CanonEOSII RebelT7i modified UV-IR @ Hutech using a Canon 75-300mmRefurbished $100.00 Lens @ 200mmFL setting with a Baader 7nm HydrogenAlpha 2in. filter with a step-ring from 58mm down to 48mm . It took me a long time to get this image because the USB-3 Port Hub that I thought I fixed with a bad plug was making the 'pointer' jump around in the laptop and I thought it was a 'virus' but I dis-connected the plug and the 'pointer' stopped hopping around . but it still works otherwise . This image is in a rough condition with just four 307secISO6400 images but it shows the size of the nebula and only a slight edge cropping was done to it . The next time I image Simeis147 I will use the 180mmFL setting and see if I can get the nebula away from the image edges better . If that doesn't do it I'l set the Zoom lens to 150mmFL setting and try that , which should do the trick . <<< There could be a chance that the settings in the DSLR are causing the 'light' in the edges of the image because I see that the 'Peripheral Illumination' is 'Enabled' so I now have that turned 'Off' , and the same with the other settings in the section so the DSLR shouldn't do anything to the image ... which is an electronic event in the Processor and I think it also happens even if a Lens isn't attached to the DSLR and imaging thru a Telescope but I'm not sure of that yet . As a CR2. in Canon Digital Development 4 in the info window it says 'Peripheral Illumination-ON ... no data ' but it might be using some setting because it shows in the 'Tool Palette' for 'Lens' with about ' 63.0 ' which is over the halfway mark and when I 'un-check' it the illumination decreases and when I press the 'arrow' to change it a message shows 'return to camera settings' and it was back to 'checked' and at ' 63.0 ' with the edge 'illuminated' again , the image was with the Canon 18-55mmLens that came with the RebelT7i but there wasn't any Data for the Lens at the time and I did a 10minISO-Auto which shows it used ISO400 , but I 'downloaded' the Data last night . When I try the Spaghetti Nebula again I'l try at the end with the Baader H-Beta filter .... some 'one-shotColor' shots at ISO-Auto for 8min and 10min and see if another ISO is used instead of ISO400 because there will be more light .. but ISO400 might be OK for the purpose ... and use Canon Digital Photo Professional to work on the images and save as 16BIT TIFF . Another thing I read on the Internet was the ' Q ' on the back of the Canon DSLR has between the 'Exposure' setting and the 'ISO' setting a ' f/5.6 to f/22 ' which with a Lens will darken the image a lot at f/22 and supposedly ' f/7.1 ' can be a good setting for a little more sharpness ... like in the case of the Spaghetti Nebula ..... this might be like a Neutral Density filter and is another electronic Processor event . Also , with ISO-Auto and doing RAWMonochrome FITS images in MaximDL Pro V6.16 , when you 'calibrate' the image it will 'calibrate' using any ISO for Bias and Dark and Flat Masters and different ISO's for each so you don't know what will be used until you look at the FITS Header . >>>> . An Internet site said that Zoom lenses don't have real good 'lens' elements inside and the 'fixed focal length' lenses are a lot better quality , that's why I have to find what seems to be a good mmFL setting . 180mmFL might do the trick or 150mmFL and these two are available on the Internet . I saw on Astrobin.com an image of the Spaghetti Nebula with an 85mm Lens and one with a 135mm Lens and they look good . ////// I was reading in the Canon RebelT7i - EOS Utility Manual with RebelT7i Camera Manual and it shows a picture of some cards with a King card in focus with a fast f/# like f/5.6 and cards in the background are blurred because of the shallow depth-of-field of a fast f/ratio# , then they show the same image with a higher f/# like f/32 and all the cards are in focus ; this section is in the ' AV: Changing the Depth of Field ' section of the book manual . When I was doing the Spaghetti Nebula I had the f/# ratio at ' f/5.6 ' which is it's lowest setting and the stars are in focus if I'm lucky and probably the background nebulosity is being blurred electronically to imitate a faster f/# ratio . A site on the Internet said , " When in doubt .. use f/7.1 for a starting point and if a higher f/# ratio seems to be needed , then increase to the next higher f/# ratio and take the exposure and see if the background detail looks sharper .". \\\\\ . x
