Thread: Ha 7nm vs 5nm
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Old 29-09-2014, 08:30 AM
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gregbradley
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Quote:
Originally Posted by pluto View Post
I haven't tested myself but according to the Astrodon site the 3nm should transmit the same amount of light at the target wavelength as the 5nm filters. So exposure times should be about the same. Obviously this doesn't apply to the 3nm Ha as it misses out on a significant amount of NII light which the 5nm doesn't.
Ah right, I was referring to the Ha. Not sure about the others, perhaps no difference. Some here use all 3 and would know. I do read posts about extra exposure time needed with 3nm Ha filters. Its been a consideration for me about getting one. Probably will anyway.

Greg.
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