© O.Hainaut / ESO-Chile (1992)
© O.Hainaut / ESO-Germany (1993)
© O.Hainaut / K. Meech -- IfA/UHawaii and TOPS Workshop (1997)
© O.Hainaut / ESO-Chile (2001)

The observatory and city list comes mostly from that included in XEphem, the great interactive astronomical ephemeris program for X-Windows, http://www.ClearSkyInstitute.com/xephem ecdowney@ClearSkyInstitute.com, with personal additions and deletions. Any errors in the current list is mine.

Several subroutines come from "Astronomical Formulae for Calculators" by Jean Meeus. Richmond, Va., U.S.A., Willmann-Bell, (c) 1982.

Plots performed in SuperMongo, by Robert Lupton and Patricia Monger, http://www.astro.princeton.edu/~rhl/sm/.