The Night Sky of April
Dr. Wayne Wooten
Professor of Astronomy
Escambia Amateur Astronomers' Association
For April 2009, the Moon will be first quarter on April 2nd. The waxing gibbous moon is passing about 5.5 degrees south of Saturn on April 7th. The full moon occurs on April 9th; this is the Paschal Moon in tradition, setting the following Sunday as Easter. The last quarter
moon rises about midnight on April 17th, the passes about two degrees north of bright Jupiter on April 19th. On April 22nd, the waning crescent moon passes in front of Venus for most of the US. This occultation just misses us, with the Moon passing just north of Venus about 7:30 PM, already after sunrise locally.
The new moon is on April 25th.
While the naked eye, dark adapted by several minutes away from any bright lights, is a wonderful instrument to stare up into deep space, far beyond our own Milky Way, binoculars are better for spotting specific deep sky objects. For a detailed map of northern hemisphere skies, about April
1st visit the www.skymaps.com website and download the map for the new month; it will have a more extensive calendar, and list of best objects for the naked eyes, binoculars, and scopes on the back of the map. Also available as the next month begins is wonderful video exploring the April 2009 sky, featuring many
different objects, available from the Hubble Space Telescope website at: http://hubblesite.org/explore_astronomy/tonights_sky/.
Venus is low in the east just before dawn as the month begins, having passed eight degrees north of the Sun on March 27th. She is a large, slender crescent visible easily in binoculars, but pulls away from the earth and higher in the eastern sky, becoming brightest in the morning on April
29th. Jupiter dominates the morning sky, the brightest object well up in the southeast, rising about midnight. Red Mars is low in the eastern twilight; Venus passes 4 degrees north of his on April 24th. Saturn is in the east in souterheastern Leo, just under the lion's tail. This is the best time to observe the
most beautiful object in the sky. When viewed with a telescope, near Saturn's equinox now, the edge on rings are so narrow they almost disappear with most telescopes. Note also how now Saturn's moon, like Jupiter's always do, appear in a straight line on either side of its equator.
Yellow Capella, a giant star the same temperature and color as our much smaller Sun, dominates the northwestern sky. It is part of the pentagon on stars making up Auriga, the Charioteer (think Ben Hur). Several nice binocular Messier open clusters are found in the winter milky way here. East
of Auriga, the twins, Castor and Pollux highlight the Gemini. South of Gemini, Orion is the most familiar winter constellation, dominating the southern sky at dusk. The reddish supergiant Betelguese marks his eastern shoulder, while blue-white supergiant Rigel stands opposite on his west knee. Just south of the
belt, hanging like a sword downward, is M-42, the Great Nebula of Orion, an outstanding binocular and telescopic stellar nursery. The bright diamond of four stars that light it up are the trapezium cluster, one of the finest sights in a telescope. In the east are the hunter's two faithful companions, Canis major
and minor. Procyon is the bright star in the little dog, and rises minutes before Sirius, the brightest star in the sky. Sirius dominates the SE sky as darkness falls. At 8 light years distance, Sirius is the closest star we can easily see with the naked eye from West Florida.
To the northeast, look for the Big Dipper rising, with the top two stars of the bowl, the pointers, giving you a line to find Polaris, the Pole Star. Look for Mizar-Alcor, a nice naked eye double star, in the bend of the big dipper's handle. Just below the handle is M-51, the famed Whirlpool
Galaxy. This cosmic fender bender was captured by new EAAA member Phil Phillips, one of his first astrophotos with his new scope. Call that beginner's luck, Phil!
Take the pointers at the front of the dipper's bowl south instead to the head of Leo, looking much like the profile of the famed Sphinx. The bright star at the Lion's heart is Regulus, the "regal star", but brighter still is Saturn, just east of Regulus.
Now take the curved handle of the Big Dipper, and follow the arc SE to bright orange Arcturus, the brightest star of the spring sky. Recent studies of its motion link it to the Sagittarius Dwarf Galaxy, a companion of our Milky Way being tidally disrupted and spilling its stars above and
below the plane of the Milky Way, much like dust falling away from a decomposing comet nucleus. So this brightest star of Bootes the Bear Driver is apparently a refugee from another galaxy!
Now spike south to Spica, the blue-white gem in Virgo rising in the SE. Virgo is home to many galaxies, as we look away from the obscuring gas and dust in the plane of the Milky Way into deep space. To the southwest of Spica is the four sided Crow, Corvus.
For more information on the Escambia Amateur Astronomers and our local star gazes for the public, visit our website at www.eaaa.net or call our sponsor, Dr. Wayne Wooten at PJC at (850) 484-1152, or e-mail him at email@example.com.
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