CCD Notes July 15-16, 2004 Connelly's Springs, NC. Milky Way invisible overhead. 64oF, calm. Looking for Alternate Focus Positions Messier 13 (5 seconds) 5-inch Astro-Physics refractor @ F6 SBIG ST2000XM / CFW-8a cooled to -20oC (92% cooling). A quick look to measure image scale and confirm focus. A-P Maxbright diagonal, Robofocus only 275 units out from stop. (Original position: 41,000 units out.) No guiding on Losmandy G-11 mount. Acquired with Maxim 4.01, no dark, no flats, no bias. Messier 13 (5 seconds) 5-inch Astro-Physics refractor @ F4.5 SBIG ST2000XM / CFW-8a cooled to -20oC (92% cooling). With 2 short rings of a Nikon K-ring set behind telecompressor. Robofocus 5,675 units from in-travel stop (~20,000 w/o rings). (Ringset: K3+K4+K2. K2 & K3 are end rings, K4 a spacer. Try K5 instead.) Compared to the first image, the scale is 0.75x. W/o K-rings, telecompressor yields 0.77x. No guiding on Losmandy G-11 mount. Acquired with Maxim 4.01, no dark, no flats, no bias. Messier 13 (30 minutes) Oops. 5-inch Astro-Physics refractor @ F6 SBIG ST2000XM / CFW-8a cooled to -20oC (92% cooling). Six 300 second exposures through IR-blocked clear filter, unbinned. A-P Maxbright diagonal. Self-guided on Losmandy G-11 mount. Acquired with Maxim 4.01, no flats, no bias. It would have helped if I had saved the light frame from the main CCD instead of the guide star image from the guiding routines. Live and learn. Messier 101 (45 minutes) 5-inch Astro-Physics refractor @ F6 SBIG ST2000XM / CFW-8a cooled to -20oC (80% cooling). Nine 300 second exposures through IR-blocked clear filter, unbinned. Maxim sigma combine. A-P Maxbright diagonal. Self-guided on Losmandy G-11 mount. Acquired with Maxim 4.01, dark frames subtracted, no flats, no bias. Messier 101 (45 minutes) An alternate processing of the data described immediately above. 9, 300-second images averaged, Lucy-Richardson deconvolved in Maxim, range stretched in PhotoShop 7.0. <=Previous Next=>