home

HartRAO Home > HartRAO 15m Radio Telescope Details

HartRAO 15m Radio Telescope Details

Coordinates

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
X +5085490.772 m
Y +2668161.463 m
Z --2768692.604 m
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 2007.0397Rate
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 coordinatesGeographical
Latitude 25 53' 23".05075 South
Longitude27 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.

Antenna Parameters

Diameter 15 m
Focal Ratio (f/D) 0.5
Surface weighted rms error 1.6 mm rms
Feed System Prime focus
Pointing Resolution 0.001 degrees
Repeatability 0.004? 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 axis1.0 deg/s/s
Max. acceleration on elevation axis0.7 deg/s/s
Notes:
Surface accuracy was measured by microwave holography.
Accelerations were measured in manufacturer's acceptance tests.

Receivers

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.

Photographs

map
Left click on image for large version.
HartRAO 15m telescope showing prime focus SX receiver and 0.5 f/D.

map
Left click on image for large version.
HartRAO 15m telescope mount with offset elevation axis side view.

map
Left click on image for large version.
HartRAO 15m telescope mount with offset elevation axis front view.