More info.
Here are 2 @ 30 sec @ 1600 ISO, a more normal exposure value.
I had previously found an article on someone else's filter tests with graphs on a 'standard' light source. I'd credit the author if I could remember where I found it but I grabbed two of his images, one for the Astronomik CLS filter which I have ( not the CCD one ) and for the C80A. Hope he doesn't mind.
But I was interested in the similarity of the profiles with the 80A being a much less pronounced variation of the CLS. My thinking is that the 80A may have enough LP blocking to be useful yet not filter out too much of the rest of the spectrum. And help my guiding issue as well.
LP has virtually limted my exposures to max of 30 secs so far, sometimes less, 20 -25. So being able to extend exposures to more than a minute or so in my books is useful.
Testing will continue ..
P.S. Ignore the trailing stars, no guiding. Of the graphs, first one is the CLS with yellow lines for the sodium and mercury vapour lights, second the 80A. Purple line is the light source.
2" LP filters are EXPENSIVE !!
