This Week's Sky at a Glance, March 1 – 9

FRIDAY, MARCH 1

■ Sirius blazes highest in the south on the meridian soon after nightfall now. Using binoculars or a telescope at low power, examine the spot 4° south of Sirius: directly below it when near the meridian. Four degrees is somewhat less than the width of a typical binocular's or finderscope's field of view. Can you see a little patch of speckly gray haze there? That's the open star cluster M41, about 2,300 light-years away. Its total magnitude adds up to 5.0.

Sirius, by comparison, is only 8.6 light-years away — and being so near to us, it shines some 400 times brighter than that entire cluster.

■ If you spot M41, next give a try for the cluster M50 on the other side of Sirius! It's 10° north-northeast from Sirius, dimmer, smaller and more subtle than M41.

Find it by sweeping from Sirius first to Theta Canis Majoris, the 4th-magnitude pointy nose of the Big Dog's stick figure, then on again nearly as far in the same direction and just a touch to the left. It's not exactly easy, but it's there. I can spot it without too much difficulty using 10x50 binoculars through moderate suburban light pollution. Use averted vision! If you're trying under tougher conditions, get finer guidance using the Pocket Sky Atlas, chart 27.

SATURDAY, MARCH 2

■ The last-quarter Moon rises around 1 or 2 a.m. tonight. (It's exactly last quarter at 10:23 a.m. EST Sunday morning.) The rising Moon shines very close to Antares, especially as seen from the East Coast. In fact the Moon occults Antares soon after rising as seen from much of the American South and Midwest.

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 behind the Moon's bright limb; the second its reappearance out from behind the Moon's dark limb. Scroll to be sure you're using the correct table; watch for the new heading as you scroll down. The first two letters in each entry are the country abbreviation. The times are in UT (GMT) March 3rd. UT is 5 hours ahead of Eastern Standard Time, 6 hours ahead of CST, 7 ahead of MST, and 8 ahead of PST.

For instance: Use the first table to see that for Atlanta, Antares disappears on the bright limb at 2:04 a.m. March 3rd EST when the Moon is only 4° high in the east-southeast (azimuth 126°). Then Antares reappears from behind the dark limb at 2:56 a.m. EST when the Moon is 13° high in the southeast. The latter is clearly the better event!

By dawn on Sunday March 3rd the Moon has moved farther to Antares's east, as drawn above.

SUNDAY, MARCH 3

■ Look east after dusk this week for the constellation Leo already climbing well up the sky. Its brightest star is Regulus. The Sickle of Leo (about a fist and a half tall) extends upper left from there.

■ These moonless nights are a fine time to collect some telescopic triple stars with Bob King's guide to 17 of them: Winter's Finest Triple Stars, with finder charts and data about each trio. Yes, Iota Cancri and Beta Mon are famous. Bet you didn't know about the others.

MONDAY, MARCH 4

■ It's early March. So quite soon after dark now, the Big Dipper rises as high in the northeast as Cassiopeia has descended to in the northwest. Midway between them, as always, is Polaris.

■ And go on a telescopic galaxy hunt around the Big Dipper with Ted Forte's "Galaxy-Hopping in the Great Bear" in the March Sky & Telescope, page 18.

TUESDAY, MARCH 5

■ This is still a fine time to look for the zodiacal light if you live in the world's mid-northern latitudes, with the early-evening sky moonless and the ecliptic tilting high upward from the western horizon at nightfall. From a clear dark site with clean air, look west at the very end of twilight for a vague but huge, tall pyramid of pearly light. It's tilted to the left, aligned along constellations of the zodiac.

What you're seeing is sunlit interplanetary dust, from old asteroid collisions and evaporated comets, orbiting the Sun near the ecliptic plane.

