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 Gralak'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 ..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 debris 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 ** This JPG is at a Bin1 and was worked on that way . A lot of smoothing was done with the "Kernal Filter-GaussianBlur at 5.00 and pixel-restrictions from about 125 to 13000 and Radius 9.0 and Feathering 20.0 " " . *** &&&&&&&&&&&&&&&&&&&& And , as I was searching the "GOOGLE" Search for 'Highlight Tone Priority' info with the Canon DSLR .... I also saw the ideas about the " 18% Gray " that is normal in an image . One site said that the 'Highlight Tone Priority-Enabled' uses a tone curve to reduce over-saturation of bright areas and also dips into the next lower ISO and uses some of that ISO's data to complete the image . Without 'Highlight Tone Priority-Enabled' the DSLR creates what it believes to be OK and might use a little of various 'light' shade areas . But with the 'Highlight Tone Priority-Enabled' , the DSLR creates an image that reveals more of what should be shown in an image . <> So , what I saw in videos 'You-Tube' , was a Bergman video that show why you would use an '' 18% '' gray card for a 'White Balance Evaluation' and then take an image using that evaluation which for 'Custom White Balance' you would have the image ready in the LCD screen and select it for the 'Custom White Balance' and use that icon instead of the 'Daylight' icon ... and maybe the shown 'light' shades would be more visible . Because if the background is mostly dark ... like deep sky objects ... the DSLR might over-brighten the dark areas and wash out the 'mid-tone' 'light' shades you want to show ... like galaxies or nebulas . I did an '' 18% '' image of a laptop cooling pad that is gray with the TeleVue .8XReducer/Flattener connected to the RebelT7i at ISO100 for a short exposure and a light overhead illuminated the gray colored pad . It had a slight 'red' tint , though . Then I showed it in the LCD screen and I used the 'Custom White Balance' selection in the Menu and a 'Set' option is there and you press 'Set' and then go to the 'White Balance' selections and use the 'Custom' icon instead of the 'Daylight' icon and .... I took an image of the gray cooling pad again for 'color' and it was gray . I then turned on the 'Highlight Tone Priority-Enabled' and I took another pad image and it was brighter than the previous image . This setting might work at the Telescope like for M33 , and I'l try two 5 minute ISO400 exposures with 'Highlight Tone Priority-Enabled' and with 'Long Exposure Noise Reduction-Enabled' using the 'Daylight' icon 'White Balance' and then I with repeat the process using the 'Custom' icon for 'White Balance' and I'l see if there is a difference in how much of M33 is shown . It would be a good idea to have a few 'gray' images in the DSLR that are at different exposures for a darker one up to the brightest one so each one can be used if necessary . Sept. 29 , 2021 is the earliest to do it because the Moon rises at 11:15 pm EST and Sept. 30 , 2021 at 12:00 am midnight , it rises almost an hour later each day . x <> . x
