Sky this month: December 2021
Jupiter begins in December in the eastern part of Capricorn, about 16.5 ° east of Saturn. It shines at magnitude -2.3, but rapidly decreases to magnitude 0.1, then changes to Aquarius on December 14. The waxing Moon is below Jupiter on December 8, while Jupiter is 10 ° west of the Moon on December 9.
Jupiter’s 37 “diameter disc looks great through a telescope – your best views will be at dusk and for about an hour after dark. In late December, Jupiter dips below 20 ° around 19 hours local time and sets at 9 PM
Check the configuration of its four Galilean moons – their relative positions change every night. On December 1, an eclipse occultation and reappearance occur in close proximity to each other. First, Callisto reappears behind Jupiter at 9:13 p.m. EST, followed by Europa leaving Jupiter’s shadow at 11:15 p.m. EST.
Watch Io disappear behind Jupiter on December 4 at 9:35 p.m. EST. The following night, Io and his shadow cross the face of Jupiter shortly after dark. Io’s transit ends at 9:14 p.m. EST, followed by his shadow 75 minutes later. Two days later, Ganymede, Jupiter’s largest moon, transits on December 7 from 9:03 p.m. EST. The event continues for more than 3 hours.
Neptune is a binocular object shining at magnitude 7.8 for most of the month and located in Aquarius the water carrier. It rises high in the southern sky on December 1 and remains visible all evening until it drops very low after 11 p.m. local time. The distant planet is located 3 ° northeast of the 4th magnitude star Phi (ϕ) Aquarii on December 1. That night, Neptune is at its stationary point; he barely moves all month. Neptune is 4.5 ° north of a first quarter moon on December 10.
At the ice giant’s enormous distance of almost 30 astronomical units (where 1 astronomical unit or AU is the average Earth-Sun distance) from us, its disc extends only 2 “through a telescope. Use magnification. brought up on a regular night of vision to reveal its blue-green disc.
Uranus sits high in the sky against the backdrop of Aries the Aries every night and goes to bed early in the morning. It lies about 11 ° southeast of Hamal, the brightest star in Aries. Uranus glows at magnitude 5.7, an easy object for binoculars once you’ve found the right field of view. The ice giant is about 3 ° northeast of the Gibbous Moon on December 14.
December is a great time to view Uranus with a telescope, given its high altitude after dark. Uranus spans 4 “with a distinctive greenish-blue hue. At a distance of 1.7 billion miles (19 AU), it is a wonder to behold.