Spring is almost here, and that means a shift in the night sky. Winter’s bright constellations and famous old stars—Orion, the hunter and taurus, the bull with their bright stars Betelgeuse, Rigel and Aldebaran—begin to sink towards the western sky after the Sun sets. In their place, rising in the east, are the stars of Spring—Leo, the Lion, Boötes, the herdsman, and the most familiar stars of all—Ursa Major, the great bear, best known for its “Big Dipper” shape of stars.
There are so many great reasons to get outside at night this month, especially since the nights will be shorter than the days come equinox on Saturday, March 20.
Here’s when and where to look in March 2021:
1. Mars near the Pleiades
When: After sunset on Wednesday, March 3, 2021
A planet moving in front of a famous star clusters can be a beautiful sight. In April 2020 the super-bright planet Venus became part of the Pleiades open cluster for a few nights. Something similar will grace the southwestern night sky after dark today when the red planet Mars will be close to the Pleiades (also known as the “Seven Sisters”). Look for the spectacle a few nights either side of its closest pass on 3 March, 2021.
2. Mercury and Jupiter in a very close conjunction
When: Before sunrise on Friday, March 5, 2021
Look low on the southeastern horizon this morning and you’ll see the tiny, fast-moving planet Mercury super-close to Jupiter. Of course, it’s merely a line-of-sight illusion since Mercury is the closest planet to the Sun while Jupiter is the fifth-closest.
3. The Moon meets Mars
When: After sunset on Friday, March 19, 2021
A conjunction of our satellite with a planet is always a highlight for sky-watchers. Mars spends much of March in and around the Pleiades star cluster. On March 18 the red planet will form a nice triangle with the Pleiades and a waxing crescent Moon while a day later it will be much closer to the Moon.
4. Spring or ‘vernal’ equinox
When: Saturday, 20 March, 2021
At precisely 9:37 Universal Time (5:37 a.m. EST and 2:37 a.m PST) it’s the spring equinox, the beginning of the astronomical season of spring, which sees the length of night and day almost identical (equi means equal and nox means night).
Equinox is the moment in Earth’s orbit around the Sun when our star appears to cross the celestial equator. As the northern hemisphere begins to tilt towards the sun it means longer and warmer days. In the southern hemisphere the effect is the complete opposite.
5. The Big Dipper ‘springs up’
When: all month
You know the Big Dipper, but do you know the saying “spring up, fall down” to describe its seasonal position? You’ve likely not seen the famous stars of the Big Dipper lately, but now its spring the cluster is high in the north-eastern night sky after dark. The Big Dipper is not a constellation, but an “asterism”—a simple shape of seven stars—comprising Alkaid, Mizar, Alioth, Megrez, Phecda, Merak and Dubhe.
6. A full ‘Super Worm Moon’ sparkles
When: 18:48 Universal Time, Sunday, March 28, 2021
All eyes to the east at dusk on March 28 at moonrise where you are for the first “supermoon” of 2021. By some definitions this weekend’s full Moon—the first of spring 2021—can be called the “Super Worm Moon.” A supermoon occurs close to its perigee—the point in the Moon’s monthly orbit when it’s closest to Earth—which for the “Worm Moon” occurs a couple of days later. A supermoon is a full Moon that occurs within 90% of its closest approach to Earth in a given orbit. Either way, March’s full Moon—sometimes also called the “Crow Moon,” “Crust Moon,” “Sap Moon” and “Sugar Moon”—will be dressed in bright orange for its monthly moonrise moment.
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.