If you live in the Northern Hemisphere and thought you didn’t need street lights to meander outside last night, you will have the same brightness tonight – unless you are in or around Chicago’s expected first big snowfall.
The bright light is thanks to the Long Night Moon, a full moon also called the Cold Moon, it shines from dusk to dawn.
Considered by some as the last full moon of the decade, it will be at its fullest at 9:28 CT Dec. 29, 2020. But because it is still lighting the sky after midnight it might be on some calendars as Dec. 30.
Other sky watchers consider Dec. 12, 2019 the last full moon of the decade.
Graphic made from a simulation program, showing a view of the 2020 great conjunction through the naked eye just after sunset. (NASA photo)
We, in the Northern Hemisphere, may hate that nights leading up to the Winter Solstice Dec. 21, 2020 have gotten longer. But this year the darkness is a bonus.
Because, shortly after the sun sets, Monday, Dec. 21, sky watchers should be able to see two of our planets, Jupiter and Saturn, closer to each other’s orbits then they will be for years.
In addition, staying darker longer also means being able to watch the Ursid Meteor shower which peaks Dec. 21 and what’s left of the Geminids early Monday (or Tuesday) morning.
(BTW, even though the Winter Solstice has the shortest amount of daylight, the earliest sunset already occurred and the latest sunrise is still a few days off. See what your sunrise and set times are.
Prime time to see the two planets at their closest is 4:15 p.m. CST Monday, low in the southwest. But you can see them fairly close to each other through December.
What regular sky watchers know is that the two planets do pass near each other every 20 years as they last did in 2000. The difference this year is that their orbits bring them 10 times closer than in 2000.
Indeed, they will be closer than they have been seen at night than in 800 years and closer during the day in 400 years. Seen together as a “great conjunction,” they may resemble one large or elongated planet or star.
As for the meteors, the Ursids which shoot across the sky seemingly radiating from Ursa Minor about 10 meteors per hour, aren’t as plentiful as the Geminids. However, both can be seen Dec. 20-22. The Ursid comet parent is 8P/Tuttle.
Look up early, early morning after midnight, Sunday, Dec. 13 or Monday, Dec. 14, 2020. The Geminids will be flying across the sky.
Considered the best meteor shower of the year, the Geminids turn out about 120 meteors per hour.
Fortunately the moon, now in its new phase, won’t be a factor. But weather, at least in the Chicago area, is.
However, the Geminids whose radiant is the bright Castor star in the constellation Gemini (The Twins), can be seen in both hemispheres. Its parent is 3200 Phaethon.
Best viewing is away from street and commercial lights so consider bringing a friend to keep you company.
