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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:
- 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 mapping in the Q and W bands is available with a bandwidth of 2.5 GHz.
- Total power continuum On-the-fly mapping is also available using the FFT spectrometers. Simultaneous observations at up to 8 frequencies in the Q or W bands are possible, with bandwidths up to 2.5 GHz per frequency. To request this mode, select "On the Fly map" in the Observing Goals section of RAYO, and specify your continuum requirements (frequencies and bandwidths) in the "Special Remarks, Particular Offsets, and Scheduling Constrains" box underneath.
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.
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