Sunday, December 5
It’s Comet C/2021 A1 (Leonard)’s time to shine! Rising by 2 A.M. local time, your best bet for catching this comet until next week is in the few hours before sunrise, as it climbs higher in the southeastern sky in the constellation Boötes. This tiny ball of ice and dust currently sits less than 6.5° north of the constellation’s brightest star, magnitude –0.1 Arcturus. It’s also floating tonight just 7° east-southeast of the 6th-magnitude globular cluster M3, which lies just over the celestial border in Canes Venatici.
In the right pair of binoculars, you should be able to just capture both the comet and the cluster in the same field of view. Compare their appearance: M3 is about 18' across, while 8th-magnitude Leonard should appear smaller, about 8' wide.
Make sure to keep an eye on this comet as it skims southeast each morning: By the end of this week, Leonard is estimated to reach naked-eye brightness before quickly fading again back to 8th magnitude by the end of the year.
Sunrise: 7:07 A.M.
Sunset: 4:34 P.M.
Moonrise: 8:48 A.M.
Moonset: 5:56 P.M.
Moon Phase: Waxing crescent (3%)
Monday, December 6
Now moving away from the Sun, the Moon’s first stop is Venus: Our satellite sits less than 3.5° below the bright planet this evening. Just over 2.5 days old, the Moon is a delicate waxing crescent perfect for showing off earthshine. This phenomenon occurs when sunlight reflects off Earth, partly illuminating the portion of the Moon’s face still in shadow.
The pair is located in Sagittarius, which lies in the direction of the Milky Way’s rich central bulge. There are plenty of deep-sky targets here, although the fading twilight and low altitude will make them a challenge. But nearby Aquarius hosts three Messier catalog entries to hunt down: globular clusters M2 and M72, as well as the strange object M73. Consisting of only four stars that astronomers don’t believe are physically related, this asterism lies about 1.5° east of M72.
Sunrise: 7:08 A.M.
Sunset: 4:34 P.M.
Moonrise: 9:54 A.M.
Moonset: 7:05 P.M.
Moon Phase: Waxing crescent (9%)
Tuesday, December 7
After sliding under Venus yesterday, today the Moon passes 4° south of Saturn at 9 P.M. EST. They’ll have already set by then, but you can easily catch the pair earlier at sunset, located in the constellation Capricornus.
The Moon is now a slightly larger waxing crescent, slowly growing brighter as the number of days since New Moon increases. Saturn is magnitude 0.6, sitting midway between much fainter, 5th-magnitude Eta (η) and Rho (ρ) Capricorni. Zoom in with a telescope to see the planet’s fantastic ring system, stretching 35" across — more than half the width of the planet’s disk, which is 16" in diameter. You may also spot the planet’s largest and brightest moon, magnitude 8 Titan, sitting nearly 1.5' northwest of Saturn tonight.
Now is the time to enjoy views of Saturn, as it will steadily sink lower each night. As objects get closer to the horizon, we’re looking at them through more of Earth’s atmosphere, which blurs the image and degrades its quality.
Sunrise: 7:09 A.M.
Sunset: 4:34 P.M.
Moonrise: 10:48 A.M.
Moonset: 8:18 P.M.
Moon Phase: Waxing crescent (17%)