lunar observing

The past two nights have had good clear skies, and I took advantage of the more or less quarter-moon to do some lunar observing. The 9.25" Celestron is a good tool for the target, coupled with good eyepieces, and mine are pretty good. My main one is a fat TeleVue 12-mm, about the size and weight of a standard hand grenade. Then a modest TeleVue 7-mm and the clever 3-to-6-mm TeleVue, with click stops at 3, 4, 5, and 6.

In terms of power, the 12mm gives me 196X, the 7mm, 336X. That's normally as much magnification as the atmosphere can handle. But the air's been clear and steady the past two nights, and I delighted in clicking the little one from 392X through 470X and 588X to a ridiculous 783X. The best telescope in the best air will start to break down around 1000X, and the usual theoretical limit is fifty power per inch of aperture, which would be 462X for me. Indeed, my best view was the 5-mm. view at 470X. And it was gorgeous.

Magnification doesn't do any good with a shaky mount, and although my iOptron has its shortcomings, once it settles down it's like a rock. The slow-motion controls are silk-smooth, and drifting along at 462X is like a close approach, five hundred miles above the lunar surface. The subtle details of the rubble-strewn landscape are endlessly fascinating.

I don't really have the patience or the velocity to be a good lunar artist (the appearance changes sometimes minute-by-minute under high power), but I do enjoy sketching anything. Here are pictures of the crater Copernicus on two consecutive nights. On the 12th, the sun was at a low enough angle to reveal a lot of shadow detail. On the 13th, 28 hours later, it's getting close to local noon, and the details are washed out. Hope I'll be able to take another look tonight.

Joe