Coudé Auxiliary Telescope (decommissioned)

The ESO Coudé Auxiliary Telescope (CAT) was housed in a smaller dome, adjacent to the 3.6-metre telescope at ESO's La Silla Observatory, and fed the 3.6-metre's Coudé Echelle Spectrometer through a light tunnel. The CAT was fully computer controlled and was used for many different types of astronomical observations, including measuring the ages of ancient stars.

La Silla: Coudé Auxiliary Telescope enclosure (attached to the 3.6-m)

  • Height: 3670 cm
  • Diameter: 1520 cm

Science goals

High resolution spectroscopy.

Coudé Auxiliary Telescope

Name: Coudé Auxiliary Telescope
Site: La Silla
Altitude: 2375 m
Enclosure: Classical dome connected to ESO 3.6 m dome
Type: Spectrographic telescope
Optical design: Coudé (feeds the spectrograph of the 3.6-metre)
Diameter. Primary M1: 1.47 m
Material. Primary M1: Borosilicate
Diameter. Secondary M2: 0.22 m
Material. Secondary M2: N/A (four interchangeable M2 secondaries mounted on a turret)
Diameter. Tertiary M3: 0.254 m
Mount: Equatorial siderostat mount
First Light date: 5 May 1981
Decommissioning date: Connected to ESO's 3.60 m telescope via optical fiber in 1998
Images taken with CAT: Link
Images of CAT: Link
Videos of CAT: Link
Press Releases with CAT: Link