April 28, 2010
CCDInspector2 results after removing the 2.2" focuser extension from the
image train, and attaching the AP Field Flattener directly to the 4" focuser
drawtube. I did this because I noticed a bit of a gap on one side of the Field
Flattener attachment to the 2.2" extension, no matter how careful I was
tightening the thumbscrews. No such gap appears between the Field
Flattener and the 4" focuser drawtube, which has similar thumbscrews.
Curvature map using 15 subexposures below, indicating much less tilt and
perfect collimation, in contrast to my earlier test (click here for link ). All
are one minute exposures, autodark, 1.57 arcsec per pixel image scale with
similar fwhm. 10 subs using first starfield below, 5 subs using second.