This Week's Sky at a Glance, November 24 – December 3

FRIDAY, NOVEMBER 24

■ The Moon shines near bright Jupiter this evening and tomorrow evening, as shown below. They are the two brightest things in the evening sky.

■ Algol in Perseus should be at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 7:44 p.m. EST Friday evening. Comparison-star chart.

At any random time you glance up at Algol, you have only a 1-in-30 chance of catching it at least 1 magnitude fainter than normal.

SATURDAY, NOVEMBER 25

■ As the stars come out, the Cassiopeia W stands on end (its fainter end) high in the northeast. Watch Cas turn around to become a flattened M, even higher in the north, by late evening.

SUNDAY, NOVEMBER 26

■ Full Moon, both this evening and tomorrow evening (because it's exactly full at 4:16 a.m. Monday morning EST, about halfway between).

This evening the glary Moon is just 1° or 2° from the delicate Pleiades (evening for North America). Bring binoculars.

MONDAY, NOVEMBER 27

■ Vega still shines brightly well up in the west-northwest after dark. The brightest star above it is Deneb, the head of the big Northern Cross formed by the brightest stars of Cygnus. At nightfall the shaft of the cross extends lower left from Deneb. By about 11 p.m., it plants itself more or less upright on the northwest horizon.

TUESDAY, NOVEMBER 28

■ The Moon, just past full, rises in the northeast in mid-twilight. Bright Capella, magnitude 0, sparkles about two fists to the Moon's upper left. As night deepens, watch for Beta Tauri, magnitude 1.6, to come into view only about a fifth as far to the Moon's upper right.

Moonrise tonight is special. That's because the Moon is just about as far north on the celestial sphere as you can ever possibly see it.

Why is this? First, the Moon is at the northernmost part of the ecliptic (which is at the Gemini-Taurus border); the ecliptic is inclined 23.4° with respect to the celestial equator.

Second, this evening the Moon stands 4.3° north of the ecliptic itself. That's less than 1° from the Moon's greatest possible ecliptic divergence; its orbit is inclined to the ecliptic by 5.14°.

That farthest-north side of the Moon's orbit precesses westward around the entire ecliptic with a period of 18.6 years (the "precession of the lunar nodes"). Tonight everything lines up; this year the north edges of both tilts nearly coincide, and tonight that is where the bright almost-full Moon stands.

So as twilight fades, note carefully where the Moon comes up over your horizon. You've probably never seen it rise that far north over your landscape and you might never again, at least when it's this close to full.

WEDNESDAY, NOVEMBER 29

■ As dawn begins to brighten Thursday morning, look east for Venus having a rather distant conjunction with Spica as shown below. They're 4¼° apart.

THURSDAY, NOVEMBER 30

■ Now that the Pleiades and (below them) Aldebaran are shining due east after dark, can Orion be far behind? Orion's entire iconic figure, formed by its seven brightest stars, takes about 1 hour 20 minutes to clear the eastern horizon. By 9 or 10 p.m. it's up in fine pre-winter view.

FRIDAY, DECEMBER 1

■ Two faint fuzzies naked-eye: The Andromeda Galaxy (M31) and the Perseus Double Cluster are two of the most famous deep-sky objects. They're both cataloged as 4th magnitude, and in a fairly good sky you can see each with the unaided eye. Binoculars make them easier. They're located only 22° apart, very high toward the east early these evenings — to the right of Cassiopeia and closer below Cassiopeia, respectively.

But they look rather different, the more so the darker your sky. See for yourself. You can find them by carefully using the all-sky constellation map in the center of the November or December Sky & Telescope.

SATURDAY, DECEMBER 2

■ The Summer Triangle is still pretty high right after dark. Vega, its brightest star, shines in the west-southwest. Deneb is about two fists above it. Altair is farther to Vega's left.

Above Altair by hardly more than a fist is little Delphinus, the Dolphin. Closer to Altair's upper right is smaller, fainter Sagitta, the Arrow. Binoculars help! Both constellations are about 5° long, so they will just fit into the field of view of most binoculars.

■ Polaris is, as always, due north. This is the time of year when the Little Dipper extends lower left from it in early evening. The only moderately bright stars of the Little Dipper are Polaris and Kochab, the star marking the lip of its bowl. Both are 2nd magnitude. They're 17° apart. How much of the rest of the faint Little Dipper can you make out between them, if any, given the quality of your sky?

