■ Bright Jupiter and Saturn are almost as close together now (2.6° apart) as modest, 3rd-magnitude Alpha and Beta Capricorni above them (2.3° apart), as shown below. Wait for full dark to catch the faint stars.

Jupiter and Saturn continue in the southwest during and after twilight. This evening they're 2.6° apart. Above them all week, once the sky grows dark, are the 3rd-magnitude binocular double stars Alpha and Beta Capricorni. Alpha is the wider one; can you split it with your bare eyes? Binoculars do it easily. The stars of Beta are only half as far apart and quite unequal, making them harder to separate with binocs.


■ This evening the bright, almost-full Moon shines between Aldebaran below it and the Pleiades above it. Some 30° off to their left, bright Capella looks on. For more about Capella and its surroundings, see this week's Meet Capella, the Goat Star.

Right of Capella by 3° to 5°, look for the narrow, elongated triangle of 3rd and 4th-magnitude stars called "The Kids." Maybe the Goat Star is the mommy goat.


■ Full Moon (exactly full at 4:30 a.m. Monday morning EST.) The Moon is between Aldebaran below it and the Pleiades above it. Aldebaran is easier to see through the moonlight than the Pleiades are.

■ A penumbral eclipse of the Moon happens early Monday morning for North America. The Moon's north side will skim through the penumbra, the pale outer fringe, of Earth shadow. The Moon will be deepest into the penumbra at mideclipse, at 4:43 a.m. Monday morning EST; 1:43 a.m. PST; 9:43 UT.

You may see a trace of shading on the Moon as much as 45 minutes before and after that time. When can you first and last detect a definite sign of this?


■ This evening the Moon shines about midway between Aldebaran (Alpha Tauri) to its right and El Nath (Beta Tauri) to its left (for North America).


■ The Moon tonight is in the middle of the gigantic Winter Hexagon. By 9 p.m. the Moon is high enough for you to easily see Orion to its lower right, with orange Betelgeuse and white Rigel; and Gemini with Castor and Pollux to the Moon's lower left.

Upper left of the Moon is Auriga with bright Capella. Upper right of the Moon spot orange Aldebaran, the Moon's companion yesterday and the day before.


■ This evening the waning gibbous Moon rises about a half hour after the end of twilight. It's in the middle of Gemini between the stick figures of the Twins (hard to see through the moonlight). Once the Moon is well up, look for Castor to its left and Pollux below Castor.


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


■ Jupiter and Saturn, now 1.8° apart, continue closing toward their record-breaking conjunction 0.1° apart on December 21st.

Getting closer... Jupiter and Saturn now appear closer together than Alpha and Beta Capricorni above them.


■ 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, which is made of the brightest stars of Cygnus. At nightfall the shaft of the cross extends lower left from Deneb. By about 10 p.m., it plants itself more or less upright on the northwest horizon.

■ The waning gibbous Moon rises in the east-northeast around 9 or 10 p.m., close to the Sickle of Leo. By dawn on Sunday morning the 6th the Moon has moved far over to the high southwest, as shown below.

Moon and Sickle of Leo at dawn, Dec. 6, 2020
As dawn begins to break on Monday the 6th, the waning gibbous Moon forms a flattish, isosceles triangle with Regulus and orange Algieba (Gamma Leonis) for skywatchers in North America.

This Week's Planet Roundup

Mercury, magnitude –0.8 but very low in the eastern dawn, is sinking farther down and away from sight day by day.

Venus (magnitude –3.9, in Libra) continues to shine in the eastern dawn as the bright "Morning Star." It's getting a little lower every week.

Far to Venus's upper left shines Arcturus, pale yellow-orange.

Look for fainter Spica about half as far to Venus's upper right.

Mars (about magnitude –1.1, in Pisces) shines bright yellow in the east-southeast at dusk. Mars is fading and shrinking into the distance, but it's still 15 or 14 arcseconds wide in a telescope, big enough to show surface detail during steady seeing. Widespread yellow dust storm activity is under way, as seen in the recent image below.

Mars on November 21st, imaged by Christopher Go. South is up. The striking dark diagonal streak at left is part of Sinus Sabaeus reframed by dust clouds. In the upper center "the region around Mare Erythaeum is covered with dust," writes Go. "Even Sinus Meridiani [lower left of center] is shrouded in dust. The eastern part of Sinus Sabeaus is dust free, but the area attached to Meridiani has dust going through! This region of Mars is unrecognizable!"

To get a (dustless) map of the side of Mars facing Earth at the date and time you observe, you can use our Mars Profiler. The map there is square; remember to mentally wrap it onto the side of a globe. (Features near the map's edges become very foreshortened.)

