The JKT CCD camera and its dedicated A&G box form one unit, described
in more detail in Section . In addition to facilities for acquisition
and guiding, the following are provided:
Grisms. These are for slitless spectroscopy and
are described in Section .
Filter wheels. 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.
Changing the filter wheel is a manual operation and may take up to 20
minutes. If possible, avoid a change during the night.
A large set of 50mm filters is available, and is shared between
INT, JKT and WHT Auxiliary port. Details are given in Appendix
Drift-scan table. The drift scan table allows the chip to be moved
across the focal plane by a stepping motor driving a lead screw.
As the chip moves it is read out a row at a time, the progress being
displayed by the instrumentation computer. Until the chip has moved
one column's length the rows will not have received their full exposure.
This is known as the ``ramp-up''. It is an unavoidable overhead with
this technique which is consequently not economic unless used over
several times the length of one column. Drift scanned exposures are
implicitly flat fielded in the column direction and only need to be
flat fielded in the row direction.
CCD detector. The available detectors are summarised in Table