Bakersfield Night Sky – May 1, 2010
By Nick Strobel
On this first day of May, one very bright planet and two medium-bright planets grace our evening sky and yet another very bright planet takes over for the early morning sky. Very bright Venus is high in the west just after sunset. It will be the first star-like object you see after the Sun sets. About a week ago, Venus passed by the Pleiades, the star cluster in the shoulder of Taurus. Venus is now near the head of the bull Taurus. In the second week of May, Venus will be between the two long horns of the bull. Mars is now of the left side of Cancer as it continues to drift eastward toward its rendezvous with Regulus at the end of the sickle part of Leo in the first week of June. Saturn is slowing down in its retrograde motion below the bright star Denebola at the tip of the tail of Leo, so its position is pretty much the same as it was in my previous column a couple of weeks ago. Thankfully, the bright Waning Gibbous Moon doesn't rise until after midnight so it won't wash out the evening stars and planets.
The first star chart below shows the sky to the left of Saturn (i.e., the eastern sky) at about 9 PM. The very bright star with an orange tint to it is Arcturus in Bootes (the shepherd). Arcturus is the second brightest star visible in the United States (behind Sirius in Canis Major, now low in the southwest at 9 PM). How I locate Arcturus (and then the rest of Bootes) easily is to use the handle of the Big Dipper part of Ursa Major (the big bear). If you follow the arc of the handle, the first bright star you come to is Arcturus. Remember "arc to Arcturus". Arcturus is a giant star almost 40 times the diameter of our Sun but cooler than the Sun so it has an orange color. At about 36 light years away, it is also one of the closer stars to the Sun. The outline of Bootes is something like a kite on its side. Then almost straight to the right of Arcturus is the brightest star of Virgo: Spica. Remember "spike to Spica" (it is a hard "c" in the pronunciation of its name). Spica is a very hot star about 3 to 3.5 times hotter than the Sun, almost 10 times the diameter of the Sun and over 260 light years away. While most of the stars in our galaxy are smaller and fainter than the Sun, the ones we see most easily in the light-polluted skies of Bakersfield are mostly the hot large ones. I guess I should mention that a light year is the distance that light travels in a year (approximately 6 trillion miles, that's 6 with twelve zeroes next to it). So we're seeing Arcturus as it was 36 years ago and Spica as it was over 260 years ago because of the long time it has taken their light to reach us.
Below the kite-shaped Bootes is the backward "C"- shape of Corona Borealis ("northern crown"). Just beginning to come up now in the northeast is Hercules. High, high up in the northeast is the Big Dipper. The two end stars of the bowl part of the Big Dipper are the pointer stars that will point you to the north star. Simply extend a line formed by the two stars toward the left and you will get to the Polaris, the "north star". All of the stars seem to rotate around Polaris, although it does take several hours to trace that motion. The first star chart also shows the location of the closest large cluster of galaxies to us, the Virgo Cluster. It is in the green circle in the picture. Many hundreds of galaxies reside in the galaxy cluster.
In the early morning sky look for very bright Jupiter in the east starting at about an hour before sunrise. Jupiter will be below one end of Pisces (the fish). A thin sliver Waning Crescent Moon will pass above Jupiter on May 9th. The second star chart below shows the sky for this time.
Want to see more of the stars at night and save energy? Shield your lights so that the light only goes down toward the ground. See www.darksky.org for how.
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com