Moravian Instruments C1+ Series User manual

C1+ Series
Cooled CMOS Cameras
User’s Guide

Version 1.1
Modified on September 2nd, 2020
All information furnished by Moravian Instruments is believed to be
accurate. Moravian Instruments reserves the right to change any
information contained herein without notice.
C1+ 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 © 2000-2020, 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
C1+ Camera Overview ................................................................................... 8
C1+ Camera System .................................................................................. 9
CMOS Sensors and Camera Electronics ...................................................... 11
Camera Electronics .................................................................................. 12
Sensor linearity ................................................................................... 13
Download speed ................................................................................. 14
Camera gain ........................................................................................ 15
Conversion factors and read noise ...................................................... 15
Exposure control ................................................................................. 16
Cooling and power supply ........................................................................... 17
Power supply ........................................................................................... 19
Autoguider port .......................................................................................... 21
Mechanical Specifications ........................................................................... 23
C1+ Camera with C1 compatible adapter ............................................... 25
C1+ Camera with C2 compatible adapter ............................................... 25
C1+ Camera with “XS” External Filter Wheel .......................................... 26
Optional accessories ................................................................................... 28
Telescope adapters ................................................................................. 28
Adapters for C1+ cameras with C1 compatible adapter base ............. 28
Adapters for C1+ cameras with C2 compatible adapter base and
external filter wheel ............................................................................ 29
Attaching camera head to telescope mount ........................................... 30
Moravian Camera Ethernet Adapter ....................................................... 31
Adjusting of the telescope adapter ............................................................. 32

Camera Maintenance .................................................................................. 35
Desiccant exchange ................................................................................. 35
Exchanging the silica-gel...................................................................... 36
Changing the telescope adapter ............................................................. 38
Changing the C1 compatible adapter .................................................. 38
Changing the C2 compatible adapter .................................................. 38

5
Introduction
Thank you for choosing the Moravian Instruments camera. C1+ camera
models are designed to fulfil the gap between small and lightweight C1
models, intended as Moon and planetary cameras and auto-guiders, and
C2 cameras, equipped with active sensor cooling and mechanical shutter
and thus intended for more serious astronomical imaging and research.
C1+ cameras are able to work as C1 ones, only being somewhat heavier
and bulkier, and at the same time C1+ can replace the cooled C2 models,
only with slightly less cooling performance and lack of mechanical shutter.
C1+ cameras are designed to operate from USB power lines only. However,
some functions are available only if external 12 V DC power supply is
connected. C1+ functions equal to C1 cameras when powered from USB
only:
 Image acquisition.
 Mount guiding through standard “autoguider” 6-pin connector.
When a 12 V DC power is plugged in, C1 camera functions extend with:
 Active and regulated sensor cooling with Peltier cooler.
 Ability to control external filter wheel.
Still, C1+ capabilities lack some functionality, available in larger and heavier
C2 cameras only:
 C1+ have no mechanical shutter, necessary for automatic dark
and bias frame acquisition in remote or robotic setups.
 C1+ lack the possibility to use internal filter wheel.
 C1+ cooling performance is slightly lower than in the case of C2,
but the sensor temperature difference is only a few degrees
Celsius.
Mechanical design of this series makes it fully compatible with vast range
of telescope adapters, off-axis guider adapters, internal or external filter
wheels, Camera Ethernet adapters, guiding cameras etc.

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Rich software and driver support allows usage of C1+ 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 C1+
camera with broad variety of camera control programs.
The C1+ 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.
C1+ cameras are designed to be attached to host PC through very fast
USB 3.0 port. While C1+ 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 C1+, but also C1, C2, 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.

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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.
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.
Figure 1: Comparison of the C1+ camera head (middle) with C1 camera (left) and C2
camera (right)

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C1+ Camera Overview
C1+ camera head is designed to be as small and compact as a cooled
camera with rich features and compatible with broad set of accessories
can be.
C1+ cameras are equipped with tiltable telescope interface and tripod
mounting threaded holes. They are also compatible with external filter
wheels designed for larger C2 cameras – camera head contains connector
to control filter wheel. If the external filter wheel is used, the tiltable
mechanism on the camera head is inactive and tiltable adapters for
external filter wheels are used instead. Therefore, C1+ cameras can utilize
vast range of telescope and lens adapters including off-axis guider
adapters.
Figure 2: C1+ Camera without (left) and with (right) with attached External filter
wheel
There are two sizes of the External filter wheels, each capable to accept
two sizes of filters, available for the C1+ cameras:

