First quarter Moon on January 28, 2023, at 15:19 GMT. (Chris Vaughan) | SkyNews
First quarter Moon on January 28, 2023, at 15:19 GMT. (Chris Vaughan)

This Week’s Sky: January 23-29

The Moon takes centre stage this week — joining the Venus-Saturn conjunction, passing Neptune and Vesta, sharing a view with Jupiter and Juno, and shining close to Uranus.

Every week, SkyNews publishes a list of key events in the Canadian sky in This Week’s Sky. This series gives you all the latest news in Solar System movements, including where the planets are in our sky and Moon phases. From eclipses to meteor showers, This Week’s Sky keeps you updated on the best in upcoming astronomical highlights.

Monday, January 23 – Crescent Moon with Venus and Saturn (after sunset)

Crescent Moon with Venus and Saturn on January 23, 2023, at 5:48 p.m. (Chris Vaughan) | SkyNews
Crescent Moon with Venus and Saturn on January 23, 2023, at 5:48 p.m. (Chris Vaughan)

On Monday, January 23, the slender crescent of the young Moon will join the Venus-Saturn conjunction, setting up a wonderful widefield photo opportunity in the west-southwestern sky in early evening. The Moon, which will be positioned a generous palm’s width to the upper left of the two planets, may exhibit Earthshine. Sometimes called the Ashen Glow or the Old Moon in the New Moon’s Arms, the phenomenon is visible within a day or two of the new Moon — when sunlight reflected off Earth and back toward the Moon slightly brightens the unlit portion of the Moon’s Earth-facing hemisphere. 

Tuesday, January 24 – Crescent Moon passes Neptune and Vesta (evening)

Crescent Moon passes Neptune and Vesta on January 24, 2023, at 7:15 p.m. (Chris Vaughan) | SkyNews
Crescent Moon passes Neptune and Vesta on January 24, 2023, at 7:15 p.m. (Chris Vaughan)

On Tuesday evening, January 24, the easterly orbital motion of the waxing crescent Moon (green line) will carry it towards Neptune and the large asteroid Vesta. In the Americas, the Moon will set while it is still about a palm’s width below (or celestial southwest) of them. Observers across the International Date Line in eastern Asia, New Zealand, and Australia can see the Moon posing between them on Wednesday evening, when magnitude 7.9 Neptune will be located a generous thumb’s width below the Moon. During this time, magnitude 8 Vesta will shine several finger widths to the Moon’s upper left. 

Wednesday, January 25 – Waxing Moon meets Jupiter and Juno (evening)

Waxing Moon meets Jupiter and Juno on January 25, 2023, at 7 p.m. (Chris Vaughan) | SkyNews
Waxing Moon meets Jupiter and Juno on January 25, 2023, at 7 p.m. (Chris Vaughan)

The Moon will continue its trip past the planets on Wednesday evening, January 25. Tonight the 23 per cent illuminated crescent Moon will dance several finger widths below (or celestial south-southwest of) very bright Jupiter, close enough for them to share the field of view in binoculars (green circle). Sky-watchers in westerly time zones will see the pair closer together before they drop below the rooftops in mid-evening. The relatively faint, magnitude 9.6 asteroid Juno will be positioned a palm’s width to the left of Jupiter all week. 

Thursday, January 26 – The Hyades cluster (all night)

The Hyades cluster on January 26, 2023, at 8 p.m. (Chris Vaughan) | SkyNews
The Hyades cluster on January 26, 2023, at 8 p.m. (Chris Vaughan)

Located only about 150 light years away from the Sun, Taurus’ triangular face is actually one of the nearest open star clusters to us. It is commonly called the Hyades, named for the five daughters of Atlas in Greek mythology. It also has the designations Melotte 25 and Caldwell 41. 

The cluster contains several hundred stars, with a half-dozen or so readily seen under moonless suburban skies — many as close pairs. It is a superb target to view in binoculars (green circle). The five brightest members, all naked-eye stars, are within a few light years of one another. 

The cluster’s stars likely formed together about 625 million years ago. The bright orange star Aldebaran, at the lower (southeastern) vertex of the Hyades, is actually not part of the cluster. It is less than half as far away! On late January evenings, the Hyades are very high in the southern sky. 

Saturday, January 28 – First quarter Moon (at 15:19 GMT)

First quarter Moon on January 28, 2023, at 15:19 GMT. (Chris Vaughan) | SkyNews
First quarter Moon on January 28, 2023, at 15:19 GMT. (Chris Vaughan)

When the Moon completes the first quarter of its orbit around Earth at 10:19 a.m. EST (or 15:19 GMT) on Saturday, January 28, the relative positions of the Earth, Sun, and Moon will cause us to see it half-illuminated on its eastern side. At first quarter, the Moon always rises around midday and sets around midnight, so it is visible in both the afternoon daytime sky and during the evening. The evenings surrounding the first quarter are the best for seeing the lunar terrain when it is dramatically lit by low-angle sunlight. 

Saturday, January 28 – Half Moon buzzes Uranus (late night)

Half Moon buzzes Uranus on January 28, 2023, at 11:30 p.m. (Chris Vaughan) | SkyNews
Half Moon buzzes Uranus on January 28, 2023, at 11:30 p.m. (Chris Vaughan)

On Saturday evening, January 28 in the Americas, the slightly gibbous Moon will shine two finger widths to the lower right (or about two degrees to the celestial west) of the magnitude 5.7 planet Uranus. The Moon’s eastward orbital motion will carry Luna closely past Uranus during the night, eventually allowing them to share the view in a backyard telescope (green circle). Observers in Alaska, far northern Canada, Svalbard, and Greenland can see the Moon occult Uranus starting around 04:30 GMT on January 29. You can use an app like Starry Night to determine the start and end times for the occultation where you live. 

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.

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