Multi-night, multiple-flat integration?

[footbag]

What is the best way to integrate multiple nights of data when the camera orientation has changed?  I have to integrate the first nights data using the old flats and the most recent data using the new ones. 

Thanks,
Adam

[bianry]

If you have different flats then you need to do different calibrations. Then star align followed by integration. Star align process will twist and turn your frames until they fit (if they fit at all). I have aligned frames where some are 180 degrees rotated from the others and that was not a problem.

I think the BatchPreProcess script can handle multiple flats in one go. But someone wiser than me can fill you in on that.

regards

Mats

[footbag]

Can I calibrate the images with darks, flats, bias separately, and then integrate them all together?

Maybe I could just use the batch preprocessing script on the previously calibrated frames?

[bianry]

I am the first to admit that I am no expert on this but here are my 2 ct.
If using BPPS I would feed all the frames using same flats/darks/bias at one time. Then you can switch to next batch with new light frames and new flats/darks.... By choosing the same output directory all frames will be neatly laid out in their own folders. Ready for integration. Just remember to use same reference frame for all images that will be stacked (integrated) together. Otherwise they will not line up.

I can give you an example of a run I did last week. I had 10 red, 10 blue, 10 green and 20 lum frames. I used BPPS four times. Every time different flat and correct dark/bias. For each stack I picked the one with the best FWHM as reference for the star alignment. Output directory stayed the same for all runs. I did not use BPPS for integration.
So after four runs I had 4 folders named Blue, Green, Lum and Red. Each folder contained 10 or 20 images that were calibrated and aligned. Ready to be fed to the integration (stacking) process.

Hope this helps

regards

Mats

[pfile]

yeah - i do this all the time. i still do all my calibration and registration manually though, so a single night or multiple nights are all the same thing as far as that flow goes. as mats says as long as the registration reference is the same for every nights' work, you're good to go.

there is probably a way to convince BPP to do this with custom frame types but i have not experimented with that.

rob