Video images of Moon, Feb 26, 1999

On Feb 26, 1999, I went to the Observatory to try out our Astrovid video camera on the Autoscope 16" telescope. My goal was to take pictures of the Moon and record them on videotape for later examination.

The skies were clear, but the seeing wasn't very good. In addition, a moderate wind shook the telescope every minute or so. Even when the wind wasn't blowing, the telescope wobbled east-west with a period of about 2 to 4 seconds and an amplitude of -- a guess -- 4 arcseconds. It was annoying. I tried moving weights from the west to east forks of the telescope, but that didn't have any appreciable effect.

At about 7:30 PM, a family of five walked into the compound. They thought that this night was a make-up date for our Public Night on Feb 19, the previous week (which was clouded out). It wasn't a make-up night, but I was having trouble with the VCR, so I took about 20 minutes to show them the moon. They seemed happy.

The VCR must be set to channel "L" (for "line input") to record images from the Astrovid camera. It took me a long time to figure this out.

I spent about 15 minutes taking pictures of the moon, starting at 8:21 PM EST and ending at 8:38 PM EST. I started at the south pole, moved northwards along the terminator, and finished with a quick scan down the center of the disk to the south pole again. Pictures of the moon are shown below.

I then tried taking pictures of the Orion Nebula. No good -- even at the longest exposure time and maximum gain, the camera showed no nebulosity. Perhaps the moon was too close and too bright. I could see all four stars in the Trapezium, separated clearly, and a fifth very faint star near one of the Trapezium members.

Now, some pictures of the Moon. Here's the procedure:

Then import the images to Photoshop and play with them there. One reasonable option is Unsharp Masking, with parameters of

All images below were created following the above prescriptions. One could probably improve them a little bit with more work.


The large crater in the middle of the picture is Gassendi, about 110 km in diameter. It has a nice set of central peaks. At its northern rim is Gassendi A, about 33 km in diameter. Gassendi sits at the northern edge of Mare Humorum.


The crater Kepler sits at the middle of a system of light-colored rays, formed from material squirted outwards from the site of the impact which formed the crater. The crater is about 32 km wide; the shadow in this picture might allow one to estimate the depth of its floor below the crater's rim.

The almost hexagonal crater below Kepler is Enke. On the western (left-hand) rim sits the small crater Enke N, which is only 3.5 km in diameter.


Near the bottom of the picture lies the small crater Brayley, aobut 14.5 km wide. A few other craters appear in the smooth expanses of Mare Imbrium; the large crater in the upper right is Diophantus (18.5 km wide). Near the top of the picture, a range of mountains rise up from the surface of the mare: the Montes Harbinger catch the first rays of the rising sun and cast long shadows towards the west. The shallow crater below the mountains, its southern walls eroded almost completely, is Prinz. Further south and west, almost hidden from the sun, is Aristarchus (about 40 km in diameter).


Diophantus appears again at the bottom right of this picture; just above it is the larger crater Delisle (diameter 25 km). The rough area to the west (left) of Delisle is called Dorsum Brucher, or Brucher's ridge. Further north lies the crater Gruithuisen (diameter 16 km). Near the top of the picture, two large massifs rise from the edge of Mare Imbrium: on the east (right) is Mons Gruithuisen Delta, and to its west, the dome-shaped Mons Gruithuisen Gamma.


The Sinus Iridum, a "bay" off the Mare Imbrium, fills the right-hand side of this picture. The Montes Jura run along its western edge. Three craters run in a rough diagonal line from top right to bottom left: Bianchini (diameter 38 km) at top right, Sharp (diameter 40 km) in the middle, and Mairan (diameter 40 km) at bottom left.

The Russian Luna 17 spacecraft landed in the flat area near the center of the bottom edge of this picture. It carried the Lunakhod 1 rover, which travelled across portions of Mare Imbrium under remote control.


The Mare Frigoris lies near the northern edge of the Moon. It is surrounded by rough terrain and some old, eroded craters. The large walled plain at top left, its eastern rim throwing long shadows across its floor, is J. Herschel (diameter 156 km). The fresher (and, obviously, younger) crater Horrebow covers a portion of its southern rim. At bottom center is the shallow crater la Condamine; its walls span a distance of 37 km. Mare Frigoris Gassendi Kepler Brayley and Montes Harbinger Delisle and Montes Gruithuisen Sinus Iridum and Montes Jura