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Frank,

Thank you for the clarification and patience with my occasional dumb question. I suspect I had read this in the past and maybe even taken it to heart but since it’s not something that arises in the normal course of taking sights, it had evaporated from my memory. When I came to think things through starting from first principles recently I was operating under the assumption you couldn’t possibly create an almanac based on a time scale that is not known in advance. I guess DUT1 must predictable enough to make this possible. It’s good to see at least that both the NA and I come up with the same 0.2' longitude as the maximum size of the error,

Regards,
Robin