integration of different exposure times

[vpcirc]

I'm sure this has been asked, but I can't find it.... If I am stacking files of different integration times say one night I shot 600 seconds, the next time 900 seconds, do I still choose weights "noise evaluation" ? I see an option for exposure time so I wonder if that's a better choice?

[Phil Leigh]

I depends why you are using different exposure lengths... what are you trying to achieve?

[vpcirc]

I didn't feel there was quite enough signal, so I increased time. I didn't want to lose the other data though. In CCDStack, I would simply choose the longer exposure time and it would weight the images accordingly. I guess I'm trying to see the best way to do that in PI

[Phil Leigh]

Oh - OK. just throw them all into the BPP script and let Pi work its magic... noise weighting is / should always be used for best results when integrating the light frames (the BPP script does this automatically). If you are using darks, remember to check "optimise darks".

[vpcirc]

I never use BPP for integration. Too often I have different amounts of frames. I may want to use Percentile on one color and linear fit on another. BPP doesn't give you that flexibility.

[Phil Leigh]

Regardless of using the script or doing each batch of durations manually and then combining them with HDRComposition later, you would always use noise evaluation weighting.