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 :

δ_p = pointing accuracy

HPBW = -3 dB beam width (main lobe)

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

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).