This image was already taken in February this year, during the Covid-19 curfew and thus from my balcony. No Polaris in view, provisional PA alignment by the Sun's shadow. 80 minutes total exposure – more was not possible between the trees and the mountains. So I am quite satisfied having been able to use that clear winter night despite the light pollution of our city in front of my eyes, directly in my angle of view.
Two more "particular" details ...1. While using my unmodified
Canon EOS 5D4 and the very nice
Canon EF 1:2.8/300mm L IS USM, I removed the clip-in filter holder of the lens and simply pushed an old
2" UHC filter from my Dobson telescope into the lens tube. I fixed it (more or less) with some dark fabric and glue tape to keep it in place and hold the darkness in the tube.
Seems, the
UHC filter worked nice.
2. These days I first time tried to create and use a
"synthL" (synthetic luminance) which I extracted in
Siril from the previously stacked FITS result: First conversion was RGB to R + G + B and the second was RGB to H + S + L. Then I re-combined L + R + G + B, after having tried do make L.fit looking a bit more crisp and with (a hint of) better detail.
Seems,
syntL + RGB worked, too.
We had a fine and very helpful
forum discussion about Luminance recently – feel free reading!
Comments