Saturday, Sept. 1

Sunday, Sept. 2

Monday, Sept. 3

Compare Mars with similarly bright and similarly colored Antares ("Anti-Mars" in Greek), three fists to its left and perhaps higher. Which of the two looks deeper orange?

Tuesday, Sept. 4

Look left of Altair, by a bit more than a fist-width, for the dim but distinctive little constellation Delphinus, the Dolphin, splashing in the edge of the Milky Way. For more on Delphinus, its legendry, and telescopic double stars, see the September Sky & Telescope, page 47.

Wednesday, Sept. 5

Friday, Sept. 7

Up before dawn? Watch the Moon wave from morning to morning as if passes between Jupiter and Aldebaran. (The scene is drawn for the middle of North America. European observers: move each Moon a quarter of the way toward the one for the previous date. The Moon is shown three times actual size.)

Sky & Telescope diagram

Saturday, Sept. 8

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 map in the center of each issue of Sky & Telescope, the essential guide to 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 charts).

Sky Atlas 2000.0 (the color Deluxe Edition is shown here) plots 81,312 stars to magnitude 8.5. That includes most of the stars that you can see in a good finderscope, and typically one or two stars that will fall within a 50× telescope's field of view wherever you point. About 2,700 deep-sky objects to hunt are plotted among the stars.

Sky & Telescope

The standards are the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope effectively.

You'll also want a good deep-sky guidebook, such as Sue French's Deep-Sky Wonders collection (which includes its own charts), Sky Atlas 2000.0 Companion by Strong and Sinnott, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the classic if dated Burnham's Celestial Handbook.

Can a computerized telescope replace charts? I don't think so — not for beginners, anyway, and especially not on mounts and tripods that are less than top-quality mechanically (able to point with better than 0.2° repeatability). As Terence Dickinson and Alan Dyer say in their invaluable 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."

Mercury is lost low in the glow of sunrise.

Venus (magnitude –4.3, in Gemini) rises in darkness around 3 a.m. daylight saving time (depending on where you are), emerging above the east-northeast horizon like a witching-hour UFO a good two hours before the first glimmer of dawn. By dawn Venus is blazing high in the east — vastly outshining Pollux and Castor to its upper left and Procyon to its right or lower right.

Mars (magnitude +1.2, in Libra) and Saturn (magnitude +0.8, in Virgo) are low in the west-southwest in twilight. This week they widen from 10° to 13° apart: a fist-width at arm's length or more. Look for them far lower left of bright Arcturus. Saturn is the one on the right. You may still be able to see Spica twinkling 5° below Saturn.

The side of Jupiter away from the Great Red Spot on August 23rd. South is up. The huge, reddish northern-hemisphere belt is resolving itself back into the North Equatorial Belt (NEB) and, below it here, the North Temperate Belt (NTB), with the light North Tropical Zone re-emerging between them. Notice the thin, unusual Equatorial Band in the middle of the bright Equatorial Zone.

John H. Rogers, the British Astronomical Association's Jupiter Section director, says the recent regrowth of the NEB is its first "full-scale revival" since 1926, "and the NTB is reviving via a super-fast jet-stream outbreak as last seen in 2007. Sectors of the belts and the intervening NTropZ which were still light in June have now filled in with intense turbulence and reddish (ochre) colour, producing one vast brown-and-ochre belt from the NEBs to the NTB."

Christopher Go

Uranus (magnitude 5.7, at the Pisces-Cetus border) and Neptune (magnitude 7.8, in Aquarius) reach good heights in the southeast by mid- to late evening. Finder charts for Uranus and Neptune.

All descriptions that relate to your horizon — 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 (also known as UT, UTC, or GMT) minus 4 hours.

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