Moravian Instruments G3 Mark II Series User manual

G3 Series Mark II
Cooled CCD Cameras
User’s Guide

Version 1.3
Modified on August 12th, 2019
All information furnished by Moravian Instruments is believed to be
accurate. Moravian Instruments reserves the right to change any
information contained herein without notice.
G3 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 © 2000-2019, Moravian Instruments
Moravian Instruments
Masarykova 1148
763 02 Zlín
Czech Republic
phone: [phone]
web: http://www.gxccd.com/
e-mail: [email protected]

Table of Contents
Introduction .................................................................................................. 5
G3 Camera Overview .................................................................................... 8
CCD Detectors and Camera Electronics ...................................................... 13
CCD sensor .............................................................................................. 16
Model G3-1000 ................................................................................... 16
Model G3-6300 ................................................................................... 16
Model G3-11000 ................................................................................. 17
Model G3-11000C ............................................................................... 17
Model G3-16200 ................................................................................. 17
Model G3-16200C ............................................................................... 17
Camera Electronics .................................................................................. 18
Model G3-1000 ................................................................................... 18
Model G3-6300 ................................................................................... 19
Model G3-11000 ................................................................................. 19
Model G3-16200 ................................................................................. 19
Cooling and power supply ........................................................................... 20
Power supply ........................................................................................... 21
Mechanical Specifications ........................................................................... 24
Camera with Internal Filter Wheel .......................................................... 25
Enhanced cooling variant ........................................................................ 26
Camera with “S” External Filter Wheel ................................................... 27
Enhanced cooling with External filter wheel variant .............................. 28
Optional accessories ................................................................................... 29
Telescope adapters ................................................................................. 29
Off-Axis Guider Adapter (OAG) ............................................................... 30

Attaching camera head to telescope mount ........................................... 32
Camera head color variants .................................................................... 33
Gx Camera Ethernet Adapter .................................................................. 33
Adjusting of the telescope adapter ............................................................. 35
Camera Maintenance .................................................................................. 38
Desiccant exchange ................................................................................. 38
Exchanging the silica-gel...................................................................... 39
Desiccant containers for Standard cooling and Enhanced cooling
cameras ............................................................................................... 41
Changing Filters ....................................................................................... 41
Opening the camera head ................................................................... 42
Changing the Whole Filter Wheel ........................................................... 42
Changing the Telescope Adapter ............................................................ 43
Power Supply Fuse .................................................................................. 44

5
Introduction
Thank you for choosing the Moravian Instruments camera. The cooled G3
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 G3 Mark I cameras but brings
some significant enhancements. G3 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 G3 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 G3
camera with vast variety of camera control programs.
The G3 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.
G3 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
G3, but also G0, G1, G2 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 G3 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. G3 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
G3 Camera Overview
G3 camera head is designed to be easily used with a set of accessories to
fulfil various observing needs. Camera head itself is manufactured in
several variants.
First, there are variants differing in the cooling performance:
 Standard cooling
 Enhanced cooling (11 mm thicker due to increased heat sink)
Second, there are variants differing if filter wheel control:
 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: G3 Camera Mark II without filter wheel (far left), with Internal filter wheel
(left) and with attached “S” (right) and “L” (far right) External filter wheel
G3 camera model with Internal filter wheel accepts 5 filters for unmounted
D50 mm filters or filters in standard 2” threaded cells.
There are three sizes of the External filter wheels, capable to accept
various sizes of filters, available for the G3 cameras:

