Moravian Instruments G2 Series Mark II User manual

G2 Series Mark II
Cooled CCD Cameras
User’s Guide

Version 1.1
Modified on July 27th, 2018
All information furnished by Moravian Instruments is believed to be
accurate. Moravian Instruments reserves the right to change any
information contained herein without notice.
G2 cameras are not authorized for and should not be used within Life
Support Systems without the specific written consent of the Moravian
Instruments. Product warranty is limited to repair or replacement of
defective components and does not cover injury or property or other
consequential damages.
Copyright © 2000-2018, Moravian Instruments
Moravian Instruments
Masarykova 1148
763 02 Zlín
Czech Republic
phone: [phone]
web: http://www.gxccd.com/
e-mail: [e-mail]

Table of Contents
Introduction .................................................................................................. 5
G2 Camera Overview .................................................................................... 8
CCD Detectors and Camera Electronics ...................................................... 12
CCD sensor .............................................................................................. 15
Model G2-0400 ................................................................................... 16
Model G2-1600 ................................................................................... 16
Model G2-3200 ................................................................................... 16
Model G2-8300 ................................................................................... 16
Model G2-2000 ................................................................................... 17
Model G2-4000 ................................................................................... 17
Camera Electronics .................................................................................. 17
Model G2-0400 ................................................................................... 18
Model G2-1600 ................................................................................... 19
Model G2-3200 ................................................................................... 19
Model G2-8300 ................................................................................... 19
Model G2-2000 ................................................................................... 19
Model G2-4000 ................................................................................... 19
Cooling and power supply ........................................................................... 21
Power supply ........................................................................................... 22
Mechanical Specifications ........................................................................... 24
Camera with Internal Filter Wheel .......................................................... 25
Camera with “XS” External Filter Wheel ................................................. 27
Camera without filter wheel ................................................................... 28
Optional accessories ................................................................................... 30
Telescope adapters ................................................................................. 30

Off-Axis Guider Adapter (OAG) ............................................................... 30
Attaching camera head to telescope mount ........................................... 31
Camera head color variants .................................................................... 32
Gx Camera Ethernet Adapter .................................................................. 33
Adjusting of the telescope adapter ............................................................. 34
Camera Maintenance .................................................................................. 37
Desiccant exchange ................................................................................. 37
Exchanging the silica-gel...................................................................... 38
Changing Filters ....................................................................................... 39
Opening the camera head ................................................................... 39
Changing the Whole Filter Wheel ........................................................... 40
Changing the Telescope Adapter ............................................................ 41
Power Supply Fuse .................................................................................. 42

5
Introduction
Thank you for choosing the Moravian Instruments camera. The cooled G2
series Mark II CCD cameras were developed for imaging under extremely
low-light conditions in astronomy, microscopy and similar areas.
Design of this series inherits from earlier G2 Mark I cameras but brings
some significant enhancements. G2 cameras employ precise electronics
providing uniform frames and extremely low read noise limited only by
CCD detector itself.
Modular mechanical construction allows various camera variants to be
combined with rich set of accessories, including telescope adapters, off-
axis guider adapters, internal or external filter wheels, Ethernet adapters,
guiding cameras etc.
Rich software and driver support allows usage of G2 camera without
necessity to invest into any 3rd party software package thanks to included
free SIPS software package. However, ASCOM (for Windows) and INDI (for
Linux) drivers, shipped with the camera, provide the way to integrate G2
camera with vast variety of camera control programs.
The G2 cameras are designed to work in cooperation with a host Personal
Computer (PC). As opposite to digital still cameras, which are operated
independently on the computer, the scientific slow-scan, cooled cameras
usually require computer for operation control, image download,
processing and storage etc. To operate the camera, you need a computer
which:
1. Is compatible with a PC standard and runs modern 32 or 64-bit
Windows operating system.
2. Is compatible with a PC standard and runs 32 or 64-bit Linux
operating system.
Drivers for 32-bit and 64-bit Linux systems are provided, but the
SIPS camera control and image processing software, supplied
with the camera, requires Windows operating system.

