This Week's Sky at a Glance, January 5 – 14

FRIDAY, JANUARY 5

■ At this near-coldest time of the year, Sirius rises around the end of twilight. Orion's three-star Belt points down almost to Sirius's rising place; watch there.

Once Sirius is up, it twinkles slowly and deeply through the thick layers of low atmosphere, then faster and more shallowly as it gains altitude. Its flashes of color also moderate and blend into shimmering whiteness as it climbs to shine through thinner air. See Steve O'Meara's "Scintillating Sirius" in the January Sky & Telescope, page 45, with a photo of its scrambled-rainbow twinkling when reflected on water.

SATURDAY, JANUARY 6

■ It's a busy evening among Jupiter's moons, with four pairs of events. And they include a double shadow transit!

– At 5:47 p.m. EST, Io disappears into occultation behind Jupiter's west (preceding) edge. Just 9 minutes later, Ganymede emerges from in front of the same edge. These two events will only be visible from the Eastern and Atlantic time zones, and the sky there may still be bright with twilight depending on where you are.

– At 8:27 p.m. EST, Europa exits Jupiter's west limb. Nine minutes later Europa's tiny black shadow, trailing behind, comes onto Jupiter's opposite limb.

– At 10:13 p.m. EST, Io emerges from eclipse by Jupiter's shadow a small distance off the planet's east edge. Seven minutes later Ganymede's shadow crosses onto Jupiter's opposite edge, thus beginning a 35-minute period of two shadows in transit at once.

– At 10:55 p.m. EST, Europa's shadow leaves the western limb. Just over an hour later, at 11:58 p.m. EST, Ganymede's larger shadow does the same.

And on Jupiter itself, the Great Red Spot (neither very great nor particularly red these days) should cross the planet's central meridian around 11:05 p.m. EST.

■ Algol should be at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 9:01 p.m. EST. Comparison-star chart.

SUNDAY, JANUARY 7

■ Sirius and Procyon in the balance. Sirius, the Dog Star, sparkles low in the east-southeast after dinnertime. Procyon, the Little Dog Star, shines in the east about two fists at arm's length to Sirius's left. If you live around latitude 30° (Tijuana, New Orleans, Jacksonville), the two canine stars will be at the same height above your horizon soon after they rise. If you're north of that latitude, Procyon will be higher. If you're south of there, Sirius will be the higher one.

■ The moonless evenings this week are a fine time to explore telescopic sights in Eridanus west of Orion — including the sky's easiest white dwarf, many interesting doubles, and a fine, globular planetary nebula. Use Ken Hewitt-White's "Suburban Stargazer" column and chart in the January Sky & Telescope starting on page 55.

■ On Monday morning the 8th, the waning crescent Moon will occult 1st-magnitude Antares low in the southeast during darkness or dawn for the western U.S. and Canada. The occultation will happen in full daylight for most of the rest North America, Central America, and the Caribbean. In a bright sky the event may be a tough catch even with a telescope, depending on the atmospheric seeing (usually poor in the daytime but often excellent around sunrise) and also the clarity of the air.

Map and timetables for this event. The first two tables, for many cities, are very long. The first gives the times of Antares's disappearance; the second its reappearance out from behind the Moon's dark limb. Scroll to be sure you're using the right table; watch for the new heading as you scroll down. The first two letters in each entry are the country abbreviation ("CA" is Canada, not California). The times are in UT (GMT) January 8th; UT is 5 hours ahead of Eastern Standard Time, 6 ahead of CST, 7 ahead of MST, and 8 ahead of PST.

For instance: Use the first table to see that for Denver, Antares disappears at 6:43 a.m. MST, when the Sun is 7° below the horizon (bright twilight) and the Moon is 15° above the horizon toward the east-southeast (azimuth 114°).

MONDAY, JANUARY 8

■ If your sky is even moderately dark, try tracing out the winter Milky Way arching across the sky. In early evening it extends up from the west-northwest horizon along the vertical Northern Cross of Cygnus, up and over to the right past dim Cepheus and through Cassiopeia high in the north, then to the right and lower right through Perseus and Auriga, down between the feet of Gemini and Orion's Club, and on down toward the east-southeast horizon between Procyon and Sirius.

