Venus, Mars, Jupiter at dawn, Nov. 11, 2017
Before sunrise on Saturday the 11th, Jupiter is creeping up on Venus from below.

Friday, November 10

• The eclipsing variable star Algol in Perseus should be at its minimum brightness, magnitude 3.4 instead of its usual 2.3, for a couple hours centered on 7:45 p.m. Eastern Standard Time. At any random time you glance up at Algol, you have only a 1 in 30 chance of catching it at least a magnitude fainter than normal.

Regulus emerged from behind the crescent Moon's bright limb last July 25th as seen from Kuala Lumpur, Malaysia, where Shahrin Ahmad took a telescopic video.

• Plan for this one now: In broad daylight on Saturday morning the 11th, the Moon, just past last quarter, occults Regulus for much of North America in a blue sky. You'll need a telescope and very clear air. The star disappears on the Moon's bright limb and reappears from behind the dark limb. See the November Sky & Telescope, page 51. Map and local timetables.

Saturday, November 11

• Vega is the brightest star shining in the west in early evening. Its little constellation Lyra extends to the left. Somewhat farther left, about a fist and a half at arm's length from Vega, is 3rd-magnitude Albireo, the beak of Cygnus — a beautiful telescopic double star.

Sunday, November 12

• Orion is clearing the eastern horizon by 8 or 9 p.m. this week (depending on how far east or west you live in your time zone). His three-star belt is nearly vertical. 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.

Monday, November 13

• Around 7 or 8 p.m. this week, the Great Square of Pegasus stands in its level position very high toward the south. (It's straight overhead if you're as far south as Miami.) Its right (western) side points very far down toward Fomalhaut. Its eastern side points less directly toward Beta Ceti (also known as Deneb Kaitos or Diphda), not as far down.

Looking lower: If you have a very good view to a dark south horizon — and if you're not much farther north than roughly New York, Denver, or Madrid — picture an equilateral triangle with Fomalhaut and Beta Ceti as its top two corners. Near where the third corner would be is Alpha Phoenicis, or Ankaa, in the constellation Phoenix. It's magnitude 2.4, not very bright but the brightest thing in its area. It has a yellow-orange tint; binoculars help to check. Have you ever seen anything of the constellation Phoenix before?

Tuesday, November 14

• Once you've found Beta Ceti (see yesterday), you're on the way to the Silver Coin Galaxy, NGC 253 in Sculptor. It's 7° south of Beta Ceti, a little more than the width of a typical binocular's field of view. But you'll want a detailed chart to determine the exact position to examine among the faint foreground stars — such as the chart in Matt Wedel's Binocular Highlight column in the November Sky & Telescope, page 43.

The waning Moon at dawn passes Mars, Spica, Jupiter and Venus November 15-17, 2017.
The waning Moon passes Mars, Spica, Jupiter and Venus during dawn these mornings. (The Moon's position is exact for skywatchers in the middle of North America.)
 Saturn and Mercury in twilight, mid-November 2017
Not so easy! The visibility of faint objects in bright twilight is exaggerated here.

The galaxy is 7th magnitude but large and diffuse, so a really dark sky is a big help. Under excellent sky conditions, binoculars show it easily. It appears "obviously elongated, distinctly brighter in the western half," writes Wedel.

• As dawn begins on Wednesday morning the 15th, the waning crescent Moon forms a triangle with Mars to its upper right and Venus to its lower right, as shown here.

Wednesday, November 15

• As Thursday's dawn brightens, the very thin waning crescent Moon hangs about 6° above Jupiter (for North America) and 10° lower left of Spica, as shown here. Venus is 3° lower left of Jupiter. You'll find Mars 9° above Spica.

Thursday, November 16

• As dawn brightens on Friday the 17th, a hair-thin Moon (only about 24 hours from new for North America) hides about 4° left or lower left of Venus, as shown here. Bring binoculars and sharp eyes! Upper right of Venus is Jupiter.

Friday, November 17

• Two challenge planets! As twilight fades, look low in the southwest for Saturn and Mercury, as shown here. They're about a fist at arm's length apart. Binoculars help.

• With the Moon not yet back in the evening sky, take advantage of the dark nights to explore the galaxies inside the northwest corner of the Great Square of Pegasus — they're magnitudes 11 to 13 — using your 6-inch or larger scope and Sue French's Deep-Sky Wonders article, chart and photos in the November Sky & Telescope, page 55.

For a deeper challenge with a large scope, tackle the rich Abell 194 galaxy cluster in Cetus using Ken Hewitt-White's Going Deep column and photos on page 58.

Saturday, November 18

• Around 8 p.m., depending on where you are, zero-magnitude Capella rises exactly as high in the northeast as zero-magnitude Vega has sunk in the west-northwest. How accurately can you time this event? Astrolabe not required. . . but it might help.

• New Moon (exact at 6:42 a.m. EST).


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.

Pocket Sky Atlas, 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 above is the Jumbo Edition for easier reading in the night. Larger view. Sample chart.

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.

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, is 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, or the bigger 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."

This Week's Planet Roundup

Mercury (magnitude –0.3) is emerging very low in the sunset afterglow. Scan for it with binoculars 20 or 30 minutes after sunset, just above the southwest horizon.

Venus (magnitude –3.9) and Jupiter (magnitude –1.7) rise together soon after dawn begins. On the morning of Saturday November 11th, Jupiter is 2° below Venus. They're in conjunction on the morning of the 13th, an unusually close 1/3° apart. How different their surface brightnesses appear in a telescope! They're almost equally reflective — but Venus is 7½ times closer to the illuminating Sun, so its surface brightness is more than 50 times greater.

Thereafter they separate by almost 1° per day, now with Jupiter on top.

Look for them barely above the east-northeast horizon about 30 or 40 minutes before your local sunrise time. Scan with binoculars if necessary, especially as dawn grows bright.

Mars (magnitude +1.7, in Virgo) rises around 3 or 4 a.m. and glows moderately high in the southeast by the beginning of dawn. Don't confuse it with Spica, slightly brighter than Mars and twinkling well below it.

In a telescope Mars will remain just a tiny, fuzzy dot for several more months. But next summer it will have its closest opposition since 2003.

Saturn (magnitude +0.5, in southern Ophiuchus) glimmers very low in the southwest during dusk.

Uranus (magnitude 5.7, in Pisces) and Neptune (magnitude 7.9, in Aquarius) are well placed in the southeast and south these evenings. Neptune is 0.6° southwest of Lambda Aquarii. Use our finder charts online or in the October Sky & Telescope, page 50.


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, GMT, or Z time) minus 5 hours.


"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


"Objective reality exists. Facts are often determinable. Vaccines save lives. Carbon dioxide warms the globe. Bacteria evolve to thwart antibiotics, because evolution. Science and reason are not fake news, not a liberal political conspiracy. Civilization's survival depends on our ability, and willingness, to use them."
— Alan MacRobert, your Sky at a Glance editor


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



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