My first look at the Moon through binoculars changed my life. I was maybe nine years old. The reality of its craters and mountains, the whole thing was just astonishing. But somehow, when we built Overlook Observatory in 1982, the Moon got short shrift. We were too busy showing off distant galaxies, nebulae and clusters. The Moon seemed too ordinary, I guess.
No more. After installing a new incredible secondary telescope and also sprucing up the observatory in various ways, I’ve returned to the Moon, only to be amazed all over again. We’re mentioning it this week because the months of very low optimum Moons have now ended. This coming week is among the best. That’s because the sideways illumination from the Sun now maximally reveals mountain ranges and craters and other lunar detail; plus, the seven-to-11-day-old Moon is no longer low like it is in summer. Even inexpensive optics seem impressive when the Moon is the target.
I also neglected the Moon when it came to memorizing stuff. I had a lifetime obsession with knowing by heart the names and distances of all the stars, all the planets’ inclinations and so on. But I could only recognize a dozen lunar craters, a few maria and just a single lunar mountain range. Now I’m having so much fun, as the optimum illumination slithers over the lunar surface at ten miles per hour and new features emerge night by night, learning the names of wondrous features about which I’ve been ignorant all these many years.
I think next spring I’ll offer a “Moon Night” at the observatory for our readers. It’s just too good not to share. But meanwhile, if you have any old telescope lying around, make the Moon the target this weekend. Even steadily braced binoculars are better than nothing. Look for the mountain range that’s just above dead center: These are the lunar Apennines. By Sunday evening, they curve to the left and aim at a stunning crater, the terraced Copernicus.
Notice how the bottom or south part of the Moon is a jumbled mass of countless craters. Some 30,000 are visible from Earth, and this is where most of them live. It’s not that this section was struck by more meteors than the rest of the Moon; it’s that these are the Highlands that managed not to get inundated by flowing lava four billion years ago. These objects were never engulfed. They remain the oldest lunar features.
Check out the vast dark smooth regions, the so-called seas or maria. These are the blotches that stand out to the naked eye. Through telescopes, you see very few craters on them. But the ones that are there represent the most recent lunar impacts. In short, you can read the Moon like a book.
It’s a book whose every page brims with new delights. Sure, most of their ages have birthdays in the billions of years, not millions. Doesn’t matter; they’re new to me.
Want to know more? To read Bob’s previous “Night Sky” columns, visit our Almanac Weekly website at HudsonValleyAlmanacWeekly.com.