I did this Cave Nebula by stacking all five RAWMonchrome images that were at Bin1 and only a "ConvertColor" command done to the five Fits 'light' frames with Sigma-Clip_Normalization:30% and Linear with Sigma-Factor: 9.98 ... and the Log showed about a 7.4% pixels rejection for each pixel value in the stacked FITS while still keeping a Bin1 3.72micron pixel 'light' frames to stack which were only processed with "Convert Color" . I used the "Stretch" command with Gamma: 0.8 and MaxPixel and Unlimited one time . I tried smoothing with "Kernal Filter- GaussianBlur radius:5.00 and a large amount of Feathering two times . [[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[152mm A+M Refractor(OfficinaStellare-1200mmF/L) using a TeleVue 2XPowerMate for an effect of 2400mmFL using a DeepSky Lumicon 2in. filter . .*****x Also , the DSLR's 'Long Exposure Noise Reduction ON' was used . I did do what Astro-Physics site said which was go to ASCOM and download the latest Platform and then I 'installed' it . I went back to the Astro-Physics site and followed the link to Ray Garalak's ASCOM Astro-Physics V2 Driver and I downloaded and 'installed' the v5.30.00 Driver which replaced the v5.10.02 Driver I was using .... and last night Aug. 4 2021 I started imaging the 'Bubble Nebula' as UHC-SII Ha but UHC and Ha were really dim at 247secISO3200-6400 and SII for 487secISO3200-6400 was also dim , but I didn't try to stack them yet ..The 'Backyard Astronomer's Book' say they always use the DSLR's 'Long Exposure Noise Reduction ON ' which is on page 305 top right instead of 'dark-frames' . Also , it seems as though the Sulfur-II (SII) filter with the Astronomically friendly Hutech modified DSLR needs three times the exposure length as the UHC and Ha filters because the DSLR's internal cut-off filter only allows about 20% passage of the SII region ]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]] . {{{{{ I have been using Aspect Ratio 2:3 in the RebelT7i's 'in-camera' Menu , which is the only way the DSLR does an image , but , the changed Aspect ratio only is for an effect which draws lines that is only readable in the DSLR or Canon Digital Photo Professional to crop an image correctly with the guide lines ... but I will continue to use the ' 3:2 ' Aspect Ratio instead because the other Aspect Ratios like 16:9 aren't re-constructing the pixels and making them larger for horizontal width and a lower vertical height to imitate a cinema panorama look , like for a wide mountain scene , it's just an 'in-camera effect . But , to do a Sigma-Clip stacking at Bin1 for the 'light' frames it would be better if you know the pixels are square so the Sigma-Factor setting can discard values from each individual square pixel ... instead of a re-constructed array which would be a mix of pixels to change the Aspect Ratio and it would be nearly impossible to reject the bad data from the pixels because they would be blended together , but , this isn't happening and the image is always an Aspect Ratio of ' 3:2 ' and retains it's square pixels ... .! . }}}}}} %%%%% What , else I am using now is the Canon EOSII RebelT7i's 'in-camera' Menu option for "Highlight Tone Priority-Enabled" because the book manual says that when you take an image , it is an ' 18% ' gray type image , but , if you use the 'Highlight Tone Priority-Enabled' it will add extra values that pertain to the image giving it more Dynamic Range , which , might be rejecting less 'light' shades between strong 'light' shades that might be rejected otherwise without 'Highlight Tone Priority-Enabled' . This can be important when using the 'in-camera' 'Long Exposure Noise Reduction-Enabled' to remove a mass amount of debri along with the ' 18% ' regular gray-scale values which might make the image a lot dimmer . %%%%% . [[[[[ When I 'focus' the UHC filter to start 'false color' filter imaging I found that a 'sub-frame' area and 'RAW Color' will show the smaller stars to 'focus' on instead of the RAWMonochrome option which only shows the largest stars ...... but , Autosave Sequences should be taken as RAW Monochrome FITS images . ]]]]] .x
