INT prime focus unit

When imaging at the prime focus of the INT is required, the top ring assembly which otherwise carries the secondary mirror support is replaced by a top ring carrying the INT Prime Focus Unit. In addition to the facilities for acquisition and guiding described in Section 2.2.6, the following are provided:

• Filters. The filter wheels carry up to six 50 mm square filters. There are ample spare wheels to mount any particular set of filters that the observer requires, but only one wheel can be mounted at a time.

  A large set of 50mm filters is available, and is shared between INT, JKT and WHT Auxiliary port. Details are given in Appendix .

• CCD detector. The available detectors are summarised in Table .