Waning crescent Moon at 8:10 AM CDT (13:10 UTC), 11-3-10, seven minutes after sunrise at my location. 8″ f8 reflector, 25mm eyepiece, LG VX8360 cell phone camera. Click for larger view.
As I look at the stats for my blog, I see that people who stop by frequently have been making searches like “Is the Moon’s orbit changing” and the like. It makes me wonder, is there a rumor floating around that the Moon’s orbit is changing or running amok in some way? Somebody please let me know when you stop by! The truth is, the Moon’s orbit is very complex, and in some ways is always changing, but in regular, predictable ways. Rather than try to explain it all, I’ll refer you to the Wikipedia article on the Orbit of the Moon, which can be a bit technical, but nevertheless gives a good overview of the subject. Among other things, the Moon is very slowly spiralling outward. Its average distance from the Earth is increasing at the rate of 38 millimeters per year. This means that the Moon’s average distance from the Earth increases by one mile every 42,351 years. Not much difference during my life span, how about you?! In today’s photo, the Moon once again is approaching perigee, its closest approach to Earth during its elliptical orbit. We’ve been in a period of time when perigee comes close to New Moon, but that will gradually, steadily change. I’ll keep you posted, but be patient – things in the sky happen when they happen!
Bonus lunar closeup from a few days ago: The North end of the Moon at 6:28 AM CDT (11:28 UTC) 10-29-10, 8″ f8 reflector, 25mm eyepiece, 2x Barlow.