Thanks for providing all those links. Indeed, the key there is peak magnitude. BlueWalker 3 has a giant array that reflects light like a mirror. So when you happen to get the angle of incidence exactly equal to the angle of reflection, it shines quite brightly. Of course since it's reflecting all sunlight in one direction, that means from all other spots on earth it will be extremely dim.
Also note that BlueWalker 3, like most low-earth orbit satellites, is only visible during "terminator conditions", when the satellite itself is illuminated by the sun but the telescope is still in darkness. Those times are typically an hour or so after sundown or an hour or so before sunrise. So one solution is to schedule astronomy for the middle of the night, when none of these low earth satellites will lit by the sun at all. Which certainly increases the costs of astronomy, since you can't use your telescope for as many hours per day.
Or, just use your space object catalog to look elsewhere in the sky when bright satellites happen to be in the sky during terminator illumination conditions. Which I see is one of the things your last link, "Mitigation of LEO Satellite Brightness and Trail Effects on the Rubin Observatory LSST", suggests!
SpaceX has offered their space-rated mirror technology at cost to other satellite manufacturers, but it seems AST SpaceMobile hasn't taken them up on the offer. I can't see any mirrored surfaces on BlueWalker 3.
>that means from all other spots on earth it will be extremely dim
The second paper I linked (see Figure 1) shows a minimum magnitude after array deployment of 5.5 magnitude, from multiple observatories at multiple locations on the Earth. That's still 10 times brighter than the IAU limit.
>just look elsewhere in the sky
The hottest thing right now is whole-sky surveys like Vera Rubin (which are important because they can alert other telescopes to transient events), which can't really do that because they're already looking at... the whole sky.
Not really. Astronomical dusk and dawn are different than civil dusk or dawn, you'd normally skip an hour or so after sunset and before sunrise anyway.
Also note that BlueWalker 3, like most low-earth orbit satellites, is only visible during "terminator conditions", when the satellite itself is illuminated by the sun but the telescope is still in darkness. Those times are typically an hour or so after sundown or an hour or so before sunrise. So one solution is to schedule astronomy for the middle of the night, when none of these low earth satellites will lit by the sun at all. Which certainly increases the costs of astronomy, since you can't use your telescope for as many hours per day.
Or, just use your space object catalog to look elsewhere in the sky when bright satellites happen to be in the sky during terminator illumination conditions. Which I see is one of the things your last link, "Mitigation of LEO Satellite Brightness and Trail Effects on the Rubin Observatory LSST", suggests!