This Week’s Sky at a Glance, November 12 – 20 – Sky & Telescope

Nova Cassiopeiae 2021 was still about magnitude 8.2 as of November 11th, almost 8 months after it erupted. Charts and comparison stars.


■ This evening the Moon shines left of Jupiter and Saturn, forming a gentle curving arc with them.

■ For binoculars: The largest asteroid, 1 Ceres, is currently passing just above the little tilted House asterism in the Hyades, located a finger-width at arm’s length west of Aldebaran. At magnitude 7.3, Ceres is not too hard in binoculars. Its path is mapped in the November Sky & Telescope, page 50 (where the date ticks are for 0:00 Universal time, which falls on the evening of the previous date for North America.)

Aldebaran and the Hyades are well up in the east by 9 p.m. standard time, and better by 10. Robert C. Victor points out to us that tonight, “Ceres is passing north of the naked-eye pair Theta-1 and Theta-2 Tauri,” the brightest stars of the House. “These stars are 5.5 arcminutes apart, magnitudes 3.8 and 3.4. The 5.0-mag. star 75 Tauri [the House’s pointed roof] is 24 arcminutes north of Theta-1. On November 12, Ceres passes within 9 arcminutes north of 75 Tauri. This conjunction takes place in the afternoon for North America, with Ceres moving west by 12 arcminutes per day.”

You’ll need a low east-northeast horizon to try for Mercury departing and Mars emerging in the dawn. Bring those binoculars! Day by day, Mercury will sink lower and Mars will creep just a little higher. Spica points the way.


■ Look very high above the Moon for the Great Square of Pegasus. When you face south, the Square is level like a box by about 7 p.m. It’s somewhat larger than your fist at arm’s length. Its stars are 2nd and 3rd magnitude.

A sky landmark to remember: The west (right-hand) side of the Great Square points far down almost to 1st-magnitude Fomalhaut. The east side of the Square points down toward Beta Ceti not as directly, and not as far.

■ Vega is the brightest star high in the west on November evenings. Its little constellation Lyra extends to its left, pointing as always to Altair, which is currently the brightest star in the southwest.

Three of Lyra’s stars near Vega are interesting doubles. Barely above Vega is 4th-magnitude Epsilon Lyrae, the Double-Double. Epsilon forms one corner of a roughly equilateral triangle with Vega and Zeta Lyrae. The triangle is less than 2° on a side, hardly the width of your thumb at arm’s length.

Binoculars easily resolve Epsilon. And a 4-inch telescope at 100× or more should, during good seeing, resolve each of Epsilon’s wide components into a tight pair.

Zeta is also a double star for binoculars. It’s much closer and tougher, but is plainly resolved in a small telescope.

And Delta Lyrae, upper left of Zeta by a similar distance, is a much wider and easier binocular pair. Its stars are reddish orange and blue.


■ In early evening Altair shines in the southwest about halfway up the sky, three or four fists left of brighter Vega. Altair is the only bright star in that area. It’s the eye of Aquila, the Eagle.

Just upper right of Altair, by a finger’s width at arm’s length, is 3rd-magnitude Tarazed. Down from there runs Aquila’s dim backbone, along the Milky Way when the sky is dark and moonless.

This arrangement reminds me of another Summer Triangle bird, Cygnus the Swan, whose long neck and backbone also run along the Milky Way. Cygnus currently flies high to Aquila’s upper right.

■ Algol in Perseus should be at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours tonight centered on 12:36 a.m. EST (9:36 p.m. PST). Algol takes several additional hours to fade and to rebrighten.


■ By about 8 or 9 p.m. Orion is clearing the eastern horizon (depending on how far east or west you live in your time zone). High above Orion shines orange Aldebaran. Above Aldebaran is the little Pleiades cluster, the size of your fingertip at arm’s length.

Far left of Aldebaran and the Pleiades shines bright Capella.

Down below Orion, Sirius rises around 10 or 11 p.m. No matter where they are, Sirius always follows two hours behind Orion. Or equivalently, one month behind Orion.


■ Around 9 or 10 p.m., depending on where you live, zero-magnitude Capella rises exactly as high in the northeast as zero-magnitude Vega has sunk in the west-northwest. The season is tipping to cold.

