Venus is in the southeast at dawn, approaching Saturn. Venus passes Saturn the morning of January 9; the two planets are less than one tenth of one degree apart! They’re easy to tell apart, as Venus outshines all the stars we see at night and is almost 100 times brighter than Saturn.
Mars is now in the south at dawn. Much dimmer than Venus now, Mars is getting a little brighter each day until its opposition next spring.
Jupiter now dominates the southwestern sky at dawn. As Jupiter approaches its opposition on march 8, you can also begin looking for it in late evening. By January 31, for example, Jupiter rises by 9:00 and will have cleared most horizon obstacles by 9:30 or 10.
In January, the Big Dipper is only partly risen at dusk. As the Big Dipper rises, though, Cassiopeia remains high. This is a pattern of five stars in a distinct W (or M) shape which lies directly across the North Star from the Big Dipper. Look for Cassiopeia high in the north on fall and winter evenings.
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.
Last Quarter Jan. 1, 11:30 p.m.; Jan. 31, 9:28 p.m.
New Jan. 9, 7:31 p.m.
1st Quarter Jan. 16, 5:26 p.m.
Full Jan. 23, 7:46 am
At 4:49 pm on Saturday, January 2, the Earth was as close to the Sun as it will get this year. Thus we say that the Earth was at perihelion. However, Earth was only about 1.6% closer to the Sun than average on this date. That’s why being closer to the Sun at this time does little to warm us up. The effect of Earth’s tilt on its axis dominates the small effect of Earth’s varying distance in causing the seasons.
Although the shortest day (least daylight) occurs on December 21, the latest sunrise occurs for us about January 10. That’s because the Earth speeds up on its orbit as it approaches perihelion. This acceleration shifts sunrise, local noon, and sunset slightly later each day for the first part of this month. The effect is smaller than that of the Sun taking a slightly higher path across the sky, which normally dominates in causing later sunsets and earlier sunrises. But the Sun’s apparent path varies very little near the solstice itself, allowing the secondary effect of the Earth approaching the Sun to predominate until mid-January. Most people, then, will notice that both sunrise and sunset are now happening earlier than in December. As we move farther from the solstice, the effect of the Sun taking a slightly higher path each day again predominates.
On most clear Saturday nights at the George Observatory, you can hear me do live star tours on the observation deck with a green laser pointer. If you’re there, listen for my announcement.