Quote:
Originally Posted by Spartacus
Hi Brian,
With my 294 I do a dark library once a year. As I tend to only image at gain 120 as this is the lowest read noise for this sensor that gives a gain to keep exposures low.
I do a library for 30 sec, 60 sec, 90 sec, 120 sec, 180 sec, 240 sec and 300 sec. I don't use bias masters apart from calibrating flats.
The reason for stopping at 300 sec is that for my location longer exposures start to get more light pollution and my equipment may start to run into guiding issues etc. You may want longer if you go narrowband but I would use a broadband or light pollution filter first if you are in suburbs or metro urban areas and probably none in a dark sky site.
You will need to do say 30-50 frames for each then integrate each set into masters that are used in the calibration process.
You will need to do bias frames, darks and flats all integrated into masters that attempt to remove as much from your light frames that is not related to the signal that you want. That is, intrinsic chip noise, general thermal and other noise and problems with the chip (cold and hot pixels) finally the dreaded amp glow. Then there is the imaging train stuff like dust on your optics and vignetting that are removed with flats. Oh also don't try to get the temp down too low as the advantages are less in CMOS and it causes a lot of current draw in cooling. I try to stick to -10 as this is unlikely to lead to cooler power more than 60%.
Here is a reference article that will help to familiarise you with how the calibration works especially if you use pixinsight but are still relevant for the other calibration and stacking software. https://pixinsight.com/forum/index.p...bration.11547/
I really would encourage you to read it as it contains great insights in regards to calibration and the videos from Robin Glover that I referenced in a previous post.
Remember to stick to the same temp (I use -10 degC), gain 120 would be a good start "so called unity gain", unlike the 294 there is not a sudden change in read noise that makes a particular gain perfect but 120 is middle of the road. I am not sure about offset as this may be fixed in the driver. If you change any of these parameters in your lights you will need a new set of calibration frames especially if for any reason you change offset as this can lead to clipping in the calibrated light frames. Also avoid using automatic white balance values. In the 294 these auto values in the native driver can lead to problems. Check for the best values (in the 294 this is WB-B 50 and WB-R 50). Check online for advice.
Let us know how you get on. Generally users of this camera get pretty good results and there is a lot of information on common problems and their solutions. This is the advantage of getting a camera that has been released for a few years.
Good luck and clear skies
Mike |
In Australia, What temperature setting u guys are using on Summer and winter?
i was thinking -5 to -10 for summer and -15 to -20 for winter..