Bessel's 1838 parallax of 61 Cygni
Digital scans of the
pages of the original paper in "Astronomische Nachrichten" of 1838,
in a much better readable form than given by NASA's ADS literature
server. The files are only about a factor of two larger than the ADS files.
1st page, original scan in uncompressed form
(7.7 MB; pnm format)