MichiP Posted December 19, 2013 Report Share Posted December 19, 2013 Hello, I’m currently using a SBIG ST-9 XE from a colleague. It’s very nice and extremely sensitive CCD. Currently we have bad weather so I decided to produce masterdarks for most used time and CCD temperatures. My first set took about 28 hours to complete all sub frames. So I’m not sure it is a problem for the CCD to keep it running for several days to make several other sets for other temperatures. How many sub exposures for one masterdark should be done become a very good masterdark? I’m currently doing 25 frames sub exposures for each master. Is this enough/too much or less? Best regards,Michael Link to comment Share on other sites More sharing options...
MarkS Posted December 20, 2013 Report Share Posted December 20, 2013 Hi Michael, I can't answer the question on the camera on-time. I suggest you ask SBIG - they are usually prompt with their replies. I have settled on 25 subs for Master Bias, Dark, and Flats Most of my deep sky exposures are in the range 5-20min. with the ASA10N scope. 25 seemed a reasonable compromise to me - given that one is doing multiple subs to minimise noise in the Masters. 25 subs give 1/5 the noise of one; to get twice as quiet would need 100 - too many for me! Regards, Mark Link to comment Share on other sites More sharing options...
MarkS Posted December 20, 2013 Report Share Posted December 20, 2013 PS: If you are using Pixinsight for calibrating your images you do not really need different Dark exposure times: Pixinsight will scale the Master as needed - but it does need to have minimum noise. Mark Link to comment Share on other sites More sharing options...
MichiP Posted December 21, 2013 Author Report Share Posted December 21, 2013 Hi Mark, thank you for your answer. I have contacted SBIG, but they are on holidays till January 6th. I made a 60 hour run with the SBIG and it seems that it is working very well, but before I continue, I will wait for the support answer Did you made some comparisons between scaled darks and temperature fitting darks in Pixinsight? Regards, Michael Link to comment Share on other sites More sharing options...
MarkS Posted December 22, 2013 Report Share Posted December 22, 2013 I always use the same temperature - minus 25C - so it is only the time that scales. I haven't yet done a direct comparison, but I have used the scaling on narrow band sub calibration. It seems to be fine. If I get a chance in the near future to do a direct comparison I'll post the result. Regards, Mark Link to comment Share on other sites More sharing options...
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