Stereo Saturn |
| Explanation |
Get out your red/blue glasses [ http://mpfwww.jpl.nasa.gov/MPF/mpf/glasses.html ] and launch [ http://beacon.jpl.nasa.gov/exhibits/voyager/ default.html ] yourself into this stereo [ http://cass.jsc.nasa.gov/research/stereo_atlas/ SS3D.HTM ] picture of Saturn! The picture is actually composed from two images recorded weeks apart by the Voyager 2 spacecraft [ http://nssdc.gsfc.nasa.gov/database/ MasterCatalog?sc=1977-076A ] during its visit to [ http://sse.jpl.nasa.gov/missions/sat_missns/ sat-voy2.html ] the Saturnian System in August of 1981. Traveling at about 35,000 miles per hour, the spacecraft's changing viewpoint from one image to the next produced this exaggerated but pleasing stereo effect [ http://antwrp.gsfc.nasa.gov/apod/ap970404.html ]. Saturn is the second largest planet [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ saturn.html ] in the Solar System, after Jupiter. Its spectacular ring system [ http://ringmaster.arc.nasa.gov/saturn/saturn.html ] is so wide that it would span the space between the Earth and Moon. Although they look solid here, Saturn's [ http://antwrp.gsfc.nasa.gov/apod/ap000129.html ] rings consist of individually orbiting bits of ice and rock ranging in size from grains of sand to barn-sized boulders. |
|
Messiers and Mars
| Title |
Messiers and Mars |
| Explanation |
A telescopic tour of the constellation Sagittarius [ http://www.hawastsoc.org/deepsky/sgr/index.html ] offers the many bright clusters and nebulae of dimensioned space [ http://antwrp.gsfc.nasa.gov/apod/ap010418.html ] in a starscape [ http://antwrp.gsfc.nasa.gov/apod/ap000629.html ] surrounding the galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap990911.html ]. This gorgeous color deep-sky photograph [ http://home.earthlink.net/~fct150/mars_visits_messier.htm ] visits two such lovely sights, cataloged by the 18th century cosmic tourist Charles Messier [ http://www.seds.org/messier/xtra/history/biograph.html ] as M8 and M20. M20 (upper left), the Trifid Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000328.html ], presents a striking contrast in red/blue colors and dark dust lanes. Just below and to the right is the expansive, alluring red glow of M8, the Lagoon Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap010103.html ]. Both nebulae are a few thousand light-years distant but at the far right, the dominant celestial beacon is a "local" source, the planet Mars [ http://www.seds.org/nineplanets/nineplanets/mars.html ]. Just passing through Sagittarius and strongly overexposed in this picture, the Red Planet [ http://mars.jpl.nasa.gov/ ] was a short 4 light-minutes away. Now headed [ http://www.lpl.arizona.edu/~rhill/alpo/mars.html ] for its closest approach [ http://skyandtelescope.com/observing/objects/planets/ article_985_1.asp ] to planet Earth in recorded history, Mars rises in the east southeast by midnight shining brightly at about -1.4 magnitude [ http://csep10.phys.utk.edu/astr162/lect/stars/ magnitudes.html ]. Urban imager [ http://home.earthlink.net/~urbanimager/cartoon.htm ] Michael Cole recorded this photograph at 3:00 AM on May 20th, 2001 in clear skies over Camp Hancock, Oregon, USA. |
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Good Morning Sydney
| Title |
Good Morning Sydney |
| Explanation |
Rising before dawn on May 5th, Stephen Thorley looked out [ http://www.asnsw.com/info/index.html ] across the skyline of Sydney, Australia [ http://www.nla.gov.au/ ]. And while a leisurely lunar eclipse [ http://antwrp.gsfc.nasa.gov/apod/ap040506.html ] was clearly in progress, from his vantage point [ http://science.nasa.gov/headlines/y2003/ 04nov_lunareclipse2105.htm ] on planet Earth the Moon set as the total phase [ http://skyandtelescope.com/observing/objects/eclipses/ article_1219_1.asp ] of the eclipse began. Still, before the setting Moon was hidden by the cityscape he captured this striking image of a nearly eclipsed lunar disk sliding [ http://antwrp.gsfc.nasa.gov/apod/ap030515.html ] past the beacon and lights of Centerpoint Tower [ http://nla.gov.au/nla.pic-an23301253 ], one of Sydney's familiar landmarks. So what's that star just visible above and to the right of the reddened Moon? That's Zubenelgenubi [ http://www.astro.uiuc.edu/~kaler/sow/ zubenel.html ], of course. |
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Phases of Venus
