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Bloom

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Everything posted by Bloom

  1. This is a reprocessing of old data. My first choice for a telephoto lens was a manual focus Nikon 180mm AI ED f/2.8 - very nice lens, and cheap on ebay, but it had some colour fringing, which in astronomical images shows. Later, I replaced it with a Canon 200mm f/2.8, which is much better, but with which I haven't imaged the Orion area yet. In my new effort of postprocessing I mainly used Imagesplus, and managed to remove the significant vertical banding the initial stack had (reading the manuals of the products always pays off... ). 25x2min, Nikon 180mm ED f/2,8, stopped at f/4, CG5 mount, Canon EOS 40d. Guiding: Starlight Xpress Lodestar with Stellarvue FV50 9x50 finderscope, and PHD. Image scale is 6.53 arcsec/pixel. Image processing was done with IRIS, Astroart 5, Imagesplus 6.5, and Paint Shop Pro X5
  2. It is the best cosmology book I ever read. When I finished it (I was not just reading it, like a novel, or a popular science book; I was closely following the equations - but they are not that many, and not extremely advanced), I felt illuminated.
  3. We have the same OTA, and the first thing I noticed was that your fringing (the blue halos) is far more than mine. If you use a UV cut filter, it is not due to the OTA! My best guess is that the culprit is your field flattener. I have a Televue TRF-2008, and it adds no fringing. I also have a Skywatcher field flattener, which I do not use anymore, and it adds quite some fringing. To be honest, when I bought the Televue, it did not cost 350 pounds, but I guarantee it is worth every penny of it. It is a sine qua non for refractors with focal length up to 600mm.
  4. The birth of my second daughter a few years ago proved too much for my spare time, so I was forced to quit the hobby in 2020. Now, it seems I can start again, at least now that it is summer. The heat wave here in Greece has produced stable and quite clear nights. This is my effort on a rather difficult target, taken through three successive nights, and from my summer residence under Bortle 3 skies (but I have two street lamps at close proximity). Maybe some will find my equipment, and especially my software, outdated - well, it suits me fine. When I stopped deep sky imaging, CMOS were just a novelty, and now, three years later, they have outclassed CCD cameras in almost all aspects (except for binning, I guess). Time flies. 91x3min, GSO 6'' f/5 newtonian, NEQ6, Atik450L OSC camera, Baader MPCC coma corrector, Baader UV/IR filter. Guiding: Starlight Xpress Lodestar with Stellarvue FV50 9x50 finderscope, and PHD. Image scale is 0.95 arcsec/pixel. Image processing was done with IRIS, Astroart 5, Imagesplus, and Paint Shop Pro X5
  5. As promised yesterday, I stayed till late and imaged Mars. Seeing conditions were good, but were a bit worse than yesterday. Well, the planet is never easy - it is just 17 arcsec wide. Only good, at 02:45 the planet was high... Taken with a 6 inch f/5 GSO Newtonian and a barlow lens x2,5. Programs used: Sharpcap, Autostakkert, IRIS, Astroart. I took 5 minute frames at 160 fps, and stacked the best 50%. Then, I split the stack into R, G, and B components, and I recreated a new stack, using the red channel as luminance.
  6. I hadn't noticed the green colour! I used all the automatic Colour Balance functions of IRIS and Astroart, and I did not pay attention. I' ll fix it in ImagesPlus; thanks.
  7. After more than 14 years in the hobby, and after a two year hiatus, this is the first time I manage to get decent images of the gas giants. I think it was back in 2008 when I was trying to force an unmodified Toucam Pro in creating anything close to satisfactory - I don't know what others have achieved with such meagre equipment, but my verdict has been that these webcams, along with all the hype about them, were just inadequate, and I lost many nights trying for the impossible. Anyway, technology has advanced, and it has done it in an impressive way. I cannot stress how absolutely fantastic the ASI camera is. I almost did not read the instructions, yet I managed to surpass all my previous webcam efforts by a huge margin. I can't wait for tonight to get my hand on Mars. The images were taken with a 6 inch f/5 GSO Newtonian and a barlow lens x2,5, sitting on top of my old, rusty, but still in (almost) proper working order CG5. The quality of the videos was such, that I rescaled some of the stacks, and worked from there, as if I had a x5 barlow lens. Programs used: Sharpcap, Autostakkert, IRIS, Astroart.
  8. Two days ago, I used an improper power supply on my 12 years old CG-5. So, whenever I turn on the mount, enter time, date, and then press for alignment, the mount immediately starts slewing in RA in its greatest of speeds. Theory says most probably the mount control board got damaged; and you cannot buy a spare one from Celestron, since they have been discontinued. Yesterday, I decided to at least check what would happen with the correct power supply, and by pure chance I discovered a quick fix. Here it goes: When you turn on your mount, before anything else, before aligning, or entering any sort of time and date data, before anything, you adjust the slew speed to "8" or "9", and then you press the RA motion button just once, as much as is necessary to create motion. Then, you perform a "quick align" (to be honest, I rarely use anything other than quick align), and the mount works! Well, not everything goes smoothly after that; for example, I ordered the mount to slew to Vega, and it started searching it in the opposite direction, to the west. But until I decide if it is worth to spend money on a repair effort, or buy a new mount, I can keep on doing basic work. Hope this will help others with similar issues.
  9. Don't know if anybody has already mentioned it: Being an owner of both a dSLR and an OSC CCD camera, I know from experience that in general dSLR cameras cannot compete with cooled dedicated astro cameras. Still, dSLR cameras do keep a couple of advantages. First, they have big chips in a very attractive price - CCD cameras cannot compete in this. Second, there is a multitude of brilliant photographic lenses suitable for wide field imaging, and dSLR cameras are the best solution for these lenses. Third, and I think nobody has mentioned it, is that (unmodified) dSLR cameras are much better in white balancing. They almost always get the colour balance correct and beautiful right from the first stack. This is often not the case with dedicated astro cameras, either OSC or Mono. These are a few details which imho keep the dSLR cameras still in the game. So, should a beginner start with a dSLR?Well, I am not sure! Given modern technology, one can start with dedicated astro cameras and I guess it is not that difficult to find one's way around with using telephoto and wide angle lenses with all sorts of weird adaptors. I myself started imaging with a Canon 400d. If I were to start the hobby all over again, I would buy a midrange dSLR, not any sort of CCD. But I am also an amateur photographer (among my many hobbies), so maybe my opinion shouldn't count. P.S.: I think we all mean APS-C sized dSLRs. Full frame cameras are much better in all aspects than their APS-C counterparts, but they are too expensive, and for the benefit of less noise and extra sensitivity, they reach a price which compares with the best of dedicated cameras - comparing to them, they are inferior. In the past couple of years, I did consider getting a used full frame camera, but I shied away because of another two reasons: the 35mm format reveals even the slightest inaccuracies of even the best optics, and these cameras also put a heavy burden on the focusers, since they are not the lightest piece of equipment.
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