Oral title: Pre-SEST IR and Mm wave heterodyne observations from la Silla.

Oral abstract: A presentation will be given about the pioneering development of optical/infrared and 
mm-wave heterodyne receivers and their first observations in the 70's from La Silla observatory.
In 1973 and 1975, observing time was allocated to use ESO’s largest telescope for infrared 
heterodyne detection observations at 3.4 m and at 10 m of planets and stars. The equipment, still in 
an experimental state, was located in the Coudé room of the 1.5 meter telescope. The outcome of 
the two observing runs were two PhD theses from the Univ. of Utrecht. (Herman van de Stadt; Thijs 
de Graauw) Several years later the Utrecht-ESTEC team came back with a complete mobile mm-
wave receiver and made CO (2-1) observations of14 HII regions in the LMC, in the Cass focus of 
the 3.6 m. In 1981 and 1982 a large CO survey of Southern HII regions was carried out with the 
CAT. This exploratory mm-wave program was strongly supported by ESO's DG Woltjer and staff 
and  created interest for a dedicated telescope: SEST.