I would like access to CLOCK_TAI in the time package, for systems where it is available (such as linux, but not, alas, macOS). For systems that are properly configured CLOCK_TAI is very useful as a *standard* monotonic time with a standard epoch. Use cases include message timestamps and pointing telescopes… I am willing to do most or all of the work, but before I start on that I would like to know if this pull request is likely to be approved. Will this need a PEP first? Regards, Russell P.S. For systems that are not properly configured CLOCK_TAI typically returns the same thing as CLOCK_UTC. This is a well known issue, but Python is in no position to do anything about it other than warn in the documentation.