This page contains links to a number of unpublished technical notes on Hipparcos
and Gaia, produced by Lund Observatory staff L. Lindegren and S. Söderhjelm over
a period of more than 30 years. The notes are collected below under the headings
"Hipparcos notes" (covering roughly the period 1976-1995), and "Gaia notes"
(1997-2007). The notes reflect the varied and substantial involvement of Lund
Observatory in the development of these missions, and trace the evolution of
several important ideas.
The documents are ordered by date, in the format yyyymmdd Title. Notes written by
specifically for the (Hipparcos) Northern Data Analysis Consortium (NDAC)
were numbered NDAC/LO/XXX, and are here designated yyyymmdd XXX Title. The Gaia
notes are designated Gaia-LL-XXX yyyymmdd Title, where XXX is a sequential number.