add functions for converting magnitudes to counts, getting noise levels for images, etc.

[beckermr]

No description provided.

[beckermr]

cc @esheldon

[aboucaud]

Sounds like a set of useful functions related to pure survey numbers. Thanks for suggesting :)

You were mentioning that these are already implemented somewhere. Is this in https://github.com/LSSTDESC/WeakLensingDeblending ?

[beckermr]

There are functions in there, but IDK if they are correct for the adopted units / conventions here:

https://github.com/LSSTDESC/WeakLensingDeblending/blob/master/descwl/survey.py#L125

[beckermr]

There is also lots of stuff done in the init here: https://github.com/LSSTDESC/WeakLensingDeblending/blob/master/descwl/survey.py#L47

Some of that appears useful.

[beckermr]

Maybe this: https://github.com/LSSTDESC/WeakLensingDeblending/blob/master/descwl/survey.py#L110

[aboucaud]

Right, so for a given survey you'd like

• a method that takes an AB mag and returns the number of counts
• a method that takes a sky_brightness and returns the mean_sky_background

Am I correct ?

[beckermr]

@esheldon should confirm, but I think this is the whole thing.

[esheldon]

Yes. In addition, we would also like to know what a typical expected background is, say on a moonless night. This varies a lot for different sites.