152mm A+M Refractor(OfficinaStellare-1200mmF/L) using a CanonEOSII RebelT7i modified UV-IR @ Hutech thru a TeleVue 2.5XPowerMate with a BreakThrough X4-UV 49mm filter with step-rings to 48mm . RAWMono Autosaves for ten 67secISO1600-3200-6400-12800-25600 and four 127sec exposures for a total of fourteen images were 'Calibrated' with a BiasMaster and a FlatDARKMaster and a FLATMaster ... the FLATMaster used had the 'Auto-Remove Gradient' filter applied to shift the 'gradient' in the FLATMaster from a darkness on the right side and brightness on the left side to try to make the FLATMaster look more even with the light differences and this also lowered the 'Standard Deviation' in the "Information" window for 'Area' and .... this FLATMaster has alot of spots and other artifacts that hopefully were extracted out of the 'light' frames during the 'Calibrate' , and I Sum stacked and I did use the "Auto-Remove Gradient" on each ISO finished FITS which helped make them look more even across the image . After stacking as Sum I used the "Digital Development-FFT_Low-Pass" and then I worked on the FITS image a long time with smoothing and sharpening and reducing color saturation in the faint areas of the galaxy and increasing saturation in the stars ... . But , the idea is the "Auto-Remove Gradient" filter applied to the 'original' FLATMasters and a "Save As...IEEEFloat" with an add 'RemovedGradient" to identify it and use it which doesn't seem to damage the image and it does 'Calibrate' . x This FITS version will "PinPoint Astrometry" 'USNO-A2.0' 'solve' with 'StandardDeviation: 1.' and 'Maximum Number of Stars Used to Solve: 451' and 'Use stars from magnitude: 5.00 to 20.0' and 'Search Area [as % of image] 451 ' and will show about ' FL 2937 mm 1.83"/Pixel' and it might match 376 stars .x At this time of the year it would be a good idea to start imaging this NGC6946 about 2-hours before the Meridian in the East before the light of morning happens for more exposures than this image and some longer exposures starting with two at 47sec and two at 67sec and two at 107 sec for each ISO and then 127sec for a few at each ISO except ISO25600 which shows distortion on the image edges . x
