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Dwarf Elliptical Galaxy NGC
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| Title |
Dwarf Elliptical Galaxy NGC 205 in the Local Group |
| Explanation |
Our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] is not alone. It is part of a gathering of about 25 galaxies known as the Local Group [ http://www.seds.org/messier/more/local.html ]. Members include the Great Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap991114.html ] (M31), M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ], M33 [ http://antwrp.gsfc.nasa.gov/apod/ap980721.html ], the Large Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap000222.html ], the Small Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap000430.html ], Dwingeloo 1 [ http://antwrp.gsfc.nasa.gov/apod/ap000109.html ], several small irregular galaxies [ http://www.seds.org/messier/irre.html ], and many dwarf elliptical [ http://nedwww.ipac.caltech.edu/level5/Ferguson/frames.html ] and dwarf spheroidal galaxies [ http://www.astro.uu.se/~ns/review.html ]. Pictured [ http://www.cfht.hawaii.edu/Science/Astros/Imageofweek/ciw061299.html ] on the lower left is one of the many dwarf ellipticals [ http://www.astro.psu.edu/users/pdurrell/dE.html ]: NGC 205 [ http://www.seds.org/messier/m/m110.html ]. Like M32 [ http://www.seds.org/messier/m/m032.html ], NGC 205 [ http://nedwww.ipac.caltech.edu/level5/Hodge/Hodge5_5.html ] is a companion to the large M31, and can sometimes be seen to the south of M31 [ http://www.seds.org/messier/m/m031.html ]'s center in photographs. The above image [ http://www.cfht.hawaii.edu/Science/Astros/Imageofweek/ciw061299.html ] shows NGC 205 to be unusual [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998ApJ...499..209W ] for an elliptical galaxy [ http://antwrp.gsfc.nasa.gov/apod/elliptical_galaxies.html ] in that it contains at least two dust clouds [ http://antwrp.gsfc.nasa.gov/apod/ap990919.html ] (at 1 and 4 o'clock - they are visible but hard to spot) and signs of recent star formation [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ]. This galaxy is sometimes known as M110, although it was actually not part of Messier [ http://antwrp.gsfc.nasa.gov/apod/ap960626.html ]'s original catalog [ http://antwrp.gsfc.nasa.gov/apod/messier.html ]. |
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Moon Over Andromeda
| Title |
Moon Over Andromeda |
| Explanation |
The Great Spiral Galaxy in Andromeda [ http://antwrp.gsfc.nasa.gov/apod/ap051222.html ] (aka M31), a mere 2.5 million light-years distant [ http://arxiv.org/abs/astro-ph/0511045 ], is the closest large spiral to our own Milky Way. Andromeda is visible to the unaided eye as a small, faint, fuzzy patch, but because its surface brightness is so low, casual skygazers [ http://www.physics.ucla.edu/~huffman/m31.html ] can't appreciate the galaxy's impressive extent in planet Earth's sky. This entertaining composite image compares the angular size [ http://chandra.harvard.edu/photo/scale.html ] of the nearby galaxy to a brighter, more familiar celestial sight. In it, a deep exposure of Andromeda [ http://www.caelumobservatory.com/gallery/m31abtp.shtml ], tracing beautiful blue star clusters in spiral arms far beyond the bright yellow core, is combined with a typical view of a nearly full Moon. Shown at the same angular scale, the Moon covers about 1/2 degree on the sky, while the galaxy is clearly [ http://www.regulusastro.com/regulus/papers/ m31/ ] several times that size. The deep Andromeda exposure also includes two bright satellite galaxies, M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ] and M110 [ http://antwrp.gsfc.nasa.gov/apod/ap060908.html ] (bottom). |
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A Galaxy is not a Comet
| Title |
A Galaxy is not a Comet |
| Explanation |
This gorgeous galaxy and comet portrait [ http://science.nasa.gov/spaceweather/comets/ gallery_iz.html ] was recorded on April 5th in the skies over the Oriental Pyrenees near Figueres, Spain [ http://www.odci.gov/cia/publications/factbook/geos/ sp.html ]. From a site above 1,100 meters, astrophotographer [ http://www.skylook.net/nav/indexe.htm ] Juan Carlos Casado used a guided time exposure, fast film, and a telephoto lens to capture the predicted conjunction of the bright Comet Ikeya-Zhang [ http://antwrp.gsfc.nasa.gov/apod/ap020404.html ] (right) and the Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap000908.html ] (left). This stunning celestial scene would also have been a rewarding one for the influential 18th century comet hunter Charles Messier [ http://www.seds.org/messier/xtra/history/ biograph.html ]. While Messier scanned French skies for comets, he carefully cataloged positions of things which were fuzzy and comet-like in appearance but did not move against the background stars and so were definitely not comets. The