Some daily events in the changing sky for May 15 – 23.
Friday, May 15
Saturday, May 16
Sunday, May 17
Monday, May 18
Tuesday, May 19
Wednesday, May 20
Thursday, May 21
Friday, May 22
Saturday, May 23
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 is hidden in the glare of the Sun.
Venus (magnitude –4.6, in Pisces) 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 now a thick crescent about 40% sunlit. The best telescopic views of it come in full early-morning daylight, when Venus is higher in steadier air.
Mars (magnitude +1.2, in Pisces) still remains 6° lower left of Venus all this week. Bring binoculars; Mars is about 200 times fainter than Venus! There are four reasons for this: Mars is farther from the Sun so it gets illuminated less brightly; its surface is darker than Venus's white clouds; it's a smaller planet than Venus; and it's currently farther from us.
Jupiter (magnitude –2.4, in Capricornus) shines brightly in the southeast before and during dawn.
Saturn (magnitude +0.9, in Leo) is highest in the south at dusk and moves to the southwest later. Regulus, not quite as bright, sparkles 15° to its right at dusk, and to its lower right later. This week Saturn ends its retrograde (westward) motion toward Regulus and begins drawing away from it eastward again.
In a telescope Saturn's rings appear 4° from edge on, their widest this year. But look at the picture at right; see how the rings have dimmed! The caption tells why.
Uranus (6th magnitude, in Pisces) is between Venus and Jupiter in the dawn.
Neptune (8th magnitude, in Capricornus) is in the background of Jupiter.
Pluto (14th magnitude, in northwestern Sagittarius) is highest in the south before the first light of dawn.
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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