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 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.
C1+ Camera System
Figure 3: Schematic diagram of C1+ camera system components

10
Components of the C2 Camera system include:
1. C1+ camera with C1 compatible adapter
2. C1+ camera with C2 compatible adapter
When used without spring and pushing screws, this adapter also
works as base for External filter wheels.
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 OAG
or on standalone guiding telescope.
6. Off-Axis Guider with M48×0.75 thread
7. C1 compatible Nikon bayonet adapter
8. C1 compatible Canon EOS bayonet adapter
9. C1 compatible M42×0.75 (T-thread) adapter, 55 mm BFD
10. C1 compatible M48×0.75 adapter, 55 mm BFD
11. C2 compatible M42×0.75 (T-thread) or M48×0.75 threaded
adapter, 55 mm BFD
12. C2 compatible Canon EOS bayonet adapter
13. C2 compatible Nikon bayonet adapter
14. Camera Ethernet Adapter (x86 CPU)
15. Camera Ethernet Adapter (ARM CPU)
Moravian Camera Ethernet Adapter allows connection of up to
four 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.
16. 8-positions external filter wheel “XS” for 1.25”/D31 mm filters
17. 7-positions external filter wheel “XS” for D36 mm filters
18. 12-positions external filter wheel “S” for 1.25”/D31 mm filters
19. 10-positions external filter wheel “S” for D36 mm filters
20. 7-positions external filter wheel “S” for 2”/D50 mm filters

11
CMOS Sensors and Camera Electronics
C1+ series of CMOS cameras are equipped with Sony IMX global shutter
CMOS detectors with 3.45 × 3.45 μm or 4.50 × 4.50 μm square pixels.
All used sensors utilize global electronic shutter, which means every pixel
within the image is exposed in the same time, as opposed to rolling
shutter, which exposes individual lines one after another. There is no
difference for long exposures of static objects, but imaging of moving
objects using short exposure time using rolling shutter leads to image
shape distortions.
Three lines of C1+ cameras are available depending on the available
dynamic range (bit-depth of the digitized pixels) and pixel size:
 C1+ cameras with Sony IMX sensors with 3.45 × 3.45 μm pixels,
supporting 8- and 12-bit digitization. Because every 12-bit pixel
occupies two bytes when transferred to host PC, 12-bit image
download time is longer compared to 8-bit image. Maximal FPS in
8-bit mode is then significantly higher.
 C1+ cameras with Sony IMX sensors with 3.45 × 3.45 μm pixels,
supporting 12-bit digitization only. As the 12-bit read mode is
always used for long-exposure applications (astronomical
photography, scientific research) either way, lower theoretical
download speed in 8-bit mode brings no limitations for real-world
scenarios. All other parameters being same (sensor size,
resolution, pixels size, noise, …), lower price of “A” cameras may
be then very attractive.
 C1+ cameras with Sony IMX sensors with 4.50 × 4.50 μm pixels
and 12-bit digitization only. Greater pixels mean higher dynamic
range (more electrons can be stored in each pixel before it
saturates), but also higher read noise. Still the theoretical S/N is
almost the same because of higher signal camera can accumulate.
This camera is more suitable for longer focal length telescopes,
where small pixels provide oversampled images, and also for
research applications, where dynamic range is important.

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C1+ camera models with 3.45 × 3.45 μm pixels and 8- and 12-bit
digitization:
Model C1+3000 C1+5000 C1+12000
CMOS sensor IMX252 IMX250 IMX253
Resolution 2064 × 1544 2464 × 2056 4112 × 3008
Pixel size 3.45 × 3.45 μm 3.45 × 3.45 μm 3.45 × 3.45 μm
Sensor size 7.12 × 5.33 mm 8.50 × 7.09 mm 14.19 × 10.38 mm
C1+ camera models with 3.45 × 3.45 μm pixels and 12-bit digitization only:
Model C1+3000A C1+5000A C1+12000A
CMOS sensor IMX265 IMX246 IMX304
Resolution 2064 × 1544 2464 × 2056 4112 × 3008
Pixel size 3.45 × 3.45 μm 3.45 × 3.45 μm 3.45 × 3.45 μm
Sensor size 7.12 × 5.33 mm 8.50 × 7.09 mm 14.19 × 10.38 mm
C1+ camera models with 4.50 × 4.50 μm pixels and 12-bit digitization only:
Model C1+7000A
CMOS sensor IMX428
Resolution 3216 × 2208
Pixel size 4.50 × 4.50 μm
Sensor size 14.47 × 9.94 mm
Cameras limited to 12-bit read mode are marked with letter A, following
the model number. For instance, if C1+3000 marks camera with both 8-
and 12-bit read modes, C1+3000A denotes camera model with only 12-
bit read mode. All other parameters (sensor size, pixel resolution) are
equal.
Camera Electronics
CMOS camera electronics primary role, beside the sensor initialization and
some auxiliary functions, is to transfer data from the CMOS detector to the
host PC for storage and processing. So, as opposite to CCD cameras, CMOS
camera design cannot influence number of important camera features, like
the dynamic range (bit-depth of the digitized pixels).

