This Week’s Sky at a Glance, November 21–29

Some daily sky sights among the ever-changing Moon, planets, and stars.

Moon and Mars in twilight, Nov. 24-26, 2014

Track the growth of the waxing crescent Moon as it passes Mars in the evening twilight. (These scenes are drawn for the middle of North America. European observers: move each Moon symbol a quarter of the way toward the one for the previous date. For clarity, the Moon is shown three times its actual apparent size.)

Friday, November 21

Does night already seem to be falling about as early as it ever will? You're right! We're still a whole month away from the winter solstice — but the Sun sets its earliest around December 7th, and right now it already sets within only about 5 minutes of that time (if you're near latitude 40° north). A surprising result of this: The Sun actually sets a trace earlier on Thanksgiving than on Christmas, even though Christmas is around solstice time.

This offset is made up for by the opposite happening at sunrise: the Sun doesn't come up its latest for the year until January 7th. You can blame the tilt of Earth's axis and the eccentricity of its orbit.

Saturday, November 22

High in the northeast, the W pattern of Cassiopeia stands on end as early as 6 p.m. now. Whenever this happens, the dim handle of the Little Dipper (far lower left of Cassiopeia) extends straight left from Polaris.

Algol in Perseus should be at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 11:50 p.m. EST (8:50 p.m. PST). Algol takes several hours to fade beforehand and to rebrighten after.

New Moon (exact at 7:32 a.m. EST).

Sunday, November 23

We're two thirds of the way through fall, so Capella shines well up in the northeast as soon as the stars come out. As night grows darker, look to its right by about three fists at arm's length for the frosty little Pleiades cluster, the size of your fingertip at arm's length.

Monday, November 24

With the waxing Moon still thin, plan some deep-sky observing while the evenings are still dark! Around the spilling water bucket of Aquarius are the Helix Nebula, the R Aquarii nebula, a little-known globular cluster, and some galaxies in the 11th- and 12th-magnitude range — as told in depth by Sue French in her Deep-Sky Wonders column in the November Sky & Telescope, page 56, with map and photos.

Tuesday, November 25

Look for Mars left of the crescent Moon in twilight, as shown above.

Algol is at minimum light for a couple hours centered on 8:39 p.m. EST.

Wednesday, November 26

The Moon now shines near Alpha and Beta Capricorni at nightfall, as shown above (depending on your location). Both Alpha and Beta Cap are wide double stars for binoculars. Alpha is easy to resolve; Beta is somewhat less so with its narrower separation and greater brightness difference.

It's still Summer Triangle season. The Triangle's brightest star is Vega, well up in the west-northwest after dinnertime. The brightest star above Vega is Deneb. The Triangle's third star, Altair, is farther to Vega's left.

Thursday, November 27

Whenever Fomalhaut is "southing" (crossing the meridian due south, which it does around 6 or 7 p.m. this week), you know that the first stars of Orion are just about to rise in the east, and the Pointers of the Big Dipper stand directly below Polaris (if you're in the world's mid-northern latitudes).

Friday, November 28

First-quarter Moon (exactly so at 5:06 a.m. Saturday morning EST). Look for Fomalhaut far to its lower left, and Enif, the nose of Pegasus, almost as far to the Moon's upper right.

Saturday, November 29

The Moon stands high in the south soon after nightfall, with the western side of the Great Square of Pegasus pointing down at it from above.

By 10 or 11 p.m. now (depending in how far east or west you live in your time zone), the dim Little Dipper hangs straight down from Polaris.

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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).

Pocket Sky Atlas

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — which may sound like a lot, but it's still less than one per square degree on the sky. Also plotted are many hundreds of telescopic galaxies, star clusters, and nebulae.

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 fairly heavy and expensive). 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

Jupiter with Red Spot on Nov. 8, 2014

Jupiter is always changing. Here it is on November 8th. . .

Jupiter on Nov. 18, 2014

. . . and 10 days later. South here is up. I've never seen the Great Red Spot looking like this: with a dark rim looping up from the Red Spot Hollow and curling all the way around the Red Spot's following end. Note how much its shape changed in 10 days. South of the Red Spot, in the South Temperate Belt, are gray-rimmed Red Spot Junior (Oval BA) and a run of smaller white ovals. Images by Christopher Go.

Mercury is disappearing deep into the glow of sunrise.

Venus is still buried deep the sunset.

Mars (magnitude 1.0) remains visible in the southwest during and after twilight. It sets around 8 p.m. local time.

Jupiter (magnitude –2.2, in western Leo) rises in the east-northeast around 10 or 11 p.m. About 45 minutes later, fainter Regulus (magnitude +1.4) rises below it. By dawn they shine high in the south, with Regulus now to Jupiter's left.

Saturn is hidden behind the glare of the Sun.

Uranus (magnitude 5.7, in Pisces) and Neptune (magnitude 7.9, in Aquarius) are high in the southeast and south, respectively, right after dark. They move westward as the evening progresses. You'll need binoculars or a small telescope and our finder charts for Uranus and Neptune.

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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.


"I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."

— Isaac Newton, 1642–1727

(From the Memoirs of the Life, Writings, and Discoveries of Sir Isaac Newton, David Brewster, 1855)