This is the Northen Sky Narrowband Survey.  The author asked us to
mirror it from his own personal page, and we will update it as
appropriate.

The original download used a script cp.sh from mirror.tar, which is in
data at this point, together with a bunch of .gzs telling cp what to
pull.  All that can go once we transfer that data in a different way
(the author can't do rsync from his server, it seems).

After mirroring, the properties files need to be fixed.  Just run
bin/fix_properties.py for that.  See comments there for the background.

The test set is the properties files from the mirrored hips subdir,
obtained like this:

rsync -av --exclude="Norder*" --exclude "*.tar.gz" alnilam:/data/gavo/inputs/nsns/data/ data/