Quote:
|
Originally Posted by tornado33
Fantastic shot. How long were the subexposures?. Do you find fewer very long subexposures, or shorter but more of them is best?
I see that SBIG camera is a self guided one. If so does the guiding chip have to "look through" the narrowband filters or can it see unfitered starlight?
Thanks.
Scott
|
Hi Scott,
Thanks!
I have 1 hour subs for narrowband exposure.
Your shortest sub exposure should be set to a time that overcomes your cameras readout noise. For my setup it's about 45-50min with a narrowband filter, about 3mins for clear and 5mins for RGB. The darker your skies are the longer it takes to overcome readout noise.
You don't gain alot from longer sub exposure once you overcome readout noise.
http://www.starizona.com/ccd/advtheoryexp.htm
http://www.ccdware.com/resources/subexposure.cfm
Yes, the guider CCD is filtered also; I use 7 sec guided exposures.
Hope this helps,
Brad Moore