Editor’s Note: We are looking up as HMNS Astronomer James Wooten jumps into the new year with January sky happenings, including perihelion.
Saturn is well placed for observing in early evening. Face south-southwest at dusk to observe it.
Jupiter is prominent high in the sky, almost overhead at nightfall. No star at night is as bright.
Venus remains in the morning sky. Look for it in the southeast at dawn this month.
Mars begins to emerge from the Sun’s glare late this month. Look to the lower left of Venus at dawn. Mercury passes by on the 27th.
Watch for the Great Square of Pegasus in the west at dusk. Taurus, the Bull is high in the south. Look for the Pleiades star cluster above reddish Aldebaran. Dazzling Orion, the Hunter takes center stage on winter evenings. Surrounding Orion are the brilliant stars of winter. Orion’s belt points down to Sirius, the Dog Star, which outshines all other stars we ever see at night. The Little Dog Star, Procyon, rises with Sirius and is level with Orion’s shoulder as they swing towards the south. To the upper left of Orion’s shoulder is Gemini, the Twins.
Moon Phases in January 2024
Last Quarter Jan. 3, 9:30 p.m.
New Jan. 11, 5:57 a.m.
1st Quarter Jan. 17, 9:53 p.m.
Full Jan. 25, 5:54 p.m.
At 6:38 pm on Tuesday, January 2, the Earth was as close to the Sun as it will ever get this year; it reached perihelion. So why is it cooler now than in summer? That’s because Earth’s orbit is almost, but not quite, a perfect circle. The Earth-Sun distance varies only by about three percent, which is just not enough of a difference to make us warmer when we come closer to the Sun. The Earth’s tilt on its axis, not its changing distance from the Sun, causes the seasons.
The latest sunrise of the year (7:17 am) occurs on January 10. That’s due to the same effect I mentioned last month; Earth’s slight acceleration near perihelion makes sunrise, noon, and sunset all occur a little later each day. Most of us sleep through sunrise but are awake for sunset, so you’ve probably noticed that sunsets are significantly later than last month. However, the days aren’t really that much longer, as sunrises have been getting later as well. Although the midday Sun is a little higher in the sky now than on the solstice, the difference is still small. After mid-month, when the Sun starts taking a much more noticeably higher, longer path across the sky each day, we’ll start seeing earlier sunrises and later sunsets as days lengthen.
Our George Observatory is now open every Saturday night for observing! Purchase tickets in advance on our website.
Looking for December’s sky happenings? See them here.