Location of Photo:
US Naval Observatory Washington DC
Date/Time of photo:
04:22 UT 29 Oct. 2007
USNO 12-inch f/15 Clark refractor, Nikon D100 camera, prime focus, stack of 61 images, each from 6 to 10 second integrations at effective ISO 6400.
These are rotational gradients created by rotating an image of Comet Holmes plus and minus 45 degrees (rot 45a.jpg)centered on the nucleus, then differencing the two rotated copies from the original image. This technique enhances features that are rotationally asymmetric. Note the possible tail or jet in the south-west quadrant, as well as a faint anti-tail to the north-east.