Friday, July 13
Saturday, July 14
The Moon actually occults Jupiter for most of Europe and parts of Asia; map and timetable. Jupiter disappears behind the Moon's sunlit limb.
Sunday, July 15
Monday, July 16
Tuesday, July 17
Wednesday, July 18
Thursday, July 19
Friday, July 20
Saturday, July 21
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'll need a detailed, large-scale sky atlas (set of charts). 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 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."
This Week's Planet Roundup
Mercury is lost in the sunset.
Venus and Jupiter (magnitudes –4.7 and –2.1) shine dramatically in the east before and during dawn. They're stacked about 8° apart now, with Jupiter on top. Look for Aldebaran, much fainter, moving away from Venus to its upper right. Also in Venus's starry background are the Hyades, and above Jupiter are the Pleiades. See the scenes above.
The asteroids Ceres and Vesta, magnitudes 9.1 and 8.4, are there too! See article Predawn Treats for Early Risers for the naked-eye aspect, and to find the asteroids, Ceres and Vesta: July 2012 – April 2013.
Mars (magnitude +1.0, in Virgo) glows orange in the west-southwest at dusk. It's lower right of the Saturn-and-Spica pair, by about 16°. Mars is heading their way; it will pass right between them in mid-August. In a telescope Mars is gibbous and very tiny, only 6 arcseconds wide.
Saturn (magnitude +0.8, in Virgo) shines in the southwest as the stars come out. Below it by nearly 5° is Spica, nearly the same brightness. After dark they move lower to the west-southwest.
Uranus (magnitude 5.8, at the Pisces-Cetus border) and Neptune (magnitude 7.8, in Aquarius) are high in the southeast and south before the first light of dawn. Finder charts.
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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