0.75m (Decommissioned – Jan 2015)

SAAO 0.75-m Telescope


The 0.75-m reflector, built by Grubb Parsons, was added to the Multiple Refractor Mounting (MRM) in 1974. The multiple photographic refractors originally placed on this mounting in 1964 have been removed.  The instrumentation available for use with the 0.75-m is listed in the table below; the optical diagram is given in Figure 1.

Cassegrain Focus f/15, ~17 arcsec/mm
Instrumentation SHOCTRIPOLInfrared Photometer Mk II
Finder 102 mm f/10


Figure 1.  Optical diagram of the SAAO 0.75-m telescope.


Telescope Control

Since 2006, position read-out and telescope pointing have been controlled by electronics from DFM Engineering.  The Telescope Control System (TCS) has been upgraded to DFM’s WindowsTM– based application, WinTCS.  Copies of the WinTCS Operations Manual and a basic User’s Guide to the system can be found here.

Visitors’ Instrumentation

Special equipment should weigh less than 50 kg. The layout of mounting holes for attaching instruments is shown in the Cassegrain instrument adaptor diagram below. An acquisition box and mount plate for use with visitors’ instrumentation are also available, please see the following figures.  Mounting an instrument on the acquisition box gives a distance to the focal plane of 226 mm, cf. 71 mm when mounting to the filter box.

Figure 2. 0.75-m Cassegrain instrument adapter.

Figure 3.  0.75-m acquisition box.  All dimensions are in mm.

Figure 4. 0.75-m acquisition box mount plate.  All dimensions are in mm.