Quote:
Originally Posted by avandonk
I can get a colour image in about 120s with the stars just starting to saturate. What people have been calling HA is really a mixture of HA and NII. For example the Helix Nebula is about three times brighter in NII than HA.
I want to do deep NB and long exposures of about eight and sixteen minutes.
Bert
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Yes, I'm aware that many Ha filters also overlap with NII and that yours doesn't because of its ultra narrow bandwidth. But the reason I asked is that most of the targets you've been shooting are Ha rich, not so much NII rich. ie you haven't been shooting planetary nebulae like Helix.