See the Andromeda Galaxy on November 26, 2021 | SkyNews
See the Andromeda Galaxy on November 26, 2021 (Chris Vaughan, Starry Night Education)

This Week’s Sky: November 22 to 28, 2021

This week’s new Moon means it’s an excellent time for deep-sky gazing. Also, look for dwarf planet Ceres at opposition.

Friday, November 26 – The Andromeda Galaxy (all night)

See the Andromeda Galaxy on November 26, 2021 | SkyNews
See the Andromeda Galaxy on November 26, 2021 (Chris Vaughan, Starry Night Education)

In late November, the Andromeda Galaxy is positioned very high in the southeastern sky during evening. This large spiral galaxy, also designated Messier 31 and NGC 224, is 2.5 million light years from us, and covers an area of sky measuring 3 by 1 degrees (or six by two full Moon diameters)! Under dark skies, M31 can be seen with unaided eyes as a faint smudge located 1.4 fist diameters to the left (or 14 degrees to the celestial northeast) of Alpheratz, the star that occupies the left-hand (northwestern) corner of the Great Square of Pegasus. The three westernmost stars of Cassiopeia — Caph, Shedar and Navi (Gamma Cas) — also conveniently form an arrow that points towards M31. Binoculars (green circle) will reveal the galaxy very well. In a telescope, use your lowest magnification eyepiece and look for M31’s two smaller companion galaxies, the foreground, brighter Messier 32 and the more distant, fainter Messier 110.

Saturday, November 27 – Third quarter Moon (at 12:27 GMT)

Third quarter Moon on November 27, 2021 | SkyNews
Third quarter Moon on November 27, 2021 (Chris Vaughan, Starry Night Education)

The Moon will officially reach its third quarter phase at 7:27 a.m. EST, or 12:27 GMT, on Saturday, November 27. At third quarter, our natural satellite always appears half-illuminated on its western side, toward the pre-dawn Sun. It rises in the middle of the night and remains visible in the southern sky all morning. The name for this phase reflects the fact that the Moon has completed three quarters of its orbit around Earth, measuring from the previous new Moon. The ensuing week of moonless evening skies will be ideal for observing deep sky targets.

Saturday, November 27 – Ceres at opposition (all night)

Ceres at opposition on November 17, 2021
Ceres at opposition on November 17, 2021 (Chris Vaughan, Starry Night Education)

On Saturday, November 27, the dwarf planet Ceres will reach opposition, its closest approach to Earth for the year – a distance of 163.5 million miles or 263 million km or 14.6 light-minutes. On the nights around opposition, Ceres will shine with a peak visual magnitude of 7, well within reach of binoculars and backyard telescopes. As a bonus, Ceres will be situated only a thumb’s width above (or 1.4 degrees to the north of) the bright star that marks the chin of the bull, Gamma Tauri. Both objects, and the rest of Taurus’ triangular face, will easily fit within the field of view of binoculars (green circle). Ceres will already be climbing the eastern sky after dusk. It will reach its highest elevation, and peak visibility, over the southern horizon at about midnight local time.

Sunday, November 28 – Io’s shadow and the Red Spot Cross Jupiter (from 23:20 to 01:30 GMT)

Io's shadow and the Red Spot cross Jupiter | SkyNews
Io’s shadow and the Red Spot cross Jupiter (Chris Vaughan, Starry Night Education)

On Sunday evening, November 28, observers in the Americas with telescopes can watch the small, black shadow of Jupiter’s moon Io move across Jupiter’s disk, accompanied by the Great Red Spot. The pair will begin to cross at 6:20 p.m. EST, which converts to 5:20 p.m. CST, 4:20 p.m. MST, 3:20 p.m. PST, and 23:20 GMT. The transit will last for approximately 2 hours. For observers in the western United States and Canada, only the later stages of the event will be occurring in a dark sky.

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.

Get a Free Digital Issue