This Week’s Sky at a Glance, February 5 – 13 – Sky & Telescope


■ Before and through early daybreak on Saturday morning the sixth, spot the waning crescent Moon within the south-southeast with Antares some 4° or 5° to its decrease proper, as proven beneath.

The waning Moon steps down over Scorpius earlier than and through daybreak, because it nears its new-moon rendezvous with the Sun that may finish its present lunation.■ High within the northern sky these moonless evenings, within the seemingly empty wastes between Capella overhead and Polaris due north, sprawls huge, dim Camelopardalis, the Giraffe — maybe the most important usually-seen constellation you do not know. Unless you’ve gotten a actually darkish sky, you will want binoculars to work out its nondescript sample utilizing the constellation chart within the middle of Sky & Telescope — a problem venture that may construct your abilities for appropriately relating what you see in binoculars to what you see, a lot smaller, on a constellation map.

If you are new at this, begin with brighter, simpler constellations and save the shy Giraffe for if you get good at it.


■ The sky’s greatest asterism (casual star sample) — at least the most important that is well known — is the Winter Hexagon. It fills the sky towards the east and south these evenings. Start with sensible Sirius at its backside. Going clockwise from there, march up by Procyon, Pollux and Castor, then Menkalinan and Capella on excessive, right down to Aldebaran, then to Rigel in Orion’s foot, and again to Sirius. Betelgeuse shines contained in the Hexagon, effectively off middle.The Hexagon is considerably distended. But for those who draw a line by its center from Capella right down to Sirius, the “Hexagon” is pretty symmetric with respect to that axis.

■ Algol ought to be at its minimal brightness tonight, magnitude 3.Four as an alternative of its regular 2.1, for a couple hours centered 12:46 a.m. EST ( 9:46 p.m. PST). Algol takes a number of extra hours to fade and to rebrighten.


■ Have you ever intently in contrast the colours of Betelgeuse and Aldebaran? Can you detect any distinction of their colours at all? I am unable to, actually. Yet Aldebaran, spectral kind K5 III, is usually referred to as an “orange” large, whereas Betelgeuse, spectral kind M1-M2 Ia, is normally referred to as a “red” supergiant. Their temperatures are certainly a bit totally different: 3,900 Kelvin and three,600 Kelvin, respectively.

A complication: Betelgeuse is brighter, and to the human eye, the colours of vibrant objects seem, falsely, to be desaturated: tending paler (whiter) than they are surely. You can get a barely higher learn on the colours of vibrant stars by defocusing them a bit, to unfold their mild over a bigger space of your retina.Compare them each to Mars. Mars is about two fists at arm’s size decrease proper of Aldebaran and barely fainter. To me, it appears to have a very barely extra yellowish hue than both star.


■ This being early February, Orion is now excessive within the south-southeast proper after darkish. Left of him is Gemini, headed up by Castor and Pollux at far left. The stick-determine Twins are nonetheless mendacity on their sides.Below their legs is vibrant Procyon. Standing 4° above Procyon is third-magnitude Gomeisa, Beta Canis Minoris, the one different straightforward bare-eye star of Canis Minor. The Little Dog is seen in profile, however solely his again. Procyon marks his rump, Beta CMi is the again of his neck, and two fainter stars simply above which might be the highest of his head and his nostril. Those final two are solely 4th and fifth magnitude, respectively. Binoculars assist by mild air pollution.

For extra concerning the Little Dog Star, see Fred Schaaf’s “In Praise of Procyon” within the February Sky & Telescope, web page 45.


■ After it’s good and darkish, look due east for twinkly Regulus, not very excessive. Extending higher left from it’s the Sickle of Leo, a backward query mark, outlining the Lion’s forequarters. “Leo announces spring,” goes an outdated saying. Actually, Leo displaying up after darkish proclaims the chilly, clammy, messy again half of winter. Come spring, Leo will already be excessive.

■ Algol ought to be at minimal mild for a couple hours centered on 9:35 p.m. EST.


■ A favourite discipline excessive overhead these nights is the wealthy Milky Way space at the dragging foot of the Castor stick determine, one of many Gemini twins. Here lie two third-magnitude crimson giants and the massive, filmy, distended speckle of the open star cluster M35, whole magnitude about 5. But there’s extra: the compact cluster NGC 2129 gathered intently round a pair of Seventh- and eighth-magnitude stars; the very unfastened group Collinder 29 bordered by a little Y asterism; and the deep crimson stars TV and 6 (or V) Geminorum. See Matt Wedel’s Binocular Highlight column, “In the Twins’ Toes,” within the February Sky & Telescope, web page 43, with chart. But a scope will do higher than binocs.


■ Sirius the Dog Star blazes excessive within the southeast after dinnertime, the brightest star of Canis Major. In a darkish sky with a lot of stars seen, the constellation’s factors will be related to type a convincing canine profile. He’s at present prancing on his hind legs; he wears Sirius on his chest.

But by the sunshine air pollution the place most of us reside, solely his 5 brightest stars are simply seen. These type a brief-dealt with meat cleaver. Sirius is the cleaver’s prime again nook, its blade faces proper, and its stubby deal with is right down to the decrease left.

