Bakersfield Night Sky – August 20, 2016
By Nick Strobel
School is now in session for many of the K12 school districts and will start for Bakersfield College and Cal State Bakersfield on Monday. A couple of days ago, Bakersfield College was closed, so the classified staff could join faculty and administration in the “Opening Day” events that set the stage for what will be coming up in the academic year and exceptional faculty leaders were recognized. While faculty and administrator leaders get the public exposure, the classified staff are the unsung heroes who make sure everything functions smoothly behind-the-scenes, so I’m glad President Christian gives them a “holiday” to join in the festivities of Opening Day.
Summer break is over but the Summer Triangle of Deneb, Vega, and Altair is still up high in the evening sky (see the attached star chart below). At around 9 p.m. face southeast and look up high overhead. On the left point of the Summer Triangle is the white hot star Deneb that is at the tail of Cygnus the swan. At 8500 Kelvin, Deneb is hotter than the sun which is “only” 5800 Kelvin. Deneb is a supergiant about 114 times larger in diameter than the sun and radiates over 54,000 times as much energy as the sun. Deneb is about 1425 light years away from us.
The brighter stars of Cygnus look like a cross, so it is sometimes called the “northern cross”. Cygnus is flying down the midline of the Milky Way, so if you’re under light-polluted skies, Cygnus can help you see where the Milky Way is supposed to be.
Almost directly overhead is the top point of the Summer Triangle, the white hot star Vega in the constellation Lyra. Vega is about 9500 Kelvin and appears so bright because it is so close to us, at just 25 light years away. Vega emits about 36 times as much light as the sun and it has a circumstellar dust disk that could be forming planets. That is why it was featured in Carl Sagan’s novel, “Contact” (made into a movie). Vega’s other claim to fame is that it will be the “north star” about 12,000 years from now as the precession of the earth’s rotation axis shifts the north celestial pole away from Polaris, our current “north star”. Actually, Deneb will also get a crack at being the “north star” 4000 years before Vega does but Vega will get closer to the actual north celestial pole than will Deneb.
The right point of the Summer Triangle is the white-hot Altair at a cooler but still toasty 7550 Kelvin. Altair is just 16.7 light years away and 10.6 times brighter than the sun. Altair is in the neck of Aquila the eagle.
A bit closer to the southern horizon you’ll see Mars almost lined up between Saturn and Antares. On the evenings of August 23 and 24, Mars will travel right between Antares and Saturn (on our sky, of course, because Antares is 550 light years away from us, Saturn is 3.5 million times closer, and Mars even closer than Saturn!). The name “Antares” means “like Mars” or “rival of Mars”, so the upcoming celestial line-up will allow you to compare the two easily.
At the end of the month on August 27, see if you can spot Venus and Jupiter low in the west shortly after sunset. They will be very close together—less than half a pinky at arm’s length. In fact, you’ll probably need binoculars to split them apart but be sure to view them after the sun sets. If you put Venus-Jupiter at the top of the field of view of your binoculars, you might be able to spot fainter Mercury at the bottom edge (see the inset of the attached star chart).
Next month will be the first of the shows for the fall season at the William M Thomas Planetarium. That will be the ever-popular show, “Black Holes” on the evening of September 22. It includes a ride into the supermassive black hole at the center of the Milky Way. In between Scorpius, Sagittarius, and Ophiuchus is the central bulge of the Milky Way and just above the line connecting the tip of the Teapot part of Sagittarius and the stinger at the tip of Scorpius tail is the center of the Milky Way where the supermassive black hole resides.
In October will be a show about Mars that I’m still working on. The Mars show will serve as preparation for the Cerro Author visit of Andy Weir, author of “The Martian”. He will give a public talk on Tuesday, October 25 in the SPArC at BC at 7 PM. The November planetarium show will be a new one, “Incoming!” that I described in the previous column. The fall season will end with the traditional holiday show, “Seasons of Light”.
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