This Week's Sky at a Glance, February 18 – 26

FRIDAY, FEBRUARY 18

■ On these February evenings Canopus, the second-brightest star after Sirius, lurks either just below or just above your south horizon (for mid-northern latitudes). In one of the many interesting coincidences that devoted skywatchers know about, Canopus lies almost due south of Sirius, by 36°.

That's far enough south that it never appears above your horizon unless you're below latitude 37° N (southern Virginia, southern Missouri, central California). And there you'll need an open, flat south horizon. Canopus crosses due south 21 minutes before Sirius does.

When to look? Right when Beta Canis Majoris — Murzim the Announcer, the star about three finger-widths to the right of Sirius — is at its highest due south over your landscape. That's about 8 or 9 p.m. now, depending on how far east or west you live in your time zone. Drop straight down from Murzim then.

SATURDAY, FEBRUARY 19

■ Right after night turns completely dark, the W of Cassiopeia shines high in the northwest, standing almost on end.

The brightest star between Cassiopeia and the zenith at that time (for the world's mid-northern latitudes) is Alpha Persei or Mirfak, magnitude 1.8. It lies on the lower-right edge of the Alpha Persei Cluster: a large, elongated, very loose swarm of fainter stars about the size of your thumbtip at arm's length. At least a dozen are 6th magnitude or brighter. They show best in binoculars.

Alpha Per, a white supergiant, is a true member of the group and its brightest light. It and the rest are about 560 light-years away.

SUNDAY, FEBRUARY 20

■ Sirius blazes high in the south on the meridian by about 8 or 9 p.m. now. Using binoculars or a scope at low power, examine the spot 4° south of Sirius (directly below it when on 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 gray haze, very faintly speckled if your sky is good and dark? That's the open star cluster M41, about 2,200 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, it shines some 400 times brighter than the entire cluster.

MONDAY, FEBRUARY 21

■ High in the northern sky these dark evenings, in the seemingly empty wastes between Capella overhead and Polaris due north, sprawls big, dim Camelopardalis, the Giraffe — perhaps the biggest often-visible constellation you don't know. Unless you have a really dark sky, you'll need binoculars to work out its loose, faint, 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.

TUESDAY, FEBRUARY 22

■ With the Moon gone and Monoceros walking across the south behind Orion as if being led by a rope, now's a fine time to trace out the Unicorn's big, dim stick figure. Use the constellation chart in the center of the February or March Sky & Telescope.

Many binocular starwatchers know about its distinctive star cluster NGC 2244, a boxy, rectangular pattern in the center of the vastly fainter Rosette Nebula. It's right about where the Unicorn's eye might be in his triangular head. The brightest stars of the pattern are 6th and 7th magnitude. Find it 10° to the celestial east-southeast of Betelgeuse. The elongated rectangle currently stands upright.

If you've got big binoculars or a small telescope, try next for the larger but fainter Christmas Tree Cluster, NGC 2264, at 15 Monocerotis: the 5th-magnitude star marking the tip of the Unicorn's horn above the back of its head. The stars outlining the Christmas Tree are 7th and 8th magnitude. The tree currently hangs downward from its base, which is 15 Mon. See Matt Wedel's Binocular Highlight column and map in the February Sky & Telescope, page 43.

WEDNESDAY, FEBRUARY 23

■ Last-quarter Moon (exact 5:32 p.m. EDT). The Moon rises very late tonight, around 2 a.m. depending on your location. It's in Scorpius, and once it's up you'll find orange Antares 3° to its right (for North America). Other stars of Scorpius are to their upper right. By the beginning of dawn, the Moon and stars are higher in the south.

THURSDAY, FEBRUARY 24

■ It's late February, so Orion stands at his highest in the south at the end of twilight. Here he looks smaller than you probably remember him appearing early in the winter when he was low. You're seeing the "Moon illusion" effect. Constellations, not just the Moon, look bigger when they're low.

■ Under Orion's feet, and to the right of Sirius now, hides Lepus the Hare. Like Canis Major, this is a constellation with a connect-the-dots that really looks like what it's supposed to be. He's a crouching bunny, with his nose pointing lower right, his faint ears extending up toward Rigel (Orion's brighter foot), and his body bunched to the left. His brightest two stars, 3rd-magnitude Alpha and Beta Leporis, form the back and front of his neck, respectively.

■ And what's under Lepus? Columba the Dove, a modestly dim constellation that doesn't look like a dove any way I can connect the dots. See the constellation chart in the center of the February Sky & Telescope. Its brightest star, Alpha Columbae or Phact, is magnitude 2.6. To find it, draw a line from Rigel through Beta Leporis and extend it the same distance straight on.

FRIDAY, FEBRUARY 25

■ After dinnertime at this time of year, five carnivore constellations are rising upright in a ragged 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. They 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 slithering up the southeast, Canis Minor the Little Dog higher in the south-southeast, and bright Canis Major the Big Dog in the south.

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

What you're seeing is sunlit interplanetary dust orbiting the Sun near the ecliptic plane.

SATURDAY, FEBRUARY 26

■ Certain deep-sky objects hold secret surprises within or near them. With the Moon gone and the sky dark, get out your sky atlas and telescope these evenings for a go at Bob King's eight Hidden Gems in Common Deep-Sky Objects now in evening view.

 

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This Week's Planet Roundup

Mercury, Venus, and Mars continue to shine in early dawn, as shown at the top of this page. They're low in the southeast, forming a triangle that lengthens slightly through the week.

Brightest is Venus, dazzling at magnitude –4.8. In a telescope it's a thick crescent; its globe has grown to about one-third sunlit. And Venus is shrinking into the distance, as always when it's waxing.

Mars is only about one three-hundredth as bright, at magnitude +1.3. Look for it 6° to Venus's lower right.

Mercury is much farther to Venus's lower left. Their separation increases from 17° to 20° this week. Mercury remains magnitude 0.0.

Jupiter is on its way out of the evening sky. Early in the week, you might try looking for it just over the west horizon a mere 15 or 20 minutes after sunset. Bring binoculars.

Saturn is hidden deep in the glow of dawn.

Uranus (magnitude 5.8, in Aries) is high in the west right after dark. Finder chart.

Neptune is sinking away into the sunset, following behind Jupiter.

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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 (also called UT, UTC, GMT, or Z time) minus 5 hours.

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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 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 magazine of astronomy.

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, are the even larger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to magnitude 9.75). And be sure to 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 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."

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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 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