■ New Moon (precise at 2:06 p.m. EST).


■ Orion stands his highest within the south by about Eight p.m., trying smaller than you most likely keep in mind him showing early within the winter when he was low. You’re seeing the “Moon illusion” impact. Constellations, not simply the Moon, look greater once they’re low.

■ Under Orion’s toes, and to the suitable of Sirius now, hides Lepus the Hare. Like Canis Major, that is a constellation with a join-the-dots that basically seems like what it is purported to be. He’s a crouching bunny, along with his nostril pointing decrease proper, his faint ears extending up towards Rigel (Orion’s brighter foot), and his physique bunched to the left. His brightest two stars, third-magnitude Alpha and Beta Leporis, type the front and back of his neck.


■ By 9 p.m. or so, the Big Dipper stands on its deal with within the northeast. In the northwest, Cassiopeia additionally stands on finish (its brighter finish) at about the identical peak. Between them is Polaris.


This Week’s Planet Roundup

Mercury, Venus, Mars, and Jupiter are gone from sight within the glare of the Sun. . . except you wish to attempt a tremendous-laborious problem utilizing a huge-discipline telescope perhaps 10 minutes earlier than dawn late within the week. The diagram beneath units the scene; it is for 20 minutes earlier than dawn at 40° north latitude, however clearly you will want to attend a little longer for the planets to climb a bit whereas the sky grows even brighter. Jupiter and Venus often is the least hopeless. You can neglect Saturn and particularly Mercury.

Four of the 5 bare-eye planets defy commentary simply earlier than dawn. Mars (magnitude +0.5, in Aries) shines pale yellow-orange excessive within the southwest proper after darkish. It units within the west-northwest round 1 a.m. Mars is just Eight or 7 arcseconds huge now, however at least a telescope will present its gibbous form.

At Mars itself, then again, February is a busy month for arriving spacecraft. The United Emirates’ Hope craft will take up excessive-altitude orbit on February ninth to check the planet’s ambiance. China’s Tianwen-1 orbiter, lander and rover will arrive lower than a day later. The largest and most formidable mission is NASA’s Perseverance rover, which is able to land on the 18th to, amongst different issues, acquire samples for future return to Earth and launch a miniature reconnaissance helicopter.

Why are the three missions bunched collectively? Because the minimal-power switch orbit to get a craft from Earth to Mars turns into out there solely when the 2 planets line up a specific manner with respect to one another each 2.14 years. Dedicated Mars observers will acknowledge this because the synodic interval of Mars with respect to Earth — the identical as the common time from one opposition to the following. All three missions launched final July.

Uranus (magnitude 5.8, in Aries) is roughly 10° levels beneath Mars in early night. In binoculars Uranus is a little pinpoint “star.” But with an obvious diameter of three.5 arcseconds, it is a tiny, fuzzy ball at excessive energy in even a smallish telescope with sharp optics — throughout spells of excellent seeing. Finder chart (with out Mars).

Neptune (magnitude 8.0) is sinking out of sight in night twilight.

All descriptions that relate to your horizon — together with the phrases up, down, proper, and left — are written for the world’s mid-northern latitudes. Descriptions that additionally rely on longitude (primarily Moon positions) are for North America.

Eastern Standard Time, EST, is Universal Time minus 5 hours. (Universal Time is often known as UT, UTC, GMT, or Z time. For extra see Time and the Amateur Astronomer.)

Want to grow to be a higher astronomer? Learn your manner across the constellations. They’re the important thing to finding every part fainter and deeper to hunt with binoculars or a telescope.

This is an outside nature pastime. For a straightforward-to-use constellation information masking the entire night sky, use the massive month-to-month map within the middle of every problem of Sky & Telescope, the important journal of astronomy.

Once you get a telescope, to place it to good use you will want a detailed, giant-scale sky atlas (set of charts). The fundamental normal is the Pocket Sky Atlas (in both the unique or Jumbo Edition), which exhibits stars to magnitude 7.6.

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and lots of of telescopic galaxies, star clusters, and nebulae amongst them. Shown right here is the Jumbo Edition, which is in laborious covers and enlarged for simpler studying outdoor at night time. Sample charts. More concerning the present editions.Next up is the bigger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; practically 3 times as many. The subsequent up, as soon as you understand your manner round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to magnitude 9.75). And make sure to learn learn how to use sky charts with a telescope.

You’ll additionally need a good deep-sky guidebook, equivalent to Sky Atlas 2000.0 Companion by Strong and Sinnott, or the larger (and illustrated) Night Sky Observer’s Guide by Kepple and Sanner.

Can a computerized telescope change charts? Not for freshmen, I do not assume, and never on mounts and tripods which might be lower than prime-high quality mechanically, which means heavy and costly. And as Terence Dickinson and Alan Dyer say of 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.”

Audio sky tour. Out below the night sky with yourearbuds in place, take heed to Kelly Beatty’s monthlypodcast tour of the heavens above. It’s free.

“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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