Hey all, I recently added more data to my NGC 2997. It is now 8 hours and ten minutes with a 110mm f6 refractor, five min subs calibrated.
I initially got some help with Star Tools from Ivo, the source himself!, and he was kind enough to write down a menu to help in processing, which I followed on this reprocessed with added data...
I also tried to eliminate the dead pixel columns with mixed success (I tried on the right only). First one is a crop to avoid these..
I wondered why they sprang up as I as dithering in nebulosity (small or medium dither/0.2 sec)
I never noticed them on the original set of subs (these were taken on four different nights) but they might have been there all along.
Anyway
8 hrs 10 x 300sec with QHY 8 OSC f6 110mm
Processed (thanks again Ivo!) StarTools after stacking and calibration in DSS.
I think this is my best effort yet (my efforts so far have been climbing up Mount Modest at the best of times!).
Cheers for looking
Graham
Last edited by graham.hobart; 11-03-2014 at 10:34 PM.
occasional columns with reduced sensitivity seem to be an issue with QHY8. Sander supplied a bit of code that apparently can repair this problem when darks/flats will not. http://qhyccd.com/ccdbbs/index.php?topic=2665.0
Much appreciated Ray. Will have to digest that code when not so late at night!
One question, why does the last poster say darks are a NO No for the QHY 8?
Mine is the old style square one with an updated TEC 2 cooler but still I would have thought that everyone except StrongManMike uses darks?
Much appreciated Ray. Will have to digest that code when not so late at night!
One question, why does the last poster say darks are a NO No for the QHY 8?
Mine is the old style square one with an updated TEC 2 cooler but still I would have thought that everyone except StrongManMike uses darks?
The QHY8 does not have a regulated temperature, so dark calibration is less reliable than on set point cameras (unless yours has a set point capability). However, the thermal noise is so low anyway that there is no real need for darks - just do a bad pixel mapping and replacement to get rid of hot pixels and the residual thermal noise will be well below the shot noise in the sky signal. Dither will remove any fixed pattern in the residual dark current if needed, but I never found it to be a problem.
Ngc 2997
