To install the Gx USB or Gx ETH driver for TheSkyX, just download
and run the installation package 'X2CameraGxUSB_Setup.exe' or
'X2CameraGxETH_Setup.exe' from the download section of this web site. Setup program
installs driver DLL files es well as description files so TheSkyX
recognizes them and offers them to the user.
Setup also installs Microsoft Visual C++ 2008 SP1
Redistributable Package, used by the driver. If this package is
already installed on the target PC (which is quite likely, because
this package is used by numerous other programs), it is not installed
and the already present version will be used.
TheSkyX then allows choosing of the Moravian Instruments Gx ETH
camera in the Imaging System Setup window:
Clicking the 'Settings...' option in the 'Imaging System Setup'
window opens driver specific configuration window.
Camera specific configuration window of the Gx USB (left)
and Gx ETH (right) driver
Adapter IP address box is available on the Gx Ethernet
driver only. It allows entering of the Gx Camera Ethernet Adapter IP
address (because the device works as a server, fixed address must be
assigned to it, see the device documentation for further reference).
It is also possible to enter FQDN if the device has assigned name in
the Domain Name System. Up to four Gx cameras of any type can be
connected to the Gx Camera Ethernet Adapter. Scan cameras
button asks the device for a list of all connected cameras, which are
then offered in the Select Gx ETH camera combo-box. It is
necessary to scan for cameras when the IP address was changed.
The Select Gx USB camera combo box always offers all
cameras currently connected to the host PC (note the USB is
This configuration window adopts itself (enables/disables specific
settings) according to the selected camera type. Beside choosing of
the particular connected camera, the configuration dialog box allows
definition of other parameters.
Camera read mode allows choosing desired read mode. Gx
imaging cameras offer one slower mode with lower read noise (marked
Low noise) and one faster mode (marked Preview).
Guiding cameras offer Slow read and Fast read
Preflash time defines time in seconds, for which the CCD
is illuminated with near-IR LEDs to eliminate Residual Bulk Image
(RBI), accumulated during previous exposure (more precisely not to
eliminate RBI, but to make it uniform and reproducible regardless of
the illumination of the scene previously imaged). If the LED preflash
is not desired, this parameter must be set to zero.
Num. clears parameter defines the number of commands
performed to purge the charge accumulated during preflash. If no
preflash is performed (preflash time equals zero), default single
clear is performed regardless of the value of this parameter.
Max. step defines the speed of temperature changes in
degrees Celsius per minute. Ramped temperature changes (as opposed to
rapid cooling/heating, often with temperature overshot on both sides)
protects the CCD from shocks and ensures its longer life.
CCD chamber window heating allows increasing of heating of
the CCD chamber front window, which limits condensation on the window
front surface. Gx cameras already implement some level of chamber
window heating to suppress fogging. Increasing of heating power can
slightly limit the cooling efficiency on the one side, but on the
other side it can prevent condensation in front of the CCD, which
Camera fan on allows controlling of the camera fan. It is
desired to keep the fan on in most cases because it very significantly
reduces the detector temperature by keeping it close to ambient. This
also reduces the CCD dark current (thermal noise pattern). Dark
current doubles with every approx. 6 ºC, so lowering the
temperature by 12 ºC causes 4-times lower dark current.
Gx USB/ETH Camera Filter Wheel in TheSkyX
Each G2 and G3 camera can be equipped with internal filter
wheel. All G2, G3 and G4 cameras also support external filter
wheels with larger number of filter positions, which operate the
same way like internal wheels (they are indistinguishable from
internal filter wheels from the software point of view). Such
external filter wheel is the only option for the large detector G4
cameras, their filter wheel is too big to fit inside the camera
Filter can be also chosen from the Imaging System Setup
Because there is no way how to determine the actual filters in
the filter wheel automatically, the camera driver reads the
'X2GxUSB.ini' or 'X2GxETH.ini' file (located in 'C:\Program
Files\Software Bisque\TheSkyX Professional
Edition\Resources\Common\PlugIns\CameraPlugIns' directory, where
the driver DLL is also located) to determine actual configuration
of filters, which will be then reported to TheSkyX. This file is
ordinary text file following the .INI files conventions.
If multiple cameras handled by the same driver are used, it is
possible to include camera ID into the file name, e.g.
'X2GxUSB.2158.ini' will be used for camera ID=2158 only (note
leading zeros are not allowed in the ID). Driver searches for the
ID-specific file name first and only if it is not found, it tries
to open generic ini file name.
Example of the configuration file:
Luminance, Gray, 660
Red, LRed, 660
Green, LGreen, 660
Blue, LBlue, 660
Clear, 0, 0
Filters are described in the [filters]
Section. Every line in this section describes one filter
position. Filter description is a comma-separated list of three
Filter name: This name is returned to the client
application, which can use it to list available filters in the
Filter color: This color can be used by client
application to display the filter name with a color,
hinting the filter type. The color can be expressed by a name
(White, Red, LRed, etc.) or directly by number representing the
particular color (0 represents black).
Filter offset: Distance to move the focuser to
refocus upon filter change. Plan-parallel glass shifts the
actual focus position back for 1/3 of the glass thickness (exact
value depends on the glass refraction index, but for almost all
glasses 1/3 is very close to exact value). Refocusing is useful
when changing filters of different thickness among exposures or
when some exposures are performed through filters and other
without filters at all.
Filter offsets can be defined in focuser dependent steps or in
micrometers (μm). If the micrometers are used, it is
necessary to inform driver by the MicrometerFilterOffsets
parameter in the [driver] section of the ini
MicrometerFilterOffsets = true
Luminance, Gray, 660
Value of the MicrometerFilterOffsets parameter can
be expressed as true or false, as well
as 0 (for false) or 1 (for true).
Unfortunately the current X2 Camera API used by TheSkyX to
communicate with camera and filter wheel drivers does not support
passing of the filter offsets from the driver to TheSkyX. It is
necessary to enter filter offsets manually in TheSkyX Filter Names
Drivers version 1.0 support following camera models,
including possible internal filter wheels:
G2-0402, G2-1600 and G2-3200 (revisions 3 and
G0-0300(C), G0-0301(C), G0-0800(C), G0-2000(C)
G1-0300(C), G1-0301(C), G1-0800(C), G1-1200(C),
Supported external filter wheel models:
For the documentation of Gx cameras, refer to the 'G0 and G1
CCD Camera Operating Manual', 'G2 CCD Camera Operating
Manual' and 'G3 and G4 CCD Camera Operating Manual'. These manuals
are supplied with each camera in the printed form and can be also
downloaded as PDF file from the web site