BPP problem

[BillM]

Hi
I consider myself a fairly seasoned user of PI but I have noticed an issue with BPP script and matching flat darks. I have a new cmos camera and I am experimenting with flats darks. Say, for example, I have taken flat darks at 0.75sec and 0.15sec. when I add the 0.75sec darks they are correctly identified as such. But when I add the 0.15sec darks, they are added in as 0.75sec.

Am I doing something wrong or is this just a limitation of BPP script?

I have also tried the modified BPP script that uses Bias as Dark Flats but with same result.

I know I can do it all manually, but I would like to use the BPP script if at all possible.

Any help much appreciated.

Thanks
Bill

[RickS]

Have you checked the FITS headers to see if the 0.15 sec darks are tagged correctly?

[BillM]

Have you checked the FITS headers to see if the 0.15 sec darks are tagged correctly?

Yes. The only discrepancy I can see is that the Green FlatDark has an exposure of 0.29999999999999999 sec  rather than 0.3 sec.

[RickS]

I have a bunch of short darks of different durations that I took to do some camera characterisation.  I'll see if I can reproduce the problem...

[RickS]

Hi Bill,

On the Darks tab of BPP there is an Exposure Tolerance value.  You need to reduce it from the default of 10 seconds...

Cheers,
Rick.

[BillM]

Tried that.

All Red flat darks and Lum flat darks are grouped together as a single Master Bias ( even though they have different exposures - (0.75sec and 0.25sec). This master bias has no Exposure Length field in the FITS Header. How does this Master Flat Dark calibrate the individual Red and Lum flats? Is it possible to integrate individual Master Flat Darks for each filter/exposure length?

Thanks
Bill