#astronomy This Week’s Sky at a Look, January 29 – February 6 – Sky & Telescope

January 30, 2021 - Comment

FRIDAY, JANUARY 29 ■ The Moon, a day previous full, rises in late twilight. As soon as it is effectively up search for Regulus four° or 5° to its decrease proper, and Algieba, barely fainter, an analogous distance to the Moon’s left or decrease left. These are the 2 brightest stars of the Sickle of


■ The Moon, a day previous full, rises in late twilight. As soon as it is effectively up search for Regulus four° or 5° to its decrease proper, and Algieba, barely fainter, an analogous distance to the Moon’s left or decrease left.

These are the 2 brightest stars of the Sickle of Leo. Will the others be misplaced within the moonlight?


■ As soon as it is totally darkish, spot the equilateral Winter Triangle within the southeast. Sirius is its brightest and lowest star. Betelgeuse stands excessive above Sirius, by about two fists at arm’s size. To the left of their midpoint is Procyon.

Are you able to discern their colours? Sirius (spectral kind A0) is chilly white, Betelgeuse (M2) is pale yellow-orange, and Procyon (F5) is paler yellowish white.


■ Excessive within the east this night, the asteroid 18 Melpomene, magnitude 9.four, creeps alongside solely about Zero.1° from 4th-magnitude Alpha Cancri, which itself is lower than 2° from the open cluster M67. To determine the asteroid you should utilize the chart within the February Sky & Telescope, web page 49, however which will require close-up work with a magnifying glass and a pencil level. Simpler might be a zoomable astro-software chart displaying Melpomene’s real-time place amongst fainter stars at a a lot bigger scale.

And about 1° southwest of Melpomene, such a chart also needs to determine the 10.Zero-magnitude asteroid 60 Echo. Each are very close to opposition tonight.

Trace: Indoors beforehand, overview the right way to use a chart with a telescope (whether or not a paper chart or on a display screen) if you have not but mastered the tips.

Final name for Mercury! Its visibility in vivid twilight (and definitely that of the faint stars) is vastly exaggerated right here. Carry binoculars.


■ Orion is now excessive within the southeast proper after darkish. Left of it’s Gemini, headed up by Castor and Pollux at far left. The stick-figure Twins are nonetheless mendacity on their sides.

Nicely beneath their legs is vivid Procyon. Standing four° above Procyon is Third-magnitude Gomeisa, Beta Canis Minoris, the one different simple naked-eye star of Canis Minor. The Little Canine 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. These final two are solely 4th and fifth magnitude, respectively.


■ After it’s good and darkish, look due east, not too excessive, for twinkly Regulus. Extending higher left from it’s the Sickle of Leo, a backward query mark. “Leo broadcasts spring,” goes an previous saying. Really, Leo displaying up within the night broadcasts the chilly, clammy, messy again half of winter. Come spring, Leo will already be excessive.


■ A favourite subject excessive overhead these nights is the wealthy Milky Approach space on the dragging foot of the Castor stick determine, one of many Gemini twins. Right here lie two Third-magnitude purple giants and the massive, filmy, distended speckle of the open star cluster M35, whole magnitude about 5. However there’s extra: the compact cluster NGC 2129 gathered carefully round a pair of Seventh- and Eighth-magnitude stars; the very free group Collinder 29 with somewhat Y asterism subsequent to it; and the deep purple stars TV and 6 (or V) Geminorum. See Matt Wedel’s Binocular Spotlight column, “Within the Twins’ Toes,” within the February Sky & Telescope, web page 43, with chart. However a scope will do higher than binocs.

■ The waning Moon, nearly final quarter, rises round 11 p.m. relying in your location. As soon as it is up, search for Spica about 6° to its proper. Almost 30° to the Moon’s left or higher left is brighter Arcturus.


■ Final-quarter Moon (actual at 1:47 p.m. EST). Tonight the Moon rises round midnight relying in your location. Discover Arcturus about three fists to the Moon’s higher left and lesser Spica about half as far to the Moon’s higher proper.

By early daybreak on Friday the fifth the Moon is excessive within the south, Arcturus could be very excessive over it, and Spica is to its proper. A lot much less far to the Moon’ decrease left are the pinnacle of Scorpius and Antares, as proven beneath.