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Sensor linearity
The sensors used in C1+ cameras show very good linearity in response to
light. This means the camera can be used also for entry-level research
projects, like for instance photometry or brighter variable stars etc.
Figure 4: Response of the Sony IMX sensors with 3.45 × 3.45 μm pixels (IMX252)
Figure 5: Response of the Sony IMX sensors with 4.50 × 4.50 μm pixels (IMX428)

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Download speed
As already noted, there are two lines of C1+ camera series, differing in the
used sensor. The first series with 3.45 × 3.45 μm pixels offers four different
read modes:
 8-bit slow mode with ~132 MPx/s digitization speed
 12-bit slow mode with ~72 MPx/s digitization speed
 8-bit fast mode with ~263 MPx/s digitization speed
 12-bit fast mode with ~132 MPx/s digitization speed
The slow variant of both read modes can be used to slightly lower the
amount of heat generated by the sensor, as the communication
interface operates at half speed compared to fast mode. Also, when
the camera is connected using USB 2.0 interface, fast read mode
provides data at higher speed than the USB 2.0 can handle and thus
causes more interruptions of image digitization process.
The “A” version of C1+ cameras with 3.45 × 3.45 μm pixels offers only
single read mode:
 12-bit fast mode with ~132 MPx/s digitization speed
And the “A” version of C1+ cameras with 4.50 × 4.50 μm pixels offers also
only one read mode:
 12-bit fast mode with ~151 MPx/s digitization speed
The digitization speeds mentioned above are valid for USB 3.0 connection.
Also please note the digitization speeds do not necessarily lead to
corresponding FPS, because every image downloaded has to be processed
and displayed, which also consumes time. This time is negligible, if slow-
scan camera needs many seconds for image download, but in the case of
fast CMOS cameras, time for image processing in the PC (e.g. calculation of
image standard deviation etc.) can be longer than image download itself.
Despite one byte per pixels is transferred from camera to PC in the 8-
bit read mode, many astronomical processing software packages work
with 16-bit or 32-bit images only (e.g. SIPS). So, images occupy the
same space in the computer memory regardless of the read mode.

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Also, standard format for image storage in astronomy is FITS. While
this format supports 8-bit per pixel, this variant is rather unusual and
16 or 32-bit integer or 32-bit floating-point pixels are typically stored
to disk files to achieve as wide compatibility as possible.
Camera gain
Sensors used in C1+ cameras offer programmable gain from 0 to 24 dB,
which translates to the output signal multiplication from 1× to 15.9×. Gain
can be set with 0.1 dB step.
Note the C1+ camera firmware supports only analog gain, which
means real amplification of the signal prior to its digitization. The used
sensors support also digital gain control, which is only numerical
operation, bringing no real benefit for astronomical camera. Any such
operation can be performed later during image processing if desired.
Conversion factors and read noise
Generally, all sensor characteristics depend on the used gain. So, we
provide two list of parameters for both minimal and maximal gain.
Camera/sensor parameters for sensors with 3.45 × 3.45 μm pixels:
Digitization 12-bit 12-bit 8-bit 8-bit
Sensor gain 0 dB 24 dB 0 dB 24 dB
Full well capacity 11000 e- 1100 -e 2600 e- 1100 e-
Conversion factor 2.8 e-/ADU 0.3 e-/ADU 10.0 e-/ADU 4.4 e-/ADU
Read noise 2.2 e- RMS 2.0 e- RMS 4.2 e- RMS 9.7 e- RMS
Camera/sensor parameters for sensors with 4.50 × 4.50 μm pixels:
Digitization 12-bit 12-bit
Sensor gain 0 dB 24 dB
Full well capacity 26000 e- 2100 -e
Conversion factor 6.3 e-/ADU 0.5 e-/ADU
Read noise 5.3 e- RMS 3.9 e- RMS
Please note the values stated above are not published by sensor
manufacturer, but determined from acquired images using the SIPS