By about 11 p.m. Kochab has swung to be straight under Polaris.

SUNDAY, DECEMBER 3

■ M31, the Andromeda Galaxy, passes your zenith sometime around 8 p.m. (if you live in the mid-northern latitudes). The exact time depends on how far east or west you live in your time zone. Binoculars will reveal the dim little glow of M31 just off the knee of the Andromeda constellation's stick figure. See the big evening constellation chart in the center of the December Sky & Telescope.

■ The waning Moon, nearly last quarter, rises around 10 or 11 p.m. in the east-southeast. As it gains height, catch an early sighting of Regulus, usually thought of as a star of late winter and spring, 3° or 4° to the Moon's right.

Regulus is the brightest star of the Sickle of Leo, which extends upper left from Regulus (the bottom of the Sickle's handle) by a fist at arm's length or a little more.

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This Week's Planet Roundup

Mercury, magnitude –0.4, glimmers very low in the southwest in early twilight. Look for it about 30 or 40 minutes after sunset. Binoculars help. Nothing else in that area is nearly as bright.

Venus, brilliant at magnitude –4.2, shines as the "Morning Star" in the southeast before and during dawn. It rises above the eastern horizon about 2 hours before dawn's first light.

This week Venus is passing Spica, which is only 1% as bright. On the morning of November 26th look for Spica 6° below Venus. They appear closest together on the morning of the 30th, with Spica now 4° to Venus's lower right.

Mars is out of sight behind the Sun.

Jupiter (magnitude –2.8, in Aries) is that bright white dot dominating the east in early evening. It stands highest in the south around 9 or 10 p.m. In a telescope Jupiter is still a big 48 or 47 arcseconds wide.

Saturn (magnitude +0.8, in dim Aquarius) glows yellowish high in the south at nightfall. Fomalhaut, similarly bright, twinkles almost two fists at arm's length to Saturn's lower left. Saturn declines toward the southwest as evening progresses and sets by about 11. So get your telescope on it early!

Uranus, magnitude 5.6 in Aries, shyly beckons 13° east of Jupiter. In a telescope at high power Uranus is a tiny but distinctly nonstellar ball, 3.8 arcseconds in diameter. Use the finder charts for Uranus in the November Sky & Telescope, pages 48-49.

Neptune, magnitude 7.8 at the Aquarius-Pisces border, is high in early evening 24° east of Saturn. Neptune is only 2.3 arcseconds wide: harder to resolve as a ball than Uranus, but definitely nonstellar at high power.

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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 and graphics that also depend on longitude (mainly Moon positions) are for North America.

Eastern Standard Time (EST) is Universal Time minus 5 hours. UT is also known as UTC, GMT, or Z time.

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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 a more detailed 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.

Once you get a telescope, to put it to good use you'll need a much more detailed, large-scale sky atlas (set of charts). The basic standard is the Pocket Sky Atlas (in either the original or Jumbo Edition), which shows all stars to magnitude 7.6.

Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many. The next up, once you know your way around, are the even larger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to mag 9.75). And read How to Use a Star Chart with a Telescope. It applies just as much to charts on your phone or tablet as to charts on paper.

You'll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham's Celestial Handbook. An impressive more modern one is the big Night Sky Observer's Guide set (2+ volumes) by Kepple and Sanner.

Can computerized telescopes replace charts? Not for beginners I don't think, especially not on mounts and tripods that are less than top-quality mechanically. Unless, that is, you prefer spending your time getting finicky technology to work rather than learning the sky. And 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."

But finding a faint telescopic object the old-fashioned way with charts isn't simple either. Learn the tricks at How to Use a Star Chart with a Telescope. 

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Audio sky tour. Out under the evening sky with your
earbuds in place, listen to Kelly Beatty's monthly
podcast tour of the naked-eye heavens above. It's free.

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"The dangers of not thinking clearly are much greater now than ever before. It's not that there's something new in our way of thinking, it's that credulous and confused thinking can be much more lethal in ways it was never before."
            — Carl Sagan, 1996

"Facts are stubborn things."
            — John Adams, 1770

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