This Week’s Sky at a Glance, January 5 – 13

Jupiter aligns with Mars in the dawn of Jan. 6, 2017

Step out early Saturday morning January 6th (if you dare) to catch Jupiter with Mars. They'll appear just as close on Sunday the 7th, but with Mars now under Jupiter.

Mars, Jupiter, Moon at dawn, Jan. 10-11-12, 2018

Mars and Jupiter have moved farther apart in the dawn by the time the Moon passes them . . .

Moon, Antares, Saturn, Mercury in the dawn, Jan. 13, 2018

. . .and then the Moon approaches Mercury and Saturn in conjunction. Look for the two planets very low as dawn grows bright. (Their visibility in bright twilight is exaggerated here.)

Friday, January 5

• Orion strides boldly up the southeastern sky after dusk in the January cold. Above it glitters orange Aldebaran, 65 light-years away. Above Aldebaran are the Pleiades, about 435 light-years away. Far left of Aldebaran and the Pleiades, brilliant Capella shines from a distance of 42 light-years.

• Before dawn on Saturday morning the 6th, spot bright Jupiter in the south-southeast. Fainter Mars is barely to its right, by just 1/3° — less than the width of a chopstick at arm’s length. The two planets will fit in a medium-power telescopic view, but both are near their maximum distances from Earth and about as small as they ever look. Mars is especially tiny.

Saturday, January 6

• Before dawn on Sunday the 7th, again spot bright Jupiter in the south-southeast. Mars is now 1/3° below it (at the times of dawn for North America). To their right is 3rd-magnitude Alpha (α) Librae, a very wide double star for binoculars.

Sunday, January 7

• The Northern Cross in Cygnus, with Deneb at its top, plants itself nearly upright on the northwest horizon around 7 or 8 p.m. at this time of year.

Monday, January 8

• Last-quarter Moon (exact at 5:25 p.m.). The Moon rises around midnight or 1 a.m. tonight, in Virgo. Once it does, look for Spica about 6° or 7° to its left or lower left. Brighter Arcturus shines 25° to the Moon's upper left.

By the time dawn begins to brighten on Tuesday the 9th they're all high in the south, and the line they form is more nearly vertical.

Tuesday, January 9

• After dinnertime now, the enormous Andromeda-Pegasus complex runs from near the zenith down toward the western horizon.

Just west of the zenith, spot Andromeda's foot: 2nd-magnitude Gamma Andromedae (Almach), slightly orange. About halfway from the zenith to the west horizon is the Great Square of Pegasus, balancing on one corner. Down from its bottom corner run the stars outlining Pegasus's neck and head, ending at his nose: 2nd-magnitude Enif, due west and also slightly orange.

• Both Venus and Pluto pass through conjunction with the Sun today, just 3 hours apart (although they're 1.6° apart on the sky).

Wednesday, January 10

• Before dawn on Thursday morning the 11th, spot the waning crescent Moon in the southeast with Jupiter and fainter Mars to its lower right.

Thursday, January 11

• After dinnertime at this coldest time of the year (on average, for many places), the dim Little Dipper hangs straight down from Polaris, the end of its long handle — as if from a nail on the cold north wall of the sky. In warm June, by contrast, the Little Dipper's bowl floats up from Polaris, like a helium balloon escaped from a summer party, trailing its string.

• In the early dawn of Friday the 12th, the waning crescent Moon hangs to the lower left of Jupiter and Mars. It's above Antares by a fairly similar distance.

Very far to their lower left, near the southeast horizon, use binoculars to help find Mercury and Saturn as dawn brightens. They're only about 1° apart. Mercury, on the right, is the brighter of the two.

Friday, January 12

• Sirius, the Dog Star, rises in the east-southeast around the end of twilight now, if you're near latitude 40° north (New York, Denver, Madrid, Athens). From such latitudes, Procyon — 2½ fists at arm's length to Sirius's left — precedes it up; "Procyon" is from the ancient Greek for "before the dog."

But if you're as far south as San Diego, the Gulf Coast, Jacksonville, or Cairo, Egypt, they rise almost at the same time.

• In early dawn of Saturday the 13th, the waning crescent Moon hangs far to the lower left of Jupiter and Mars and upper left of Antares.

Far lower left of the Moon, near the southeast horizon, use binoculars to help find Mercury and Saturn as dawn brightens. They're still roughly 1° apart, but now Mercury is below Saturn.

Saturday, January 13

• Vega still twinkles quite low in the northwest after dusk. It’s sometimes called the Summer Star, but it’s certainly out of season now. It’ll soon be gone, to return to the evening sky next spring.


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

Jupiter on Jan. 3, 2018

Jupiter before dawn on January 3rd, imaged by Christopher Go in the Philippines. South here is up. Oval BA, aka "Red Spot Junior," is near the meridian in the South Temperate Zone. But an unusually prominent blue festoon in the Equatorial Zone was the most easily seen feature on this face of the planet after the belts and zones themselves (squint your eyes and look from a distance).

Uranus on Dec. 16, 2017

Yes, this is a ground based image of Uranus — taken on December 16th by Damian Peach and the Chilescope Team with the 1-meter Chilescope in the Andes. They took the image in infrared light and colorized it to mimic the planet's visible-light hue.

Mercury (magnitude –0.3) is having a fine morning apparition. Look for it low in the southeast in early dawn, very far lower left of Jupiter and Mars. (Don't confuse Mercury with twinklier Antares, which is about 15° or 20° to Mercury's upper right.)

Venus remains hidden in conjunction with the Sun.

Mars and Jupiter (magnitudes +1.5, and –1.8, respectively) rise in the east-southeast around 3 a.m. and are high in the south-southeast by early dawn. Jupiter is the brightest point in the sky. Mars and Jupiter begin the week in a close conjunction, just 0.3° apart on the mornings of January 6th and 7th. Then Jupiter pulls away to the upper right, widening their separation to 3° by January 13th.

Upper right of Jupiter is 3rd-magnitude Alpha (α) Librae, a very wide double star for binoculars.

Saturn (magnitude +0.5) begins the week very deep in the dawn, 8° lower left of brighter Mercury on the morning of the 6th. But they close in on each other by more than 1° per day, and are only about 3/4° apart (for North America) on their morning of conjunction, January 13th.

Uranus (magnitude 5.8, in Pisces) and Neptune (magnitude 7.9, in Aquarius) are best hunted right after dark — when Uranus is high in the south and Neptune hasn't yet sunk too low in the southwest. 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 (also called UT, UTC, GMT, or Z time) minus 5 hours.


"Science is built up of facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house."
— Henri Poincaré (1854–1912)


"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 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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