Andromeda Galaxy [ http://nedwww.ipac.caltech.edu/level5/ANDROMEDA_Atlas/ frames.html ], also known as M31, is the 31st object in his famous not-a-comet catalog [ http://seds.lpl.arizona.edu/messier/xtra/history/ m-cat.html ]. Not-a-comet object number 110 [ http://www.seds.org/messier/m/ m110.html ], a late addition to Messier's catalog, is one of Andromeda's small satellite galaxies, and can be seen here just below M31. Our modern [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/ debate20.html ] understanding [ http://www.astr.ua.edu/goodies/data_resources/ galaxies.text ] holds that the Andromeda galaxy is a large spiral galaxy some 2 million light-years distant [ http://www.anzwers.org/free/universe/localgr.html ]. The photogenic Comet Ikeya-Zhang [ http://www.stardate.org/nightsky/comet_IZ.html ], now a lovely sight in early morning skies [ http://www.spaceweather.com/images2002/08apr02/ skymap_north.gif ], is about 80 million kilometers (4 light-minutes) from planet Earth. |
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Local Group Galaxy NGC 205
| Title |
Local Group Galaxy NGC 205 |
| Explanation |
The Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950908.html ] is not alone. It is part of a gathering of about 25 galaxies known as the Local Group [ http://www.csc.fi/jpr/galaxy/lbang.html ]. Members include the Great Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950724.html ] (M31), M32 [ http://antwrp.gsfc.nasa.gov/apod/ap960106.html ], M33 [ http://seds.lpl.arizona.edu/messier/m/m033.html ], the Large Magellanic Clouds [ http://antwrp.gsfc.nasa.gov/apod/ap950918.html ], the Small Magellanic Clouds [ http://antwrp.gsfc.nasa.gov/apod/ap950919.html ], Dwingeloo 1 [ http://antwrp.gsfc.nasa.gov/apod/ap951017.html ], several small irregular galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap950728.html ], and many dwarf elliptical galaxies [ http://www.physics.mcmaster.ca/Grads/PRD2.html ]. Pictured is one of the many dwarf ellipticals: NGC 205. Like M32, NGC 205 is a companion to the large M31, and can sometimes be seen to the south of M31 [ http://seds.lpl.arizona.edu/messier/m/m031.html ]'s center in photographs. The above image [ http://crux.astr.ua.edu/gifimages/m110r.html ] shows this galaxy to be unusual for an elliptical galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950913.html ] in that it contains at least two dust clouds [ http://antwrp.gsfc.nasa.gov/apod/ap951107.html ] (at 7 and 11 o'clock - they are visible but hard to spot) and signs of recent star formation. This galaxy is sometimes known as M110, although it was actually not part of Messier [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#messier ]'s original catalog. |
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A Galaxy is not a Comet
| Title |
A Galaxy is not a Comet |
| Explanation |
This gorgeous galaxy and comet portrait [ http://science.nasa.gov/spaceweather/comets/ gallery_iz.html ] was recorded on April 5th, 2002, in the skies over the Oriental Pyrenees near Figueres, Spain [ http://www.odci.gov/cia/publications/factbook/geos/ sp.html ]. From a site above 1,100 meters, astrophotographer [ http://www.skylook.net/nav/indexe.htm ] Juan Carlos Casado used a guided time exposure, fast film, and a telephoto lens to capture the predicted conjunction of the bright Comet Ikeya-Zhang [ http://antwrp.gsfc.nasa.gov/apod/ap020404.html ] (right) and the Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap021021.html ] (left). This stunning celestial scene would also have been a rewarding one for the influential 18th century comet hunter Charles Messier [ http://www.seds.org/messier/xtra/history/ biograph.html ]. While Messier scanned French skies for comets, he carefully cataloged positions of things which were fuzzy and comet-like in appearance but did not move against the background stars and so were definitely not comets. The Andromeda Galaxy [ http://nedwww.ipac.caltech.edu/level5/ANDROMEDA_Atlas/ frames.html ], also known as M31, is the 31st object in his famous not-a-comet catalog [ http://seds.lpl.arizona.edu/messier/xtra/history/ m-cat.html ]. Not-a-comet object number 110 [ http://www.seds.org/messier/m/ m110.html ], a late addition to Messier's catalog, is one of Andromeda's small satellite galaxies, and can be seen here just below M31. Our modern [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/ debate20.html ] understanding [ http://www.astr.ua.edu/goodies/data_resources/ galaxies.text ] holds that the Andromeda galaxy is a large spiral galaxy some 2 million light-years distant [ http://www.anzwers.org/free/universe/localgr.html ]. The photogenic Comet Ikeya-Zhang [ http://www.stardate.org/nightsky/comet_IZ.html ], then a lovely sight in early morning skies was about 80 million kilometers (4 light-minutes) from planet Earth. |
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