6
3. Support for x64 based Apple Macintosh computers is also
included.
Only certain software packages are currently supported on Mac.
G2 cameras require at last one free USB 2.0 port to communicate with a
host PC.
A simple and cheap device called “USB hub” can expand number of
available USB port. Typical USB hub occupies one computer USB port
and offers four or seven additional USB ports. Make sure the USB hub
is USB 2.0 high-speed compatible.
Alternatively, it is possible to use the “Gx Camera Ethernet Adapter”
device. This device can connect up to four Gx cameras of any type (not only
G2, but also G0, G1, G3 and G4) and offers 1 Gbps and 10/100 Mbps
Ethernet interface for direct connection to the host PC. Because the PC
then uses TCP/IP protocol to communicate with the cameras, it is possible
to insert WiFi adapter or other networking device to the communication
path.
Please note while the USB standard allows usage of cable no longer
than approx. 5 meters, the TCP/IP communication protocol used to
connect the camera over the Ethernet adapter is routable, so the
distance between camera setup and the host PC is virtually unlimited.
The G2 cameras need an external power supply to operate. It is not
possible to run the camera from the power lines provided by the USB
cable, which is common for webcams or very simple imagers. G2 cameras
integrate highly efficient CCD chip cooling, shutter and possibly filter
wheel, so their power requirements significantly exceed USB line power
capabilities. On the other side separate power source eliminates problems
with voltage drop on long USB cables or with drawing of laptop batteries
etc.
Also note the camera must be connected to some optical system (e.g. the
telescope) to capture images. The camera is designed for long exposures,
necessary to acquire the light from faint objects. If you plan to use the

7
camera with the telescope, make sure the whole telescope/mount setup is
capable to track the target object smoothly during long exposures.

8
G2 Camera Overview
G2 camera head is designed to be easily used with a set of accessories to
fulfil various observing needs. Camera head itself is manufactured in two
different variants:
 Camera with Internal filter wheel.
 Camera with control port for External filter wheel. This model
allows attachment of several variants of external filter wheels
with various number of filter positions and sizes.
Figure 1: G2 Camera Mark II without filter wheel (left), with Internal filter wheel
(middle) and with attached External filter wheel (right)
G2 camera model with Internal filter wheel accepts two sizes of filters:
 Filter wheel with 5 positions for unmounted D31 mm filters or
filters in 1.25” threaded cells.
 Filter wheel with 6 positions for unmounted D26 mm (or 1”)
filters.
There are two sizes of the External filter wheels, each capable to accept
two sizes of filters, available for the G2 cameras:
 Extra small “XS” size wheel for 8 unmounted filters D31 mm or
filters in 1.25” threaded cells.

9
 Extra small “XS” size wheel for 7 unmounted filters D36 mm.
 Small “S” size wheel for 12 unmounted filters D31 mm or filters in
1.25” threaded cells.
 Small “S” size wheel for 10 unmounted filters D36 mm.
Because G2 series of cameras can work with various sensors, not all
filter wheel/filter variants can be used with every detector. For
instance, G2-8300 camera works with CCD measuring 22.7 mm
diagonally. Depending on the used optics f/ratio, 1” or even 1.25”
filters can cause more or less significant vignetting when combined
with such sensor.
Please note the camera head is designed to either accept Internal filter
wheel or to be able to connect to the External filter wheel, but not both. If
the Internal filter wheel variant is used, External filter wheel cannot be
attached.

