Some daily events in the changing sky for September 12 – September 20.
Friday, September 12
Saturday, September 13
Sunday, September 14
Monday, September 15
Tuesday, September 16
Wednesday, September 17
Thursday, September 18
Friday, September 19
Saturday, September 20
Want to become a better amateur astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope. For an easy-to-use constellation guide covering the whole evening sky, use the big monthly foldout map in each issue of Sky & Telescope, the essential magazine of astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).
Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of maps; the standards are Sky Atlas 2000.0 or the smaller Pocket Sky Atlas) and good deep-sky guidebooks (such as Sky Atlas 2000.0 Companion by Strong and Sinnott, the even more detailed Night Sky Observer's Guide by Kepple and Sanner, or the classic Burnham's Celestial Handbook). Read how to use them effectively.
Can a computerized telescope take their place? As Terence Dickinson and Alan Dyer say in their Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand and a curious mind."
Without these, they wisely say, "the sky never becomes a friendly place."
More beginners' tips: "How to Start Right in Astronomy".
This Week's Planet Roundup
Mercury (about magnitude +0.2) is sinking away below much-brighter Venus, low in the west-southwest in bright twilight, as shown at the top of this page. Try with binoculars.
Venus (magnitude –3.8) is still low in the glow of sunset. Look for it above the west-southwest horizon in bright twilight about 30 minutes after sundown. Fainter Mercury, Mars, and Spica accompany it, as shown above. Try for them with binoculars.
Mars (a dim magnitude +1.7!) passed 1/3° south of Venus on September 11th; now it's moving away to Venus's lower right. Binoculars required; good luck.
Jupiter (magnitude –2.5, in Sagittarius) shines bright and steady in the south right at dusk, and lower in the southwest later. It's above the Sagittarius Teapot and below the end of the smaller, dimmer Teaspoon.
Saturn is hidden deep in the glow of sunrise.
Uranus and Neptune (magnitudes 5.7 and 7.8, respectively, in Aquarius and Capricornus) are in the southeast to south during evening. Use our article and finder charts or the chart in the September Sky & Telescope, page 63.
Pluto (magnitude 14.0, in the northwestern corner of Sagittarius) is still in the south-southwest right after dark.
All descriptions that relate to your horizon or zenith — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America. Eastern Daylight Time (EDT) equals Universal Time (known as UT, UTC, or GMT) minus 4 hours.
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