[Dylan16807]

Precision isn't a binary, it's a continuum. The question at hand is whether there are significant use cases where 1 second of slack in matching the Earth's rotation is acceptable, but 30 seconds is too much.

GPS isn't an example of that because 1 second is already a quarter mile off.

[welterde]

Pretty much all telescopes (under computer/time control) on this planet rely on UTC being quite close to UT1, since every second difference leads to a 15 arcsecond error in the pointing of the telescope (error between where you want to point the telescope on the sky and where you are actually pointing).

While <5s is usually not a problem (except for some instruments with very very small FoV), at 30s it really becomes a problem for instruments with modest fields of view.

[guenthert]

I would think this is an argument for telescopes using UT1, not whether UTC should be adjusted for leap seconds. This is such a fringe application and all involved are aware of the issue, that I don't think it's relevant here at all.

[welterde]

UTC is defined to be within 1s of mean solar time at 0deg longitude (= UT1).

If leap seconds are a problem for the intended application then UTC is the wrong thing to use. There are other scales that are defined differently that can be used in it's place (such as TAI).

However if exact frequency is not critical one could also directly use UT1 instead of UTC (people that use leap second smearing for instance should have no issue with that..).