Comet ISON has brightened suddenly in the last few days to 4th magnitude as of November 20th — a popsicle comet with a small, bright green-white head and a long, thin, dim tail. It's speeding sunward near Spica and Mercury low in the east just before dawn, accelerating every day toward its November 28th perihelion and trial by fire. See new S&T press release.
Meanwhile, Comet Lovejoy glows only a little less bright much higher before dawn. Both comets are visible in binoculars despite moonlight returning to the morning sky. They're being detected naked-eye by skilled observers under good conditions. Finder charts for both. This is getting exciting!
Sky & Telescope and Celestron are sponsoring a Comet ISON photo contest with some serious prizes.
Friday, November 15
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Monday, November 18
Tuesday, November 19
Wednesday, November 20
Thursday, November 21
Friday, November 22
Saturday, November 23
Want to become a better astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.
This is an outdoor nature hobby. 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 guide to 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 once you know your way around, the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope.
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 beloved if dated Burnham's Celestial Handbook.
Can a computerized telescope replace charts? Not for beginners, I don't think, and not on mounts and tripods that are less than top-quality mechanically (able to point with better than 0.2° repeatability, which means heavy and expensive). 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 (magnitude –0.6) shines low in the east-southeast in early dawn. This is its best morning apparition of 2013. Don't confuse Mercury with Spica to its upper right. The gap between them widens from 12° to 18° this week. To their upper left by about 30° is Arcturus.
Venus (magnitude –4.8) is the brilliant "Evening Star" in the southwest during dusk, shining just about as high and bright as it's going to this year. It sets more than an hour after dark. In a telescope, Venus has waned to its thick-crescent phase and has enlarged to about 32 arcseconds tall.
Mars (magnitude 1.4, in Leo) rises around 1 a.m. It's moving eastward against the background stars, pulling farther away to the lower left from Regulus. By dawn, Mars and Regulus are high in the south-southeast. Mars is still a tiny disappointment in a telescope, only 5 arcseconds wide.
Jupiter (magnitude –2.5, in Gemini) rises in the east-northeast around 8 or 9 p.m. with Pollux and Castor to its left. It blazes highest around 3 or 4 a.m. In a telescope Jupiter has grown to 43 arcseconds wide as it heads toward its January 5th opposition.
Saturn is deep in the glow of sunrise.
Uranus (magnitude 5.7, in Pisces) and Neptune (magnitude 7.9, in Aquarius) are high in the southeast to south in early evening. Finder charts for Uranus and Neptune. See also the October Sky & Telescope, page 50.
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 Standard Time (EST) is Universal Time (known as UT, UTC, or GMT) minus 5 hours.
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