Some daily events in the changing sky for December 4 12.
Friday, December 4
Saturday, December 5
Sunday, December 6
Monday, December 7
Tuesday, December 8
Wednesday, December 9
Thursday, December 10
Friday, December 11
Saturday, December 12
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 Sky Atlas 2000.0 or the smaller Pocket Sky Atlas) and good deep-sky guidebooks (such as Sky Atlas 2000.0 Companion by Strong and Sinnott, the more detailed and descriptive Night Sky Observer's Guide by Kepple and Sanner, or the classic Burnham's Celestial Handbook). Read how to use them effectively.
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 and a curious mind." Without these, "the sky never becomes a friendly place."
More beginners' tips: "How to Start Right in Astronomy".
This Week's Planet Roundup
Mercury (magnitude 0.5) is low in the sunset but getting a little higher every day. About 30 minutes after sundown, use binoculars to scan for it just above the horizon due southwest. On what day will you first see it with your unaided eyes?
Venus (magnitude 3.9) is lost deep in the sunrise. Not until late this winter (Northern Hemisphere winter) will it emerge into view again in the sunset.
Mars (magnitude 0.2, at the Cancer-Leo border) rises around 9 or 10 p.m. local time, far below Castor and Pollux a bit north of east. A little later, twinkly Regulus rises a fist-width beneath it. Mars and Regulus are very high in the south in the hours before dawn.
In a telescope, Mars is 10.4 arcseconds wide and growing. The planet's north polar cap is in good view this season, bordered by a wide, dark collar. Any other surface features? Clouds? See the Mars map and observing guide in the December Sky & Telescope, page 57. Mars is on its way to opposition in late January, when it will be 14.1 arcseconds wide.
Jupiter (magnitude 2.2, in Capricornus) shines brightly in the south-southwest in twilight, and lower in the southwest later. It sets by 10 p.m. local time.
Saturn (magnitude +1.0, in the head of Virgo) rises around 1 a.m. and shines high in the southeast before and during dawn. Its rings are still narrow, tilted only 4° from edge-on.
Uranus (magnitude 5.8, below the Circlet of Pisces) is highest in the south during early evening.
Neptune (magnitude 7.9, in Capricornus) lurks closely in the background of Jupiter, which shines 11,000 times brighter. Nevertheless Neptune is detectable in good binoculars. Jupiter and Neptune are 2½° apart on December 4th and 1½° apart on the 11th. To identify Neptune (and Uranus) you'll need to use our finder charts for these two faint planets.
Pluto is behind the glare of the Sun.
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 Standard Time (EST) equals Universal Time (also known as UT, UTC, or GMT) minus 5 hours.
To be sure to get the current Sky at a Glance, bookmark this URL:
If pictures fail to load, refresh the page. If they still fail to load, change the 1 at the end of the URL to any other character and try again.