Intra-night master cals

Hi there,

I was just wondering if there is any way within the stack to create and use master calibs (master bias etc) using subsets of calib data taken throughout a night. To give a specific example: cases where the biases etc may not be stable throughout a whole night, so one may need to take biases throughout the night, and only use biases taken close in time to a given science exposure.

I can see how one could create such intra-night cals by using some kind of identifier extracted from the header (e.g., a range of frame-ids), perhaps. But I’m not sure how I would tell the stack to only apply a given cal to a science frame, since the --validity flag only works in units of “days”, whereas we’d need something more fine-grained.

Has anything like this been discussed/considered before?

Thanks in advance for your help,

The current butler only supports days. The “coming soon” new “generation 3” butler will support more accurate dates.

It is claimed that you could use higher resolution time stamps now in gen2 (I need to for the PFS spectrograph), but I’ve never checked that this is true.

Thanks for your responses. It sounds like this is something that we should probably put on hold until gen3. I don’t think it’s desperately urgent, and we can probably do some kind of workaround until we’ve moved over to gen3. Thanks again, J.