2. Antenna Structure



2.4 Pointing Errors


The accuracy of the pointing increases with the observing frequency, i.e. as the antenna beam width decreases.

It is commonly assumed that :


δp = pointing accuracy

HPBW = -3 dB beam width (main lobe)

For the Medicina antenna the values are listed in Table 2.4 :







1.5 29 ≤ 2.9
22 2 ≤ 0.2

Tab. 2.4 : Beam and pointing errors


The systematic errors are usually quite high (several arcminute). A pointing model has been derived from observations of radio sources with accurately known coordinates.

Once the model has been applied, the residual error is  0.13' (both in azimuth and elevation).

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