NavList:

Why would anyone want downloadable data equivalent to Pub.249 vol.1 for the year 2020??

If someone is going to prepare homebrew, download versions of 249, then why in the name of all sanity would you do the same five-year cycle, which was driven by choices made in the 1950s, and which is necessarily hobbled by the P&N table?! Just prepare the tables for every year! Better yet, if they're strictly for download or for a la carte printing (as Gary suggested), then prepare them for every month, and that way you can include stellar aberration (which will buy you only a small rounding difference at 1' of arc precision but can also allow 0.1' precision). And if you're preparing homebrew versions of 249, then why in the name of all sanity would you regurgitate the same star choices, with numerous errors, found in the original government-issue series? Make better star choices, maybe using the old tables as a starting point. 

Now if your goal is to produce volumes that you can sell, staying in sequence and in style with the old g.i. publications, as Celestaire has done, that's one thing. You mimic the old system for market value. But if your goal is to have access to navigation data, then copying 249 line-for-line is pointless ...and mindless. It's form without function.

Oh, by the way, the 2020 volume has been available from Celestaire for years. Tony's original post suggested that this was something new. It is not. The file has been available for years. We do not need to "wait" until a certain date to publish the 2020 tables or, for that matter, the 2047.5 tables. One could easily prepare editions of Pub.249 vol.1 for decades into the future today. They are not dependent on any unknowns.

Frank Reed