The waning Moon slides down over Scorpius earlier than and through daybreak, because it nears its rendezvous with the Solar to finish its present lunation.


■ Earlier than and through early daybreak Saturday morning the sixth, spot the waning crescent Moon within the south-southeast with Antares some four° or 5° to its decrease proper, as proven above.


■ The sky’s largest asterism (casual star sample) — a minimum of the largest one which’s widely known — is the Winter Hexagon. It fills the sky towards the east and south these evenings. Begin with good Sirius at its backside. Going clockwise from there, march up by Procyon, Pollux and Castor, then Menkalinan and Capella on excessive, all the way 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. However should you draw a line by its center from Capella all the way down to Sirius, the Hexagon is pretty symmetric with respect to that axis.

■ Algol must be at its minimal brightness tonight, magnitude three.four as a substitute of its ordinary 2.1, for a pair hours centered 12:46 a.m. EST; 9:46 p.m. PST. Algol takes a number of further hours to fade and to rebrighten.


This Week’s Planet Roundup

Mercury is dropping down from final week’s good apparition in night twilight, and it is also fading quick. On Friday January 29th Mercury continues to be nearly as excessive within the south-southwest because it was final week, however at simply magnitude +Zero.5 it might be surprisingly laborious to identify if you have not regarded in just a few days.

Simply three days afterward February 1st it is solely magnitude +1.5 and dropping quicker; see the highest picture above. Thus ends Mercury’s final night apparition till Could.

Venus is hidden deep within the glow of dawn. Anticipate it again within the night twilight come late spring.

Mars (magnitude +Zero.5, in Aries) shines pale yellow-orange excessive within the southwest after darkish. It units within the west-northwest round 1 a.m. Mars is just eight arcseconds broad now and continues to be as gibbous because it will get, 89% sunlit.

Jupiter and Saturn are out of sight behind the glare of the Solar.

Uranus (magnitude 5.eight, in Aries) is a number of levels beneath Mars in early night. In binoculars Uranus is somewhat pinpoint “star.” However with an obvious diameter of three.6 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 7.9, in Aquarius) is sinking out of sight into the west-southwestern 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 upon longitude (primarily Moon positions) are for North America.

Jap Commonplace Time, EST, is Common Time minus 5 hours. (Common Time is also referred to as UT, UTC, GMT, or Z time. For extra see Time and the Newbie Astronomer.)

Wish to change into a greater astronomer? Be taught your means across the constellations. They’re the important thing to finding every thing fainter and deeper to hunt with binoculars or a telescope.

That is an out of doors nature interest. For an easy-to-use constellation information protecting the entire night sky, use the massive month-to-month map within the middle of every difficulty of Sky & Telescope, the important journal of astronomy.

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

Pocket Sky Atlas cover, Jumbo editionThe Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and tons of of telescopic galaxies, star clusters, and nebulae amongst them. Proven right here is the Jumbo Version, which is in laborious covers and enlarged for simpler studying outside at night time. Pattern charts. Extra concerning the present editions.

Subsequent up is the bigger and deeper Sky Atlas 2000.Zero, plotting stars to magnitude eight.5; practically 3 times as many. The following up, as soon as you already know your means round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.Zero (stars to magnitude 9.75). And make sure to learn the right way to use sky charts with a telescope.

You will additionally desire a good deep-sky guidebook, equivalent to Sky Atlas 2000.Zero Companion by Robust and Sinnott, or the larger (and illustrated) Night time Sky Observer’s Information by Kepple and Sanner.

Can a computerized telescope substitute charts? Not for freshmen, I do not suppose, and never on mounts and tripods which might be lower than top-quality mechanically, that means heavy and costly. And as Terence Dickinson and Alan Dyer say of their Yard Astronomer’s Information, “A full appreciation of the universe can’t come with out creating the talents to search out issues within the sky and understanding how the sky works. This data comes solely by spending time below the celebrities with star maps in hand.”

Audio sky tour. Out below the night sky along with your
earbuds in place, take heed to Kelly Beatty’s month-to-month
podcast tour of the heavens above. It is free.

“The risks of not considering clearly are a lot higher now than ever earlier than. It is not that there is one thing new in our mind-set, it is that credulous and confused considering will be rather more deadly in methods it was by no means earlier than.”
            — Carl Sagan, 1996

“Info are cussed issues.”
            — John Adams, 1770


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