SharpCap Forums

Is it possible, or alternatively, is there any reason to collect flats and darks as individual frames vs the averaged masters that seem to be the only choice in SC. I ask because the PixInSight weighted batch preprocessing only seems to work with individual frames (it wants to make its own masters). It's possible to get around this by using the individual calibration process to separately calibrate with masters from SC, but is one way better than the other? Also, do the calibration frames require debayering (assuming you collect color calibration frames - I have an ASI294MC Pro OSC camera) along with the debayering required to make calibrated lights in PI? And finally, after reading numerous threads here on the above camera, is the consensus that bias frames are unnecessary/harmful? Sorry for the various questions, but they are all about calibration frames, so maybe it is allowed? Thanks,
Broz

Hi,

currently there isn't a way to get SharpCap to create both an averaged flat/dark *and* save the individual frames at the same time - not a bad idea for the future though.

I'm going to pass on the question of whether you need to ask PI to debayer the frames - the dark frames will have colour info in them, so something needs to be done about the bayer pattern, but the usual procedure is (I think) to subtract the dark and then debayer the subtracted result (at least that's the way SharpCap does it - who knows about PI).

My understanding of bias frames is that they are only useful if you are trying to use darks of the wrong exposure length (compared to the lights). If your dark and light frames match then they should have no impact.

cheers,

Robin

Broz

No bias frames, a real world example https://www.astrobin.com/v8200q/0/. Word is that modern CMOS cameras don't need them. The example, 12x300s with a ZWO ASI2600MC, was captured using remote robotic equipment. Bias frames were not offered (darks & flats were) so I had to go without bias frames. The lack of bias frames doesn't seem detrimental to the image.

The ultimate test with your own equipment of course is to process with and without bias frames and compare the results.

Dave

Thanks again to robin and turfpit.
Broz

Simplest way would seem to be via Capture. Set target name to dark/flat respectively and capture desired number with desired settings.

Then take the captured set over to PI.

Am I missing something?

Robin, re the bias.

Wouldn't you also need them if you were taking flats separately, i.e., without the automatic subtraction from flats that SC does?

Hi,

yes, for proper flat correction you would either use dark flats or bias frame to remove the constant offset from the flat frame image data. Well spotted

Cheers, Robin