The coordinates of the 15m telescope were obtained from geodetic VLBI experiments R4554 and R4555, courtesy David Gordon and Sergei Bolotin, GSFC VLBI Analysis Centre:
|Coordinate||ITRF20??, epoch 2012-11-08|
|Antenna axis offset||1.464 m|
The coordinates of the 15m telescope reference point were determined by a differential GPS campaign run by Attie Combrinck from 2007 Jan 12 to 16.
The GPS reference point was located at the top of the concrete pedestal during construction, design height is 6.25 m above the nominal ground level. It was concentric with the rotation axis of the telescope.
The elevation axis design height above the nominal ground level was measured as 9.710 m.
The elevation axis design offset from the azimuth axis was measured as 1.495 m.
As built measurements may differ.
The following tables refer to the GPS reference point, not the intersection of the axes. The position change rates are those measured with the adjacent 26m telescope, and have not been independently determined yet.
|Coordinate||ITRF2005, epoch 2007.0397||Rate|
|X||+5085448.1729 m||-0.0002 m/y|
|Y||+2668159.9945 m||+0.0193 m/y|
|Z||-2768691.2774 m||+0.0173 m/y|
Converted to geographical (WGS84) coordinates, these are:
|15m Telescope coordinates||Geographical|
|Latitude||25 53′ 23″.05075 South|
|Longitude||27 41′ 03″.36453 East|
|Height above ellipsoid (WGS84)||1406.109 m|
To convert the ellipsoidal heights to heights above the geoid at Hartebeesthoek, approximately 25.475 metres should be subtracted from the ellipsoidal height.
|Focal Ratio (f/D)||0.5|
|Surface weighted rms error||1.6 mm rms|
|Feed System||Prime focus|
|Pointing Resolution||0.001 degrees|
|Max. slew rate on azimuth axis||2.0 deg/s|
|Max. slew rate on elevation axis||1.0 deg/s|
|Max. acceleration on azimuth axis||1.0 deg/s/s|
|Max. acceleration on elevation axis||0.7 deg/s/s|
Surface accuracy was measured by microwave holography.
Accelerations were measured in manufacturer’s acceptance tests.
The telescope is equipped with a concentric feed S/X band cryogenic receiver, installed 2012 March 30, replacing the original L-band receiver.
Preliminary calibration gives a System Equivalent Flux Density (SEFD) of 1050 Jy at S band and 1400 Jy at X band.
Last Updated on March 27, 2023