10
Figure 2: Schematic diagram of G2 camera system components

11
Components of G2 Camera system include:
1. G2 camera head with Internal Filter Wheel (5 or 6 positions)
2. G2 camera head capable to control External Filter Wheel
3. External Filter Wheel “XS” size (7 or 8 positions)
4. External Filter Wheel “S” size (10 or 12 positions)
5. G0 guider camera
6. G1 guider camera
G0 and G1 cameras are completely independent devices with
their own USB connection to the host PC. They can be used
either on G2 OAG or on standalone guiding telescope.
Both G0 and G1 camera can share the Gx Camera Ethernet
Adapter with up to 3 other Gx cameras to be accessed over
network.
7. Off-Axis Guider with M48×0.75 thread
8. Off-Axis Guider with M42×0.75 thread (T2)
9. Thick adapter base, compensating EFW thickness to achieve
proper back focal distance for cameras without filter wheel
10. 1.75” dovetail rail for G2 camera head
11. Gx Camera Ethernet Adapter (x86 CPU)
12. Gx Camera Ethernet Adapter (ARM CPU)
Camera Ethernet Adapter allows connection of up to 4 Gx
cameras of any type on the one side and 1 Gbps Ethernet on the
other side. This adapter allows access to connected Gx cameras
using routable TCP/IP protocol over unlimited distance.
13. 5-positions internal filter wheel for 1.25”/D31 mm filters
14. 8-positions external filter wheel “XS” for 1.25”/D31 mm filters
15. 7-positions external filter wheel “XS” for D36 mm filters
16. 12-positions external filter wheel “S” for 1.25”/D31 mm filters
17. 10-positions external filter wheel “S” for D36 mm filters
18. 7-positions external filter wheel “S” for 2”/D50 mm filters
19. M42×0.75 (T-thread) or M48×0.75 threaded adapters, 55 mm BFD
20. Canon EOS bayonet lens adapter
21. Nikon bayonet lens adapter

12
CCD Detectors and Camera Electronics
G2 Mark II series of CCD cameras are manufactured with two kinds of CCD
detectors:
 G2 cameras with OnSemi KAF Full Frame (FF) CCD architecture.
Almost all Full Frame CCD detector area is exposed to light. This is
why these detectors provide very high quantum efficiency. FF CCD
detectors, intended for research applications, are not equipped
with so-called Anti Blooming Gate (ABG – a gate, which prohibits
blooming of the charge to neighboring pixels when image is over-
exposed) to ensure linear response to light through the whole
dynamic range. FF CCD detectors used for astrophotography are
equipped with ABG to eliminate disrupting blooming streaks
within field of view.
Cameras with Full Frame, non-ABG detectors are suitable for
scientific applications, where linear response is necessary for
photometric applications in astronomy, microscopy etc. High
quantum efficiency could be used also for narrow-band imaging,
where overexposure is a rare exception, and for imaging of small
objects without a bright star in the field of view.
Figure 3: “Full Frame” CCD schematic diagram

13
 G2 cameras with OnSemi KAI Interline Transfer (IT) architecture.
There is a shielded column of pixels just beside each column of
active pixels on these detectors. The shielded columns are called
Vertical registers. One pulse moves charge from exposed pixels to
shielded pixels on the end of each exposure. The the charge is
moved from vertical registers to horizontal register and digitized
in the same way like in the case of Full Frame detectors. This
mechanism is also known as “electronic shuttering” because it
allows very short exposures and also digitization of the image
without mechanically shielding of the detector from incoming
light.
Also, G2 cameras with IT CCDs are equipped with mechanical
shutter, because electronic shutter does not allow dark-frame
exposures, necessary for proper image calibration etc.
The price for electronic shutter if lower quantum efficiency
(sensitivity) of IT detectors compared to FF ones. Also, all IT
detectors are equipped with ABG, so they can acquire images of
very bright objects without charge blooming to neighboring pixels.
Figure 4: “Interline Transfer” CCD schematic diagram