9
 Small “S” size wheel for 7 unmounted filters D50 mm or filters in
2” threaded cells.
 Small “M” size wheel for 7 unmounted filters D50 mm or filters in
2” threaded cells.
 Small “M” size wheel for 5 square filters 50×50 mm.
 Large “L” size wheel for 9 unmounted D50 mm or filters in 2”
threaded cells.
 Large “L” size wheel for 7 square filters 50×50 mm.
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.
And third, there are two sizes of adjustable adapters, which can be used
with G3 cameras:
 Small “S” adapters, compatible with G2 cameras, are used for e.g.
M48×0.75 and M42×0.75 threaded adapters, Nikon bayonet
adapter, 2” barrel adapter etc.
 Large “L” adapters, compatible with G4 cameras, intended for
large diameter attachments between camera and telescope, e.g.
M68×1 threaded adapter or G3-OAG, which is also equipped with
M68×1 thread.
Adjustable adapters are mounted on adapter base when camera with
internal filter wheel or camera without any filter wheel is used or directly
on the external filter wheel front surface. This means both “S” and “L”
adapter bases can be mounted on any camera, external but filter wheels
are made for one particular adapter size only:
 “S” external filter wheels are compatible with “S” adapters
 “M” and “L” external filter wheels are compatible with “L”
adapters
Note the “S” and “M” filter wheels are of very similar dimensions and
hold the same number of the same filters. They differ in the adjustable
adapter size only.

10
Figure 2: Schematic diagram of G3 camera with “S” size adapter system
components

11
Figure 3: Schematic diagram of G3 camera with “L” size adapter system
components

12
Components of G3 Camera system include:
1. G3 camera head with Internal Filter Wheel (5 positions)
2. G3 camera head with Internal Filter Wheel (5 positions) and
Enhanced Cooling option
3. G3 camera head capable to control External Filter Wheel
4. G3 camera head capable to control External Filter Wheel and
Enhanced Cooling option
5. 1.75” dovetail rail for G3 camera head
6. Gx Camera Ethernet Adapter (x86 CPU)
7. 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.
8. 5-positions internal filter wheel for 2”/D50 mm filters
9. 5-positions filter wheel for “S” or “M” housing for 50×50 mm
filters
10. 7-positions filter wheel for “S” or “M” housing for 2”/D50 mm
filters
11. 9-positions filter wheel for “L” housing for 2”/D50 mm filters
12. 7-positions filter wheel for “L” housing for 50×50 mm filters
13. External Filter Wheel “S” size (7 or 5 positions)
14. External Filter Wheel “M” size (7 or 5 positions)
15. External Filter Wheel “L” size (9 or 7 positions)
16. M42×0.75 (T-thread) or M48×0.75 threaded adapters, 55 mm BFD
17. Canon EOS bayonet lens “S” size adapter
18. Nikon bayonet lens adapter
19. M68×1 threaded adapter, 47.5 mm BFD
20. Canon EOS bayonet lens “L” size adapter
21. Off-Axis Guider with M68×1 thread, 61.5 mm BFD
22. G0 guider camera
23. G1 guider camera

13
CCD Detectors and Camera Electronics
G3 Mark II series of CCD cameras are manufactured with two kinds of CCD
detectors:
 G3 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 4: “Full Frame” CCD schematic diagram

14
 G3 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, G3 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 5: “Interline Transfer” CCD schematic diagram

15
G3 camera Mark II models with Full Frame CCD detectors:
Model G3-1000 G3-6300 G3-16200 G3-16200C
CCD sensor KAF-1001E KAF-6303E KAF-16200 KAF-16200
Resolution 1024 × 1024 3072 × 2048 4540 × 3640 4540 × 3640
Pixel size 24 × 24 μm 9 × 9 μm 6 × 6 μm 6 × 6 μm
Sensor size 24.6 × 24.6 27.7 × 18.4 27.2 × 21.8 27.2 × 21.8
ABG No No Yes Yes
Color mask No No No Yes
G3 camera models with Interline Transfer CCD detectors:
Model G3-11000 G3-11000C
CCD sensor KAI-11002 KAI-11002
Resolution 4032 × 2688 4032 × 2688
Pixel size 9 × 9 μm 9 × 9 μm
Sensor size 36.3 × 24.2 36.3 × 24.2
ABG Yes Yes
Color mask 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,
which of course limits resolution of color image. Imaging using color
detectors is described in the “Color images” chapter.

