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Old 30-11-2016, 06:00 PM
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Shiraz (Ray)
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Shiraz is offline
Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,798
Originally Posted by rustigsmed View Post
hmmm looking about 1 to 2 mins for me.

got me thinking should the sky value change when using a light pollution filter like a cls ccd?
Hi Russell. hadn't thought about CLS, but, since the filter will get rid of about half the bandwidth, set the filter to 150nm. The filter will also selectively attenuate the sky - not able to find any measurements, but suggest that you try making the sky about 1-2 mags darker as a first try.

Originally Posted by Slawomir View Post
Hi Ray,

Just letting you know that I plugged in numbers to your spreadsheet to the best of my knowledge, and the graph confirms what I was getting before, that about 15-minute subs in my case are optimal and that there is minimal gain past that length. I guess sky brightness is the largest uncertainty for me, but with narrowband it should be comparable to an extremely dark site?
thanks Suavi.
Sky brightness is a real pain, because the spectrum varies with location. Have finished the narrowband version, but need to validate it to make sure it is producing reasonable numbers for my location. Would be nice to have it checked elsewhere. Maybe will be fit to post tomorrow... In the meantime, just set the bandwidth to that of your filters if you want to try some narrowband ideas with the broadband model - it will not be very accurate, but is also not totally useless.

Originally Posted by clive milne View Post
Ray... someone should name a single malt whisky after you...

well done.
Hi Clive. Thanks very much for that. I will never have a malt named after me, but I have every intention of drinking a little bit over the next few years.

regards ray
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