The old moon and Mercury will appear close together on the mornings of November 1, 2 and 3, 2021. The stars Arcturus and Spica may also be visible at either side of Mercury. Mercury will be 1.2 degrees south of the moon on November 3, 2021, at 19:00 UTC.
Moon and Mercury: beauties!
Mercury, the smallest planet and innermost to the sun, is now wrapping up a string of morning appearances that began in mid-October. Early risers can still spot it above the sunrise point in late October and during the first few days of November. At that time of the morning, it’ll be in brightest twilight, near the not-yet-risen sun. Mercury can be difficult to identify. Northern Hemisphere observers must look outside at exactly the right time (not so early that Mercury hasn’t risen yet, and not so late that Mercury fades from view against the bright morning twilight). If you choose that magic moment, the mornings of November 1, 2 and 3, 2021, provide a good opportunity for positively spotting the planet near the waning crescent moon, or “old” moon. The steep autumn angle of the ecliptic for those of us in the Northern Hemisphere will help. Look near the horizon for the thin crescent. Mercury will be the point of light just below it, or – on the morning of November 3 – next to it.
Here is a great way to start your day: Break out the binoculars to spot the little world and to examine the earthshine on the moon’s dark side.
Because of the tilt of the ecliptic, Southern Hemisphere viewers unfortunately won’t have a good view of Mercury or the moon on November 3, or at any other time during the October-November morning apparition of Mercury.
The moon will occult, or cover Mercury, on November 3, 2021. The occultation will be visible from most of Canada and the northeastern United States. But it will be during daylight hours. So this will be a challenging observation to do, and only veteran observers, with telescopes or other optical aids, will have a shot at success. A very clear sky will be essential!
The Mercury occultation will be visible across a swath of Canada and in the northeastern U.S., but during daylight. Map via IOTA.
Bottom line: The old moon will sweep near Mercury on the mornings of November 2 and 3, 2021. From Canada and the northeastern U.S., the moon will occult – cover – Mercury during daylight on November 3.
“I can sometimes see the moon in the daytime” was a cosmic revelation that John Jardine Goss first discovered through personal observations at age 6. It shook his young concept of the universe and launched his interest in astronomy and stargazing, a fascination he still holds today. John is past president of the Astronomical League, the largest U.S. federation of astronomical societies, with over 24,000 members. He's earned the title of Master Observer and is a regular contributor to the video series, “Global Star Party.” He has authored the celestial observing guides “Exploring the Starry Realm,” and “Carpe Lunam,” and “Take Your First Steps, an Introduction to Amateur Astronomy.” John also wrote for twenty years the monthly stargazing column, Roanoke Skies, for the Roanoke Times, and currently writes a bimonthly column, Skywatch, for Blue Ridge Country magazine. He has contributed to Sky and Telescope magazine, the IDA Nightscape, the Astronomical League’s Reflector magazine, and the RASC Observer’s Handbook.
Deborah Byrd (asteroid 3505 Byrd) helps edit EarthSky.org and is a frequent host of EarthSky videos. Deborah created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named in her honor in 1990, a Public Service Award from the National Science Board in 2003, and the Education Prize from the American Astronomical Society in 2020. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.
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