Editor’s Note: Look to the sky as HMNS Astronomer talks winter solstice for the final sky happenings of 2024. Thank you for watching the stars alongside us.
Saturn is an evening object. Look in the south at dusk.
Venus is also in the evening sky. Look low in the southwest at dusk, near the point of sunset.
Jupiter is opposite the Sun, and up precisely all night long, the night of December 7. For the rest of the month, it is prominent in the east right at nightfall. No star at night is as bright.
Mars also rises in late evening, by 9:20 as December begins and before 7:00 by New Year’s Eve.
The Summer Triangle sets in the west. Watch for the Great Square of Pegasus almost overhead at dusk now and in the west by Christmas. Taurus, the Bull rises in the east, with Jupiter in his horns. Look for the Pleiades star cluster above the reddish Aldebaran. Dazzling Orion, the Hunter rises shortly after dusk (by month’s end, it is already up at dusk). As Orion enters the evening sky, we transition from the relatively dim evening skies of autumn to the brilliant stars of winter. We are beginning to face directly away from the center of the galaxy, looking at stars behind us in our own arm of our galaxy (the Orion Spur).
The Summer Triangle sets in the west. The Great Square of Pegasus is high in overhead. Across the southern sky, we see a region of only dim stars, where only Fomalhaut stands out. Jupiter is in the east, while Saturn is in the south at dusk. Brilliant Venus sets in the southwest. Taurus, the Bull, rises in the east, joined by Orion, the Hunter. These stars herald the coming winter.
Moon Phases in December 2024
New Dec. 1, 12:21 a.m.; Dec. 30, 4:27 p.m.
1st Quarter Dec. 8, 9:27 a.m.
Full Dec. 15, 3:02 a.m.
Last Quarter Dec. 22, 4:18 p.m.
At 3:20 am on Saturday, December 21, the Sun is overhead as seen from the tropic of Capricorn, the farthest point south where this is possible. That’s because Earth’s North Pole is now tilted as far as possible away from the Sun. That’s why this is our winter solstice, the day when we have more night and less daylight than any other. Below the equator, this is the summer solstice because the South Pole is tilted towards the Sun as much as possible.
You will notice, however, that sunset on New Year’s Eve is up to ten minutes later than on December 1. Why, if the 31st is closer to the solstice? Although the shortest day (least daylight) occurs on December 21, the earliest sunset occurs for us about December 1. This is because the Sun’s apparent position in our sky varies like a sine wave; there is little difference in the Sun’s apparent height for about a month before and after the solstice. Due to Earth’s tilt, the Sun does indeed take a shorter, lower path across the sky on December 21 than on December 1, but only by about 1.5 degrees (your pinky at arm’s length blocks one degree). Meanwhile, Earth is slightly accelerating as it approaches perihelion just after the new year. This makes both sunrise and sunset happen a little later each night during December. Near the solstice, this small effect can dominate. Since most of us sleep through sunrise and watch the sunset, days seem to lengthen from December 1-21 when they are in fact still getting shorter.
Our George Observatory is now open every Saturday night for observing! Purchase tickets in advance on our website.
Clear Skies!
Trace your way back through the sky happenings of this year. Find November’s here.
