Bakersfield Night Sky – August 21, 2010
By Nick Strobel
After their close positioning with Saturn near the beginning of the month, Venus and Mars have left Saturn behind and are closing in on the bright star Spica of Virgo low in the west (see the first star chart below). At the end of the month Venus will pass just below Spica. At that time, all three (Venus, Mars and Spica) will fit within the same field of view of a typical pair of binoculars (see the inset on the first chart). Over these past few months Venus has been catching up to Mars and passed it just a couple of nights ago. While Venus has been doing that, it has also been catching up to the Earth and growing brighter as a result. Views through a telescope have shown Venus going from a small diameter gibbous phase to a larger diameter crescent phase. Venus will be in a fat crescent phase by the end of August. The crescent phase will get gradually thinner sideways but longer up-down as Venus gets closer to Earth over the next several weeks. Even though less of its daylight side will be facing us, Venus will get brighter until the beginning of October at which point the tiny fraction of the daylight side facing us becomes more important than its closer distance to us. Venus will pass by the Earth at the end of October/beginning of November.
You can check out this Venus action through the Kern Astronomical Society's telescopes at one of their public star parties at Barnes and Noble this evening (August 21st) and September 18th and October 16th. They will have their telescopes set up next to Barnes and Noble for viewing from just after sunset to about 10 PM or so (depending on the amount of foot traffic). A map to the public star parties is available at www.kernastro.org.
Depending on the particular location of the telescopes you may be able to get a quick view of Saturn through the KAS telescopes but it may be too low in the sky to view it by the time the sky gets dark enough. A big bright Waxing Gibbous Moon will already be up before sunset so take a look at it through a telescope if a building isn't blocking the way. More detail will be seen near the boundary between the day and night side because the shadows from the crater rims and mountains will be noticeable. Later in the night you may be able to see Jupiter. Jupiter rises at about 9 PM (the same time Saturn sets) so the August star party probably won't be the one to view Jupiter through the telescopes---it will still be quite low in the southeast at 10 PM. The September 18th and October 16th star parties will be better for Jupiter viewing. Through even a small telescope you can see the four largest moons (called the Galilean satellites after Galileo, the first person to see them through a telescope) and some of the cloud bands. Without a telescope, Jupiter will be the brightest "star" in the southeast in the late evening. Venus will be the very bright "star" in west in the early evening.
Jupiter will be up the rest of the night and set after sunrise. The second star chart below shows the early morning sky. Those of you under very dark skies and with much better eyes than mine may just barely be able to pick out a faint object to the right of Jupiter. That is Uranus. It does require exceptional skies and eyes to see it without a telescope or binoculars. The second star chart below will help you find it. The Moon will set by 4:30 AM tonight but in a few nights it will be full and near the two planets (and up all night!).
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