# Provide a "stackfitCalib" for coadds

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#### Details

• Type: Improvement
• Status: Won't Fix
• Resolution: Done
• Fix Version/s: None
• Component/s:
• Labels:
None
• Story Points:
4
• Team:
Data Release Production

#### Description

Coadds have a Psf class that returns the proper sum of input PSFs at a point. We need the same functionality for the Calib object associated with the Coadd Exposure.

This will require making a Calib a baseclass (it currently doesn't have a virtual dtor (although it does have virtual protected members))

#### Activity

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Tim Jenness added a comment -

Jim Bosch is this 8-year-old ticket still relevant?

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Tim Jenness added a comment - Jim Bosch is this 8-year-old ticket still relevant?
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John Parejko added a comment -

Calib was replaced with PhotoCalib several years ago. If we do want similar functionality for PhotoCalib, we should probably write an entirely new ticket for it.

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John Parejko added a comment - Calib was replaced with PhotoCalib several years ago. If we do want similar functionality for PhotoCalib, we should probably write an entirely new ticket for it. See also RFC-545 , where I advocate to just calibrate all images to nJy, and have the coadd be in nJy as well.
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Jim Bosch added a comment -

Calling this Won't Fix as I don't think we need it at all; our coadds are already calibrated to a common zero point (and while the target should be expressed in units of nJy rather than a magnitude zero point, that doesn't matter here). And getting more to what I suspect was the point of this ticket, we've decided that the PhotoCalib is only responsible for the overall/grey calibration - sub-band chromatic photometric corrections are the responsibility of the TransmissionCurve or some future extension thereof, and that already has a coadd implementation.

Show
Jim Bosch added a comment - Calling this Won't Fix as I don't think we need it at all; our coadds are already calibrated to a common zero point (and while the target should be expressed in units of nJy rather than a magnitude zero point, that doesn't matter here). And getting more to what I suspect was the point of this ticket, we've decided that the PhotoCalib is only responsible for the overall/grey calibration - sub-band chromatic photometric corrections are the responsibility of the TransmissionCurve or some future extension thereof, and that already has a coadd implementation.

#### People

Assignee:
Unassigned
Reporter:
Robert Lupton
Watchers:
Jim Bosch, John Parejko, Robert Lupton, Tim Jenness