[nullc]

Leap seconds are problematic for astronomers whom either are doing things that don't care (e.g. 1 star calibrated against the sky, that calibration approximately incorporates whatever difference between UT1 and their local clock exists) or where they do care they have to back the leap seconds out in order to apply a more accurate model of UT1.

It's actually quite tricky to back out leap seconds accurately because the underlying time will be discontinuous for you and you can't reliably tell when leap seconds have or haven't been applied... you might even, without knowing it, be being fed leap-smeared time which could evenmake your sidereal tracking wrong and can't be backed out because different smearers do it differently. Because leapseconds they're infrequent, you also don't get many live fire tests.

I'm aware of multiple observatories that just shut down operations across leap seconds. The significant amount of work to handle leapseconds correctly and be confident you're correct isn't justified vs taking some downtime.