Each Monday I pick out the northern hemisphere’s celestial highlights (mid-northern latitudes) for the week ahead, but be sure to check my main feed for more in-depth articles on stargazing, astronomy, eclipses and more.
The Night Sky This Week: April 17-23, 2023
What a week to be a sky-watcher. It features a New Moon and a rare kind of solar eclipse happening only seven times in the 21st century. Though the latter is only visible from a “path of totality” in the southern hemisphere, this week also sees 2023’s first major meteor shower and a fabulous conjunction of a crescent Moon and a star cluster. No wonder, then, that it’s also International Dark Sky Week. With a bright Moon nowhere to be seen all week it’s a fabulous time to go stargazing.
Here’s everything you need to know about stargazing and the night (and day) sky this week:
Thursday, April 20: New Moon and a hybrid-total solar eclipse
Today our satellite is directly between the Sun and the Earth. It’s invisible because it’s both lost in the Sun’s glare and because its illuminated side is facing away from us.
However, those lucky enough to be inside a narrow path across the Indian Ocean, Timor Sea and Pacific Ocean will experience a rare kind of “hybrid” total solar eclipse. The curvature of the Earth on this occasion causes the Moon to be momentarily slightly too far away, and so too small, to eclipse the Sun, but only for a fraction of time as the Moon’s shadow clips the edge of Earth. So while two partial “ring of fire” eclipses will be visible—both at sea—the main event will see totality on the bulging part of Earth where the Moon-Earth distance is reduced, making the Moon appear just big enough to cause a total solar eclipse—and a mesmerizing totality.
Lookout for images flashed around the world on social media from places like Exmouth, Western Australia, Timor Leste and West Papua.
Friday, April 21: Crescent Moon, Pleiades and Venus
Look low to the western horizon just after sunset tonight and you’ll see the beautiful sight of a slender 4% lit crescent Moon not only visible to you, but also close to the sparkling star cluster, the Pleiades. Above the pair will be brilliant Venus, just in case you weren’t impressed enough.
Saturday, April 22: Pleiades, Crescent Moon and Venus
Almost exactly the same sight is available to you tonight, the only change being the Moon will have moved between the Pleiades and Venus and it will now be 9%-lit. You’ll also now be able to see a delicate light on the Moon’s darkened limb. That’s “Earthshine,” sunlight reflected off the Earth and back on to the Moon. It’s always there, but only easily visible to the naked eye when the Moon is a slim crescent a few days after New Moon (in the western evening sky) or before New Moon (in the eastern morning sky).
Saturday, April 22: Lyrid meteor shower
With the slim crescent Moon sinking soon after sunset we’ll have ideal sky conditions for this year’s Lyrids meteor shower. The radiant is near the bright star Vega in the constellation of Lyra, from which around 20 “shooting stars” per hour can often be seen. It peaks as it gets dark in North America, so it’s worth staying outside after viewing the crescent Moon with Venus and the Pleiades. Europeans should look after midnight.
Sunday, April 23: Crescent Moon and Venus
Tonight the Moon will be only 15% lit, so still displaying “Earthshine,” and only a few degrees above bright Venus. Again, look west after sunset.
Constellation of the week: Coma Berenices
A simple L-shape of three stars, Coma Berenices is not an imaginative constellation. Sandwiched between Boötes, the Big Dipper and the tip of the tail of Leo, the lion, this constellation is relatively close to orange star Arcturus.
The brightest star in Coma Berenices is Beta Comae Berenices, the middle star, which is a mere 30 light years distant. However, sweep binoculars across it and you’ll come across 20 or so bright stars—and many dimmer stars—that are part of an open cluster called the Coma Star Cluster or Melotte 111.
It’s around 288 light years distant, making it one of the nearest star clusters to our Solar System.
Times and dates given apply to mid-northern latitudes. For the most accurate location-specific information consult online planetariums like Stellarium and The Sky Live. Check planet-rise/planet-set, sunrise/sunset and moonrise/moonset times for where you are.
Wishing you clear skies and wide eyes.