Moravian Instruments C2 Series Manuel utilisateur
C2 Series
Astronomical Cameras
User’s Guide
Version 1.6
Modified on October 13th, 2023
All information furnished by Moravian Instruments is believed to be
accurate. Moravian Instruments reserves the right to change any
information contained herein without notice.
C2 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 © 2000-2023, Moravian Instruments
Moravian Instruments
Masarykova 1148
763 02 Zlín
Czech Republic
phone: +420 577 107 171
web: https://www.gxccd.com/
e-mail: [email protected]
Table of Contents
Introduction .................................................................................................. 5
C2 Camera Overview ..................................................................................... 7
C2 Camera System .................................................................................... 9
C2 with global shutter CMOS Sensors ......................................................... 11
Camera Electronics .................................................................................. 12
Sensor linearity ....................................................................................... 13
Download speed ..................................................................................... 14
Camera gain ............................................................................................ 15
Conversion factors and read noise .......................................................... 15
Exposure control ..................................................................................... 16
Mechanical shutter ............................................................................. 16
C2 with rolling shutter CMOS Sensors ........................................................ 17
Camera Electronics .................................................................................. 17
Sensor linearity ....................................................................................... 17
Download speed ..................................................................................... 18
Camera gain ............................................................................................ 19
Conversion factors and read noise .......................................................... 20
Binning .................................................................................................... 20
Hardware binning ................................................................................ 21
Adding vs. averaging pixels ................................................................. 21
Binning in photometry ........................................................................ 23
Exposure control ..................................................................................... 23
Mechanical shutter ............................................................................. 24
GPS exposure timing ........................................................................... 24
Cooling and power supply ........................................................................... 27
Overheating protection ....................................................................... 29
Power supply ........................................................................................... 29
Mechanical Specifications ........................................................................... 32
Camera with Internal Filter Wheel .......................................................... 34
Camera with “XS” External Filter Wheel ................................................. 35
Camera without filter wheel ................................................................... 36
Back focal distance .................................................................................. 37
Adapters without back focal distance defined .................................... 38
Adapters with defined back focal distance ......................................... 40
Off-Axis Guider Adapter ...................................................................... 41
Optional accessories.................................................................................... 44
Telescope adapters ................................................................................. 44
Off-Axis Guider Adapter (OAG) ............................................................... 44
GPS receiver module ............................................................................... 46
GPS receiver module handling ............................................................ 47
Attaching camera head to telescope mount ........................................... 48
Camera head color variants .................................................................... 49
Camera Ethernet Adapter ....................................................................... 49
Adjusting of the telescope adapter ............................................................. 51
Camera Maintenance .................................................................................. 54
Desiccant exchange ................................................................................. 54
Exchanging the silica-gel...................................................................... 55
Changing Filters ....................................................................................... 57
Opening the camera head ................................................................... 57
Changing the Whole Filter Wheel ........................................................... 58
Changing the Telescope Adapter ............................................................ 58
Power supply fuse ................................................................................... 59
5
Introduction
Thank you for choosing the Moravian Instruments camera. The cooled C2
series CMOS cameras were developed for imaging under extremely low-
light conditions in astronomy, microscopy, and similar areas.
Mechanical design of this series inherits from earlier CCD-based G2 Mark II
cameras, which makes the C2 series fully compatible with vast range of
telescope adapters, off-axis guider adapters, internal or external filter
wheels, Camera Ethernet adapters, guiding cameras etc.
Rich software and driver support allows usage of C2 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 C2
camera with broad variety of camera control programs.
The C2 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.
3. Support for x64 based Apple Macintosh computers is also
included.
Only certain software packages are currently supported on Mac.
6
C2 cameras are designed to be attached to host PC through very fast
USB 3.0 port. While C2 cameras remain compatible with older (and slower)
USB 2.0 interface, image download time is significantly longer.
Alternatively, it is possible to use the “Moravian Camera Ethernet Adapter”
device. This device can connect up to four Cx (and Gx) cameras of any type
(not only C2, but also C1, C3 and C4) 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.
Download speed is naturally significantly slower when camera is attached
over Ethernet adapter, especially when compared with direct USB 3
connection.
The C2 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 simple imagers. C2 cameras integrate highly
efficient CMOS sensor 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
camera with the telescope, make sure the whole telescope/mount setup is
capable to track the target object smoothly during long exposures.
7
C2 Camera Overview
C2 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: C2 Camera without filter wheel (left), with Internal filter wheel (middle)
and with attached External filter wheel (right)
C2 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 C2 cameras:
8
Extra small “XS” size wheel for 8 unmounted filters D31 mm or
filters in 1.25” threaded cells.
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.
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.
C2 cameras are manufactured with a wide range of CMOS sensors.
Probably the most important differentiating factor, fundamentally
affecting camera operation, is an electronic shutter implemented in the
sensors. C2 cameras support sensors with:
Global shutter, allowing capturing of the whole frame in the very
same instance of time. This means all pixels are reset and start to
capture light simultaneously. Global shutter is particularly
suitable for capturing fast moving scenes, because they ensure
image does not suffer from motion distortion, caused by rolling
shutter sensors. On the other side, frame rate of global shutter
sensors is lower compared to rolling shutter ones, because each
frame must be fully digitized prior to start of next exposure.
Rolling shutter, which resets individual image rows in a
sequence. The exposure of each image row is delayed typically by
a few tens of microseconds. Depending on this delay and number
of rows, the first and last row exposure time may be shifted by up
to several tenths of a second. The inherent feature of rolling
shutter sensors is a distortion of fast-moving scenes, when image
moves within the time individual rows are exposed. Luckily such
fast moving scenes are very rare in astronomy. The plus side of
rolling shutter is much higher FPS, as each image is already
exposed while the previous image is digitized.
9
C2 Camera System
Figure 2: Schematic diagram of C2 camera system components
10
Components of the C2 Camera system include:
1. C2 camera head with Internal Filter Wheel (5 or 6 positions)
2. C2 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. C1 guider camera
C1 cameras are completely independent devices with their own
USB connection to the host PC. They can be used either on C2
OAG or on standalone guiding telescope.
C1 camera can share the Moravian Camera Ethernet Adapter
with up to 3 other Cx or Gx cameras to be accessed over
network.
6. Off-Axis Guider with M48×0.75 thread
7. Off-Axis Guider with M42×0.75 thread (T2)
8. Thick adapter base, compensating EFW thickness to achieve
proper back focal distance for cameras without filter wheel
9. 1.75” dovetail rail for C2 camera head
10. Camera Ethernet Adapter (x86 CPU)
11. Camera Ethernet Adapter (ARM CPU)
Camera Ethernet Adapter allows connection of up to 4 Cx
cameras of any type on the one side and 1 Gbps Ethernet on the
other side. This adapter allows access to connected Cx cameras
using routable TCP/IP protocol over unlimited distance.
12. 6-positions internal filter wheel for D27.5 mm filters
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
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