Sky at a Glance | January 17th, 2014

By: Alan MacRobert January 17, 2014 0

Supernova in M82! On Tuesday January 21st astronomers first noticed an 11th-magnitude supernova in the galaxy M82 in Ursa Major. It's in the evening sky in reach of amateur telescopes, and it may not be done brightening yet. See our article, Bright Supernova in M82.

Friday, January 17

As the stars come out this week, face north and look very high overhead for Cassiopeia, oriented now like a flattened letter M. As the night proceeds, the M swings down in the northwest and tilts sideways.

Saturday, January 18

This the Big Dipper's time of year to swing up from the low north-northeast after dusk, to stand on its handle in the northeast by about 9 p.m.

Sunday, January 19

This week Sirius twinkles brightly after dinnertime below Orion in the southeast. Around 8 or 9 p.m., depending on your location, Sirius shines precisely below fiery Betelgeuse in Orion's shoulder. How accurately can you time this event for your location, perhaps using a plumb bob or the vertical edge of a building? Sirius leads early in the evening, Betelgeuse leads later. Welcome to pre-telescopic astronomy.

Monday, January 20

Jupiter's moon Io crosses Jupiter's face from 8:07 to 10:22 p.m. EST, with its tiny black shadow (much more visible in a telescope) following 23 minutes behind. Later, Jupiter's Great Red Spot transits the planet's central meridian around 11:54 p.m. EST.

Look southwest before dawn Wednesday and Thursday for the Moon grouping up with Mars and Spica. (These scenes are drawn for the middle of North America. European observers: move each Moon a quarter of the way toward the one for the previous date. The Moon is shown three times actual size.)

SkyandTelescope.com

Tuesday, January 21

The waning gibbous Moon rises around 11 tonight, then Mars and Spica follow up below it in the next hour and a quarter. By dawn Wednesday morning (the 22nd) the three are posing in the southwest, with Spica and Mars to the Moon's left and upper left as shown here.

Jupiter's Great Red Spot transits around 7:45 p.m. EST.

Wednesday, January 22

The waning Moon rises around midnight tonight very close to Spica, with Mars shining to their upper left. By dawn on the 23rd they move over to the southwest, with Mars now to the Moon's upper right as shown above.

Algol is at minimum brightness, magnitude 3.4 instead of its usual 2.3, for a couple hours centered on 1:20 a.m. Thursday morning EST (10:20 p.m. Wednesday PST). Algol takes several additional hours to fade and to rebrighten.

Okay, you know Algol well. But what about the remarkable galaxies and clusters near it? Now that the Moon is gone from the evening sky, explore the depths around Algol with Sue French's Deep-Sky Wonders article, maps and photos in the January Sky & Telescope, page 58.

Thursday, January 23

Last-quarter Moon tonight (exact at 12:19 a.m. Friday morning EST). The Moon rises around 1 a.m. local time. To its upper right is the Mars-Spica pair, and rising to its lower left more than an hour later is Saturn. By dawn on the 24th they're lined up horizontally in the south to southwest.

Jupiter's Great Red Spot transits around 9:23 p.m. EST.

Friday, January 24

Mercury has become easy to see; look for it low in the west-southwest as twilight fades. Don't confuse it with twinkly Fomalhaut off to its left in the southwest. Mercury is beginning its best evening apparition since last June for mid-northern skywatchers.

Waning further, the dawn Moon now passes Saturn and Antares. (The Moon is shown three times actual size.)

Alan MacRobert

The Moon rises around 2 a.m. Saturday morning the 25th with Saturn glowing just 1° or 2° from it (as seen from the Americas). They're high in the south together by dawn, as shown here.

Saturday, January 25

Algol is at minimum brightness, magnitude 3.4 instead of its usual 2.3, for a couple hours centered on 10:09 p.m. EST. It takes several additional hours to fade and to rebrighten.

Jupiter's Great Red Spot transits Jupiter's central meridian around 11:01 p.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. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — which may sound like a lot, but that's less than one star in an entire telescopic field of view, on average. By comparison, Sky Atlas 2000.0 plots 81,312 stars to magnitude 8.5, typically one or two stars per telescopic field. Both atlases include many hundreds of deep-sky targets — galaxies, star clusters, and nebulae — to hunt among the stars.

Sky & Telescope

Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of charts). The standards are the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and once you know your way around, 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, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the beloved if dated Burnham's Celestial Handbook.

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 (able to point with better than 0.2° repeatability, which means fairly heavy and expensive). As Terence Dickinson and Alan Dyer say in their invaluable 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

Gibbous Mars was still just 7.1 arcseconds from pole to pole on January 6th when Don Parker in Florida imaged it with a 16-inch reflector. South is up. Note the North Polar Cap with hints of a rift already developing, morning clouds near the following (celestial east; right-hand) limb, haze visible over the dark Syrtis Major region on the opposite (preceding) limb, and in the south, distinctive Sinus Sabaeus ending with two-pronged Sinus Meridiani.

Donald C. Parker

Mercury (magnitude –0.9) is emerging into twilight view after sunset. Look for it above the west-southwest horizon about 30 to 45 minutes after sunset. It's becoming higher in darker twilight every day.

Venus (about magnitude –4.4) is now plain to see low in early dawn; look east-southeast. It too is becoming higher every day.

In a telescope Venus is a very thin, large crescent following its inferior conjunction on January 11th.

Mars (magnitude +0.5, in Virgo) rises around 11 or midnight. Spica, not quite as bright at magnitude +1.0, rises about 6° below it. They're highest in the south before the first light of dawn, with Spica now to Mars's lower left.

In a telescope Mars is still pretty small, 8 arcseconds wide. It'll be nearly twice this diameter (15.1″) when closest in mid-April.

Jupiter on the night of January 9–10, taken from New Hampshire by S&T's imaging editor Sean Walker. South is up. The Great Red Spot, unusually strong orange this season, is obvious even near the limb. Following (celestial east) of it is a long, diminishing series of white swirls in the South Equatorial Belt. Notice the tight trio of white ovals in the South South Temperate Belt, and the blue festoons in the Equatorial Zone.

S&T: Sean Walker

Jupiter (magnitude –2.7, in Gemini) dominates the eastern sky in the evening and crosses nearly overhead (for mid-northern observers) around 11 p.m.

In a telescope Jupiter remains a big 46 arcseconds wide. For lots about observing Jupiter see the January Sky & Telescope or the brief article online: Jupiter: Big, Bright, and Beautiful.

Saturn (magnitude +0.6, in Libra) rises around 2 a.m. and is well up in the southeast as dawn begins to brighten. By then it's far lower left of Mars and Spica, and even farther below brighter Arcturus.

Uranus (magnitude 5.9, in Pisces) is still well up in the southwest right after dark. Finder chart.

Neptune (magnitude 8.0, in Aquarius) is low in the west-southwest 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 (UT, UTC, or GMT) minus 5 hours.

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About Alan MacRobert

Alan M. MacRobert became an avid Sky & Telescope subscriber in 1966 at age 14, joined the editorial staff in 1982, and is now a senior contributing editor, semi-retired. He played a role in practically every part of the magazine and the company's other products for more than a generation, both on the amateur-observing side and the science-reporting side. In 1994 a book collection of his observing how-tos and telescopic sky tours was published as Star Hopping for Backyard Astronomers. He has produced This Week's Sky at a Glance online every week since 1989.