| Title |
Phases of Venus |
| Explanation |
Venus is currently falling out [ http://antwrp.gsfc.nasa.gov/apod/ap990903.html ] of the western evening sky. Second planet [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ venusfact.html ] from the Sun and third brightest celestial object after the Sun and Moon, Venus has been appreciated by casual sky gazers as a brilliant beacon above the horizon after sunset. But telescopic [ http://csep10.phys.utk.edu/astr161/lect/history/ galileo.html ] images have also revealed its dramatic phases. In fact, this thoughtful composite [ http://webpages.charter.net/darksky25/Astronomy/ Planets/Venus/venus.html ] of telescopic views nicely illustrates the progression of phases [ http://csep10.phys.utk.edu/astr161/lect/celestial/ aspects.html ] and increase in apparent size undergone by Venus over the past few weeks. Gliding along [ http://www.venus-transit.de/PlanetPhases/ index.html ] its interior orbit, Venus has been catching up with planet Earth, growing larger as it draws near. At the same time, just as the Moon goes through phases [ http://www.souledout.org/nightsky/venusphases/ venusphases.html ], Venus' visible sunlit hemisphere has presented an increasingly slender, crescent shape [ http://imaginesoftworks.com/ astropage/venus/venus05052004-0258.html ]. Now sharing the sky [ http://skyandtelescope.com/observing/objects/planets/ article_1194_1.asp ] with a crescent Moon, on June 8th Venus [ http://sunearth.gsfc.nasa.gov/sunearthday/2004/ index_vthome.htm ] will actually cross the face of the Sun, the first such transit since 1882 [ http://canopus.saao.ac.za/%7Ewpk/tov1882/ tovwell.html ]. |
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X-Ray Pulsar
| Title |
X-Ray Pulsar |
| Explanation |
This dramatic artist's vision shows a city-sized neutron star [ http://astro.uchicago.edu/home/web/miller/nstar.html ] centered in a disk of hot plasma drawn from its enfeebled red companion star. Ravenously accreting material [ http://imagine.gsfc.nasa.gov/docs/dictionary.html ] from the disk, the neutron star spins faster and faster [ http://universe.gsfc.nasa.gov/videos/millisecond.html ] emitting powerful particle beams and pulses of X-rays [ http://heasarc.gsfc.nasa.gov/docs/xte/learning_center/ ASM/welcome.html ] as it rotates 400 times a second. Could such a bizarre and inhospitable star system really exist in our Universe [ http://antwrp.gsfc.nasa.gov/apod/ap980302.html ]? Based on data from the orbiting Rossi X-Ray Timing Explorer [ http://heasarc.gsfc.nasa.gov/docs/xte/learning_center/ ] (RXTE) satellite, research teams have recently announced a discovery [ http://universe.gsfc.nasa.gov/new/news/1998/98-129.html ] which fits this exotic scenario well - a "millisecond" X-ray pulsar. The newly detected celestial X-ray beacon [ http://antwrp.gsfc.nasa.gov/apod/ap980211.html ] has the unassuming catalog designation of SAX J1808.4-3658 and is located a comforting 12,000 light years away in the constellation Sagittarius [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Sagittarius.html ]. Its X-ray pulses offer evidence of rapid, accretion powered [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/ cool_binary_fact.html ] rotation and provide a much sought after connection between known types of radio and X-ray pulsars [ http://astrosun.tn.cornell.edu/courses/astro201/pulsar.htm ] and the evolution [ http://astrosun.tn.cornell.edu/courses/astro201/pulsar_graph.htm ] and ultimate demise of binary star systems [ http://imagine.gsfc.nasa.gov/docs/features/movies/binaries.html ]. |
|
S is for Venus
| Title |
S is for Venus |
| Explanation |
Planet Venus [ http://www.nineplanets.org/venus.html ] traced out this S [ http://www.mentallandscape.com/V_Venus.htm ] shape in Earth's sky during 2004. Following the second planet from the Sun in a series of 29 images recorded from April [ http://antwrp.gsfc.nasa.gov/apod/ap040521.html ] 3rd through August 7th (top right to bottom left) of that year, astronomer Tunc Tezel constructed this composite illustrating the wandering planet's [ http://csep10.phys.utk.edu/astr161/lect/retrograde/ retrograde.html ] path against the background stars. The series reveals Venus' apparent retrograde motion [ http://www.scienceu.com/observatory/articles/retro/ retro.html ] transporting it from a brilliant evening star to morning's celestial beacon. Of course, in 2004, after sinking into the evening twilight [ http://antwrp.gsfc.nasa.gov/apod/ap010601.html ] but before rising above the predawn horizon [ http://antwrp.gsfc.nasa.gov/apod/ap041108.html ], Venus was seen in silhouette [ http://antwrp.gsfc.nasa.gov/apod/ap040609.html ] against the Sun (near center) - the first transit of Venus [ http://sunearth.gsfc.nasa.gov/sunearthday/2004/ index_vthome.htm ] since 1882. The next time Venus will wander across the solar disk is in 2012 [ http://sunearth.gsfc.nasa.gov/eclipse/ transit/venus0412.html ]. |