16
CCD sensor
Quantum efficiency (sensitivity) of CCD detectors used in G3 cameras
depends on the particular camera model.
Figure 6: Quantum efficiency of OnSemi CCD detectors used in G3 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.
Model G3-1000
G3-1000 model uses 1 MPx CCD OnSemi KAF-1001E.
Resolution 1024 × 1024 pixels
Pixel size 24 × 24 μm
Imaging area 24.6 × 24.6 mm
Full well capacity Approx. 220 000 e-
Output node capacity Approx. 650 000 e-
Dark current 17 e-/s/pixel at 0°C
Dark signal doubling 5.5 °C
Model G3-6300
G3-6300 model uses 6 MPx CCD OnSemi KAF-6303E.
Resolution 3072 × 2048 pixels
Pixel size 9 × 9 μm

17
Imaging area 27.6 × 18.4 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 G3-11000
G3-11000 model uses 11 MPx CCD OnSemi KAI-11000.
Resolution 4032 × 2688 pixels
Pixel size 9 × 9 μm
Imaging area 36.3 × 24.2 mm
Full well capacity Approx. 60 000 e-
Dark current 12 e-/s/pixel at 0°C
Dark signal doubling 7.0 °C
ABG >1000×
Model G3-11000C
G3-11000 model uses 11 MPx CCD OnSemi KAI-11000 with color (Bayer)
mask.
Model G3-16200
G3-16200 model uses 16 MPx CCD OnSemi KAF-16200.
Resolution 4540 × 3640 pixels
Pixel size 6 × 6 μm
Imaging area 27.2 × 21.8 mm
Full well capacity Approx. 41 000 e-
Dark current 0.08 e-/s/pixel at 0°C
Dark signal doubling 5.7 °C
ABG 2800×
Model G3-16200C
G3-16200V model uses 16 MPx CCD OnSemi KAF-16200 with color (Bayer)
mask.

18
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.
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 G3-1000
Gain 3 e-/ADU (1×1 binning)
5 e
-
/ADU (other binnings)

19
System read noise 12 e- RMS (Low noise)
15 e- RMS (Preview)
Download time 0.67 s (Low noise)
0.48 s (Preview)
Model G3-6300
Gain 1.5 e-/ADU (1×1 binning)
2.0 e-/ADU (other binnings)
System read noise 10 e- RMS (Low noise)
12 e- RMS (Preview)
Download time 3.84 s (Low noise)
2.78 s (Preview)
Model G3-11000
Gain 0.8 e
-
/ADU (1×1 binning)
1.6 e
-
/ADU (other binnings)
System read noise 11.5 e- RMS (Low noise)
13 e- RMS (Preview)
Download time 5.67 s (Low noise)
3.84 s (Preview)
Model G3-16200
Gain 0.6 e-/ADU (1×1 binning)
1.0 e
-
/ADU (other binnings)
System read noise 10 e
-
RMS (Low noise)
11 e
-
RMS (Preview)
Download time 9.61 s (Low noise)
6.77 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.

20
Cooling and power supply
Regulated thermoelectric cooling is capable to cool down the CCD chip
from 45 to 50 °C below ambient temperature, depending on the camera
type. The Peltier hot side is cooled by fans. The CCD chip temperature is
regulated with ±0.1 °C precision. High temperature drop and precision
regulation ensure very low dark current for long exposures and allow
proper image calibration.
G4 cameras are available in two variants, differing in the cooling
performance:
 Standard cooling cameras achieve regulated temperature
difference up to 45 °C below environment temperature.
 Enhanced cooling cameras can regulate temperature up to 50 °C
below environment temperature. Compared to standard variant,
enhanced cooling cameras are somewhat bulkier due to bigger
heat sink, slightly heavier and somewhat noisier because of more
powerful fans.
Figure 7: Standard cooling camera (left) and Enhanced cooling model (right) with
thicker back shell containing larger heat sink