SLAC completes construction of the largest digital camera built for astronomy

Correct, the camera is built for an all sky survey. With the wide field of view it should be able to image the full night sky once every two or three days.

It depends what you mean by a "normal telescope" (all telescopes used for astronomy are designed for specific tasks/roles, even if that's not called out in public-facing material as much). LSST is not the first large scale optical survey (and previous telescopes have chosen to have a wide field of view, but they've been quite small in comparison), and there are tradeoffs to trying to use such a large field of view (e.g. having to correct for lots of distortions, both in the design of the optics, and in software), but because of the large collecting area (being a 8-meter class telescope), you can go much fainter faster (and with higher signal to noise) than a 1-meter class telescope that has the same field of view. Wikipedia has a bit about what makes LSST special (https://en.wikipedia.org/wiki/Vera_C._Rubin_Observatory#Comp...). I don't know when they're going to start observations, but I suspect there'll be loads of announcements of cool new transients soon after.

The other difference is partly a consequence of the wide field of view. That thing has a huge front lens, which lets in a massive amount of light, so the brightness of the projected image on the sensor is much higher than a telescope that has a zoomed-in field of view. That means it is able to use a relatively short exposure and still see things in the sky that are fairly dim.

To use numbers to compare to any other camera, it has a 3.2 gigapixel sensor with a diameter of 640mm, and the "lens" (actually several mirrors) has a focal length of about 10m and a diameter of about 8m, giving it an f-ratio of f/1.2, which is very impressive (although the central part of the "lens" is obstructed, giving it a light-collecting ability more like an f/1.5 lens).

Good question. LSST was being studied as early as 2008, and it was highly ranked in the 2010 Astrophysics decadal survey - I just looked it up and in that 2010 survey the design was described as “relatively mature.” This was long before the Starlink issue became known, e.g. the first Starlink launch was in 2018.

I worked in this area around 2008-2014 and I never heard astronomers discussing communication satellite interference, it was mostly about data volume, image processing, and automated classification. Perhaps it was being considered in the later 2010s by serious optical system engineers?

In 2001 (https://en.wikipedia.org/wiki/Vera_C._Rubin_Observatory lists this as the "start date")? Unlikely much could have be done about it, other than introducing regulation to block their creation.