Moon and Constellation Gemini

On February 4 and 5, 2012, the moon passes in front of the zodiacal constellation Gemini the Twins. Though the constellation figure won’t be easy to depict in the moonlight glare, you should be able to make out Gemini’s two brightest stars, Castor and Pollux. Castor is the fainter star of the two Twin stars. On February 4 and 5, the moon will reside close to its mean distance from Earth 384,400 kilometers (238,855 miles). Because of the moon’s eccentric orbit, it’s distance from Earth varies quite a bit from this mean figure of 384,400 kilometers. The moon’s mean distance changes over the long course of time. The mean distance is now increasing at the rate of 3.8 centimeters (about 1.5 inches) per year. That adds up to 3.8 meters (about 12.5 feet) a century. The moon is now swinging from apogee to perigee. For the next few nights, watch as the waxing gibbous moon crosses the midway point between these two extremes, hovering near its mean distance from Earth.