[fitsbits] BINTABLE/TABLE column count limitation

[Jonathan McDowell]

Actually I think we did come up against it in internal Chandra stuff
at one point, and for the source catalog - but as you say, for practical
apps one should consider winnowing down the columns.
 My take is that the solutions are either unwieldy (the nnnB byte column,
clever I admit) or break back compatibility.
 In answer to a previous commenter, until a few years ago the tradition
was indeed that FITS should be back compatible both ways, so that
old readers should be able to read new files. In an era of reduced 
software budgets, breaking that (as was to some extent done with the WCS
changes, arguably) leads to different packages able to read some "FITS"
files but not others. 
 I believe that we have now reached the point where, if these features
(long keyword names, 1000+ columns) are really needed, then we need
to break another FITS tradition and go for versioning: FITS2 files
(redesign minimal or maximal according to your taste :-)) rather than
continue to layer on ever more baroque conventions (of which I am responsible
admittedly for more than my share...)
 - Jonathan McDowell,  SAO/CXC