Atlas at the terminator, Hercules to the left. Levels were pushed to darken the maria.
Archive for December 2006
A difficult image. After starting the exposure, the moon drifted about half the width of the frame before settling into position. The avi wouldn’t stay open in registax; it would crash the program. I used virtual dub to convert to grayscale, then ran three alignment points near the top, then stacked to enlarge image. This is roughly northeast-southwest. Theophilus, the prominent crater with the split central mountains is near the bottom. Above it, the crater with a line thru it is Capella. To the right is the Sea of Tranquility.
Reprocessed avi three years later with Registax 5. One alignment point. The mult-alignment wouldn’t work, as the image drifts too much. (All the yellow markers quickly turn red; I didn’t wait for the finish.)
The comet-like craters are Messier, and Messier A
The largest crater is Langrenus
The mare is MARE FECUNDITATIS; the wrinkle ridges are Dorsa Mawson
I reprocessed the previous exposure by drizzling the stack, which 4x’d the pixel count. This made it softer, so the wavelet sharpening was more aggressive. This emphasized the drizzling grid, so I removed that with a gaussian blur, then a couple of unsharp masks. Overall, it was too dark, so I changed the levels to emphasize the floor of the crater and the wrinkle ridges in the mare. The upper portions of the image were completely overexposed, so I cropped them away. Click for full size.
Twenty-one alignment points in Registax 4 results in one of the sharpest photos I’ve posted. It took three tries: the first try had 22 points, and registax hung on the last one when optimizing. The second try had an access violation when aligning. The third try I quit all other applications and let the program run without interruption.
The image is inclined about forty degrees, so at the top is Posidonius on the border of Mare Serenitatus.
Here’s the very next shot, at f/9. 34 alignment points, but I threw away half the image. This represents about a dozen.