Starlight Xpress SXV User Manual

Using the USB2.0 camera and guider interface

The USB2.0 interface is an updated replacement for the original Starlight Xpress USB1.1
unit, released in 2001. Its main function is to provide a USB2 compatible high speed
interface for the MX5, MX5C, MX716, MX7C and MX916 range of CCD cameras, but it
also includes an interface for the SXV guide camera and for STAR2000 functions. These
features make the USB2.0 interface into a very useful upgrade to the non-SXV camera
range.

Installing the software:

The USB2 interface uses the same USB drivers as the SXV series of cameras, so if you
have an SXV-H9, H9C etc. already installed, you do not need to run the USB setup
program. Otherwise, find the ‘USB2setup’ folder on the software CCD and double click
on the ‘setup.exe’ file. Once this has been done, you should find ‘SXVIOinterface.inf’
installed in C:\Windows\inf and ‘SXVIO.sys’ and ‘generic.sys’ in
C:\Windows\System32\Drivers. A copy of SXVIOinterface.inf is provided on the CD for
users with SXV camera software already installed. This should be copied into
C:\Windows\Inf, otherwise the interface will not be identified correctly.

Once the files have been installed, plug the USB cable into the computer and USB2
interface box. The computer will report that ‘New hardware’ has been found and that it is
installing the software required for your new device. The boot name of your interface is
‘Echo3’ and it requires SXVIO.sys as a driver. If the computer asks you to find the
driver, point it to C:\Windows\System32\Drivers\SXVIO.sys.

Trouble shooting the installation:

The software should install automatically, but operating systems and hardware vary in
their compatibility so problems can occur. Versions of Windows prior to Win98 SE and
Win2000 do not support USB, so make sure that you have an up-to-date release on your
machine. If you have more than one USB port, try the other ports with the interface – the
hardware can make a difference. Also, adding a USB hub can induce the installation to
initialise correctly. Note that although the interface will work with a USB1.1 port, it will
give ‘cleaner’ and faster downloads on a USB2.0 connection.

Getting up and running:

Once the USB installation is in place, the camera software can be copied to your working
folder on the computer. Although the supplied software will give good results, other
software houses are providing plug-ins for the USB2 interface. Both AstroArt and Maxim
DL have support in their latest versions.

Now connect the camera to the USB interface, using the 15 way cable provided. Plug in
the power supply lead to the camera power block and you should be all set for an imaging
session.

Using the add-on autoguider:

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 of
your mount. This output is ‘active low’ (i.e. the control relays pull the guider inputs down
to zero volts when applying a guide correction) and matches most of the autoguider
inputs on commercial mounts. If ‘active high’ inputs are needed, or a very low control
voltage drop is essential, then you will need to add a Starlight Xpress ‘relay box’ between