A finder telescope is available on the INT. A TV camera can be used to
view a field 3325 in size. The finder is in particular
useful for the location of guide stars: the TCS software will generate
overlays on the TV image of the finder field, at either focus, indicating
the areas of sky where guide stars may be selected. It is therefore important
that the zeropoint of the finder coordinate system is properly determined (see
section 
), in order to allow accurate mapping of the autoguider
acquisition areas and detector/slit positions onto the finder field.