After using a Bahtinov mask to focus on a bright star I started live stacking and was getting FWHM values of 8.2 and greater. I closed SharpCap 4.0 (the latest version) and started my older version of SharpCap 3.2. With the same exposure, gain, everything I was getting FWHM values around 4.5. How can there be such a huge difference?
Thanks,
Mark
Huge FWHM Differences between 4.0 and 3.2
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Re: Huge FWHM Differences between 4.0 and 3.2
Hi Mark,
the whole star detection code was re-written between 3.2 and 4.0, as part of that, the settings for star detection changed quite significantly too. That means that there is a good chance that different stars are being picked for measurement in 4.0. On top of that, the main goal of FWHM measurement is to give a relative measure of goodness of focus - that is that you should get lower values if the stars are smaller and larger values if the stars are bigger.
All that being said, it would be good to check just in case there is some sort of bug that is new. If you have a raw (unstacked) frame from the session and your live stacking star detection parameters from 3.2 and 4.0, I am happy to check.
thanks,
Robin
the whole star detection code was re-written between 3.2 and 4.0, as part of that, the settings for star detection changed quite significantly too. That means that there is a good chance that different stars are being picked for measurement in 4.0. On top of that, the main goal of FWHM measurement is to give a relative measure of goodness of focus - that is that you should get lower values if the stars are smaller and larger values if the stars are bigger.
All that being said, it would be good to check just in case there is some sort of bug that is new. If you have a raw (unstacked) frame from the session and your live stacking star detection parameters from 3.2 and 4.0, I am happy to check.
thanks,
Robin