Technical Details of the KOSMA telescope (2000)

Technical Details of the KOSMA telescope (2000)

Telescope

Type              : Cassegrain
f-ratio           : 10.4
Focal length      : 31.2 m
Mount             : altitude-azimuth
Observing ports   : 2 Nasmyth foci
Max. slew rate    : 1 Degree/s 
Elevation limits  : 0-90 Degree 
Pointing accuracy : 10"

Primary reflector parameters
 
Diameter          : 3m 
Shape             : parabolic 
f-ratio           : 0.43
Construction      : 18 aluminum panels, backstructure CFRP framework
Surface accuracy  : 5 micron rms (each panel) 20-30 micron rms (telescope)
Alignment         : actuator at each panel corner 

Secondary reflector parameters 

Diameter          : 27 cm 
Shape             : hyperbolic
Surface           : 4 micron rms
Construction      : aluminum
Alignment         : 3 linear and 2 angular degrees of freedom with a hexapod 
Chopper           : wobble mechanism in cross-elevation,
                    larger than +-3 arcmin on sky, 4 Hz max.

Receiver

Dual-channel-SIS receiver 

Summer Configuration   :  230 GHz/345 GHz 
Winter Configuration   :  345 GHz/660 GHz   


  Tuning ranges      Receiver Noise Temperature (DSB)
      [GHz]                     [K]

    210 - 270                   150
    330 - 365                   100
    436 - 495                   90 - 120
    630 - 690                   210     
    780 - 820                   800 - 1100 

All receivers have an IF of 1.4 GHz with a bandwith of 1 GHz

Spectrometer

LRS = Low Resolution Acousto-optical Spectrometer
MRS = Medium Resolution Acousto-optical Spectrometer
HRS = High Resolution Acousto-optical Spectrometer
VRS = Variable Resolution Acousto-optical Spectrometer

     Channels  Bandwidth  Channel Spacing  Reception   Resolution 
                                           Bandwidth   Bandwidth
                 [MHz]        [kHz]        [kHz]       [kHz]

LRS   1450      1000          688           1800        1150 
MRS   1800       300          167            560         360
HRS   2048        59           29             79          53 
VRS  max. 2048  655-1100    320-700       800-1600    550-1100

For Efficiencies and Beamwidths see here

KOSMA Observing Schedule

References with information about the Observatory

• The University of Cologne 3-m radio telescope. Winnewisser et al. 1986, Astronomy and Astrophysics 167, 207
• CO submillimeter observations from Gornergrat. Winnewisser et al. 1990, Astronomy and Astrophysics 230, 248
• The new KOSMA 3m Telescope. Kramer et al. 1998, In: Proc. SPIE Vol. 3357
• Surveys with the new KOSMA telescope. Kramer et al. 1999, In: "Imaging at Radio through Submillimeter Wavelengths", J. Mangum (ed.), PASP, Tucson/Arizona