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How To Determine The Optimal Subexposure Level For Astrophotography

Many beginning astrophotographers are confused about how long each of their subexposures should be. I know that was true for me!

There is a lot of good information on the net but I wasn’t aware of anything that covered the process from beginning to end so this video does just that.

This is what it covers:

  • 1. The formula for optimal exposure level
  • 2. The range from minimally acceptable to optimally good exposure levels
  • 3. How to measure the parameters of your camera
  • 4. How to estimate when you can’t perform the measurements (perhaps you are considering buying a camera and want to see how it would compare to your current camera).
  • 5. How to evaluate your individual subs for exposure and clipping in PixInsight
  • 6. How to evaluate your subs in Sequence Generator Pro

Here is the link to Jon Rista’s post on Cloudy Nights:

Here is the link to the page where you can find the 2DPlot script as well as many other useful PixInsight scripts:

This video doesn’t get into theory but concentrates on practice. I hope this is helpful. If there is anything that isn’t clear or you find a mistake, please let me know.

ERRATA: When I discuss the scaling from the camera bit depth to 16 bits, I erroneously said the scaling was 8 for the ASI294 when it is actually 4. Proof something three times and I still don’t catch an error until it is out the door…

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