Friday, December 17
Saturday, December 18
Sunday, December 19
Monday, December 20
P.S.: Cloudy? Here's a webcast!
Tuesday, December 21
Wednesday, December 22
Thursday, December 23
For a listing of all such Jupiter-satellite events this month, see the December Sky & Telescope, page 64.
Friday, December 24
Saturday, December 25
Sky at a Glance is now an iPhone app! Put S&T SkyWeek on your iPhone, iPad, or iPod Touch and get the above listings anytime, anywhere — with interactive sky maps! Tap a button to see the scene described, customized for your location worldwide. From there you can scroll the view all around the sky, zoom in or out, change to any time or date, and turn on animation. Go to Apple's iTunes store from your device and buy S&T SkyWeek — just 99 cents!
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 is hidden in the glare of the Sun.
Venus (magnitude –4.8) blazes in the southeast before and during dawn, at its greatest height as the "Morning Star." In fact Venus rises some two hours before the first glimmer of dawn (for skywatchers at mid-northern latitudes) — a weird UFO of a thing in the east-southeast.
Look for fainter Spica well to Venus's upper right, and for Saturn above or upper right of Spica. Far to Venus's upper left shines Arcturus.
Mars is lost deep in the glow of sunset.
Jupiter (magnitude –2.4, at the Pisces-Aquarius border) shines in the south at dusk and southwest later in the evening. It's the brightest starlike point in the evening sky. In a telescope Jupiter has shrunk to 40 arcseconds wide. Jupiter's South Equatorial Belt continues re-forming, as dark markings spread east and west all around the globe from the storm spot that broke out in the SEB's latitude more than a month ago. The original outbreak site transits Jupiter's central meridian about 3 hours and 40 minutes after the Great Red Spot.
As for the Great Red Spot, it's near System II longitude 157°. Assuming it stays there, here's a list to print out of all the Great Red Spot's predicted transit times for the rest of this observing season.
Saturn (magnitude +0.8, in Virgo) rises around 1 a.m. and is high in the south-southeast before and during dawn, far upper right of brilliant Venus. Don't confuse it with Spica below it. Saturn's rings have widened to 10° from edge-on.
In a telescope, see if you can detect the new white storm known as the North Electrostatic Disturbance, seen with dramatic clarity in the stacked-video image below. Visually the spot is much less obvious. Saturn's rings have widened to 10° from edge-on.
Uranus (magnitude 5.8) is only about 1½ east of Jupiter and closing.
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) equals Universal Time (also known as UT, UTC, or GMT) minus 5 hours.
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