This Week's Sky at a Glance, November 15 – 24

FRIDAY, NOVEMBER 15

■ Mercury is still as high and bright as it will be during its current low, mediocre evening apparition. As twilight fades, see if you can catch Mercury nearly two fists to the lower right of Venus in the southwest, as shown below. Mercury shines at magnitude –0.2 compared to Venus's mag –4.1. That means Mercury is 36 times fainter, not even counting its loss of light to atmospheric extinction so low. Mercury sets before twilight is over.

The telescopic seeing so low will be awful, but take this as a challenge: Get Mercury in a telescope as early in twilight as you can, then switch to high power. Its tiny globe is only 7 arcseconds wide, but can you resolve that the planet is now slightly more than half lit? It will become exactly half lit (like a quarter Moon) on November 21st, just six days from now.

■ Full Moon (exact at 4:29 p.m. EST). How soon after the Sun sets in the west-southwest this evening can you see the Moon rising in the east-northeast?

Once night arrives, look for the delicate Pleiades a few degrees to the Moon's lower left (for North America). Cover the Moon with your finger to block its dazzling glare.

Much farther lower left of the Moon, once night is well under way, you'll find orange Aldebaran and brighter Jupiter.

■ Much later in the night the Moon occults some of the Pleiades. However, the full Moon's brilliance and its nearly complete lack of a dark limb will make these events for telescopes only. And use high power to get most of the Moon out of the eyepiece. For details see Bob King's Watch the Moon Occult the Pleiades, Spica too!

Below is the approximate scene by early dawn Saturday and Sunday. Dawn comes late at this time of year; you may already be awake.

SATURDAY, NOVEMBER 16

■ The Leonid meteor shower should peak late tonight, but the brilliant moonlight will interfere. And the Leonids have been weak to begin with for the last decade or more.

■ Uranus is at opposition.

SUNDAY, NOVEMBER 17

■ By about 8 or 9 p.m. now Orion is clearing the eastern horizon (depending on how far east or west you live in your time zone). High above Orion shine Jupiter and, to Jupiter's right or upper right, orange Aldebaran. Above Aldebaran are the Pleiades, 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 p.m. No matter where they are, Sirius always follows two hours behind Orion. Or equivalently, one month behind Orion.

MONDAY, NOVEMBER 18

■ The waning gibbous Moon rises within an hour after dark this evening. Watch for it to come up lower left of Jupiter. Another couple hours and Castor and Pollux will stand in good view to the Moon's lower left, while Orion sparkles about three times farther to the Moon's right.

By dawn on Tuesday the 19th, the scene has twisted around clockwise and the Moon has edged closer to Castor and Pollux as shown below.

TUESDAY, NOVEMBER 19

■ Now the waning gibbous Moon rises about two hours after nightfall, forming a roughly straight line with Castor and Pollux close above it (for North America). By dawn on the 20th, the scene has again twisted around and the Moon has moved far off the Castor-Pollux line to shine between Pollux and similarly-colored Mars, as shown above.

WEDNESDAY, NOVEMBER 20

■ When Saturn and Fomalhaut are "southing" (crossing the meridian due south, which they do simultaneously this week around 7 p.m.), the Pointers of the Big Dipper also stand straight upright on the opposite side of the sky: low due north, straight down below Polaris.

A little more than an hour after that, the first stars of Orion start rising above the east horizon (for skywatchers in the world's mid-northern latitudes). Starting with the rise of Bellatrix, it takes Orion's main figure a little more than an hour to clear the horizon.

■ The waning gibbous Moon rises around 9 or 10 p.m., with ever-brightening Mars about 4° to its upper right.

THURSDAY, NOVEMBER 21

■ Vega is the brightest star high in the west-northwest these evenings. Its little constellation Lyra extends to its left, pointing to Altair, currently the brightest star in the west-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 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.

■ And a more famous double star from Vega: Continue somewhat farther leftward from Lyra's pattern, and there, about a fist and a half from Vega, is 3rd-magnitude Albireo, the beak of Cygnus. This is one of the finest and most colorful double stars for small telescopes: Pale gold and bluish, magnitudes 3.2 and 4.7, separation 35 arcseconds.

