Quick post-processing question

[Demonperformer]

When you take sets of subs over several nights, you presumably have to process them separately, as the dark & flat frames would be different. So when you combine each of these nights' results to form one final image, do you:

[a] combine the tiffs that dss produces into one final image, and then post-process the result,

post-process each image before combining in dss into your final image, or

[c] post-process each image before combining in dss into your final image and then re-post-process the result

Thanks

[Psychobilly]

[d] None of the above...

I use file groups in DSS...

You put the common files in the main group (just bias really) and the lights darks and flats for each night in seperate groups...

Peter..

[jgs001]

As you are using DSS, there is a built in method for combining images over multiple nights. When you add a file to DSS, it goes into the master group. This has another effect, it creates a new tab called group 1. Add all your data from the first night to group 1, flats, darks etc. As soon as you add a file to group 1, a new tab is created group 2. This goes on and has created more tabs than I've captured nights worth of data so far (5 being the most nights).

The way DSS processes this, calibration frames in the master group (bias) for instance are applied to all images in every group. Calibration frames in any single group are only used on the light frames in the same group. Once all the lights are calibrated they are all stacked together.

If the exposure details are different between nights, then use the entropy weighted stacking.

HTH

Peter can type faster than me

[Psychobilly]

Entropy weighted stacking needs loads of subs to control the noise...

[Demonperformer]

Thanks Peter & John for your quick response. Certainly will be easier like that. Only just beginning to get to grips with DSS really, but did wonder what the 'group 1' tab was for. Now I know.

At the moment I tend to use the same 15s subs for everything, so weighting won't be a problem.

[jgs001]

Ah... ok... thanks... I've not really used it with anything less than 70 odd subs anyway so hadn't noticed. I tend to keep my exposures the same night to night.