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Pompey Monkey

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About Pompey Monkey

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    Sub Dwarf

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    Astronomy, cycling, science.
  • Location
    Hampshire, UK
  1. It will be fine. Any dust that might manage to get on the sensors window can be corrected for with flats. If you want to clean it prior to fitting the CC, just use a puffer:
  2. I don't know how to calculate any of it But here is a nice write-up of the idea I am trying to convey. https://darkskydiary.wordpress.com/2011/05/04/twilight-vs-light-pollution/
  3. I think it might depend on your local light pollution. If the local light smog is significantly worse than the sky brightness for nautical dark, then you might as well carry on...
  4. As long as the dew point temperature is higher than ambient, dew can form. It is even more likely on surfaces like, wait for it, metal and glass that radiate their heat directly into space (under clear skies). The temperature of these materials can be considerably cooler than the surrounding air. This is why fans are often used on reflector primaries: passing the ambient air over the surface of the glass is actually a warming process. So, it could still be dew.
  5. I fhi k you may need a 35 mm extension:
  6. Hmmm. It might be time to close this thread...
  7. In my eyes, the re-process has too much noise reduction. I prefer your original. It looks a lot more natural, although the black point is still pretty clipped. The trick is to leave just a little noise in (not that I'm much good at it myself)
  8. If the pots and pans is confusing, try to think the of funnels with the same size small end (eyepiece or camera) but with different top diameters. Which funnel will fill a cup with water faster? A telescope effectively funnels photons into a smaller area to make the photon flux (photons per unit area, per time) greater.
  9. The sky background will keep the same brightness. I'd <suggest> keeping your default exposure times. Maybe someone else has better info/experience on this? Also, with a 2xBarlow, you'll need 4 times the total exposure to get the same number of target photons per unit area on your sensor. But, to quote Harry Hill: "There's only one way to find out!"
  10. How do you focus without the filter? How do you focus with the filter fitted? If you can focus, then you should at least get some stars on your subs!
  11. Me too. It's worth paying a bit extra. Cheap USB hubs have caused me all kinds of headaches over the years, and not just in astronomy.
  12. I concur with @steppenwolfthat this is a result of drift caused by imperfect polar alignment. However, I'm a bit surprised that these pixels did not get calibrated out on the stacking. What pixel rejection did you use? Also, dithering will soon be your best friend.
  13. +1 for the 7-port Startech powered USB hub. The only downside is that the LEDs (like far too many devices) are a bit bright at night. It's in here, somewhere...
  14. A (plain) t-shirt over the aperture of the scope at dusk or dawn works fine.
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