The Dwingeloo Radio Telescope
30 August 1996
This document is aimed at operators and users of the Dwingeloo 25m radio telescope, and as such concentrates on the observing modes programs and procedures for its use. The section on hardware gives only enough information for users to see what the instrument is capable of.
The Dwingeloo radio telescope is altitude-azimuth mounted on a rail and has an paraboloid dish with a diameter of 25m. It is situated in Dwingeloo (geographic latitude 52.813 north, 6.396 east)
The telescope can observe from elevation 0 to 85 degrees and from azimuth -269 (east) through 0 (south) to +269 degrees (west).
The cable wrap system forces you to turn back if you try to go past these limits, and this will take about 12 minutes ( 30deg/min in azimuth). If observations are wanted for below 2 degrees elevation, special corrections must be made for stray radiation, see for example van Woerden PhD thesis (1962) or Hartmann PhD thesis (1994). By default such low elevations are not observed.
The following receivers are available:
For more details see See section Receivers. To change between frontends takes some hours work and a few days for the cryogenic receivers to work fully. At the time of writing (30 August 1996) the 18cm and 6cm systems had not been used for more than 5 years. To get them operational again would take a few weeks work.
The Dwingeloo telescope has 3 IF systems; 2 narrow band (<20MHz) and 1 wide band (20 or 40MHz). These go to a 1024 channel autocorrelation spectrometer backend, as described in NFRA ITR 188.
The correlator supports various different configurations section Hardware.
The telescope is a present (30 August 1996) controlled by an HP-1000 computer connected through a locally designed multiplexer to the correlator, frequency synthesizer, clock and the drive control. There is also a local DCF-77 time receiver which is used to check and set the clock.
In addition to these controls from the computer, there is a manual system to override the telescope drive system in case of storm; this system points the telescope to the zenith if the wind exceeds force 7 Beaufort.
The software, See section Software, in the telescope can do the following:
The total power levels in two of the IFs is continuously recorded on a chart recorder, and one of the IFs is monitored also on a digital meter.