12/07/2021 – Ephemeris – This is the best week to view Comet Leonard

This is Bob Moler with Ephemeris for Tuesday, December 7th. Today the Sun will be up for 8 hours and 55 minutes, setting at 5:02, and it will rise tomorrow at 8:07. The Moon, halfway from new to first quarter, will set at 8:43 this evening.

The evening sky between 5:45 and 7 pm will feature Venus, the crescent Moon, with dim Saturn above it and Jupiter all in the southwestern sky. Saturn will appear dim, only in the early part of that period, due to bright twilight. Saturn is about midway between Venus and Jupiter. In the morning sky, Comet Leonard continues to fall inward toward the Sun. It’s passing relatively close to the Earth, now about 29 million miles. It will pass its closest to on Sunday at about 21 million miles, at which time we’ll have a hard time spotting it in morning twilight. Comet Leonard will stay barely bright enough to spot in dark skies by really sharp-eyed observers without binoculars or a telescope. The rest of us will need optical aid.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

Comet Leonard (C/2021 A1) finder chart for 6:30 am, December 8, 2021. The comet’s tail may not be visible visually. The comet’s head, what astronomers call a coma, may appear as a large fuzzy spot. At that time it will be 26.7 million miles away, and will come within 21.7 million miles at its closest to us on the 12th. Created using Stellarium.

Comet Leonard’s positions at 6:30 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for November 27th. The star field will be shifting to the upper right each morning at 6:30 from the November 27th date at 6:30. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. Created using Cartes du Ciel (Sky Charts). I’ve reversed the colors from previous printings of this image. Reprinted from my article in the Stellar Sentinel, the newsletter for the Grand Traverse Astronomical Society.