Farther on in roughly the same direction you come to 3rd-magnitude Tarazed and, just past it, Altair.

FRIDAY, NOVEMBER 22

■ Last-quarter Moon (exact at 8:28 p.m. EST). The Moon rises around 11 or midnight, in Leo. Regulus shines a few degrees upper right of it. The Sickle of Leo extends about a fist-width or a little more to the upper left from Regulus. They all climb together through the rest of the night.

■ Algol should be at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 11:25 p.m. EST; 8:25 p.m. PST. Algol takes several additional hours to fade and to rebrighten. Comparison-star chart.

SATURDAY, NOVEMBER 23

■ The bowl of the Little Dipper swings down in the evening at this time of year, left or lower left of Polaris in the north. Most of the Little Dipper is dim. Look as late as about 11 p.m., and it hangs straight down from Polaris.

SUNDAY, NOVEMBER 24

■ Take advantage of the darkness these moonless evenings! A small to medium telescope is all you need to explore Ken Hewett-White's five Bonus Double Stars near the little Hockey Stick asterism in Andromeda, now high overhead. These are unnamed bonuses to the brighter pair Struve 14, orange and pale bluish, at the tip of the Hockey Stick.

The five lie in the large, very loose open cluster NGC 752. See Ken's "Suburban Stargazer" story, chart, and photos in the November Sky & Telescope, starting on page 55.

This Week's Planet Roundup

Mercury (magnitude –0.3) is fairly deep in the afterglow of sunset, even though it remains at its best for this low, mediocre apparition for most of the week. Try for it with binoculars or a wide-field telescope about 30 minutes after sunset; look 18° to the lower right of Venus. See the November 15th graphic, and the Mercury's phase challenge, at the top of this page.

Venus (magnitude –4.1) gleams in the southwest in evening twilight, higher every week now. It doesn't set until about an hour after full dark.

Mars (about magnitude –0.3, in Cancer east of Gemini) rises in the east-northeast around 9 p.m. — at almost the precise point where Jupiter rose just over 3 hours earlier. Mars shows best in a telescope when very high toward the south in the hour or two before the start of dawn. It's 45° east along the ecliptic from Jupiter.

Mars has enlarged to about 10.5 arcseconds in apparent diameter. It's on its way to a relatively distant opposition in January, when it will reach a diameter of 14.5 arcseconds.

Jupiter (magnitude –2.8, in Taurus) rises in the east-northeast before the end of twilight. It's at its best high toward the south by about midnight. Jupiter is now a good 47 arcseconds wide in a telescope, basically as large as the 48-arcsecond width it will attain for the weeks around its December 7th opposition.

Saturn, magnitude +0.9 in Aquarius, glows highest in the south in early evening. Don't confuse it with Fomalhaut twinkling two fists below it.

Uranus (magnitude 5.6, at the Taurus-Aries border) is well up in the east after dark about 7° from the Pleiades. You'll need a good finder chart to tell it from its surrounding faint stars; charts are in the November Sky & Telescope, page 49.

Neptune (tougher at magnitude 7.8, under the Circlet of Pisces) is high in the south after dark, 15° east of Saturn. Again you'll need a proper finder chart.

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.

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. Both show all 30,000 stars to magnitude 7.6, and 1,500 deep-sky targets — star clusters, nebulae, and galaxies — to search out among them.

Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many, as well as many more deep-sky objects. It's currently out of print, but maybe you can find one used. The next up, once you know your way around well, are the even larger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to mag 9.75) and correspondingly more deep-sky objects. 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. The pinnacle for total astro-geeks is the new Annals of the Deep Sky series, currently at 11 volumes as it works its way forward through the constellations alphabetically. So far it's up to H.

Can computerized telescopes replace charts? Not for beginners I don't think, and not for scopes 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 how to explore the sky. 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."

If you do get a computerized scope, make sure that its drives can be disengaged so you can swing it around and point it readily by hand when you want to, rather than only slowly by the electric motors (which eat batteries).

However, finding faint telescopic objects the old-fashioned way with charts isn't simple either. Do learn the essential tricks at How to Use a Star Chart with a Telescope.

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.

"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