It is oriented exactly along an East-West axis, and the entire structure can be pointed with an accuracy of 30 arcseconds, thanks to an ingenious coupling system between the panels. The weight of the framing is 750 tons. The antennas which receive the radio waves must be positioned with an accuracy of a few millimeters, in order to follow the radio sources properly. For this purpose the carriage which contains the antennas can move along a 100 meter long, curved rail track which follows the focal surface. It contains a mechanism permitting to lift the antennas by a maximum of 1.8 meter.
All movements are hydraulic, and controled by the computer located in the telescope control room.
The waves travel through it towards a waveguide and on to an amplifier. Care has to be taken that the antennas see only the radio waves emitted by the celestial sources and reflected by the telescope mirrors, rather than the heat radiation from the ground. Therefore, a reflecting mesh screen has been placed on the ground directly in front of the carriage, which blocks the radiation from the earth. They therefore have to be suitably amplified, which does not pose any techical problem in principle, but without loosing any information. The first amplifiers located in the focal carriage contain special transistors and are cooled to a temperature of 20 Kelvin, or -250 degrees Celcius, by a Helium cooling unit .