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FOS observing modes

By now you should have decided on which of the 4 possible FOS observing modes to use. These modes are selected by selecting a dekker and field lens configuration via the commands



See appendix A for details of the different choices.

It is straightforward to change between these modes, so you can change as often as necessary during a night to suit your requirements. The 4 modes are:

Mode A: Beam switching point sources with 5", 2", or 1.2" slots, 12" apart both orders

Mode B: Beam switching extended objects with 25"slots, 85" apart, both orders

Mode C: Long slit, 200" slot, first order only

Mode D: Single object, 25" slot , both orders.

The format of the data taken in these modes is shown in appendix A figure A.1. Choosing between the modes depends on a variety of factors and personal preferences. The most commonly used modes of observing are Modes C and D.

Tue Apr 12 04:13:28 BST 1994