The Naked Eye
Summer is almost gone, but it doesn’t mean the end of your stargazing evenings. In fact, fall is even better for amateur astronomy since the cooler temperatures can yield a steadier atmosphere and clearer skies.
Mercury, Venus and Mars in the Early Morning Sky
If you haven’t had the opportunity to see the planet Mercury so far this year, September is your best chance yet. On September 12, the tiny planet that lies closest to the sun is at its highest point above the horizon, which makes it easier to notice it before it disappears in the glare of the rising sun.
Over the few days following September 12, you can catch Mercury, Venus and Mars in the predawn eastern sky. It’s a great chance to see a rare meeting of those planets. You’ll have to get up pretty early, but the sight is worth the trouble.
Mercury, Venus and Mars in the early predawn sky of September 12 (image generated on SkySafari 5 for the iPad — see www.skysafariastronomy.com).
September 20’s New Moon
A ‘New Moon’ merely means that the moon is located on the same side of Earth as the sun, which makes it ‘invisible’ in the night sky. This is the best time of the month to observe faint objects such as galaxies, nebulae, and star clusters because there is no moonlight to interfere with your eyesight and the night sky will appear darker.
This month, take this opportunity to familiarize yourself with some of the more easily recognizable constellations of the night sky. You can download and print a very handy sky chart from the website of the Rio Tinto Alcan Planetarium at http://espacepourlavie.ca/en/monthly-sky/early-birds-will-love-september. Use the map to spot a few constellations this evening, and go back the next evening, without the map, and see if you can still find and recognize those constellations. A few of the easier ones include Lyra, Cassiopeia, Ursa Major and Hercules. Have fun.
Some of the more easily identifiable constellations of the September night sky (image generated on SkySafari 5 for the iPad — see www.skysafariastronomy.com).
Jupiter in the early evening sky of September 21
If getting up at the crack of dawn to see Mercury is not your thing, you can always opt to catch Jupiter, our solar system’s largest planet, in the early evening sky of September 21. Shortly after sunset, look for the crescent moon near the horizon. You will see a bright ‘star’ to the moon’s left—it’s actually Jupiter.
Jupiter and the crescent Moon in the early evening sky of September 21 (image generated on SkySafari 5 for the iPad — see www.skysafariastronomy.com).
September 22—Autumnal Equinox
This won’t really have any bearing on your stargazing activities, but it’s an important astronomical event that signals the day when the sun shines directly on the equator, which means there will be nearly equal amounts of day and night that day. This corresponds to the first day of fall in our hemisphere, but in the Southern Hemisphere, it’s called the vernal equinox, and it corresponds to the first day of spring.