TUESDAY, JANUARY 9

■ After dinnertime now, the enormous Andromeda-Pegasus complex runs from near the zenith down toward the western horizon. Near the zenith, spot Andromeda's high foot: 2nd-magnitude Gamma Andromedae (Almach), slightly orange. Andromeda is standing on her head. About halfway down from the zenith to the west horizon is the Great Square of Pegasus, balancing on one corner. 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.

WEDNESDAY, JANUARY 10

■ Here it is the cold bottom of the year, but the Summer Star, Vega, is still hanging in. Look for it twinkling over the northwest horizon during and shortly after nightfall. The farther north you are the higher it will be. If you're as far south as Florida, it has already gone goodbye.

THURSDAY, JANUARY 11

■ Orion continues his upward march in the southeast as the hours and the weeks proceed, and his figure is beginning to rotate clockwise — as all constellations on the southern side of the sky always do. Accordingly, his three-star Belt is starting to turn away from vertical.

■ New Moon (exact at 6:57 a.m. EST on this date).

FRIDAY, JANUARY 12

■ In this coldest time of the year, the dim Little Dipper (Ursa Minor) hangs straight down from Polaris after dinnertime, as if, per Leslie Peltier, from a nail on the cold north wall of the sky.

The Big Dipper, meanwhile, is creeping up low in the north-northeast. Its handle is very low, but its bowl is nosing up toward the upper right.

SATURDAY, JANUARY 13

■ The waxing crescent Moon forms a long triangle with Saturn and Fomalhaut in late dusk, as shown above.

SUNDAY, JANUARY 14

■ The Moon, Saturn, and Fomalhaut now form a similar triangle to the one they did yesterday, but mirror-reversed along the axis between the planet and star.

■ The Gemini twins lie on their sides these January evenings, left of Orion. Their head stars, Castor and Pollux, are farthest from Orion, one over the other. (Castor is the top one.) The feet of the Castor stick figure are just left of the top of Orion's (very dim) Club.

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This Week's Planet Roundup

Mercury shines low in the dawn this week to the lower left of bright Venus. Their separation shrinks slightly from 14° on the morning of January 5th to 11° on January 12th. Mercury remains about magnitude 0.0 all this week.

Venus, magnitude –4.0, shines as the bright "Morning Star" in the southeast during dawn. It's getting lower every week. Nearby is not just Mercury but also sparkly orange Antares, magnitude +1.0. Look for Antares 7° below or lower right of Venus on the morning of the 5th. By the 12th, Antares is 9° to Venus's right.

Mars barely peeks over the eastern horizon in bright dawn, probably out of reach even with binoculars or a telescope. Mars will creep up very slowly in the dawn for the next five months.

Jupiter, magnitude –2.5 in Aries, is the bright white dot dominating the high south early these evenings. It stands at its highest soon after dark. In a telescope, it has shrunk to 42 arcseconds wide.

Saturn, magnitude +1.0 in Aquarius, is getting lower in the southwest during and after dusk. Don't confuse it with Fomalhaut, similarly bright, nearly two fists to Saturn's lower left as shown for January 12-15 above. Saturn sets around 8 p.m.

Uranus, magnitude 5.6 in Aries, awaits your binoculars in the darkness 14° east (left) of Jupiter. In a telescope at high power Uranus is a tiny but distinctly nonstellar ball, 3.8 arcseconds in diameter. Locate and identify it using the finder charts in the November Sky & Telescope, pages 48-49.

Neptune, fainter at magnitude 7.9, is at the Aquarius-Pisces border 21° east of Saturn and is still fairly high right after dark. Neptune is only 2.3 arcseconds wide: harder to resolve as a ball than Uranus, but definitely nonstellar at high power in good seeing.

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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.

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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), which shows all 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, are the even larger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to mag 9.75). 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.

Can computerized telescopes replace charts? Not for beginners I don't think, especially not 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 the sky. 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."

If you do get a computerized scope, make sure the drives can be disengaged so you can swing it around and point it readily by hand rather than only slowly by the electric motors.

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

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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.

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"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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