Each Monday, I pick out North America’s celestial highlights for the week ahead (which also apply to mid-northern latitudes in the northern hemisphere), but be sure to check my main feed for more in-depth articles on stargazing, astronomy, eclipses and more.
The Night Sky This Week: March 18-24, 2024
This week brings a way marker for stargazers, with the vernal equinox meaning the length of the day and night are the same everywhere in the world. After Tuesday, the nights will begin to get shorter than the days, making it necessary to stay up later to go stargazing. However, the vernal equinox has another effect, with the side-on-to-the-sun position of Earth’s axis meaning statistically more frequent and intense auroras.
There are some excellent views of the moon this week as it waxes towards being a full “Worm Moon,” with the best view for North America coming in the east on Sunday evening—at exactly the same time that Mercury will be at its highest point of the year in the west. The next stop for the moon, of course, is to block the sun on Monday, April 8—and bring North America a total solar eclipse.
Here’s everything you need to know about stargazing and astronomy this week:
Monday, March 18: The Moon In Gemini
Look to the east after dark, and you’ll see the two bright stars in Gemini— Castor and Pollux— appear close to a 68%-lit waxing gibbous moon. They’re 52 and 34 light-years from the solar system, respectively, and the 46th and 17th brightest stars in the night sky.
Tuesday, March 19: Vernal (spring) equinox
Today at 23:06 EDT, the Vernal Equinox—also called the northward equinox in the northern hemisphere—sees the sun passing across the equator, moving north to bring longer (and therefore warmer) days in the northern hemisphere and shorter (and colder) days in the southern hemisphere. However, on the day of the equinox itself, the length of the day and night are the same everywhere in the world.
In the northern hemisphere, the March equinox marks the beginning of astronomical spring; in the southern hemisphere, it signals the beginning of fall.
Thursday, March 21: Moon And Regulus
A waxing gibbous moon, 90% illuminated, will shine three degrees from Regulus, the brightest star in the constellation Leo, “the lion,” after dark in the eastern night sky. Regulus, “star of the Lion’s breast,” is 77 light-years distant and the 21st brightest star in the night sky.
Sunday, March 24: Mercury Rising And The Full ‘Worm Moon’ Lunar Eclipse
It’s your best chance in 2024 to see the tiny planet Mercury, which tonight reaches its greatest eastern elongation from the sun. To catch it—using binoculars—you’ll need to look about 10 degrees above the southwest horizon about 30 minutes after sunset. Act quickly because it will sink soon after—the window is only about 20 minutes.
Although it’s officially a full moon on Monday, March 25, dusk tonight will be the best time to view the third full moon of 2024 and the first of spring in the northern hemisphere. A slight penumbral lunar eclipse will result for the night side of Earth, including North and South America, Europe, East Asia, Australia and New Zealand. From North America, the event will occur between 03:12 and 05:32 a.m. EDT on Monday, March 25.
The event will put the moon on precisely the right trajectory to intersect the ecliptic on Monday, April 8 to cause a dramatic total solar eclipse visible in parts of Mexico, the U.S. and Canada.
Asterism Of The Week: The Big Dipper
The Big Dipper is a group of seven bright stars that form a distinctive pattern resembling a ladle or dipper. Its seven constituent stars make it the closest open cluster to the solar system.
“Spring up, fall down” is how to remember where to find the Big Dipper, one of the night sky’s most easily recognizable shapes. However, it’s not a constellation, but an asterism—a shape—that’s part of a much larger constellation called Ursa Major. “the Great Bear.”
The 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.
