Technical description (25 m telescope)

 

The 25 m diameter polar mounted decimetre-wave telescope was built in 1963. It is used mainly for astronomical VLBI observations of, e.g., star forming regions, radio stars, and active galactic nuclei, but occasionally as a single dish for, e.g., observations of interstellar molecules.

Position

Latitude: 57° 23' 35.0456" N
Longitude: 11° 55' 03.9685" E
Elevation: 18.01 meters

Receivers

The telescope is equipped with the following receivers:
 
​Frequency range Receiver temperature​ Receiver type​ Polarization​
0.8-1.2 GHz ​ 100 K​ HEMT amplifier​ Dual​
1.2-1.8 GHz​ 30 K​ HEMT amplifier​ Dual​
4.5-5.3 GHz ​ 80 K​ FET amplifier​ Dual​
6.0-6.7 GHz ​ 80 K​ HEMT mixer​ Dual​
 
The computer control system (Pegasus) for the 25 m antenna uses the same operating system as the 20 m telescope. Thus, essentially the same program controls both telescopes.

VLBI back-end

The VLBI back-end consists of digital base band converters (DBBC). Data is recorded on the Mark 5 system or transported directly to the correlator through the internet (e-VLBI). We have 2 parallell VLBI systems and can observe with the 20 m and 25 m telescope in VLBI-mode simultaneously.

Spectral line back-end

The back-end for spectral line observations is a hybrid digital autocorrelation spectrometer with the following characteristics:
​Spectrometer Total bandwidth​ Resolution​
ACS​ 0.05, ..., 6.4, 12.8 MHz​ 0.03, ..., 4, 8 kHz ​
 

Published: Mon 02 Sep 2013. Modified: Thu 16 Oct 2014