Starlight Xpress SXV-M7C - Manual (Page 28)

Handbook for SXV-M7C Issue 1 June 2004
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The software includes an option to generate properly matched dark frames, by
recording the number of guiding downloads executed during the taking of the image
and using this to add the correct amount of amplifier glow to the resulting dark frame.
To use this option, you must record the dark frame immediately after the ‘light
frame’, or the download count will be lost. Simply cover the ‘scope aperture, select
‘Take matching dark frame’ in the self guider part of the camera control interface and
press ‘Take Photo’. Application of the ‘Gradient filter’ (under the Filter Menu) can be
used as a final ‘tweak’, if necessary.
Flat field frames can be taken in the usual way, and are not affected by the use of
S.T.A.R. 2000.
A clip from a self-guided ‘STAR 2000’ SXV-M7C image
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Using the add-on autoguider:
An alternative to STAR2000 and a very useful accessory is the add-on autoguider
head, which takes its power and control signals directly from the SXV camera, via the
18 way socket on its rear panel. The autoguider is only 1.25” in diameter and has a
video style ‘CS’ mount thread in its nose, so video lenses may be attached. The guider
may be used with either an off-axis prism assembly mounted in front of the SXV
camera, or with a separate guide telescope, rigidly mounted alongside your imaging
telescope. I personally use it with an 80mm aperture F5, inexpensive refractor as a
guide ‘scope, but a shorter focal length lens will make more guide stars available in
any given region of sky (See the picture below).
To use the autoguider, first orient it so that the connector plug is roughly parallel to
the declination axis of your mount. This is not absolutely essential, as the training
routine will learn the angle of the head and compensate for it, but it is easier to
understand the motion of the guide star if the guider frame is aligned with the RA and
Dec axes. Now connect the head to the SXV camera, using the 18 way connector lead,
including the port divider box, if it is to be used.
The recommended way of connecting the autoguider output to the mount is to use an
RJ11 telephone lead between the socket on the SXV camera and the autoguider input