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Dear friends I'm not able to take a picture of the entire Andromeda Galaxy in one sequence: I have a TS Optics 102/520 Imaging Star with an integrated flattener and an Astrel-183-X-M camera. I can't add a reducer. As far as the processing software is concerned, I'm using StarTools or Photoshop to create my LRGB/HSO pictures. Important to know is also the fact that I'm a beginner. My question is how to process and assemble two sequences (LRGB or HSO) each with one half of Andromeda in order to get the entire galaxy. Many thanks in advance for your precious help! Kind regards Markus |
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You will have to take equally long exposures. Take one half of M31. Take the second half with equally long exposures. You can stitch the two halves together in photoshop. Here is an example. This is 5 twenty second exposures stitched together with photoshop https://www.astrobin.com/401211/?nc=user hope this helps CS |
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Dear Chris Congratulations for your beautiful stitch! With my DSLR, I'm used to make stitches in Photoshop when I take landscapes. But how can I realize a stitch with LRGB-pictures? Do I process the two halves separately and then stich them together? I believe it would be almost impossible to get two similar halves with identical colours, contrast etc. . Kind regards Markus |
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The major problem with mosaics is the proper blending at the edges. You can try to process each panel individually and then stitch with Microsoft ICE. It's free and pretty great, I use it for lunar mosaics. I am not sure how well it handles the blending with DSO images. What I use for mosaics is the AstroPixelProcessor. Granted, it's 60 EUR per year but the stacking features make it really nice and easy. I preprocess and stack each panel individually. I do not merge narrowband images into a color image. Instead I just the gradient removal tool to fix any light pollution and crop the outer edges a bit. Then I load my stacked and light-pollution-fixed panels as FITS file into a new session and select mosaic under registration and activate the blending under integration. This produces seamless mosaics. There is a free trial. And a tutorial on mosaics on its forum. Cheers, Jesco |
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Hi Jesco! Many thanks for your answer. I will learn about AstroPixelProcessor. I just wonder if I could do the stacking of the pictures of the two halves with DSS. Kind regards Markus |
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| If you have enough overlap DSS Mosaic mode does work. |
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Hi David! Many thanks for your answer! I didn't know this mosaic mode of DSS. I will check this. Kind regards Markus |
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In DSS "Register Checked pictures..." Takes you to the "Register Settings" tab. Hit the Stacking parameters button, then select "Mosaic Mode". Very easy to use but you get what you get. Be careful adjusting the number of stars under the "Register Settings" advanced tab. Too many or too few and the stack might fail. I like numbers around 100 if I can get them. I've used this to make a mosaic registration "Master" that I then use as the reference image in Pixinsight "Star Align". |
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Hi David Many thanks fpr your precious explanations. I will try this setting. I'm just not sure about the procedure: let's say I have my Ha, SII and OIII pictures, now taken two times, once for the 1st and again for the 2nd half of my target, well overlapped. Do I now first register and stack all the Ha (of both the halves), then all the SII and finally all the OIII?. In this case, how do I chose the reference star in order to get all the sequences aligned? Oh, so complicated, but also interesting for a beginner. Kind regards Markus |
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Sorry for the late reply. I don’t have an answer to the filters you are using. I use a full spectrum DSLR. the only filter I use is a LPF. I stitched my images together before I processed anything except stacking. I use DSS For all of my images CS |
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Load all of your pictures for all of your filters. Active Super pixel mode and per channel calibration by selecting the recommended setting tab. Turn the registration mode to Mosaic as described above. If you want separate color channels so that you can adjust the blending better you can uncheck "Stack after Registering" then stack each filter one at a time as a separate step. |
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Hi David! Many thanks! This is so helpful and I will follow your instructions. Have a good time, any many clear skies! Kind regards Markus |
