Summary

This chapter has discussed the selection and design of the ALIS imager and its associated subsystems. In summary these systems consist of the following items:

ALIS imager:

consisting of Optics (Section 3.4), filter-wheel (Section 3.5.1), with interference filters (Section 3.5) and the CCD Camera Head (CCH) mounted together as a removable unit. Six ALIS imagers exist to date, and they are denoted ccdcam 1-6 (See Section 3.3.1 and Tables B.1-B.6 in Appendix B. It is important not to confuse these numbers with the station numbers (Table 2.3).

Camera Control Unit (CCU):

containing power-supply and electronics for the camera head. The CCUs are individually adapted for each camera head and must not be used with a different camera head.

Filter-Wheel Control unit (FWC):

containing power-supply and electronics for the filter-wheel (Figure 3.9).

Camera Positioning System (CPS):

Supports the ALIS Imager and provides the possibility to remotely point the camera to any desired region of the sky. The CPS is attached to the camera-stand (Section 3.6).

CPS Control Unit (CCU):

containing power-supply and electronics for the CPS (Figure 3.9).

Camera stand:

consisting of four iron rods, directly attached to the corners of the iron frame supporting the house, thus the imager is not affected by vibrations in the house caused by for example strong winds (Section A.1).

A block diagram displaying the interrelationships of the various imager subsystems appears in Figure 3.12.

Figure 3.12: Block diagram of ALIS imager subsystems. Regarding the NIPU, see Section 2.2.2