If it is August, it means the Perseids! This is one of the best meteor showers going. This year, from an observational standpoint, should be an excellent one for viewing the shower. With no Moon to hinder viewing, the shower should entertain us during the evening of the 12th and the morning of the 13th with the peak of the shower during the evening of the 12th. Weather and mosquitos permitting this should be a good year.
The Perseids result when the Earth encounters the debris trail left by the Comet Swift-Tuttle which last passed by in 1992. Swift-Tuttle has a period of 133 years so it will be a while before it re-appears to dump a new load of debris behind it.
The best viewing will be from a comfortable chair in a nice dark location away from intruding light pollution. Look to the northeast in the direction of the constellation Perseus. If you are familiar with the double open star clusters in Perseus, barely visible to the naked eye, that is a good point to center your viewing angle. It is difficult to predict how many meteors to expect per hour. Under the best of circumstances it can be over 100 per hour. It just depends on which part of the debris trail the Earth passes through and how fresh the trail is. Nevertheless, under good viewing conditions such as this year, the Perseids seldom disappoint.
Venus still retains its early evening brilliance, in fact, improving its magnitude to -4.6. Even so it spends the month moving closer to the early evening horizon ending the month 15 degrees above it. Jupiter continues its westward march through the early evening southwestern sky setting around 10:30 by the end of the month as its magnitude fades slightly from -2.1 to -1.9.
Saturn continues to hang out in the constellation Sagittarius this month fairly low in the southern sky. While its magnitude fades slightly, the magnificent rings remain open at 26 degrees from edge on offering great views through small to medium sized telescopes
The real show stopper this month is Mars, shining and dominating the evening sky all month. Rising just before sunset, it should be visible all night long. This is its closest approach to Earth since 2003. At magnitude -2.8, the “Red Planet” is well placed for telescope viewing and for finding surface features such as the polar ice cap.
At the beginning of last month we were treated by being able to see 5 planets during one night!
Well, guess what? We’ll be able to do it again this month! This time however, tiny but bright Mercury will be visible in the early morning, starting on the 20th, about 45 minutes before sunrise and about 15 degrees above the eastern horizon.
You may need some binoculars to be able to pick it out of the pre-dawn light.
Often I refer to angular separation between objects or, for example, the elevation above a horizon in terms of degrees. This refers to an angle from the observer’s point of view. There is an easy way to calibrate angles in degrees. If you make a fist and hold it at arm’s length, the width of your fist is about 10 degrees. Surprisingly this works for people of all sizes since the ratio of your arm’s length to body height is about the same for everybody. To test this, find a low flat horizon somewhere. From the horizon to straight up over your head should be about 9 fist widths. Try it!
The Moon will be last quarter on the 46h, new on the 11th, first quarter on the 18th and full on the 26th.
Looking west-southwest about 1 hour after sunset on the 14th, the crescent Moon will be found about 5 degrees above brilliant Venus. Looking south-southeast on the 20th and 22nd, about an hour after sunset, the waxing gibbous Moon will first visit Saturn on the 20th and then Mars on the 22nd.
New Mexico Tech Astronomy Club