Update Wednesday Jan. 8: Auroras possible early Thursday morning. A large coronal mass ejection (CME) from the Sun should start hitting Earth's magnetosphere around 8:00 UT January 9th (3 a.m. EST, midnight PST). Details.
The CME comes from a big sunspot region that's currently visible to the unaided eye through a safe solar filter or a #14 rectangular arc-welder's filter.
Friday, January 3
Saturday, January 4
Hint: "Procyon" means "Before the Dog." That tells you something about where its namers lived.
Sunday, January 5
Monday, January 6
Tuesday, January 7
Wednesday, January 8
Thursday, January 9
Friday, January 10
Saturday, January 11
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 is hidden deep in the glow of sunset.
Venus (magnitude –4 or –3) is dropping to the southwest horizon after sunset. It passes through inferior conjunction, 5° north of the Sun, on January 11th. Seen with optical aid it's a hairline crescent a mere 2% sunlit or less. But it's big! —about 60 arcseconds in diameter.
The best time to observe Venus in a telescope is well before sunset. Hide the Sun behind a building so you can't accidentally sweep it into your view. Read our article See Venus's Thin Crescent.
Mars (magnitude +0.8, in Virgo) rises around midnight. It's highest in the south before the first light of dawn, with Spica to its lower left. In a telescope Mars is still quite small, 7 arcseconds in diameter.
Jupiter (magnitude –2.7, in central Gemini) is at opposition on January 5th: opposite the Sun, rising at sunset and highest around midnight, and shining its brightest and closest of the year. It blazes in the east during evening, the brightest point in the sky. Castor and Pollux are to its left, and fainter Gamma Geminorum is a similar distance to its right.
In a telescope Jupiter remains 47 arcseconds wide through the first half of January. See lots about observing Jupiter in the January Sky & Telescope.
Saturn (magnitude +0.6, in Libra) is well up the southeast as dawn begins to brighten. Look for it far to the lower left of Mars and Spica, and far below brighter Arcturus.
Uranus (magnitude 5.8, in Pisces) is still high in the south-southwest right after dark.
Neptune (magnitude 7.9, in Aquarius) is getting low in the southwest after dark. Finder charts for Uranus and Neptune.
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 (UT, UTC, or GMT) minus 5 hours.
Like This Week's Sky at a Glance? Watch our SkyWeek TV short, also playing on PBS.
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.