This Week's Sky at a Glance
Some night sky sights for January 18 26
Friday, January 18
Saturday, January 19
Sunday, January 20
Monday, January 21
Although they look close together, the Moon is only 1.3 light-seconds distant from Earth, while Jupiter is 1,700 times farther away at a distance of 37 light-minutes. See our article Jupiter Dances with the Moon.
Tuesday, January 22
Look below the Moon for Orion, and far below Orion for brilliant Sirius.
Wednesday, January 23
Thursday, January 24
Friday, January 25
Sirius is the brightest star in the night sky — and are you far enough south to see the second brightest, Canopus? In one of the many interesting coincidences that devoted skywatchers know about, Canopus lies almost due south of Sirius: by 36°. That's far enough south that it never appears above your horizon unless you're below latitude 37° N (southern Virginia, southern Missouri, central California). And there, you'll need a flat south horizon. Canopus transits the sky's north-south meridian just 21 minutes before Sirius does.
When to look? Canopus is at its highest point when Beta Canis Majoris — Mirzim, the star a few finger-widths to the right of Sirius — is at its highest point crossing the meridian. Look straight down from Mirzim then.
Saturday, January 26
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 guide to astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).
Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope effectively.
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 certainly not on mounts and tripods that are less than top-quality mechanically (able to point with better than 0.2° repeatability). 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 in the glare of the Sun.
Venus (magnitude –3.9) is just above the southeast horizon about 30 minutes before your local sunrise. It's lower each morning. How much longer can you keep it in view?
Mars (magnitude +1.2) still glimmers very low in the west-southwest in the fading glow of sunset. Don't confuse it with Fomalhaut far to its left. (On January 24th Mars is at perihelion, its closest to the Sun in its orbit.)
Saturn (magnitude +0.6, in Libra) rises in the east-southeast around 1 a.m. local time. By the beginning of dawn it's fairly high in the south — more or less between Spica, far to its right or upper right, and Antares farther to Saturn's lower left.
Uranus (magnitude 5.8, in Pisces) is still in view in the southwest right after dark. Finder chart.
Neptune (magnitude 8.0, in Aquarius) is disappearing into the sunset.
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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