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Astronomical cameras

Main pageProduct OverviewAstronomical cameras

C5 Series CMOS Cameras
 C5 camera series is designed to accommodate the latest generation of extremely large Sony IMX CMOS sensors with 100 and 150MPx resolution and diagonal dimension up to 67mm. Many of the used sensor properties share the exceptional features of the sensors used in the C3 series, including the 3.76μm pixel size with the full-well capacity exceeding 50ke-, very high quantum efficiency thanks to back-illuminated design and very low dark current. C5 sensors also offer 16bit digitization, perfectly linear response to light and exceptionally low read noise. Despite very large sensors, the C5 camera head dimensions are the same like the Enhanced Cooling variants of the C3 and C4 series. All these features make C5 cameras the ultimate devices for both aesthetic astro-photography as well as astronomical research.

C5 cameras look reveal the same time-proven design school of the C3 and C4 series in both outer shape and also internal construction. C5 camera head front cross-section is the same like the in the case of C3 and C4 series, although the used sensors are much larger. C5 head thickness corresponds to the thickness of the Enhanced Cooling versions of the earlier models. But still, C5 series feature completely redesigned air cooling more powerful and also quieter than even the EC variants of the C3 and C4. Also, the supplied AC/DC brick power adapter is more powerful and employs more robust power plug.

Usage of large sensors required completely new design of the telescope interface and the C5 series offers M68נ1 threaded adapter only on the smaller 100MPx C5 variant. Large 150MPx version of the C5 standardizes on the M85נ1 thread on the tiltable adapter. Like in the case of the C4 series, the internal filter wheel is not an option, external filter wheels are necessary and the C5 camera are equipped to control new EFW-5XL series of filter wheels. Huge sensors require huge 65נ65mm square filters and EFW-5XL-5 is designed for five such filters. The EFW-5XL-7 filter wheels for seven smaller 50נ50mm square filters are available for 100MPx C5 variant with smaller sensor.

Rich software and driver support allow usage of C5 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 and Linux driver libraries are shipped with the camera, provide the way to integrate C5 camera with broad variety of camera control programs.

The C5 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 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 an x86 or ARM based computer 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.

C5 cameras are designed to be attached to host PC through very fast USB 3.0 port. While the C5 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 CCD based Gx) cameras of any type (not only C5, 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.


Please note that the USB standard allows usage of cable no longer than approx. 5 meters and USB 3.0 cables are even shorter to achieve very fast transfer speeds. On the other side, 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 USB3 connection.

The camera must be connected to some optical system (e.g. the telescope) to capture images. As the C5 cameras offer really large sensors with 67mm (150MPx version) and 55mm (100MPx version) diagonals, optical system must be capable to cover such large field of view. 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.

C5 Camera Overview

C5 camera head is designed to be used with or without external filter wheel. The EFW-5XL external filter wheel with 50נ50mm filters is suitable for C5A-100M camera only, large sensor C5A-150M model needs EFW-5XL external filter wheel, designed for 65נ65mm filters.

Schematic diagram of C5 camera system

Schematic diagram of C5 camera system

Components of C5 Camera system include:

  1. C5 camera head

  2. External Filter Wheel “XL” size

  3. 7-positions filter wheel for “XL” housing for 50נ50mm square filters


    The 50נ50 mm filters are usable with C5A-100M camera, which sensor longer side measures 44mm. C5A-150M camera sensor longer side measures 53.4mm, so 48נ48 mm clear openings in the filter wheel partially cover sensor sides.

  4. 5-positions filter wheel for “XL” housing for 65נ65mm square filters

  5. Canon EOS bayonet adapter for the “XL” size External Filter Wheel with 44mm BFD

  6. M68נ1 threaded adapter, BFD is 35mm when mounted directly on camera head and 47.5mm when mounted on EFW


    The M68נ1 adapter is suitable for C5A-100M camera with smaller sensor, the C5A-150M version should use greater M85נ1 adapter not to cause vignetting.

  7. M85נ1 threaded adapter, BFD is 31mm when mounted directly on camera head and 43.5mm when mounted on EFW

  8. C5-OAG (Off-Axis Guider Adapter) with M85נ1 thread for the “XL” size External Filter Wheel with 61.5mm BFD

  9. 10mm long CS-to-1.25" adapter, used to attach CS-mount (C-thread, 12.5mm BFD) compatible guider cameras to the OAG

  10. C1 guider camera


    C1 cameras are completely independent devices with their own USB connection to the host PC. They can be used either on the 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 TCP/IP network.