16
software package. Results may slightly vary depending on the test run,
on the particular sensor and other factors (e.g. sensor temperature,
sensor illumination conditions etc.), but also on the software used to
determine these values, as the method is based on statistical analysis
of sensor response to light.
Exposure control
C1+ cameras are capable of very short exposures. The shortest exposure
time is 125 µs (1/8000 of second). This is also the step, by which the
exposure time is expressed. So, the second shortest exposure is 250 µs etc.
Long exposure timing is controlled by the host PC and there is no upper
limit on exposure time. In reality the longest exposures are limited by
saturation of the sensor either by incoming light or by dark current (see
the following sub-chapter).
Internal mechanical shutter No
Shortest exposure time 0.000125 s (electronic shutter)
Longest exposure time Limited by chip saturation only

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Cooling and power supply
As mentioned in the introduction, C1+ cameras can operate only with USB
power. Camera is then capable to acquire images and to control (guide)
telescope mount via “autoguider” port. However, active sensor cooling (as
well as filter wheel operation) is available only if external 12 V DC power
supply is connected.
Camera fan operates even without 12 V DC power attached, only with
lower fan speed. This helps to keep the camera electronics
temperature close to environment temperature. When the 12 V DC
power is plugged in, the fan turns to full speed to remove the heat
generated by the Peltier thermo-electric cooler.
Regulated thermoelectric cooling is capable to cool the CMOS sensor more
than 40 °C below ambient temperature. The Peltier hot side is cooled by
fan. The sensor 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.
Figure 6: C1+ air inlet with fan is on the bottom side of the camera head (left), air
outlet vents are on the camera top side (right)
The camera head contains two temperature sensors – the first
thermometer measures directly the temperature of the CMOS sensor. The
second one measures the temperature inside the camera shell.

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The cooling performance depends on the environmental conditions and
also on the power supply. If the power supply voltage drops below 12 V,
the maximum temperature drop is lower.
CMOS sensor cooling Thermoelectric (Peltier modules)
Maximal cooling ΔT ~45 °C below ambient
Regulated cooling ΔT 40 °C below ambient (~90% cooling)
Regulation precision ±0.1 °C
Hot side cooling Forced air cooling (fan)
Maximum temperature difference between sensor and ambient air
may be reached when the cooling runs at 100% power. However,
temperature cannot be regulated in such case, camera has no room
for lowering the sensor temperature when the ambient temperature
rises. Typical temperature drop can be achieved with cooling running
at approx. 90% power, which provides enough room for regulation.
Figure 7: C1+3000A camera reaching maximum -45°C sensor temperature below
ambient

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Power supply
Certain camera functions need 12 V DC power supply. Power can be
sourced from batteries, wall adapters etc. Universal 100-240 V AC/50-
60 Hz, 60 W “brick” adapter is supplied with the camera. Although the
camera power consumption does not exceed 25 W, the 60 W power supply
ensures noise-free operation.
Warning:
The power connector on the camera head uses center-plus pin.
Although all modern power supplies use this configuration, always
make sure the polarity is correct if you use own power source.
Camera head supply 12 V DC
Camera head power consumption <1 W without cooling
22 W maximum cooling
Power connector 5.5/2.5 mm, center +
Adapter input voltage 100-240 V AC/50-60 Hz
Adapter output voltage 12 V DC/5 A
Adapter maximum power 60 W
Power consumption is measured on the 12 V DC side. Power
consumption on the AC side of the supplied AC/DC power brick is
higher.
The camera can be powered by unregulated 12 V DC power source –
the input voltage can be anywhere between 10 and 14 V. However,
cooling efficiency can degrade if the supply drops below 12 V.
C1+ camera measures its input voltage and provides it to the control
software. Input voltage is displayed in the Cooling tab of the Imaging
Camera tool in SIPS. This feature is important especially if the camera
is powered from batteries.

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Figure 8: 12 V DC/5 A power supply adapter for C1+ camera