Bright Star Saturation

Hi, I’ve been working on bright stars… the LSST Science book estimates saturation for 15 second exposure in 0.7 arcsec seeing as u, g, r, i, z, y = 14.7, 15.7, 15.8, 15.8, 15.3 and 13.9. Does anyone know if this estimate has changed a lot?

I understand DM will correct for non-linearity as best they can, but how close do you expect to report high quality (say 1% results). I see there was a discussion some years ago that didn’t reach a simple conclusion at:

My goal is simply to understand what stars will have high quality photometry on the LSST system in the case of 15s, 30s exposures, and in the case of additional short exposures.

I haven’t heard anything new about estimates for the precision at the bright end. The noise model from about 7 years ago is still the most current one that I am aware of.

There has been a lot of work done in the interim on doing precision photometry of saturated stars with TESS and K2. I’m not sure how much of that will translate to ground-based photometry, but some of it should be applicable. Someone should test that with DecCam if they haven’t already.

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A related question is there a nominal bright star limit number in the Observing Strategy simulations that we can look at with MAF?

Right now we have stellar density models available in MAF, but I think they all start around 15th mag. If you want to make something on the brighter end we can probably do that (I imagine we could bin up gaia DR3 or something).

For the saturation limits, that seems like the kind of thing that one could calculate from the syseng_throughputs repo. This notebook might have the numbers you need to check if the bright end has changed much: