Quote:
Originally Posted by chunky
Hi Doug,
My take on it is that you are using 2 notch filters together. One is a narrow single notch - the other is multi-notch, so all you would be doing would be adding another optic with potential reflection issues and attenuating the Ha signal down another 15% or whatever the IDAS filter is for transmitting Ha. I think the Ha line averages 75% transmission on IDAS filters.
So you would just lose another 1/4 of your Ha light.
Regards
Clinton
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Thanks Clinton - I had thought there might be a disadvantage re transmission but hadn't even considered the potential for the addition of more internal reflections!
The least amount of glass between you and the stars is probably a rule of thumb to follow at all times!
Cheers for the response.
Doug
