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About don4l

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    Star Forming

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  1. That's a great improvement. The first image almost looked like the Ha was missing.
  2. The montage presentation is really quite stunning. Although there is no loss of detail when viewed at full resolution, I actually prefer it all on the screen where I can see the entire composition.
  3. I'm currently processing an Orion mosaic. The panel with Betelgeuse wasn't as difficult as the panel below for some reason. The problem extended a good 2.5 degrees from the star.
  4. Small world ... I work just off the Frimley Road. The motorway is just outside my office window!
  5. Love the OIII. Well done!
  6. I agree with the comments above. For me, the field of view is wide enough to give a lovely context to the image, but narrow enough to show lovely details in the galaxy itself.
  7. The only (fairly) sure way that I know to identify the source is to calculate the distance. You shouldn't need Chroma or Astrodon to eliminate the problem. My old (2007/8) Astronomiks were awful, but I believe that they fixed the problem later. My LRGB are Baader, and they aren't too bad - but they are the same vintage. I'm not up to date on this, I'm afraid. I think that your halos are probably caused by the filters because you have two halos on some stars. This is caused by reflections coming off the front and rear surfaces of the filters. Some filters are unidirectional. It might be worth checking if there is a little "v" printed on the edge of the filters.
  8. What a productive week! I do like the triplet. You've also done an excellent job on the trapezium. I recently did some experiments on the Trapezium and learned something new. I used my ASI120 to take some very short (2s) shots and managed to get 6 stars. 5 had clear space between them. At 15 seconds, all subs only showed 4 stars. With 2 second exposures you could clearly see the image bouncing around the screen just like Jupiter does. If I get another chance, I will try even shorter exposures. I'm confident that I can split out that 6th star. As you have pointed out, you cannot do this with a standard CCD camera. It would take all night to get the 150 subs that I took.
  9. Hello Geof. I've just seen your other thread where you mentioned this problem. I'm fairly sure that these halos are caused by reflections. Light gets reflected off one surface (usually the ccd sensor) and then back again (usually off a filter). The halo is actually the star out of focus (because the light has travelled further). There are online calculators which will tell you the distance between the reflecting surfaces when you input the diameter of the halo and the F ratio. Some filters are much worse than others. I recently changed my filters because of this problem with my NB filters. The difference is simply amazing. Unfortunately, the price of the new Chroma filters is also amazing - but not in a good way! I did try to reduce them in processing, but I never got really far.
  10. I don't know much about cmos cameras, but I do know that CCD cameras change over time. When I recently took out my STL6303 after a 9 year gap, the dark frames had got much, much worse. The old hot pixels were still there, but there were many new ones. My Atik 16HR, also CCD, hadn't changed noticeably over the same period. As far as I can tell, random cosmic ray hits cause the problem.
  11. Very nice image. The SAC catalogue in Cartes du Ciel has it perfectly positioned. Have you checked that the epoch is set the same in all your software? I had small, but annoying, discrepancies until I set everything to J2000. It took me ages to notice that EQMOD had an epoch setting!
  12. You might find some useful info in this thread :- I'm very impressed with the capabilities of this little camera. Handling the hot pixels was the biggest issue for me, but you do collect some very useful data in a very short time. I am still struggling with dark frames. The only way that I have been able to use them successfully so far is to blend them in "subtract mode" in The Gimp (Photoshop can do this the same way). I then use the opacity slider to visually determine when the hot pixels are reduced to a maximum without taking away from the target.
  13. I'm feeling quite pleased with this A couple of months ago, this would have taken me several attempts, and I wouldn't have been able to join up the panels with them being much more obvious. This is a 6 panel mosaic in Auriga. Each panel is 7 x 180s Ha binned 2 x 2. The comet didn't show up very well in the Ha, so I took 5 x 120s through the blue filter and blended it in as shown. Equipment: STL 6303, FSQ106ED at F3.6, EQ6, Calibration, Stacking: CCDStack Processing: The Gimp v2.10 Comments welcome - especially about how the background looks. I'm really not at all confident about my laptop screen!
  14. Barnard's Catalogue of Dark Objects It comes up in my Cartes du Ciel if I put "b37" in the search box. It is the area with far fewer stars in the top left of the image. There are lots of them, but I've never tried to image one before. I believe that it is a huge cloud of dust/soot blocking out the stars that lie behind.
  15. Thanks for that. I'll have a check on my processing PC when I get home to see how it looks there. I can just about make out a difference on this PC at work. I think that the uneven background is more to do with my lack of care. There wasn't much to interest me there. If I can fix it, then I've learned a very valuable lesson.
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