■ The Leonid meteor shower, typically weak to begin with, should peak late tonight but will be largely washed out by the light of the waxing gibbous Moon. If you want to try, however, you do have about an hour of moonless darkness between moonset and the beginning of dawn (for the mid-latitudes of North America).


■ Fomalhaut is the 1st-magnitude star twinkling about two fists at arm’s length lower left of Jupiter. Whenever Fomalhaut is “southing” (crossing the meridian due south, which it does around 7 p.m. this week), turn around: The Pointers of the Big Dipper stand upright low due north, straight below Polaris.

Also at this time, turn east: The first stars of Orion are soon to rise above the eastern true horizon (for the world’s mid-northern latitudes). Starting with the rising of Betelgeuse, it takes Orion’s main figure about an hour to completely clear the horizon.

■ Algol should be at minimum brightness for about two hours centered on 9:25 p.m. EST.


■ Full Moon. A weird, borderline partial-total eclipse of the Moon awaits you in the early-morning hours of Friday the 19th if you’re in North or Central America, in the middle of the night for parts of the Pacific Ocean, and on the evening of Friday the 19th local date for Australia and the Far East.

Mid-eclipse is at 9:03 November 19 UT (4:03 a.m. on the 19th EST; 1:03 a.m. on the 19th PST; 11:03 p.m. on the 18th Hawaii time). The partial phase of the eclipse begins 1 hour 15 minutes before that time and ends 1 hour 15 minutes after.

For more see the article, map, and timetable in the November Sky & Telescope, starting on page 48.

Cloudy where you are? Are you on the wrong side of Earth? The Virtual Telescope Project starts a livestream at 7:00 UT Nov. 19 (2 a.m. EST).


■ The Moon, just past full, shines in early evening almost precisely halfway between the Pleiades above it and Aldebaran below it, depending on your location. The Moon is exactly in line between them around nightfall for much of North America’s East Coast. Holding up a ruler or a pencil to the sky, how precisely can you time the Moon’s passage across this line? To mark the center of the Pleiades, pick Alcyone, the cluster’s brightest star.

Watch the Moon move farther east of this line hour by hour through the night, as it creeps eternally eastward in its orbit around Earth.


■ Venus and Jupiter, the two brightest celestial objects after the Sun and the Moon, blaze during and after twilight a little less far apart every week. Venus is low in the in the southwest; Jupiter is high in the south. Saturn glows less than halfway from Jupiter to Venus.

Watch the line shorten for the next month.



This Week’s Planet Roundup

Mercury, magnitude –1.0, is on the way out, dropping lower into the sunrise glow every morning. Have a last try for Mercury — and a very early try for Mars nearby using binoculars on the morning of the 13th. Start from Spica higher above, as shown at the top of this page.

To find Spica? It’s about three fists at arm’s length lower left of brighter Arcturus.

Venus, a very brilliant magnitude –4.7, shines in the southwest during and after twilight. This week it’s crossing the vastly fainter Sagittarius Teapot. Venus doesn’t set now until more than an hour after dark. It will continue to shine just a little higher and brighter through the end of November.

Mars, a mere magnitude +1.6, is emerging deep in the sunrise to begin its next apparition, which will last almost two years. (Mars’s opposition, the near-midpoint of the apparition, will come on the night of December 7, 2022 when, by coincidence, the Moon, necessarily full, will occult it for much of North America!)

Mars begins this week in the vicinity of Mercury even lower in the dawn, as shown at the top of this page. Bring binoculars.

Jupiter and Saturn continue to shine in the south during evening, 16° apart in Capricornus. Jupiter is the bright one at magnitude –2.4. Saturn, to its lower right, is mag +0.6. Saturn is the first to set, around 9 or 10 p.m. Jupiter follows it down about an hour later.

Look 22° (two fists at arm’s length) lower left of Jupiter for Fomalhaut, the Autumn Star, magnitude +1.2.

Uranus (magnitude 5.7, in southern Aries) is well up in the east by 7 p.m. See Bob King’s Uranus Queues Up for Opposition.

Neptune (magnitude 7.9, at the Aquarius-Pisces border) is already high in the southeast at nightfall.

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 (also called UT, UTC, or GMT) minus 5 hours.

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 magazine of the American Astronomical Society.

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 by red flashlight. Sample charts. More about the current 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 a Star Chart with a Telescope.

You’ll also want a good deep-sky guidebook, such as the big Night Sky Observer’s Guide set 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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