These are chat archives for astropy/astropy
Cadair@nlharr I am not sure if that's actually possible. The AltAz>ICRS is not just one transform, it's a few.
Cadair@eteq might be able to give you more info though.
astrofrog (@_slack_astropy_U07529085:matrix.org)@nlharr - just to check, what kind of performance bottleneck are you seeing, and are you converting many coordinates in one go?