Some daily events in the changing sky for May 1 – 9.
Friday, May 1
Saturday, May 2
Sunday, May 3
Monday, May 4
Tuesday, May 5
Wednesday, May 6
Thursday, May 7
Friday, May 8
Saturday, May 9
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 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 charts; 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 more detailed and descriptive 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? 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 and a curious mind." Without these, they note, "the sky never becomes a friendly place."
More beginners' tips: "How to Start Right in Astronomy".
This Week's Planet Roundup
Mercury fades rapidly this week (from magnitude +1 to +3) and starts dropping down into the sunset. Look for it early in the week low in the west-northwest about an hour after sunset. As darkness deepens, look for the Pleiades just to its right, as shown here.
Venus (magnitude –4.7) shines brightly low in the east during dawn. Don't confuse it with Jupiter, higher and far to the right in the southeast. In a telescope, Venus is a thickening and shrinking crescent. The best telescopic views come in full early-morning daylight, when Venus is higher in steadier air.
Mars (only magnitude +1.2) remains 5° or 6° lower left of Venus all week. Bring binoculars; Mars is 230 times fainter than Venus! Mars is beginning a long, slow apparition that will bring it to opposition on January 29, 2010.
Jupiter (magnitude –2.2, in Capricornus) shines brightly in the southeast before and during dawn.
Saturn (magnitude +0.8, in Leo) is highest in the south in early evening and moves to the southwest later. Regulus, not quite as bright, sparkles 15° to its right at dusk, and to its lower right later.
In a telescope, Saturn's rings appear 4° from edge on, their widest this year. They'll close to exactly edge-on September 4th, when, unfortunately, Saturn will be out of sight practically in conjunction with the Sun.
Uranus (6th magnitude) is low in the sunrise glow, in the background of Venus — and 17,000 times fainter.
Neptune (8th magnitude) is the background of Jupiter — and 11,000 times fainter.
Pluto (14th magnitude, in northwestern Sagittarius) is highest in the south before the first light of dawn. It's 250 times fainter than even Neptune.
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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