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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 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 must have a detailed, large-scale sky atlas (set of charts). The standards are the Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger and deeper Uranometria 2000.0 (stars to magnitude 9.75). And read how to use your charts effectively.
You'll also want a good deep-sky guidebook, such as Sky Atlas 2000.0 Companion by Strong and Sinnott, or the more detailed and descriptive Night Sky Observer's Guide by Kepple and Sanner, or the classic if dated Burnham's Celestial Handbook.
Can a computerized telescope take their place? I don't think so — not for beginners, anyway, and especially not on mounts that are less than top-quality mechanically. 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."
This Week's Planet Roundup
Mercury (magnitude +0.1) is very low in bright twilight. About a half hour after sunset, look for it near the horizon due west, well to the lower right of bright Venus. Binoculars will help.
Venus (magnitude –4.3) is the bright Evening Star sinking low in the west as twilight fades. In a telescope, Venus now appears almost exactly half lit.
Mars (magnitude +1.5) is close to Saturn, upper left of brilliant Venus in twilight. Early in the week Mars is to Saturn's lower left. By week's end it's a little farther directly left of Saturn, as shown above.
Jupiter (magnitude –2.7, in Pisces) rises around the end of twilight and shines high in the southeast by midnight. It's highest in the south before dawn — the brightest starlike point in the morning sky.
Jupiter's Great Red Spot is near System II longitude 150°. Assuming it stays there, here's a list to print out of all the Great Red Spot's predicted transit times for the rest of 2010.
Saturn (magnitude +1.1) is the slightly brighter of the two planets upper left of Venus in evening twilight. (The other is Mars.)
Uranus (magnitude 5.8, in Pisces) is 3° west of Jupiter. In a telescope Uranus is only 3.6 arcseconds wide, compared to Jupiter's 46″.
Neptune (magnitude 7.8, at the Aquarius-Capricornus border) is up in good view by late evening. See our finder charts for Uranus and Neptune in 2010.
Pluto (magnitude 14, in northwestern Sagittarius) is highest in the south after dark — and now the Moon is gone. See our big Pluto finder charts in the July Sky & Telescope, page 60.
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 (also known as UT, UTC, or GMT) minus 4 hours.
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