Starlight Xpress SXVR-M25C - Manual (Page 26)

Handbook for the SXVR-M25C Issue 1 June 2009
26
The SXVR-M25C is provided with two ports for use with accessories. The
Autoguider output port is a 6 way RJ11 socket, which is compatible with the standard
autoguider input of most telescope mounts. It provides 4 active-low opto-isolator
outputs and a common return line, capable of sinking a minimum of 5mA per output.
This socket may be used for telescope control if the SXVR-M25C is employed as an
autoguider, but is primarily intended to be the control output for the optional add-on
autoguider camera head, available for use with the SXVR-M25C.
The high density parallel port socket provides both control and power for the add-on
autoguider, but also includes a pair of serial ports for use with other devices.
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Camera maintenance:
Very little maintenance is needed to keep the SXVR-M25C in excellent operating
order, however two problems, which are common to all CCD equipment, might show
up on occasion. These are dust and condensation.
Removing Dust:
1) Dust can be deposited on either the optical window (not a big problem to cure), or
on the CCD faceplate (very difficult to eliminate entirely). When small particles
collect on the window they may not be noticed at all on deep sky (small F ratio)
images, as they will be very much out of focus. However, if a powerful contrast boost
of the image is carried out, they may well begin to show as the shadow ‘Do-nuts’
mentioned earlier. Images taken with a large F ratio optical system are more likely to
be affected by such dirt, owing to the smaller and sharper shadows that they cast. A
light polluted sky will also make these marks much more obvious. There is no great
difficulty in removing such particles on the outside surface by the careful use of a lens
cleaning cloth, ‘lens pen’, or ‘air duster’ and so you should have little trouble with
this aspect of maintenance. Dust on the CCD faceplate is a much greater nuisance, as
it casts very sharply defined and dark shadows and it entails dismantling the camera to
get rid of it! To clean the CCD you will need a good quality lens cloth (no silicone) or
tissues and some high-grade acetone or isopropyl alcohol. A very suitable cloth is the
‘Micro-Fibre’ type marketed by PENTAX etc., and suitable alcohol is available from
Maplin or Radio Shack etc. as tape head cleaning fluid. Most pharmacist shops will