14
G2 camera Mark II models with Full Frame CCD detectors:
Model G2-0400 G2-1600 G2-3200 G2-8300
CCD sensor KAF-0402ME KAF-1603ME KAF-3200ME KAF-8300
Resolution 768 × 512 1536 × 1024 2184 × 1472 3358 × 2536
Pixel size 9 × 9 μm 9 × 9 μm 6.8 × 6.8 μm 5.4 × 5.4 μm
Sensor size 6.9 × 4.6 13.8 × 9.2 14.9 × 10.0 18.1 × 13.7
ABG No No No Yes
Color mask No No No No*
* G2-8300 camera is available in the G2-8300C version with color CCD
detector (with Bayer mask), capable of single-shot color images.
G2 camera models with Interline Transfer CCD detectors:
Model G2-2000 G2-2000C G2-4000 G2-4000C
CCD sensor KAI-2020 KAI-2020 KAI-4022 KAI-4022
Resolution 1604 × 1204 1604 × 1204 2056 × 2062 2056 × 2062
Pixel size 7.4 × 7.4 μm 7.4 × 7.4 μm 7.4 × 7.4 μm 7.4 × 7.4 μm
Sensor size 11.9 × 8.9 11.9 × 8.9 15.2 × 15.2 15.2 × 15.2
ABG Yes Yes Yes Yes
Color mask No Yes No Yes
Cameras with “C” suffix contain CCD detector covered with so-called Bayer
mask. Color filters of three basic colors (red, green, blue) cover all pixels, so
every pixel detects only light of particular color.
These cameras are able to acquire color image in single exposure, without
the necessity to change color filters. On the other side color mask brings
lower sensitivity and limits the capability to perform exposures using
narrow-band filters etc.
Because each pixel is covered by one of three basic color filters, it is
necessary to compute (interpolate) remaining two colors for each pixel,

15
which of course limits resolution of color image. Imaging using color
detectors is described in the “Color images” chapter.
CCD sensor
Quantum efficiency (sensitivity) of CCD detectors used in G2 cameras
depends on the particular camera model.
Figure 5: Quantum efficiency of OnSemi CCD detectors used in G2 cameras
Inherent dark current of these detectors is quite low compared to other
CCD detectors, suitable for scientific applications, which results into very
good signal/noise ratio.
Figure 6: Dark current of some OnSemi CCD detectors, used in G2 cameras

16
Model G2-0400
G2-0400 model uses 0.4 MPx CCD OnSemi KAF-0402ME.
Resolution 768 × 512 pixels
Pixel size 9 × 9 μm
Imaging area 6.9 × 4.6 mm
Full well capacity Approx. 100 000 e
-
Output node capacity Approx. 220 000 e
-
Dark current 1 e-/s/pixel at 0°C
Dark signal doubling 6.3 °C
Model G2-1600
G2-1600 model uses 1.6 MPx CCD OnSemi KAF-1603ME.
Resolution 1536 × 1024 pixels
Pixel size 9 × 9 μm
Imaging area 13.8 × 9.2 mm
Full well capacity Approx. 100 000 e-
Output node capacity Approx. 220 000 e-
Dark current 1 e-/s/pixel at 0°C
Dark signal doubling 6.3 °C
Model G2-3200
G2-3200 model uses 3.2 MPx CCD OnSemi KAF-3200ME.
Resolution 2184 × 1472 pixels
Pixel size 6.8 × 6.8 μm
Imaging area 14.9 × 10.0 mm
Full well capacity Approx. 55 000 e-
Output node capacity Approx. 110 000 e-
Dark current 0.8 e-/s/pixel at 0°C
Dark signal doubling 6.0 °C
Model G2-8300
G2-8300 model uses 8 MPx CCD OnSemi KAF-8300.
Resolution 3358 × 2536 pixels
Pixel size 5.4 × 5.4 μm
Imaging area 18.1 × 13.7 mm
Full well capacity Approx. 25 000 e
-

