Full Wolf Moon on January 17, 2022 | SkyNews Canada
Full Wolf Moon on January 17, 2022 (Chris Vaughan, Starry Night Education)

This Week’s Sky: January 17 to 23, 2022

As the Moon reaches its full phase, look for lunar libration. Also, scan the skies for some of winter’s finest deep-sky treats

Monday, January 17 – Small full Wolf Moon (at 23:48 GMT)

Full Wolf Moon on January 17, 2022 | SkyNews Canada
Full Wolf Moon on January 17, 2022 (Chris Vaughan, Starry Night Education)

The full Moon that will occur at 6:48 p.m. EST (or 23:48 GMT) on Monday, January 17 is known as the Wolf Moon, Old Moon and Moon after Yule. The January full Moon always shines in or near the stars of Gemini or Cancer. The Indigenous Ojibwe people of the Great Lakes region call it Gichi-manidoo Giizis, the “Great Spirit Moon,” a time to honour the silence, and recognize one’s place within all of Great Mystery’s creatures. The Cree of North America call the January full Moon Opawahcikanasis, the “Frost Exploding Moon,” when trees crackle from the extreme cold temperatures. Full moons during the winter months climb as high in the sky as the summer noonday Sun, and cast similar shadows. The full moons of January and December, 2022 will appear smaller than those of the rest of the year; the three summer full moons will be supermoons.

Tuesday, January 18 – Uranus stands still (evening)

Uranus stands still on January 18, 2022 | SkyNews Canada
Uranus stands still on January 18, 2022 (Chris Vaughan, Starry Night Education)

On Tuesday, January 18, the distant, blue-green planet Uranus will temporarily cease its motion through the distant stars of southern Aries, completing a westward retrograde loop that began in late August. After Tuesday, the planet will begin to move eastward again. At magnitude 5.75, Uranus can be seen in binoculars (green circle) and backyard telescopes, and even with unaided eyes, under dark skies. Look for the planet’s small, blue-green dot a fist’s width to the lower left of (or 11.5 degrees southeast of) Aries’ brightest stars, Hamal and Sheratan. Or use binoculars (green circle) to locate Uranus using the closer star Mu Ceti.

Wednesday, January 19 – Grimaldi shows lunar libration (all night)

Grimaldi shows lunar libration on January 19, 2022 | SkyNews Canada
Grimaldi shows lunar libration on January 19, 2022 (Chris Vaughan, Starry Night Education)

Due to its orbit’s five-degree inclination and ellipticity, the Moon tilts up-and-down and sways left-to-right by a small amount while keeping the same hemisphere pointed towards Earth at all times. Over the course of many months, this lunar libration effect lets us see 59 per cent of the Moon’s total surface — without leaving the Earth! Libration can be detected by noting the way major features, such as the dark and very round crater Grimaldi, move toward and away from the limb of the Moon, and up and down. That 175-kilometre diameter basin is easy to see using your unaided eyes as well as through binoculars and telescopes. It is located near the western edge of the Moon, just south of the Moon’s equator (the up-down red curve) and below, or lunar southwest of, the large, dark patch of Oceanus Procellarum, the Sea of Storms. On Wednesday, January 19 and the following nights, libration will shift Grimaldi higher and away from the Moon’s edge.

Friday, January 21 – The Pleiades (all night)

The Pleiades on January 21, 2022 | SkyNews Canada
The Pleiades on January 21, 2022 (Chris Vaughan, Starry Night Education)

In mid-evening during late January, the Pleiades open star cluster, also known as the Seven Sisters and Messier 45 is positioned high in the southern sky. The rest of its home constellation Taurus sits below the cluster. Visually, the Pleiades is composed of the medium-bright, hot blue stars named Asterope, Merope, Electra, Maia, Taygeta, Celaeno and Alcyone. In Greek mythology, those characters were the daughters of Atlas, and half sisters of the Hyades. The stars of the Pleiades are indeed related, recently born of the same primordial gas cloud. To the naked eye, only six of the sister stars are usually apparent; their parents Atlas and Pleione are huddled together at the east end of the grouping. Under magnification, hundreds of stars appear. Not surprisingly, many cultures, including Aztec, Maori, Sioux and Hindu have noted this object and developed stories around it. In Japan, it is called Subaru, and forms the logo of the eponymous car maker. Due to its shape, the Pleiades are sometimes confused with the Little Dipper.

Saturday, January 22 – The Double Cluster (evening)

The Double Cluster on January 22, 2022 | SkyNews Canada
The Double Cluster on January 22, 2022 (Chris Vaughan, Starry Night Education)

The Double Cluster is composed of the two large and bright open clusters NGC 884 and NGC 889. It sits high in the northern sky after dusk in winter, and then descends to skim the northern horizon by dawn. Try to split the pair of clusters, each as wide as the Moon and almost a lunar diameter apart with unaided eyes. Binoculars (large green circle) or a low power, wide-field telescope (small green circle) will show them in all their glory. NGC 869, the more westerly cluster, is more compact and contains more than 100 white and blue-white stars. NGC 884, the easterly cluster, is much less compact, and hosts a handful of 8th magnitude golden stars. Use higher power to see doubles, mini-asterisms, and dark lanes of missing stars. The two clusters are inside the Perseus Arm of our Milky Way galaxy, about 7,300 light-years from the Sun. Their visual brightness has been dramatically reduced by opaque interstellar dust in the foreground.

Chris Vaughan is a science writer, geophysicist, astronomer, planetary scientist and an “outreach RASCal.” He writes Astronomy Skylights, and you can follow him on Twitter at @astrogeoguy. He can also bring his Digital Starlab portable inflatable planetarium to your school or other daytime or evening event. Contact him through AstroGeo.ca to tour the Universe together.