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 - 6.7 GHz ​ 50 K​   HEMT amplifier​ Dual​   
6.0 - 6.7 G​Hz ​ 80 K​   HEMT mixer​ Dual​   
 
The telescope control system Bifrost is used for both the 25 m telescope and the 20 m telescope. The BIFROST User's Handbook explains how to use it: Bifrost_Users_Handbook_12jun2020.pdf

VLBI back-end​

The VLBI back-end consists of digital base band converters (DBBC). Data is recorded on the Flexbuff system or transported directly to the correlator through the internet (e-VLBI). We have two 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 8192 channel FFT based spectrometer with the following characteristics:
​Spectrometer Total bandwidth​ Resolution​
HRF​ ​​50, 25, 10 MHz​ 6.103, 3.058, 1.221 kHz ​
 

Published: Wed 17 Jun 2020.