  11. Moravian Camera Ethernet Adapter (x86 CPU)

  12. Moravian Camera Ethernet Adapter (ARM CPU)


    The Ethernet Adapter allows connection of up to 4 Cx cameras of any type on the one side and 1Gbps Ethernet on the other side. This adapter allows access to connected Cx cameras using routable TCP/IP protocol over unlimited distance.

CMOS Sensor and Camera Electronics

C5 cameras are equipped with Sony IMX rolling shutter back-illuminated CMOS detectors with 3.76נ3.76μm square pixels. Despite the relatively small pixel size, the full-well capacity over 50ke- rivals the full-well capacity of competing CMOS sensors with much greater pixels and even exceeds the full-well capacity od CCD sensors with comparable pixel size.

The used Sony sensors are equipped with 16-bit ADCs (Analog to Digital Converters). 16-bit digitization ensures enough resolution to completely cover the sensor exceptional dynamic range.


While the used sensors offer also lower dynamic resolution (12 and 14 bit), C5 cameras do no utilize these modes. Astronomical images always use 2 bytes for a pixel, so lowering the dynamic resolution to 14 or 12 bits brings no advantage beside the slightly faster download. But cooled astronomical cameras are intended for very long exposures and a fraction of second saved on image download is negligible compared to huge benefits of 16-bit digitization.

C5 camera models include:

Model C5A-100M C5A-150M
CMOS sensor IMX461 IMX411
Color mask None None
Resolution 11664נ8750 14208נ10656
Pixel size 3.76נ3.76μm 3.76נ3.76μm
Sensor size 43.86נ32.90mm 53.42נ40.07mm

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).

Sensor linearity

The sensors used in C5 cameras show very good linearity in response to light. This means the camera can be used for advanced research projects, like the photometry of variable stars and transiting exoplanets etc.

Download speed

C5 cameras are equipped with on-board RAM, capable to hold several full-resolution frames. Downloading of the image to the host computer thus does not influence image digitization process, as the download only transfers already digitized images from camera memory.

Time needed to digitize and download single full frame depends on USB connection type.

Model C5A-100M C5A-150M
Full-frame, USB 3.0 (5Gbps) 0.66s 0.95s
Full-frame, USB 2.0 (480Mbps) 5.57s 6.80s

If only a sub-frame is read, time needed to digitize and download image is naturally lower. However, the download time is not cut proportionally to number of pixels thanks to some fixed overhead time, independent on the sub-frame dimensions.

Model C5A-100M C5A-150M
1024נ1024 sub-frame, USB 3.0 (5Gbps) 0.05s 0.05s
1024נ1024 sub-frame, USB 2.0 (480Mbps) 0.07s 0.07s


The driver is sometimes forced to read bigger portions of the sensor than the user defined because of a sub-frame position and dimension limitations imposed by the sensor hardware. Sometimes it is even necessary to read the whole sensor.


It is recommended to click the Adjust Frame button in the Frame tab of the SIPS camera control tool. The selected frame dimensions are then adjusted according to sensor limitations. Adjusted frame is then read from the sensor, without a necessity to read a bigger portions or even whole sensor and crop image in firmware.

C5 camera electronics supports in-camera 2נ2 binning. If this binning mode is used, download speed increases because of less amount of data read from camera.

Model C5A-100M C5A-150M
Full-frame 2נ2 HW binning, USB 3.0 (5Gbps) 0.43s 0.60s
Full-frame 2נ2 HW binning, USB 2.0 (480Mbps) 1.15s 1.71s

Download speed when using the Moravian Camera Ethernet Adapter depends if the 100Mbps or 1Gbps Ethernet is used, if USB2 or USB3 is used to connect camera to Ethernet Adapter device, but also depends on the particular network utilization etc. When the camera is connected to the Ethernet Adapter using USB3 and 1Gbps Ethernet is directly connected to the host PC, download time of the C3-61000 full frame is approx. 2.5s.

Camera gain

Sensors used in C3 cameras offer programmable gain from 0 to 36dB, which translates to the output signal multiplication from 1 to 63.


Note the C3 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.

Camera driver accepts gain as a number in the range 0 to 4030, which corresponds directly to sensor register value. This number does not represent gain in dB nor it is an exact gain multiply. However, the driver offers a function, which transforms the gain numerical value to gain expressed in dB as well as multiply. Some selected values are shown in the table:

Gain number Gain in dB Gain multiply
0 0.00 1.00
1000 2.34 1.32
2000 5.82 1.95
3000 11.46 3.74
4000 32.69 43.11
4030 35.99 63.00

Conversion factors and read noise

Generally, many sensor characteristics depend on the used gain. Also, the used sensors employ two conversion paths. One path offers very low read noise, but cannot utilize full sensor dynamic range. Another conversion path offers maximum pixel capacity, but at the price of higher read noise. The cross point is set to gain 3 (approx. 10dB), where the full well capacity drops from more than 50ke- to ~17ke-. The read noise then drops from ~3.2e- RMS to ~1.5e-RMS.

