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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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Red, White, and Blue Sky
| Title |
Red, White, and Blue Sky |
| Explanation |
Contrasting colors in this beautiful sunset sky [ http://www.schursastrophotography.com/10dastro/ vensat070107.html ] were captured on June 30 from Clear Creek Canyon Observatory in central Arizona, USA. The twilight scene includes brilliant [ http://www.digitalsky.org.uk/venus/ shadow-of-venus.html ] Venus as the evening star [ http://www.johnpratt.com/items/astronomy/eve_morn.html ], with a bright Saturn just above it, shining through thin clouds. The two wandering [ http://antwrp.gsfc.nasa.gov/apod/ap070407.html ] planets [ http://antwrp.gsfc.nasa.gov/apod/ap010601.html ] were a mere 1 degree apart or so, about twice the width of the full Moon rising above the eastern horizon on the other side of the sky. In fact, such serene skyviews [ http://www.spaceweather.com/ ] were possible from all over planet Earth as Venus and Saturn approached a conjunction [ http://en.wikipedia.org/wiki/Astronomical_conjunction# Conjunctions_of_planets_in_right_ascension_2005-2020 ]. Regulus, alpha star of the constellation Leo [ http://en.wikipedia.org/wiki/Leo_(constellation) ], is above and to the left of the close planetary pairing. At dusk, lights in tonight's sky will also feature Venus and Saturn low in the west and separated by about 2 degrees. |
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Planets over Pony Express La
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| Title |
Planets over Pony Express Lake |
| Explanation |
Beautiful sunset sky colors [ http://webexhibits.org/causesofcolor/14B.html ] are reflected in Pony Express [ http://www.ponyexpress.org/history.htm ] Lake in this twilight skyview [ http://www.pbase.com/missouri_skies/image/82364390 ] from northern Missouri, USA, planet Earth. Recorded on Monday, a two day old crescent Moon and brilliant planet Venus shine through thin clouds. Joining the conjunction [ http://antwrp.gsfc.nasa.gov/apod/ap070704.html ] on the right of the Moon's sunlit crescent is fellow wanderer [ http://www.nasm.si.edu/ceps/etp/discovery/ disc_ancient.html ] Saturn, with Regulus, alpha star of the constellation Leo, above and right of Venus. Moonlight and Venus light [ http://www.digitalsky.org.uk/venus/shadow-of-venus.html ] streak the almost-calm lake waters. |
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Bright Planets, Crescent Moo
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| Title |
Bright Planets, Crescent Moon |
| Explanation |
Early risers are currently enjoying the sight [ http://stardate.org/nightsky/planets/ ] of dazzling Venus [ http://www.nineplanets.org/venus.html ], near the eastern horizon as the morning star [ http://www.windows.ucar.edu/tour/link=/venus/ morning_star.html&edu=high ]. Recorded on October 7, this predawn skyview [ http://www.usno.navy.mil/pao/sky/sky_week.shtml ] does feature Venus at the upper right. It also includes a crescent Moon and Saturn (lower left). In fact, holding your fist at arms length would have easily covered [ http://chandra.harvard.edu/photo/scale.html ] both planets and the Moon in this 5 degree wide field. Earthshine [ http://antwrp.gsfc.nasa.gov/apod/ap020419.html ], sunlight reflected from planet Earth's dayside, illuminates features on the lunar nightside. A close inspection of Saturn itself reveals a nearby pinpoint of light corresponding to Saturn's [ http://saturn.jpl.nasa.gov/science/moons/index.cfm ] large moon Titan. Though the Moon has moved on, the tight triangle [ http://www.spaceweather.com/images2007/12oct07/ skymap_north.gif ] formed by Venus, Saturn, and Regulus (top), alpha star in the constellation Leo, will continue to look impressive in early morning skies over the next few days. Early bird astrophotographer Jay Ouellet also described Mars as [ http://www.spaceweather.com/images2007/11oct07/ skymap_north_mars.gif ] a "brilliant red diode" in his dark country sky east of Quebec City, Canada. Count the Stars: The Great World Wide Star Count [ http://www.windows.ucar.edu/citizen_science/starcount/ ] |
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Regulus Occulted
| Title |
Regulus Occulted |
| Explanation |
On May 21, viewed from the continental US, a star winked out as it passed behind the dark limb of the first-quarter Moon [ http://www.inconstantmoon.com/index.htm ]. The star, Regulus [ http://www.astro.wisc.edu/~dolan/constellations/hr/3982.html ], is hotter than the sun, about 69 light-years distant, and shines in Earth's skies as the brightest star in the constellation Leo [ http://www.astro.wisc.edu/~dolan/constellations/constellations/ Leo.html ], the Lion. The Moon [ http://nssdc.gsfc.nasa.gov/planetary/lunar/moon_tree.html ] is the brightest object in the night sky [ http://home.cwix.com/~pam.orman@cwix.com/JoeMoon.html ] and is less than 1.5 light-seconds away. As illustrated in this multiple-exposure photograph, such lunar occultations [ http://www.skypub.com/sights/occultations/occultations.shtml ] of bright stars can be majestic to watch. Their exact timing depends on the observer's location but they are not particularly rare occurrences. Astronomers can use lunar occultations to help map [ http://antwrp.gsfc.nasa.gov/apod/ap980911.html ] the surface of the Moon [ http://www.seds.org/nineplanets/nineplanets/luna.html ]. |
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