Instrument descriptors

Properties of the instrument that are associated with the instrument as a whole, rather than with a particular filter or detector channel, belong in descriptors in the instrument table file. Most of these relate to the filter mechanisms. In addition, it is convenient to have a character*72 descriptor called INSTNAM that gives the name or designation of the particular instrument; and one to describe the condition of the telescope optics, which will be treated at the end of this section. The descriptors are summarized in Table I.11.