Jupiter and Saturn (magnitudes –2.0 and +0.6, respectively) tilt ever farther down in the southwest during and after twilight. Look early. Jupiter is the bright one; Saturn is upper left of it. Watch their separation shrink from 2.6° to 1.9° this week (from November 27th to December 4th).

Don't expect a decent view in a telescope; we're wheeling around to the far side of our orbit from them, and also, the low-altitude seeing will be quite poor.

Jupiter and Saturn will pass just 0.1° apart at their conjunction on December 21st, low in the glow of sunset. The two giants have conjunctions about every 20 years — but this will be their closest one visible since March 4, 1226.

Uranus (magnitude 5.7, in Aries) is high in the east-southeast after nightfall, about 20° east (lower left) of Mars. Uranus is only 3.7 arcseconds wide, but that's enough to appear as a tiny fuzzy ball, not a point, at high power in even a smallish telescope with sharp optics.

And while you're there, find the 9th-magnitude asteroid 8 Flora about 10° south (lower right) of Uranus. See Bob King's Tiny Asteroid Flora and Mighty Uranus Team Up, with finder charts and more about both.

Neptune (magnitude 7.9, in Aquarius) is just as high but in the south in early evening. Neptune is 2.3 arcseconds wide, harder to resolve than Uranus except in very good seeing. Check in on all three of these faint targets when you're done with Mars. Or better yet before Mars, to save the bright night-vision killer for last! 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 minus 5 hours. (Universal Time is also known as UT, UTC, GMT, or Z time.)

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 magazine of astronomy.

Once you get a telescope, to put it to good use you'll need a 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 stars to magnitude 7.6.

Pocket Sky Atlas cover, Jumbo edition
The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and hundreds of telescopic galaxies, star clusters, and nebulae among them. Shown here is the Jumbo Edition, which is in hard covers and enlarged for easier reading outdoors at night. Sample charts. More about the recent new editions.

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 magnitude 9.75). And be sure to read how to use sky charts with a telescope.

You'll also want a good deep-sky guidebook, such as Sky Atlas 2000.0 Companion by Strong and Sinnott, or the bigger (and illustrated) Night Sky Observer's Guide by Kepple and Sanner.

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, meaning heavy and expensive. 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."

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

"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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mary beth

November 30, 2020 at 1:01 pm

Looking forward to the full moon tonight....I’ve always considered the full moon to be on the night when it rises as darkness falls. Very beautiful to watch it come up over Galveston Bay on the horizon. So big, so orange! Thankfully we have clear skies tonight and I will be able to see it. Hope everyone is enjoying the beautiful skies!

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November 30, 2020 at 2:41 pm

that is good mary beth. I had an excellent Thanksgiving Day, rain here today though, clearing out tomorrow and next few days it looks like. On Thanksgiving Day I enjoyed telescope views of the large sunspot AR2786 reported at and some other sites. It is 3-4x size of the Earth. Some family members also enjoyed the view of the Sun using a safe, glass white solar filter with #12 yellow filter. At that time there were 3 distinct sunspot active regions visible, AR2786, AR2785, AR2783.

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mary beth

November 30, 2020 at 10:07 pm

Hi Rod! Glad you had such a nice holiday! What an enjoyable way to spend the afternoon! Glad you are set up for safe viewing. is an interesting website. Does the sunspot activity change daily? In other words is that large spot still present?

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December 1, 2020 at 2:15 pm

mary beth, AR2786 is still there and another now rotating into view, AR2790. shows 5 active regions now. I have tracked the same large sunspot for nearly 38 days! 25+ days to complete one rotation around the Sun and then some more 🙂 If the sunspots are large and hold together (many break up and disappear quickly), it takes about 12-13 days to cross the disk of the Sun in the telescope view. You can see the Sun is spinning on an axis and is not a flat Sun that does not spin 🙂

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mary beth

December 3, 2020 at 4:50 pm

Thank you Rod. All very interesting, appreciate your explanation. Glad I asked! Also nice about your Mars/Double Star. You surely make good use of Stellarium!

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December 2, 2020 at 11:10 pm

FYI. I went out and viewed Mars tonight in Pisces between 1700-1800 EST, before the waning gibbous Moon rose tonight using my 90-mm refractor. Mars at 129x and 200x views and some 14 arcsecond size still shows some surface details. Mars was within 6-7 arcminute of a double star, HIP4978. Mars about 0.656 au, HIP4978 close to 30 million au or about 471 ly distance. Very interesting to see the planet and faint star in the same field of view. Mars about 1854x brighter (HIP4978 some 7.10 or so magnitude). At 200x the double star showed a hint of a double. Stellarium shows 1.51 arcsecond, SIMBAD portal info shows 1.4 arcsecond apart. Much fun watching Mars pass near a fainter, double star that was immensely farther away from my telescope than the planet 🙂

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