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Old 03-03-2018, 08:45 PM
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LewisM
Novichok test rabbit

LewisM is offline
 
Join Date: Aug 2012
Location: Somewhere in the cosmos...
Posts: 10,388
7nm H-a with an OSC

A mate traded me a 7nm H-a filter (2"/M48 Optolong) for one of those silly eyepiece things

ANYHOW, I know using an H-a filter OSC is entirely possible (1/4 the pixels at least get something - dithering to the rescue! ), but approx. how much longer an exposure compared to RGB OSC? I currently do 10 minute subs with the FSQ-85 and the LP filter, so what is a good ball-park on acquiring H-a data commensurate to the RGb? 20 min? More? Is it a linear relationship?

And lastly, is it necessary or advisable to use the UV/IR cut filter with the H-a filter? (I stack my filters in a special filter-adaptor I had custom made - see below - the end screws off to reveal internal M48 female threads to mount the filters)
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Last edited by LewisM; 03-03-2018 at 09:16 PM.
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