@taldcroft - like for the strings, I think several status indicators will become overly heavy. As for the exception, I guess that could be among options one could set: raise exception on so-and-so, before/after trying to download additional table, etc. Would this be here or upon opening the table? The reason I did not implement anything like this so far is that really this is a helper routine for Time and eventually coordinates, and I think it makes more sense to raise the exception in whatever calls IERS, since it can know context and thus provide a more helpful message.