Bakersfield College

July 2, 2011

Bakersfield Night Sky – July 2, 2011
By Nick Strobel

This evening see if you can spot a very thin crescent Moon very low in the west just after sunset. It will be a challenge! Try binoculars to first locate it and then try to see it without binoculars once you know where you should be looking. If you can see a bright star above and to the right of the Moon, you've found Mercury, the closest planet to the Sun (shown in the first chart below). Mercury is now in our evening sky for this month. The Moon is in a Waxing Crescent phase, so it will climb up away from the Sun over the following evenings getting fatter and fatter. On our nation's birthday, the waxing crescent Moon will provide a nice backdrop to the evening's fireworks displays in the west. The Moon will be to the left of the brightest star of Leo, Regulus. Regulus is at the end of the sickle part of Leo. July 4th also marks the farthest distance the Earth will be from the Sun this year (at 8 PM to be more precise). We will be about 1.67% farther than our average distance or 3.4% farther than our closest distance that happens in early January.

Saturn is high in the southwest at 9 PM next to the double star Porrima of Virgo. Saturn is now slowly moving eastward (left) away from Porrima. About a fist width at arm's length to the left of Saturn is Spica. The First Quarter Moon will be between the two (though a bit lower) on July 7th. High above the two is the brighter star, Arcturus. About a quarter of the way up in the southeastern sky at around 9 PM is the bright red heart of Scorpius, Antares, a red supergiant star—see the second chart below. Antares is so large that if placed in our solar system, the orbit of Mars would fit comfortably inside it. Antares has enough mass that it will go supernova sometime in the future (though, if anyone tells you they know when it will explode, they probably also have a bridge to sell you too). Antares has a companion star that is much fainter but much hotter. Although the companion is blue-white hot (much hotter than the Sun), it may look green in a telescope because of the contrast with the brighter red Antares. The two stars orbit each other at a distance of about 14 times the distance between Pluto and the Sun and take about 2500 years to complete one orbit. They orbit a common point called the center of mass that lies closer to the more massive Antares than its companion.

On July 9th when the Kern Astronomical Society has its free public star party at Russo's Bookstore in the Marketplace, the Waxing Gibbous Moon will be halfway between Spica and Antares. You can look through any of the telescopes set up there from 8:45 to 9:45 PM. During that time the Moon will be south-southwest and far enough away from Saturn that you should still get a good viewing of Saturn through the telescopes.

The central bulge of the Milky Way is to the left of Antares and includes the stars of Ophiuchus and Sagittarius. You will need to wait until about 10 PM for the sky to be sufficiently dark to see the Milky Way and also away from the lights of the city. The bright part of Sagittarius looks like a teapot if you connect the dots in the right way. Just a little ways up and to the right of the tip of the spout part of the teapot is the direction to the center of the Milky Way, about 27,000 light years away. The bright light of the gibbous Moon will pass through the stars of Scorpius, Ophiuchus, and Sagittarius July 10th through the 15th (Full Phase on July 14th) and it will wash out any view of the bulge of the Milky Way. About halfway up in the eastern sky are the three bright stars of the Summer Triangle: Deneb at the north point, Vega at the highest point and Altair at the south and lowest point. Deneb is at the tail of the Cygnus the Swan with the swan pointed toward the middle of the triangle and also flying right down the middle of the band of the Milky Way. The upper wing is the section of sky the Kepler mission is searching for Earth-sized exoplanets orbiting stars. At last count, Kepler had found over 1200 planet candidates from Earth size to larger than Jupiter, including five that are 0.9 to 2 times the diameter of the Earth that reside in their stars' habitable zones (the "Goldilocks" region where the temperature on the surface of the planets would be nice enough for liquid water to exist). For more on the methods we use to find exoplanets, see my freely available astronomy textbook, Astronomy Notes, at www.astronomynotes.com and go to the end of the tenth chapter in it.

For the early morning hours, you will see the very bright Jupiter rise a little after 2 AM, Mars rise at about 4 AM, and super-bright Venus rise only about 30 minutes before sunrise. Jupiter continues to be among the dim stars of Pisces, so use the Great Square part of Pegasus to locate it as shown in the third chart below. Mars is now next to the head of Taurus. Below it is the eye of Taurus, Aldebaran, a star slightly brighter than Mars but about the same orangish color.

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.
--
Nick Strobel
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com

Kern Community College District