Sky at a Glance | January 1st, 2010

Some daily events in the changing sky for December 31 – January 9.

Thursday, December 31

  • Full Moon (exact at 2:13 p.m. EST), with the Moon in Gemini. This is the second full Moon of the calendar month, often called a "Blue Moon"; see Kelly Beatty's blog post. The Moon is near its perigee, so it will be a trace bigger and brighter than usual.

  • A very slight partial lunar eclipse occurs for Europe, Africa, Asia, and parts of Australia, from 18:52 to 19:54 Universal Time (GMT) on this date. Details.

  • The New Year's celebration tonight will be especially meaningful; it's the end of the 00s, pronounced "the Uh-ohs," the best name I've heard for this awful decade. After the whooping at midnight, step out into the silent night under the bright Moon and stars. Face south. Far below the Moon is brilliant Sirius, the brightest star in the sky. To Sirius's upper right stands Orion, and to its upper left shines Procyon. Now turn east-southeast. There Mars shines brightly, with Regulus positioned below it. What future may these cryptic signs foretell?

    Looking east around 9 p.m.
    Watch the bright Moon make its way down to Mars and Regulus night by night. (The Moon is plotted for North America; in Europe, move each Moon symbol a quarter for the way toward the one for the previous date.)

    Friday, January 1

  • The Moon, barely past full, blazes in the east this evening with Pollux and Castor glimmering above it, as shown here.

  • After dinner, it's Orion-Stack time. That is, Orion and some of his best-known companions form a big vertical stack in the southeast (if you live in the world's mid-northern latitudes).

    Start with Orion himself, well to the right of the Moon. In his middle, the three stars of Orion's Belt are stacked nearly vertically. The Belt points up toward orange Aldebaran amid the dim Hyades, about two fist-widths at arm's length above. Poised higher over Aldebaran is the little Pleiades cluster. In the other direction, Orion's Belt points almost straight down to bright Sirius on the rise in Canis Major, about two fists below.

    Saturday, January 2

  • The Moon rises early this evening with Mars shining about 7° to its left (for North America), as shown here. They cross the sky as a pair all night.

  • The annual Quadrantid meteor shower may be active after midnight tonight, but the bright moonlight will be a serious hindrance.

  • Earth is at perihelion, its closest to the Sun for the year (one part in 30 closer than at aphelion in July).

    Sunday, January 3

  • The latest sunrise of the year comes on Monday morning, if you live near latitude 40° north. The earliest sunset was on December 7th.

    Monday, January 4

  • If you're out with a telescope in the early-morning hours of Tuesday or Wednesday, you'll find Saturn's largest moon, Titan, about four ring-lengths to Saturn's east. A 6-inch scope will begin to show the orange color of its smoggy atmosphere. A guide to identifying other Saturnian satellites often visible in amateur scopes is in the January Sky & Telescope, page 51.

    Tuesday, January 5

  • Around 11 or so tonight (depending on where you live in your time zone) the waning Moon rises in the east — with Saturn glowing pale yellow at its left. They'll be far below bright Mars.

    Wednesday, January 6

  • Auriga, high overhead these nights, is one of the brightest constellations, but how well do you know its telescopic depths? Tour the rich field right around its little Leaping Minnow asterism with Sue French's "Deep-Sky Wonders" article and chart in the January Sky & Telescope, page 65.

    Thursday, January 7

  • Last-quarter Moon (exact at 5:39 a.m. EST).

    Friday, January 8

  • If you want to observe the deep-sky depths of Orion at their highest and best — through the least amount of atmosphere and light pollution — you now have to wait up until only about 10 p.m. for Orion to get there.

    Saturday, January 9

  • This is the coldest time of the year — when the dim Little Dipper hangs straight down from Polaris after dinnertime, as if (per Leslie Peltier) from a nail on the north wall of the sky. This is also when the Northern Cross of Cygnus stands planted upright on the northwest horizon (as seen from mid-northern latitudes).


    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).

    Pocket Sky Atlas
    The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — which may sound like a lot, but that's less than one star in an entire telescopic field of view, on average. By comparison, Sky Atlas 2000.0 plots 81,312 stars to magnitude 8.5, typically one or two stars per telescopic field. Both atlases include many hundreds of deep-sky targets — galaxies, star clusters, and nebulae — to hunt among the stars.
    Sky & Telescope
    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

    Just when Jupiter is becoming low, distant, and harder to observe well telescopically, things are getting interesting! The South Equatorial Belt has faded to the point that it's almost gone, especially its southern half. And the Great Red Spot, now floating free with barely a trace of the Red Spot Hollow north of it, seems to have darkened.


    Christopher Go took these stacked-video images 19 minutes apart on December 30th, during "surprisingly good" seeing in twilight. The System II central-meridian longitude was 146° and 157°, respectively. South is up.


    Mercury and Venus are hidden in the glare of the Sun.

    Mars (a bright magnitude –0.8, in Leo) rises in the east-northeast around 7 or 8 p.m. local time, far below Castor and Pollux and a bit to the left. About an hour later, dimmer Regulus rises about a fist-width beneath it. By 2 or 3 a.m. Mars and Regulus are highest in the south, now lined up horizontally.

    In a telescope Mars is 13 arcseconds wide, nearly as large as it will become during this apparition. The north polar cap is in good view, bordered by a wide dark collar. Identify any other surface features you can make out by using the Mars map and observing guide in the December Sky & Telescope, page 57. Mars will pass closest to Earth on January 27th, when it will be 14.1 arcseconds wide.

    Jupiter (magnitude –2.1, at the Capricornus-Aquarius border) shines brightly in the southwest in twilight, but lower after dark. It sets around 8 p.m.

    Saturn (magnitude +0.9, in the head of Virgo) rises in the east around 11 or midnight and stands highest in the south before dawn. It's about 1° north of the 4th-magnitude star Eta Virginis. Saturn's rings are narrow, tilted 5° from edge-on to us, their maximum tilt until next August.

    Uranus (magnitude 5.9, just south of the Circlet of Pisces) is still pretty high to Jupiter's upper left just after dark.

    Neptune (magnitude 8.0, in Capricornus) lurks 2° or 3° lower right of Jupiter. To identify Uranus and Neptune with binoculars or a telescope, use our finder charts for these two 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.


    "Science is built up of facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house."
    — Henri Poincaré (1854–1912)


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