WEDNESDAY, MARCH 6

■ After dinnertime at this time of year, five carnivore constellations stand upright in a row from the northeast to south. They're all presented in profile with their noses pointed up and their feet (if any) to the right. These are Ursa Major the Big Bear in the northeast (with the Big Dipper as its brightest part), Leo the Lion in the east, Hydra the Sea Serpent in the southeast, Canis Minor the Little Dog higher in the south-southeast, and bright Canis Major the Big Dog in the south.

THURSDAY, MARCH 7

■ High in the north-northwest these evenings, in the seemingly empty waste between Capella on high and Polaris due north, sprawls big, dim Camelopardalis, the Giraffe — perhaps the biggest often-visible constellation you don't know. Unless you have a good dark sky, you'll need binoculars to work out its large, nondescript pattern using the constellation chart in the center of Sky & Telescope — a challenge project that will build your skills for correctly relating what you see in binoculars to what you see, much smaller, on a sky map.

If you're new at this, start with brighter, easier constellations and save the shy Giraffe until you get good at it.

FRIDAY, MARCH 8

■ Bright Sirius now stands due south on the meridian just as twilight fades out into night. Sirius is the bottom star of the equilateral Winter Triangle. The other two stars of the Triangle are orange Betelgeuse to Sirius's upper right (Orion's shoulder) and Procyon to Sirius's upper left. This is the time of year when the Winter Triangle balances on Sirius shortly after dark.

SATURDAY, MARCH 9

■ More about Sirius and Canis Major. In a very dark sky the Big Dog's realistic stick figure is plain to see — the dog is in profile, prancing to the right on his hind legs, with Sirius as his shiny dog tag — but for most of us only his five brightest stars show through. These form the unmistakable Meat Cleaver. Sirius and Murzim (to its right) are the wide top end of the Cleaver, with Sirius sparkling on its top back corner. Down to Sirius's lower left is the Cleaver's other end including its short handle, formed by the triangle of Adhara, Wezen, and Aludra. The Cleaver is chopping toward the lower right.

■ Algol shines at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 10:07 p.m. Eastern Standard Time (7:07 p.m. PST). Algol takes several additional hours to fade and to rebrighten. Comparison-star chart (with north up; celestial north is always the direction toward Polaris as you look across the sky).

■ Daylight saving time begins at 2 a.m. Sunday morning for most of North America. Clocks spring ahead an hour.

SUNDAY, MARCH 10

■ On the traditional divide between the winter and spring sky is the dim constellation Cancer. It's between Gemini to its west and Leo to its east.

Cancer holds something unique in its middle: the Beehive Star Cluster, M44. The Beehive shows dimly to the naked eye if you have little or no light pollution. It's a bit less than halfway from Pollux in Gemini to Regulus in Leo. With binoculars it's easy even under worse conditions. Look for a scattered clump of faint little stars. They're magnitudes 6½ on down.

■ New Moon (exact at 5:00 a.m. on this date Eastern Daylight Time (9:00 UT).

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This Week's Planet Roundup

Mercury is out of sight deep in the glare of sunset.

Venus, magnitude –3.8, rises in the southeast while dawn is already under way. Try for it very low 30 minutes before sunrise.

Mars, magnitude +1.3, is also deep in the sunrise, upper right of Venus but less than 1% as bright. The separation between them widens from 4° to 8° this week.

Jupiter, magnitude –2.2 in Aries, is the bright white dot high in the west in twilight, lower as evening advances. It sets around 10 p.m. In a telescope, Jupiter has shrunk to only 35 arcseconds wide; it's nearly as distant and small as it gets.

Jupiter is almost equidistant between Hamal (Alpha Arietis) a fist-width to its right, and Menkar (Alpha Ceti) a fist-width to its left. The two stars are magnitudes 2.0 and 2.5, respectively.

Saturn is gone from sight in conjunction with the Sun.

Uranus, magnitude 5.7 in Aries, is 8° above Jupiter. Use the finder charts for it in last November's Sky & Telescope, pages 48-49.

Neptune is lost in the sunset.

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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 if you want, rather than only slowly by the electric motors.

However, finding faint telescopic objects 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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