January 2018

Sky Report - January 2018

By Dr. Bob Doyle, Emeritus Faculty
Dr. Doyle taught and was Planetarium Director at Frostburg State University for over 40 years

First Quarter of January (Jan 1-8)

In early January, local sunrises are about 7:36 a.m. with sunsets about 5:05 p.m. January opens with the planet Mercury at its greatest angle to the sun in the southeastern dawn, but Mercury is so far south that it will be difficult to see. On the evening of January 1, the moon will be full and also closest to the Earth (perigee). So late in the evening, we will have the brightest and largest (in angle) full moon of 2018. Soon after midnight on January 3, the Earth will be closest to the sun for the year at a distance of 91.5 million miles. Our cold weather at this time of the year is due to the tilt of the Earth’s axis. The northern hemisphere is now tipped away from the sun, so the sun’s rays strike the ground at a low angle. Also daylight in early winter averages about 10 hours a day, so the Earth is getting less heating from the sun. At dawn on January 7, the bright planet Jupiter and the planet Mars will appear less than one moon width apart in the 6 a.m. dawn. On January 8, the moon at dawn will appear nearly half full (like a reversed ‘D’) in the South.

Second Quarter of January (Jan 9-16)

About a dozen days into January, local sunrises are about 7:35 a.m. with sunsets about 5:10 p.m. At dawn on January 11, the crescent moon will appear above the bright planet Jupiter and the planet Mars. Jupiter appears a dozen times brighter than Mars due to its bigger diameter and highly reflective clouds. The star group Orion with its prominent belt (of three stars in a row) is conspicuous in the southeastern evening sky. The bright star on the top left of Orion is Betelgeuse, a red supergiant star. On the bottom right of Orion is Rigel, a striking white-blue star. The three star belt in the middle of Orion points down and left to Sirius, the night’s brightest star. Sirius is also the closest night star seen from most of the United States. Sirius’ light takes nearly 9 years to travel to Earth. The brightest evening stars in January form a huge oval that is centered on Betelgeuse.

Third Quarter of January (Jan 17-24)

About a dozen days before the end of January, local sunrises are about 7:33 a.m. with sunsets about 5:20 p.m. The moon swings from the morning to the evening side of the sun on January 17th. By January 19th, a slender crescent moon may be sighted low in the western dusk (try 6 p.m.). The evening moon grows to half full by January 24, offering good views of the moon’s craters along the moon’s left edge where the sun there is rising. The sun is now in front of the star group Capricornus, a mythical half fish and half goat. In Greek mythology, the goddess Aphrodite was relaxing along a creek when a terrible monster appeared. In desperation, she turned herself into a goat, but then had to jump into the water. She was on her way to transform herself into a fish.

Last Quarter of January (Jan 25-31)

Several days before the end of January, local sunrises are about 7:27 with sunsets about 5:28 p.m. The moon is growing towards full. There will be a second full moon on January 31. So we can call this full moon a blue moon. The dwarf planet Ceres will be closest and brightest on January 31 between the star groups Leo and Cancer. Ceres is about the size of Texas and lies about 158 million miles from the Earth. Using a good star map, Ceres can be seen with binoculars. In the southern evening sky, five bright stars form a ‘W’. Two of the stars are in Orion, pinkish Betelgeuse and white-blue Rigel. On the left side of the W are the two dog stars, Procyon on top and Sirius below. The rightmost star of the w is orange Aldebaran, marking the eye of Taurus. The moon will be passing across this W at the end of January.