Friday, July 9
Saturday, July 10
Sunday, July 11
Monday, July 12
Tuesday, July 13
Wednesday, July 14
Thursday, July 15
Friday, July 16
Saturday, July 17
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 (about magnitude 0.6) is deep in the glow of sunset. Scan for it with binoculars shortly after sundown just above the west-northwest horizon, far to the lower right of Venus. By late in the week Mercury climbs higher and is easier to see.
Venus (magnitude 4.1, in Leo) is the bright Evening Star sinking in the west as twilight fades. The much fainter star Regulus (magnitude +1.4, less than 1% as bright) is nearby hardly more than 1° below or lower left or Venus on July 9th and 10th, and farther to Venus's lower right after that.
In a telescope Venus is still a small (17-arcsecond) gibbous disk. You'll have the cleanest telescopic views of it when it's higher in the blue sky of afternoon if you can find it then. (Don't accidentally sweep up the Sun!) Not until late summer will Venus assume its larger and more dramatic crescent phase.
Mars (magnitude +1.4, by the hind foot of Leo) is upper left of Venus. Watch Mars closing in on Saturn, glowing to its upper left, day by day. In a telescope Mars is just a tiny blob 5 arcseconds in diameter.
Jupiter (magnitude 2.6, in Pisces) rises around 11 or midnight daylight saving time and shines high in the southeast before dawn. It's the brightest starlike point in the morning sky. See our article on Jupiter's disappearing South Equatorial Belt.
Jupiter's Great Red Spot is near System II longitude 150°. Assuming it stays there, here's a list of all the Great Red Spot's predicted transit times for the rest of 2010.
Saturn (magnitude +1.1, in the head of Virgo) is in the west during evening, upper left of Mars. The diagonal line of Saturn, Mars, Venus, and Mercury is shrinking. The first three of these planets will bunch up low in the sunset in early August.
Uranus (magnitude 5.8, in Pisces) is just under 3° west of Jupiter. In a telescope Uranus is only 3.6 arcseconds wide, compared to Jupiter's 43″.
Neptune (magnitude 7.9, at the Aquarius-Capricornus border) is up in good view after midnight, well to Jupiter's west. See our finder charts for Uranus and Neptune in 2010.
Pluto (magnitude 14, in northwestern Sagittarius) is high in the south-southeast by 11 p.m. See our big Pluto finder charts for 2010.
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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