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.
What To Watch For In The Night Sky This Week: March 8-14, 2021
There is no such thing as a “quadruple conjunction,” at least technically-speaking, but it’s the easiest way to convey what’s about to happen in the pre-dawn night sky this week.
On Tuesday and Wednesday, Jupiter and Saturn will be joined on one side by a rising Mercury and on the other approached by a waning crescent Moon, creating a momentary line-up of four celestial bodies.
It’s officially a “planetary trio,” with each planet said to be in conjunction with the Moon on three successive mornings, but very early on Tuesday morning is when to look.
Here’s how to watch—and everything else you need to know about planet-spotting and stargazing this week.
Tuesday, March 9, 2021: Three planets align with a crescent Moon
Get up an hour before sunrise and look low to the southeast horizon and you’ll see the wondrous sight of a 16%-lit waning crescent Moon hanging in the sky. Scan your eyes about 3° east and you’ll see Saturn and, 3° below it, brighter Jupiter.
Really close to Jupiter, rising and brightening as the sky does so, will be Mercury. To find it, draw a line from Saturn through Jupiter and go a quarter of that distance again. Binoculars may help. But be really careful using them as the Sun rises—you must not look at the Sun through any optical equipment.
Wednesday, March 10, 2021: Three planets align with a crescent Moon
The alignment remains this morning before dawn the only differences being that Mercury will have moved further from Jupiter, and will rise slightly later. Meanwhile, the now 9%-lit waning crescent Moon will be closer to the horizon and to Jupiter.
Saturday, March 13, 2021: New Moon
The inevitable consequence of that waning crescent Moon is that it’s getting closer to the Sun, and today it gets lost in its glare completely so will become invisible.
Get outside stargazing after dark in the next week and you’ll see it emerge the other side of the Sun into the evening sky as a super-slim waxing crescent.
Constellation of the week: Gemini, the twins
Face southwest, find the famous three stars of Orion’s Belt, then look straight up and you’ll see two bright stars close together. The “twins” of Gemini, Pollux (34 light years distant) and the slightly fainter Castor (51 light years) are in our cosmic neighborhood. Pollux is a single giant star nine times the radius of our Sun, and has a confirmed exoplanet in orbit, while the Castor star system—visible to us as one point of light—is a star system of six stars all orbiting each other.
Star of the week: Cor Caroli
Go outside close to midnight and look north. You’ll see the seven stars of The Big Dipper/The Plough asterism high in the sky on its side. At the end of the handle is Alkaid. Look to the side of Alkaid—about the same distance as the handle is long—and you’ll come to the star called Cor Caroli.
A double star about 115 light-years distant, its name means “Charles’ Heart.” It was so named because it was said to shine brightly on the night King Charles II returned to England on May 29, 1660 to restore the monarchy after the English Civil War. It’s also part of the “Spring Diamond” asterism that we’ll look for later this month.
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.