January 2018 is astronomically special. It is hosting two full moons. One was on Jan. 1 and the second is Jan. 31. The most common definition of a “blue moon” is the second full moon in a month. This happens because the lunar cycle is 29 days, and all but February have more days. So, if a full moon occurs at the beginning of one of these long months, then there can be a blue moon. Another definition is the fourth full moon in a quarter.
January’s full moons also occur when the moon is at perigee. This is the point in its elliptical orbit when it is closest to the Earth. The moon is slightly larger than average: a super moon.

So watch out for the blue moon, and to see the celestial wonders come by the observatory on the first Friday each month from sunset to 10 p.m.: .

By Dr. Aaron B. Clevenson
Observatory Director, Insperity Observatory

Aaron Clevenson
Author: Aaron ClevensonEmail: This email address is being protected from spambots. You need JavaScript enabled to view it.
I am the observatory director at the Insperity Observatory in Humble ISD. I am also an adjunct astronomy professor at Lone Star College-Montgomery where I teach solar system astronomy and stars and galaxies astronomy. I am the author of the astronomy textbook, “Astronomy for Mere Mortals.” I am a past president of the North Houston Astronomy Club, and was the chair of Astronomy Day in Southeast Texas in 2015 and 2016. He is an observing program director with The Astronomical League, coordinates their Master Observer Progression Awards, and has authored six of their observing programs.