Langrenus

Anytime is a good time to take photos of the Moon. Often the terminator where the Suns grazing rays reveal stark geographic details get’s all the attention, but much of the Moon is also amazing when seen with the Sun high overhead. Along the limb as well, we can see that the Moon is not a smooth round sphere, but has its dips and valleys as. In fact some astronomers will time star or asteroid occultations (when the star or asteroid disappears and reappears) along the edge of the Moon to refine our models of celestial mechanics.

This may be one of my favorite images of the lunar surface in a long while. The crater Langrenus is the large circular feature in the middle of the frame, and you can see the rings from the terraced structure of its crater walls with the Sun nearly overhead. To the upper left is Mare Fecunditatis with the two side by side craters Messier and Messier A. Don’t miss the dual rays cast off to the left like the tail of a comet. At the upper right, we see a depression with a dark floor, that is Mare Smythii rocked towards the Earth this night (August 19, 2021) by a favorable libration (an apparent rocking back and forth we observe of the Moon due to it’s non-circular orbit around the Earth).

Tech details: Taken with an Esprit 150 refractor and a TeleVue 4x Powemate for a total focal length of 4200mm. The best 1/2 of 20,000 video frames taken with a cooled ASI 174 camera were combined for this image. All from my back yard in Lake Mary, FL on a Paramount ME II telescope mount.