Gain number Gain in dB Gain multiply Conversion factor Read noise RMS Full well capacity
0 0.0 dB 1 0.76 e-/ADU 3.52 e- 50,000 e-
2749 9.7 dB 3 0.25 e-/ADU 3.13 e- 16,500 e-
2750 9.7 dB 3 0.25 e-/ADU 1.51 e- 16,500 e-
4030 36.0 dB 63 0.17 e-/ADU 1.44 e- 11,200 e-

Sensor dynamic range, defined as full well capacity divided by read noise, is greatest when using gain 0, despite somewhat higher read noise:

  • At gain=0, dynamic range is 50,000/3.52=14,205

  • At gain=2750, dynamic range is 16,500/1.51=10,927

Also, it is worth noting that in reality the noise floor is only rarely defined by read noise. Unless the camera is used with very narrow narrow-band filter (with FWHM only a few nm) and under very dark sky, the dominant source of noise is the sky glow. When the noise generated by sky glow exceeds approximately 4e-RMS, extremely low read noise associated with gain set to 2750 or more is not utilized and dynamic range is unnecessarily limited by the lowered full well capacity.

So, which gain settings is the best? This depends on the particular task.

  • Gain set to 2750 can be utilized if imaging through narrow-band filter with appropriately short exposures, so the background noise does not exceed the read noise. This is typical for aesthetic astro-photography, where the lowered full well capacity does not negatively influence the result quality.

    But even without narrow-band filters, the extremely low read noise allows stacking of many short exposures without unacceptable increase of the stacked image background noise, caused by accumulation of high read noise of individual exposures.

  • Gain set to 0 offers maximum full well capacity and the greatest sensor dynamic range, which is appreciated mainly in research applications. Pass-bands of filters used for photometry are relatively wide and dominant source of noise is the sky glow.

    But also for RGB images, used for aesthetic astro-photography, higher dynamic range allows longer exposures while the bright portions of the nebulae and galaxies still remain under saturation limit and thus can be properly processed.


Please note the values stated above are not published by sensor manufacturer, but determined from acquired images using the SIPS 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.


The camera driver and users applications offer wide variety of binning modes up to 4נ4 pixels as well as all combinations of asymmetrical binning modes 1נ2, 1נ3, 1נ4, 2נ4 etc. To allow such flexibility, binning is performed only in the camera driver (software binning) and does not rely on the limited capabilities of the hardware binning.

The negative side of software binning is the same download time like in the case of full-resolution 1נ1 mode. For typical astronomy usage, the small fraction of second download time is irrelevant, but for applications sensitive to download time, the hardware 2נ2 binning can be useful.

Hardware binning

The C5 camera implements 2נ2 binning mode in hardware in addition to normal 1נ1 binning. This mode can be turned on and off using the HWBinning parameter in the 'cXusb.ini' configuration file, located in the same directory like the 'cXusb.dll' driver DLL file itself.

HWBinning = true

When the HWBinning parameter is set to true, the in-camera hardware binning is used and software binning is no longer available. This mode brings faster download time, but also introduces several restrictions:

  1. Maximal binning is limited to 2נ2, higher binning modes are not available.

  2. Asymmetrical binning modes (1נ2, 2נ1, ...) are not allowed.


Despite the number of pixels in the 2נ2 binned image is 1/4 of the full resolution image, the download time is not four-times lower.

Adding vs. averaging pixels

The traditional meaning of pixel binning implies adding of binned pixels. This originated in CCD sensors, where pixel charges were literally poured together within the sensor horizontal register and/or the output node.

For CMOS sensors with full 16-bit dynamic resolution, the negative side of binning is limiting of the sensor dynamic range, as for instance only 1/4 of maximum charge in each of the 2נ2 binned pixels leads to saturation of resulting pixel. CCDs eliminated this effect to some extend by increasing of the charge capacity of the output node and also by decreasing of the conversion factor in binned modes. But such possibilities are not available in CMOS detectors.


CMOS sensors with less than 16-bit precision often just add binned pixels to fulfil the available resolution of 16-bit pixels. For instance, camera with 12-bit dynamic range can sum up to 4נ4 pixels and still the resulting binned pixels will not overflow the 16-bit range.

In theory, the resulting S/N ratio of binned pixel remains the same regardless if we add or average them. Let's take for example 2נ2 binning:

  • If we add 4 pixels, signal increases 4-times and noise increases 2-times three additive operations increase noise by √((√2)^2(√2)^2 ). Resulting S/N increases 2-times, but only until the sum of all pixels is lower than the pixel capacity.

