152mmA+MRefractor(OfficinaStellare-1200mmF/L) using an APM Flattener for PrimeFocus 1200mmF/L .... and these are images of FlatMaster Frames that were 'calibrated' with Flat-DarkMasters which means the 'darks' were done at the same exposure time and the DarkMasters were done with 'Scaling - Auto Optimize' for lower RMS Noise . The 'flat' frames when I did them had two sets of a bulk type data in the 'screen-stretch' window so I know there was the full content of data , but if the data was clipped at an edge of the 'screen-stretch' window then the exposure wasn't enough or it was too much ... so it has to be about the right way . [ Another important thing I noticed is that being I was using a CanonEOSII RebelT7i modified UV-IR at Hutech which has a Bayer Matrix .... if when you try to make the FlatMaster frames that are Flat-DarkMaster calibrated and in the "Set Calibration" command there is the 'Flat Norm.' at the bottom right of the full command window with a drop-list and make sure by activating in the "Calibration Groups' area above a 'Flat' which will cause the 'Flat Norm.' window to be active and select from the drop-list the 'Bayer Planes' option ... this is important because it will retain all the data and will show when you 'open' a FlatMaster frame to look at it and you should see tha large amount of data mounds like the 'flat' frame should show when you make one . IF you use the 'Boxcar Filter' option it will 'clip' the data when you look at the FlatMaster frame and there will only be a single small data column and the FlatMaster when 'screen-stretch' is used to show the content in the image it will be coarse and varying light shades across the image which will affect a 'light' frame when you 'calibrate' them with the Flat-DarkMaster and FlatMaster and it's very difficult to remove the blemishes . NEXT , when you 'open' the FlatMaster done as 'Bayer Planes' you will see more data in the 'screen-stretch' window and there will be a kind of 'gradient' , so with the image you can see it's light illumination and you then use the "Auto Remove Gradient" filter command and the FlatMaster FITS image should look more even across it and then do a "Save AS... IEEE Float" with an added extension to it like ' ScalingManual 0.0005 BayerPlanes RemoveGradient ' and then you'l know which one it is in the ISO Folder for it . Then Copy it to a Folder in the Folder you have the 'flats' and 'darks' in and name a new Folder as the FlatMasters and then you 'open' that Folder into the "Set Calibration" command to use on 'light' frames when you 'calibrate' them with the Flat-DarkMasters and FlatMasters ... but 'Scaling Manual 1.2000 ' or similar will be needed to correctly 'calibrate' a 'light' frame and in this case you can use the 'Flat Norm.' with 'Boxcar Filter' if it preserves color better ; IF you use 'Scaling Auto Optimize or Auto-Scale' it will destroy the 'light' frame and you'l have to 'UnDo' it and use try again ... so it's 'Scaling-Manual 1.3000' areas that must be used along with 'Bayer Planes' ] .x M101 done with this new FlatMaster idea that seems to be better when making the FlatMasters-BayerPlanes option , four 200secISO1600-3200 and three 300secISO3200-6400 'calibrated' as 'Boxcar Filter' on the 'light' frames . I used the SDMask for the four 200sec Fits and the SDMask for the three 300sec Fits and then I Sum stacked the two results . I did have to use the "Auto Remove Gradient" filter which blended the background distribution a little better . I also used the "Remove Background Color" command with 'Feathering' amounts up to almost the light-shade values of the galaxy which was like 0-4000 on a 65535 image and reduces some tints you don't want . Then you can try the "Adjust Color" for some small amount of Cyan in the background . I used 'gamma' a little in the "Stretch" command and "Levels" and you use 'screen-stretch' to remove excess background light to darken it . x