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Big Dipper Castle
| Title |
Big Dipper Castle |
| Explanation |
The stars of the big dipper, a well known asterism [ http://www.seds.org/Maps/Const/asterism.html ] in the constellation Ursa Major [ http://www.allthesky.de/various/umaumi.html ], are easy to recognize in this dramatic skyscape [ http://www.allthesky.de/various/co07umacastle28.html ]. In fact, northern hemisphere skygazers often follow along [ http://www.astropix.com/HTML/C_SPRING/URSAS.HTM ] the line indicated by the two stars at the far right. Extending off the top of this image, that line leads to Polaris, the North Star [ http://www.wcsscience.com/polaris/ thenorthstar.html ], conveniently located near the north celestial pole. Following the arc [ http://www.space.com/spacewatch/ arcturus_bootes_020510.html ] of the dipper's handle also leads to another well known celestial beacon [ http://www.astro.uiuc.edu/~kaler/sow/ arcturus.html ] of the northern sky - yet this dreamlike scene takes you instead to a shining mountaintop castle. Big Dipper Castle might be an appropriate name in this stunning view, but its traditional name is Castle Hohenzollern [ http://www.preussen.de/en/today/hohenzollern_castle/ history.html ]. Poised above a sea of clouds that mute the city lights below, the castle lies in the Swabian Alb [ http://www.schwaebischealb.de/english/7keys/ geology.htm ] range of southern Germany, an area that was once a reef in an ancient sea [ http://www.sedgwickmuseum.org/exhibits/jurassic.html ]. |
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Venus Returns to the Evening
…
| Title |
Venus Returns to the Evening Sky |
| Explanation |
This serene image [ http://www.photoastronomique.net/ photo_us.php?nom=0506010077 ] of boats moored in the harbor of l'Île-Tudy, Bretagne, France was taken on June 1st, about an hour after sunset. It also features Venus [ http://antwrp.gsfc.nasa.gov/apod/ap990619.html ], third brightest celestial object after the Sun and Moon. For casual skygazers, this month marks Venus' return [ http://www.space.com/spacewatch/ 050513_venus_returns.html ] to the evening sky as the brilliant 'star' [ http://www.victorianweb.org/authors/bronte/ nockholds1.html ], shining low in the west-northwest shortly after sunset. In the picture, astrophotographer [ http://www.photoastronomique.net ] and APOD translator Laurent Laveder notes that Venus is easily mistaken for a light atop a sailboat's tall mast, giving the otherwise stunning celestial beacon an unremarkable appearance. Of course, a year ago Venus' appearance was quite remarkable. On June 8, 2004 [ http://antwrp.gsfc.nasa.gov/apod/ap040609.html ], Venus crossed the Sun's disk, the first transit of Venus since 1882. Late [ http://skyandtelescope.com/observing/ataglance/ article_110_1.asp ] this week Venus shares the evening sky with the young crescent Moon, and will next transit the Sun on June 6, 2012 [ http://sunearth.gsfc.nasa.gov/eclipse/transit/ venus0412.html ]. |
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Planets in the West
| Title |
Planets in the West |
| Explanation |
This week [ http://www.griffithobs.org/skyreport.html ]end three planets will grace the western sky [ http://science.nasa.gov/headlines/y2005/ 22jun_spectacular.htm ], forming a lovely trio easily visible shortly after sunset. Saturday evening in particular will find Saturn [ http://soc.jpl.nasa.gov/index.cfm ], Venus [ http://www.space.com/spacewatch/ 050513_venus_returns.html ], and Mercury [ http://www.fourmilab.ch/images/3planets/ elongation.html ] all within a 2 degree circle (about the size of your thumb held at arm's length) above the western horizon. Recorded last Sunday, June 19, this image shows the same three planets arrayed along the ecliptic plane [ http://antwrp.gsfc.nasa.gov/apod/ap040501.html ] above a Colorado Rocky Mountain skyline. Venus is easiest to pick out of the twilight, the brightest celestial beacon below picture center, with Saturn above and to the left of Venus, and Mercury closest to the horizon, right of prominent Pinnacle Peak. By Saturday [ http://skyandtelescope.com/observing/ataglance/ article_110_1.asp ], the wandering planets [ http://spacekids.hq.nasa.gov/osskids/ animate/mac.html ] will draw even closer together. For help spotting the planets here, put your cursor over the picture. |
