With
the installation of the new subreflector receiver changes in the prime
focus became more flexible.
Receiver changes from prime focus to secondary focus and vice versa are
now possible within 20 minutes. In addition also multi frequency
receiver boxes are installed at the prime focus, yielding again a
higher flexibility. At the moment, two multi-receiver boxes are available.
The first contains the 18/21 cm (single pixel), the
1.9 cm and the 1.0 cm receivers; the second one includes the
30 cm, 5 cm, 2.2 cm and 0.3 cm systems.
Changes within a multi-box
are done by rotating the box and shifting the subreflector, which takes about a minute.
Another multi receiver box will contain 30cm, 5cm, 2,2cm and 0,3cm.
In the  secondary
focus of the telescope the receivers are permanently mounted on
their positions described in the receiver description. In secondary
focus observations, these receivers can be used "quasi-parallel", ie
one can easily change by software from one receiver to another in a
timescale of ~ 30 sec without manual interventions. |
