Sequences and Iterators in the OT
Iterators and a feature of the OT that provide a powerful tool for creating
sequences in which observations of various types are taken while changing
instrument configurations, telescope positions, etc.
They have a structure like nested do loops. It is important therefore to
make sure that "Observe" is in the right place in the hierarchy.
Original Authors: Gillian Wright
Original : 1999/3/3, Last Modification Date 2000/08/04 - Last Modification Author:Gillian Wright