What’s Up in the Sky – August, 2010
By Peter Burkey
My observing pick of the month for August is the gathering of planets above the western horizon after sunset. Venus continues to outshine everything else (except the Moon, of course) with Mars and Saturn to its upper left on August 1. Watch the triangle formed by these three planets shift and change shape during the first week of the month. They are most tightly gathered on the 7th when they all will lie within a circle whose diameter is less than half the width of your fist held out at arm’s length.
The three are joined by a crescent Moon on August 12. The previous night, one half hour after sunset, a very thin lunar crescent lies just above the horizon with Mercury immediately above it. Both will be difficult to see even with binoculars or a small telescope due to the bright twilight glow, but it’s worth a try.
As the month progresses, the three sink lower and their separation increases. But, from August 29th through September 3rd Venus and Mars are joined by the star Spica with Venus passing closest to the star on the 31st.
A close second in this month’s observing picks is the Perseid meteor shower. It is expected to peak on the night of August 11-12. The shower occurs because Earth, in its swift journey around the Sun, passes through a cloud of tiny debris left over from Comet Swift-Tuttle. As our atmosphere encounters these particles they burn up, heating the surrounding air and making it glow. The result is a short-lived streak of light.
The best way to observe the meteor shower is to find a dark spot with a clear view of the sky, climb into a sleeping bag or wrap up in a blanket and sit back in a reclining chair. No special equipment is needed, just the naked eye. Look up at the darkest part of the sky and be patient. Under ideal conditions you may see up to 100 meteors per hour but, realistically, if you stay out for several hours, you are likely to see something like 40 or 50. And don’t forget the mosquito repellant. This year there will be no Moon to wash things out so you should have a good view of what’s up in the sky.
This month in history:
August 2: First televised liftoff of lunar module – Apollo 15’s “Falcon” – 1971
August 6: Gherman Titov first person to sleep in space aboard Vostok 2 – 1961
August 12: Mars Reconnaissance Orbiter launched – 2005
August 19: Milton Humason born – 1891
August 22: Luna 24 returns soil samples from Moon – 1976
August 25: Spitzer Space Telescope launched – 2003
Here are this month’s viewing highlights:
Planets this month: Mercury, Venus, Saturn, and Mars gather above western horizon 50 minutes after sunset as August begins. Watch each night to see changing alignments. Jupiter rises due east more than two hours after sunset, earlier as month progresses.
August 3: Last-quarter Moon
August 9: New Moon.
August 11-12: Perseid meteor shower.
August 16: First quarter Moon.
August 24: Full Moon.