December 21
The December Turning
Sun Position
The Sun is in Sagittarius, reaching its southernmost declination of approximately 23.4 degrees south at the December solstice. In the Northern Hemisphere, today is the shortest day and longest night of the year; in the Southern Hemisphere, the longest day and shortest night. The solstice occurs on December 21 or 22 depending on the year.
Sky Highlight
The December solstice marks the moment the Sun reaches its greatest southern declination and begins its return northward. Simultaneously, the Ursid meteor shower peaks on December 21-22; the shower has a radiant near the bowl of the Little Dipper (circumpolar for northern observers) and a parent body of comet 8P/Tuttle, with typical rates of 5-10 per hour though occasional outbursts have been recorded.
Deep Sky Object
M41, the open cluster south of Sirius in Canis Major, sits at a convenient elevation for southern observers on the solstice and is rising into the southeast by 10 PM for northern observers, a fine naked-eye cluster in a dark sky, containing about 100 stars spread over a region as wide as the full Moon.
Featured Star
Murzim, listed for December 21, is an alternate spelling of Mirzam (β CMa), a B1II-III blue-white giant about 500 light-years away, the herald that rises before Sirius each night. On the solstice night, its rise in the southeast marks the same ancient sequence: herald first, great dog second, the year turning from the longest dark.
Around This Date
- December 21, 1968Apollo 8 launched from Kennedy Space Center, beginning humanity's first crewed journey beyond low Earth orbit, with Frank Borman, Jim Lovell, and William Anders bound for lunar orbit.
- December 21, 2012Festivities were held across parts of Mesoamerica to mark the conclusion of b'ak'tun 13, a roughly 5,126-year cycle in the Mesoamerican Long Count Calendar, an authentic calendrical milestone that had been overlaid by New Age predictions of catastrophe or transformation that did not materialize.
The solstice is not an end. It is precisely where the turn happens, the night at its longest already beginning to shorten.