Most SBIG CCD cameras have a remote guide head port built into the camera's body,
even those cameras that already contain a separate self-guiding CCD chip. This remote
guide head port lets you use an optional external guider, such as the SBIG
#RGH remote guide head, instead of the camera's built-in guiding chip.

Internal guiding using the built-in guiding detector eliminates the need for a guide
scope and separate autoguider. It also eliminates the problem of differential flexure
of the guide scope or differential motion of the primary mirror relative to the
guide scope. However, some users prefer to use an external guider for imaging in
regions of the sky with sparse guide stars, as the remote guide head can be positioned
to find a guide star far off the camera's imaging axis. The optional remote guiding
head can be used in an off-axis guider body or attached to a separate guide scope
in such a case and plugged into the main camera body to make all the guiding corrections.

Also, using an optional external guider instead of the built-in guiding detector
is sometimes helpful during color imaging through a color filter wheel. In some
areas of the sky that have few reasonably bright stars to use for guiding, the color
filters will dim the only available guide stars to the point where guiding with
the camera's internal guiding chip may become erratic as seeing conditions fluctuate.
The use of the optional separate external guiding head will eliminate any such issues,
as it will be guiding using a star undimmed by any filtration.

The remote guide head port also lets you add an #RGH guider to an SBIG "industrial"
or "I" version of an SBIG camera (those imaging-only cameras that are supplied without
a built-in guiding chip).