17
Output node capacity Approx. 55 000 e-
Dark current 0.15 e-/s/pixel at 0°C
Dark signal doubling 5.8 °C
KAF-8300 CCD detector with color (Bayer) mask can be used in the G2-
8300C camera.
Model G2-2000
G2-2000 model uses 2 MPx CCD MPx OnSemi KAI-2020.
Resolution 1604 × 1204 pixels
Pixel size 7.4 × 7.4 μm
Imaging area 11.9 × 8.9 mm
Full well capacity Approx. 40 000 e-
Output node capacity Approx. 80 000 e-
Dark current 0.3 e-/s/pixel at 0°C
Dark signal doubling 7.0 °C
KAI-2020 CCD detector with color (Bayer) mask can be used in the G2-
2000C camera.
Model G2-4000
G2-4000 model uses 4 MPx CCD MPx OnSemi KAI-4022.
Resolution 2056 × 2062 pixels
Pixel size 7.4 × 7.4 μm
Imaging area 15.2 × 15.2 mm
Full well capacity Approx. 40 000 e
-
Output node capacity Approx. 80 000 e
-
Dark current 0.3 e-/s/pixel at 0°C
Dark signal doubling 7.0 °C
KAI-4022 CCD detector with color (Bayer) mask can be used in the G2-
4000C camera.
Camera Electronics
16-bit A/D converter with correlated double sampling ensures high
dynamic range and CCD chip-limited readout noise. Fast USB interface
ensures image download time within seconds.

18
Maximum length of single USB cable is approx. 5 m. This length can be
extended to 10 m or 15 m by using single USB hub or active USB extender
cable. Up to 5 hubs or active extenders can be used in one connection.
Gx Camera Ethernet Adapter device allows connection of up to four Gx
cameras of any type through Ethernet interface and TCP/IP network.
Because TCP/IP protocol can be routed, the distance between camera and
host PC can be virtually unlimited.
ADC resolution 16 bits
Sampling method Correlated double sampling
Read modes Preview
Low-noise
Horizontal binning 1 to 4 pixels
Vertical binning 1 to 4 pixels
Sub-frame readout Arbitrary sub-frame
Computer interface USB 2.0 high-speed
USB 1.1 full-speed compatible
Binning can be combined independently on both axes.
Image download time and system read noise depends on the CCD chip
used in particular camera model as well as on the camera read mode.
 Preview read mode provides system read noise approx. 1 or 2 e-
above CCD chip read noise.
 Low Noise read mode is somewhat slower, but ensures system
read noise roughly equal to the manufacturer-specified chip read
noise.
Model G2-0400
Gain 1.5 e-/ADU (1×1 binning)
2.0 e-/ADU (other binnings)
System read noise 13 e- RMS (Low noise)
15 e- RMS (Preview)
Download time 0.25 s (Low noise)
0.16 s (Preview)

19
Model G2-1600
Gain 1.5 e
-
/ADU (1×1 binning)
2.0 e
-
/ADU (other binnings)
System read noise 13 e- RMS (Low noise)
15 e- RMS (Preview)
Download time 0.95 s (Low noise)
0.67 s (Preview)
Model G2-3200
Gain 0.8 e-/ADU (1×1 binning)
1.3 e
-
/ADU (other binnings)
System read noise 7 e
-
RMS (Low noise)
9 e
-
RMS (Preview)
Download time 1.95 s (Low noise)
1.39 s (Preview)
Model G2-8300
Gain 0.4 e-/ADU (1×1 binning)
0.8 e-/ADU (other binnings)
System read noise 8 e- RMS (Low noise)
9 e- RMS (Preview)
Download time 4.95 s (Low noise)
3.48 s (Preview)
Model G2-2000
Gain 0.5 e-/ADU (1×1 binning)
0.8 e-/ADU (other binnings)
System read noise 7 e- RMS (Low noise)
9 e- RMS (Preview)
Download time 1.06 s (Low noise)
0.73 s (Preview)
Model G2-4000
Gain 0.5 e
-
/ADU (1×1 binning)
0.8 e
-
/ADU (other binnings)
System read noise 7 e- RMS (Low noise)
9 e- RMS (Preview)

20
Download time 2.30 s (Low noise)
1.56 s (Preview)
Stated read noise is measured on particular CCD sensor, evaluated
during camera design. Actual read noise of different sensors varies
within sensor manufacturing batch and also among various
manufacturing batches. The camera read noise is determined by the
sensor itself and the camera manufacturer cannot affect it.