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Moon River
| Title |
Moon River |
| Explanation |
Shortly after sunset [ http://science.nasa.gov/headlines/y2005/26aug_sunset.htm ] on September 6th, sky gazers around the world were treated [ http://www.davidcortner.com/regions/america/carolinas/ catawba_pan.html ] to a lovely crescent Moon [ http://www.earthsky.com/skywatching/moonphases.php ] in western skies -- joined by [ http://skyandtelescope.com/observing/highlights/ article_1456_2.asp ] bright planets Venus and Jupiter. In this colorful telephoto view from near Quebec City, Canada the Moon is nestled just above the wide St. Lawrence River [ http://en.wikipedia.org/wiki/Saint_Lawrence_River ]. Lights on the horizon are along the river's southern shore. Also known as the evening star, Venus is [ http://www.victorianweb.org/authors/bronte/ nockholds1.html ] at the upper left and Jupiter at the upper right, while another prominent celestial beacon, Spica, [ http://www.astro.uiuc.edu/~kaler/sow/spica.html ] can be seen shining through the twilight below Venus. Spica, actually a very close pair of hot blue stars some 260 light-years away, is the brightest star in the constellation Virgo [ http://hawastsoc.org/deepsky/vir/index.html ]. |
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A Martian Halloween
| Title |
A Martian Halloween |
| Explanation |
From sunset to sunrise, an unusually bright yellowish orb will hang in the sky this Halloween: Mars. Yesterday, Earth passed Mars [ http://www.nineplanets.org/mars.html ] as they orbited the Sun, bringing Mars closer [ http://science.nasa.gov/headlines/y2005/27oct_halloween.htm ] than it will be for the next thirteen years. Tonight though, Mars will be nearly as bright as last night, a beacon of extraterrestrial spookiness [ http://antwrp.gsfc.nasa.gov/apod/ap050425.html ]. Opposite [ http://www.heavens-above.com/ gloss.asp?term=opposition ] the Sun, Mars will rise just when the Sun sets, set just when the Sun rises, and be visible the entire night. Mars [ http://antwrp.gsfc.nasa.gov/apod/ap051030.html ] will not always be the brightest object in tonight's sky, though. Brighter than even Mars, almost spooky Venus will light up the western horizon for a brief time just after sunset. Please have a safe and happy All Hallows Eve [ http://antwrp.gsfc.nasa.gov/apod/ap041031.html ]. |
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December Moon Meets Evening
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| Title |
December Moon Meets Evening Star |
| Explanation |
If you've been outdoors near sunset, then you've probably noticed Venus [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ venusfact.html ] low in the west as the brilliant evening star [ http://www.digitalsky.org.uk/venus/ shadow-of-venus.html ]. Sometimes mistaken [ http://antwrp.gsfc.nasa.gov/apod/ap050609.html ] for a tower light near the horizon, Venus is the third brightest celestial beacon, after the Sun and Moon, in planet Earth's sky. That distinction is particularly easy to appreciate in this peaceful scene [ http://www.pbase.com/missouri_skies/image/53158060 ] featuring the crescent Moon, Venus, and sunset colors [ http://www.missouriskies.org/ sunset_gallery/sunsetgallery.html ] captured on December 4th near Albany, Missouri, USA. As this season's evening star, Venus [ http://www.esa.int/SPECIALS/Venus_Express/ ] will be at its most brilliant tonight, but as December progresses the bright planet [ http://antwrp.gsfc.nasa.gov/apod/ap040521.html ] will begin to fall out [ http://antwrp.gsfc.nasa.gov/apod/ap990903.html ] of the western sky. By early next week, December's Moon will have moved on to meet another bright planet overhead -- Mars [ http://stardate.org/nightsky/almanac/ s200512_alm.html ]. |
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