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Telescope efficiencies and beam widths
Telescope efficiencies after painting the surface (valid from September 2024)
MSP, 01-Dec-2025. Computations done by JSG.
Freq (GHz) |
ap. eff |
err |
Beff |
S/TA* |
Feff |
|
|
|
|
|
|
84.25 |
0.62 |
0.01 |
0.82 |
5.9 |
0.95 |
98.25 |
0.59 |
0.01 |
0.78 |
6.2 |
0.95 |
100.25 |
0.58 |
0.01 |
0.76 |
6.4 |
0.95 |
|
|
|
|
|
|
143.25 |
0.47 |
0.02 |
0.62 |
7.7 |
0.93 |
157.25 |
0.43 |
0.02 |
0.57 |
8.4 |
0.93 |
159.25 |
0.43 |
0.02 |
0.56 |
8.4 |
0.93 |
|
|
|
|
|
|
215.75 |
0.45 |
0.02 |
0.59 |
8.0 |
0.92 |
229.75 |
0.42 |
0.02 |
0.56 |
8.5 |
0.92 |
231.75 |
0.43 |
0.02 |
0.57 |
8.3 |
0.92 |
252.57 |
0.36 |
0.02 |
0.47 |
9.9 |
0.92 |
268.57 |
0.34 |
0.02 |
0.44 |
10.6 |
0.92 |
270.25 |
0.33 |
0.02 |
0.43 |
11.0 |
0.92 |
|
|
|
|
|
|
339.75 |
0.16 |
0.02 |
0.21 |
20.0 |
0.82 |
341.75 |
0.17 |
0.02 |
0.22 |
19.0 |
0.82 |
Notes about the data
- All data have been derived from Uranus observations, using ASTRO fluxes as from GILDAS Feb22.
- Each sessions consists of dozens of pointings for several bands combinations, at different elevations, always including the optimal elevation range (around 52º). Gain-Elevation correction has been applied using the CLASS procedure. Each season values are the median of all the pointing scans that passed a quality filter.
Main Beam Efficiency (Beff) in the table is supposed for the optimal elevation and computed as Beff = 1.31*ApEff.
- Feff values are the defaults used by Pako. Feff values from skytips where derived too, being only slightly different at high frequencies, but close to the current ones.
Values for deriving the Efficiency using the Ruze formula
The efficiencies from the combination of E0 and E2 bands are systematically higher than those derived from the combination E1 and E3. The reason is not well known, but it is preferred to use two separate curves, with parameters given as:
E0&E2: Ilum.eff: 0.65 (+/- 0.01), roughness: 71 (+/- 2) microns
E1&E3: Ilum.eff: 0.57 (+/- 0.01), roughness: 78 (+/- 2) microns