Friday, May 20
Saturday, May 21
Two-thirds of the way from Arcturus to Vega, look for the dim Keystone of Hercules.
Sunday, May 22
Monday, May 23
Tuesday, May 24
Wednesday, May 25
Thursday, May 26
Friday, May 27
Saturday, May 28
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 sky 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, Venus, Mars, and Jupiter continue their evolutions low in the dawn, but now they're drawing farther apart. Use binoculars about 30 minutes before sunrise; look low in the east. Jupiter is the highest. Look lower left of it for Venus. Near Venus, binoculars should show Mercury (below or lower left of Venus) and perhaps faint little Mars (left of or above Venus).
Saturn (magnitude +0.6, in Virgo) is now in excellent evening view high in the south. Just ½° to its right is fainter Porrima (Gamma Virginis), turning Saturn into a naked-eye "double star." Shining 14° to Saturn's lower left is Spica.
In a telescope Saturn's rings are 7.3° from edge on, their minimum tilt for more than a decade to come. The rings are casting a relatively wide, prominent black shadow southward onto the globe, and the globe's shadow on the rings is visible just off the globe's celestial east (following) side, as seen in the image here. On the globe itself, Saturn's six-months-old white outbreak remains very active. Read Dissecting Saturn's Big Storm for in-depth results (literally) from the Cassini Saturn orbiter and the Very Large Telescope in Chile.
See how many of Saturn's satellites you can identify in your scope using our Saturn's Moons tracker.
And don't skip over Porrima. It's a fine, close telescopic binary star with a current separation of 1.7 arcseconds. Use high power and hope for good seeing. See the article in the April Sky & Telescope, page 56.
Uranus (magnitude 5.9, in western Pisces) is very low in the east before the first light of dawn.
Neptune (magnitude 7.9, in Aquarius) is in the southeast before dawn.
Pluto (magnitude 14.0 in Sagittarius, and back here by popular request) is highest in the south before dawn. A finder chart for it, running from June 1st through the end of Pluto's observing season, will appear in the July Sky & Telescope, page 64.
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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