Pre process or not?

[simondodd]

Just wondering how much if any pre processing people do to their subs before stacking?

I'm still in decision as to what is best. I check through my files and remove the crap ones and then stack generally, but I have tried a couple of times doing some very light colour balancing and touching up of the subs before stacking but I'm just not sure if it made enough of a difference to warrant the extra time spent on the image...

What are all your thoughts?

[old_eyes]

The process I have settled on for the moment is nothing special. It is what a lot of people do.

I use Pinxinsight for processing:

• Screen out the obvious rejects using the Blink comparator.
• Calibrate the subs with Darks and Flats - Image Calibration 
• Remove remaining hot/cold pixels with Cosmetic Correction
• Debayer
• Register subs with Star Align
• Stack with Image Integration.
   

The good thing is that there are scripts in Pixinsight to do this for you (Batch Preprocessing and Weighted Batch Preprocessing). So once I have got rid of the obvious rejects, it is one step to a stacked image ready for further processing.

I do no other processing until I have a stacked image. Someone will be able to give you the mathematics justifying that, but I just follow what people who are posting great images are doing.

As I am using a CMOS camera, like your Nikon, I don’t use bias frames and I use exposure matched flats and dark flats. 
 

From my point of view the quicker you can get to a single image for further treatment, the better. Processing lots of frames  with multiple treatments gets a drag. When you want to try out alternative processing approaches having more frames to work on starts to cost serious time!