Venus continues to appear higher and higher in the sky each night, outshining everything but the Sun and the Moon. Look for it in the southwest at dusk, shifting towards due west by next month.
Mars rises in late evening and is now high in the southwest at dawn.
It rises by 10:45 as January begins and by 9:00 at month’s end. Although not nearly as bright as Venus or Jupiter, Mars has brightened enough to rival the brightest stars in the sky, and will keep brightening all winter as Earth approaches it.
Saturn remains in the morning sky this month. Look in the south at dawn, near the star Spica. (From the Big Dipper’s handle, arc to Arcturus and speed on to Spica).
The Great Square of Pegasus sets in the west.
Facing north, you’ll see five stars in a distinct ‘M’ like shape—this is Cassiopeia, the Queen. Her stars are about as bright as those in the Big Dipper, and she is directly across the North Star from that Dipper. In late autumn, as the Big Dipper hugs the horizon and actually sets for us in Houston, Cassiopeia is high in the north. Taurus, the Bull rises in the east. Look for the Pleiades star cluster above 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.
|Moon Phases in January 2012:|
|First Quarter||January 1, 12:15 am; January 30, 10:11 pm|
|Full||January 9, 1:30 am|
|Last Quarter||January 16, 3:08 am|
|New||January 23, 1:39 am|
The New Moon of Monday, January 23, is the second New Moon after the winter solstice.
Therefore, it marks Chinese New Year. Welcome to the Year of the Dragon!! On Wednesday, January 4, the Earth makes its closest approach to the Sun, known as perihelion. However, our orbit is so circular (eccentricity only 0.0167) that the difference between perihelion and aphelion is too small to affect our seasons. Days begin to lengthen slightly, now that we are past the winter solstice. However, the latest sunrise of the year here in Houston is not on the solstice, but approximately on January 10! That’s because the Earth is still going faster than average on its orbit, having just passed perihelion on the 4th. This acceleration shifts sunrise, local noon, and sunset slightly later each day this month. The effect is normally smaller that that of the Sun taking a slightly higher path across the sky, which would lead to later sunsets and earlier sunrises after the solstice. 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.
After mid-month, however, the Sun’s greater apparent height and longer apparent path across the sky are significant enough that sunrises occur earlier and sunrises occur later each day.
We have made improvements to the main telescope at George Observatory! First light on the newly improved mirror is set for Saturday, January 7. 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.
Please visit www.hmns.org to see the latest planetarium schedule.