Pixinsight batch processing script and master flats/bias/dark

[Erquy]

Hi

Still learning on pixinsight and I have some doubts on work flow:

I want to use the batch processing script together with master bias/dark/flat (instead of individual bias/dark/flat, a matter of going a bit quicker).

If one follow the tutorial

http://pixinsight.com/tutorials/master-frames/en.html

for making the masters, are they OK for use in the batch processing script as such or not?

My issue is related to the master frame calibration: In above tutorial, you calibrate the flats both substrating the bias and the dark (but you don´t substract the bias to the dark). So if you use such master in the batch processing script, does it recognized 1) the master flat is already calibrated on bias/dark (or will the batch processing repeat the process again) 2) the bias is not substracted in the dark (and it will do it) ?

Thanks for your help

[Barry-Wilson]

Hi Erquy

I'm still learning myself, so can only report my experiences.  I've followed Harry's tutorials and found them very helpful, as I'm sure others will confirm, http://www.harrysastroshed.com/index.html.

I use a ccd and just add the bias (don't use darks), flats and lights into the Batch Preprocessing script and this carries out the calibration, registration and integration (if you specify).  The script will produce Masters of each bias, darks (if you use them) and flats if you tick the box and therefore no need to separately process them.

HTH

Barry

[Erquy]

Hi

thanks. In fact I manage to find a detailed description how the script workflow is (but too stupid I did not keep the link and I could not find it again). Anyhow, indeed this is slightly different than the tutorial I copied above for what I remember of reading it (and it was answering my questions and of course the script to generate the masters etc is done with all right calibrations required).  I did some trials on different set up and found only very subtle differences anyhow

[kirkster501]

Hi

Still learning on pixinsight and I have some doubts on work flow:

I want to use the batch processing script together with master bias/dark/flat (instead of individual bias/dark/flat, a matter of going a bit quicker).

If one follow the tutorial

http://pixinsight.com/tutorials/master-frames/en.html

for making the masters, are they OK for use in the batch processing script as such or not?

My issue is related to the master frame calibration: In above tutorial, you calibrate the flats both substrating the bias and the dark (but you don´t substract the bias to the dark). So if you use such master in the batch processing script, does it recognized 1) the master flat is already calibrated on bias/dark (or will the batch processing repeat the process again) 2) the bias is not substracted in the dark (and it will do it) ?

Thanks for your help

When you do your first filter colour, say RED, PI will integrate the BIAS to make a master BIAS.  You can then use that master BIAS for the other colours of the same binning level.  Same with Darks.  After BIAS subtraction from the darks and after they are integrated you can use that same master dark for your other colours.  You have to tick the boxes on the right "use master BIAS" etc to tell the BPP script to do this.

The flats are different.  You should have a dedicated set of flats for each colour/filter.  So even though it creates a master flat for each filter you shouldn't reuse that flat for other filters/colours.  Indeed, the BPP script will not let you do so unless you edit the FITS headers.  Of course, if you want to change say the sigma clipping levels you can then say "use master flat" since the flat will always be the same, however much you tinker with the parameters used to calibrate and register the lights.

[andyo]

If you load your calibration frames into bps and they are not masters the bias is subtracted from all frames darks flats and lights.if you use masters and load darks flats and bias into the bps and tick the box saying you are using masters then the master dark should be bias subtracted beforehand as the bps will not bias subtract the master dark again.