Starlight Xpress SXV-AO unit - Manual (Page 4)

Handbook for the Starlight Xpress AO unit
Issue 1 21/8/2005
especially useful if you image with narrow band filters, such as H-alpha. A light pollution
rejection filter, such as an IDAS P1 or P2 might be best added at the output of the AO
unit, where it will improve the guide star contrast, as well as improving your camera
images. Note that the recesses are not threaded and so you should be careful that a filter
does not fall out and get damaged when dismantling the unit.
N.B. Although the SXV-AO was designed for operation with an SX camera, it is
possible to attach other imagers with an appropriate adaptor and still use the AO via one
of our USB2 interface boxes. The USB2 interface provides a convenient way to read and
control the SXV guide camera, even when no SX main imager is in use. You will need to
organise the alternative camera spacing so that it may be brought to focus simultaneously
with the guide camera.
Connecting up the AO electronics for off-axis guiding:
The method of connection will vary slightly, depending on the guiding software in use
and the equipment available. The SX software and AstroArt allow you to use the SXV
port divider box for serial control of the AO unit and so you might prefer to use this
method to cut down on the number of cables required. At the time of writing, Maxim DL
does not offer an option to connect via the divider box and so a serial cable from the PC
COM port will be required if you use Maxim. PCs with no COM port can use a
commercially available USB to serial interface for the connection.
1) Connect the serial to RJ11 cable (supplied) into the AO unit input socket.
2) Connect the RJ11 to guider port cable (supplied) from the AO output to the guider
input on the mount. This cable is not essential, but it allows the software to
‘bump’ the mount when the errors become too large for the AO unit. Most lower-
cost mount users will find it necessary for long exposure times.
3) Connect the guide camera to the socket on the SXV imaging camera, or the socket
on the SXV interface box (used with older parallel port imaging cameras, or when
imaging with other makes of camera). Include the port divider box in this cable, if
you intend to use this for serial control (Fig 1).
4) Connect the serial to RJ11 cable to the appropriate port divider output, or to the
RS232 cable from your PC (Fig 2).
5) Connect the AO power lead to the power supply block.