> I wonder how possible it is to essentially sum together lots of pictures one after another where occasionally you would reject photos that had a satellite pas

> I wonder how possible it is to essentially sum together lots of pictures one after another where occasionally you would reject photos that had a satellite passing through them? Like is that how they deal with it now? This is what LSST is going to do, sum the images to look deeper than just one image. There are a few commercial software packages that also do this co-addition (my friend has a large but still amateur telescope and that software does this). The exposures aren't terribly long, so the idea is to add a bunch of them together, since the CCD wells can become saturated, and even "leak" between them. This is why the camera is cooled down by extra cryogenics.