YEBES OBSERVATORY
A Spanish Scientific and Technical Infrastructure

40m RT basic technical information

Observing modes

Spectral observations. These observations are available under several standard modes: position switching, frequency switching and On-The-Fly (OTF) position-switch mapping (see below). Position Switch observations can be programmed ad-hoc using several phases. The spectral backends are Fast Fourier Spectrometers (FFTs) with 100 MHz, 500 MHz, 1.5 GHz and 2.5 GHz bandwidths with 6 KHz, 30 KHz, 180 KHz and 38 KHz resolution respectively.

Continuum observations. These observations are restricted to total power pointing drifts or focus drifts. Position switch using a wobbler or a beam switch are not available. Currently there are several backends offering a bandwidth of 2.5 GHz, 1.5 GHz, 500 MHz or 100 MHz depending on the observed frequency.

Important Notes:

  • Keep in mind that there is usually a strong demand for objects in the region between 2:00 and 9:00 LST. Depending on the proposal ranking, Requesting sources in this LST range could therefore find it harder for observations to be carried out
  • W band (72 - 90 GHz) observations are available for a limited number of hours in the semester (night time only, from 2 hours after sunset to sunrise, due to thermal distortion in the telescope structure), with a bandwidth of 18.5 GHz.
  • On-the-fly spectral mapping in the Q and W bands is available with the full bandwidth of 18.5 GHz.

Available observing frequencies:

  • C band: 4.9 - 5.4 GHz & 6.1 - 6.6 GHz (currently VLBI only)
  • X Band: 8.1 - 8.9 GHz (currently VLBI only)
  • K Band: 21 - 25 GHz (currently Single-Dish Director Discretionary Time observations or VLBI only)
  • Q Band: 31.3 - 50.6 GHz
  • W Band: 72 - 90 GHz

Instantaneous bandwidth, spectral resolution, angular resolution, aperture efficiency, main beam efficiency and Jy/K conversion

  • C Band. Bandwidth: 500 MHz. Spectral resolution: 6.1 & 30 KHz. θb=260’’, ηA=0.46
  • X Band. Bandwidth: 500 MHz. Spectral resolution: 6.1 & 30 KHz. θb=180’’, ηA=0.70
  • K Band. Bandwidth: 500 MHz. Spectral resolution: 6.1 & 30 KHz
    Freq (GHz) λ (mm) θHPBW (´´) Polarization ηA ηMB Jy/K
    22.3 13.5 79.1 R 0.60 0.69 3.40
    L 0.59 0.69 3.45
  • Q Band. Bandwidth: 18.5 GHz. Spectral resolution: 38 KHz. ηf = 0.97
    Freq (GHz) λ (mm) θHPBW (´´) Polarization ηA ηMB Jy/K
    32.4 9.3 54.4 H 0.53 0.61 3.83
    V 0.52 0.61 3.86
    34.6 8.7 51.0 H 0.50 0.58 4.07
    V 0.50 0.58 4.05
    36.9 8.1 47.8 H 0.49 0.57 4.11
    V 0.49 0.56 4.16
    39.2 7.7 45.0 H 0.47 0.55 4.29
    V 0.47 0.55 4.29
    41.5 7.2 42.5 H 0.46 0.53 4.39
    V 0.46 0.53 4.39
    43.8 6.8 40.3 H 0.44 0.51 4.55
    V 0.45 0.52 4.54
    46.1 6.5 38.3 H 0.42 0.49 4.78
    V 0.43 0.49 4.74
    48.4 6.2 36.4 H 0.41 0.47 4.95
    V 0.41 0.47 4.94
  • W Band. Bandwidth: 18.5 GHz. Spectral resolution: 38 KHz
    Freq (GHz) λ (mm) θHPBW (´´) Polarization ηA ηMB Jy/K
    72.5 4.1 24.3 H 0.30 0.35 6.50
    V 0.31 0.36 6.35
    74.7 4.0 23.6 H 0.28 0.33 6.91
    V 0.30 0.34 6.65
    77.0 3.9 22.9 H 0.27 0.31 7.35
    V 0.28 0.32 7.14
    79.3 3.8 22.2 H 0.26 0.30 7.72
    V 0.26 0.30 7.51
    81.6 3.7 21.6 H 0.24 0.28 8.17
    V 0.25 0.29 8.00
    83.9 3.6 21.0 H 0.23 0.27 8.48
    V 0.23 0.26 8.75
    86.2 3.5 20.5 H 0.22 0.26 8.94
    V 0.20 0.23 9.88
    88.5 3.4 19.9 H 0.22 0.26 8.70
    V 0.19 0.21 10.68

The 18.5 GHz expansion of bands Q and W has been supported by project Nanocosmos (ERC-2013-Syg-610256-NANOCOSMOS) during 2019.