f/15 single alignment on Copernicus, about 400 frames. Captured at 1280×960, processed at 150%, reduced to 960×720.
Archive for March 2007
Foolish magnification; Clavius Crater at f/42. 174 frames, used about a hundred, maybe a dozen were really any good. Chopped off all the outer edges, to remove the noise. Still some dotted lines; this is dirt on the sensor, which disappears above three hundred frames, and a Manhattan Troposphere.
My estimate is 900x, with the camera sensor equivalent to 6mm focal length. For a five inch telescope, that’s about three times recommended magnification. CCD calculator makes it .2 arcsecond per pixel, while the ‘scope is rated at 1 arcsecond resolution. At least the focus isn’t so critical at f/42.
Shot at f/15, stacked about 400 frames. I cropped Clavius out of the larger image and expanded it to match the size of the f/42 image. As you can see, there is a lot more detail resolved.
Four years of practice and an excellent camera paid off: https://finkh.wordpress.com/2011/11/06/clavius-and-tycho-3/
f/15 exposure at 1280×960, cropped and reduced. From top to bottom along the left center of the image:
Flammarion, Herschel (small, but quite distinct), Ptolemaeus, Alphonsus, Arzachel, Thebit (with a bright crater on its rim), Purbach, Regiomontanus (not too distinct) with Werner to the right and Delandres, with Walter to the right.
Saturn was within one degree of the moon last night, so I was able to establish focus using the moon and shift to Saturn. 550 frames f/15, IR blocker, no white balance, which may account for the blue. I removed the skyglow in Photoshop.