  • If we average 4 pixels, signal remains the same but the noise is lowered to 1/2 as noise is averaged √((√2)^2(√2)^2 )/4. Resulting S/N also increases 2-times, but only until the noise decreases to lowest possible 1-bit of dynamic range.

As the C5 camera read noise in the maximum dynamic range (gain 0) is around 3.5 ADU, halving it in 2נ2 binning mode still keeps the read noise above the lower 1-bit limit and at the same time binned pixel will not saturate. For higher binning modes, the noise approaches lower limit, but averaging pixels still protects from pixel saturation, which is more important than possible S/N limitation caused by underflow of read noise.

If we take into account that the image background noise is only rarely defined by the read noise of the sensor, as the noise caused by background sky glow is typically much higher, for 16-bit camera averaging pixels is definitely the better way to bin pixels compared to just adding them. This is why both software and hardware binning modes in the C5 cameras are by default implemented as averaging of pixels, not summing.

However, both software and hardware binning modes can be switched to sum binned pixels instead of average them by the BinningSum parameter in the 'cXusb.ini' configuration file:

BinningSum = true


Lets note there is one more possibility to bin pixels in the application software. This time binning is not performed in camera hardware nor in the camera driver. Full resolution 1נ1 image is downloaded from the camera and software itself then performs binning. The SIPS software adds pixels instead of averaging them, but at the same time SIPS converts images from 16-bit to 32-bit dynamic range. This means S/N of the binned images always increases, pixels never saturate and read noise newer approaches lower limit. The negative side of this option is two-time bigger images.

Binning in photometry

Saturated pixels within bright stars are no issue for aesthetic astro-photography, but photometry measurement is invalid if any pixel within the measured object reaches maximum value, because it is not possible to determine the amount of lost flux. Software performing photometry (e.g. the SIPS Photometry tool) should detect saturation value and invalidate entire photometric point not to introduce errors.

But binning efficiently obliterates the fact that any of the binned pixels saturated (with the exception of all binned pixels reached saturation value). So, using of binning modes for research applications (photometry and astrometry) can lead to errors caused by lost flux in saturated pixels, which cannot be detected by the processing software due to binning.

This is why the behavior of both software and hardware binning modes is user-configurable through the BinningSaturate parameter in the 'cXusb.ini' configuration file:

BinningSaturate = true

If the BinningSaturate parameter is set to true, resulting binned pixel is set to saturation value if any of the source pixels is saturated. For aesthetic astro-photography, keeping this parameter false could result into slightly better representation of bright star images, but for research applications, this parameter should always be set to true.

Exposure control

The shortest theoretical exposure time of the C5 cameras depends on the used sensor type:

  • C5A-100M shortest exposure is 164μs

  • C5A-150M shortest exposure is 183μs

However, such short exposures have no practical application, especially in astronomy. The camera firmware rounds exposure time to a multiply of 100μs intervals, so in reality the shortest exposure time of both camera models is 200μs.


Note the individual lines are not exposed at the same time, regardless of how short the exposure is, because of the rolling-shutter nature of the used sensors. The difference between the first and last line exposure start time is 0.49s for the C5A-150M and 0.36s for the C5A-100M camera.

There is no theoretical limit on maximal exposure length, but in reality, the longest exposures are limited by saturation of the sensor either by incoming light or by dark current (see the following chapter about sensor cooling).


Please note the short exposure timing is properly handled in the camera firmware version 6.5 and later.

Mechanical shutter

C5 cameras are equipped with mechanical shutter, which is very important feature allowing unattended observations (fully robotic or just remote setups). Without mechanical shutter, it is not possible to automatically acquire dark frames, necessary for proper image calibration etc.

Mechanical shutter in the C5 cameras is designed to be as reliable as possible, number of open/close cycles is virtually unlimited, because there are no surfaces rubbing against each other. The price for high reliability is slow shutter motion. Luckily, mechanical shuttering is not necessary for exposure control, only for taking dark frames and possibly bias frames all used CMOS sensors are equipped with electronic shuttering.

Camera firmware optimizes the shutter operation to avoid unnecessary movements. If a series of light images is taken immediately one after another, the shutter remains open not to introduce quite significant delay of the close/open cycle between each pair of subsequent light images. In the case next image has to be dark or bias frame, shutter closes prior to dark frame exposure and vice versa shutter remains closed if a series of dark frames is acquired and opens only prior to next light frame. If no exposure is taken for approx. 10seconds while the shutter is open (this means after a light image exposure), camera firmware closes the shutter to cover the sensor from incoming light.

GPS exposure timing

C5 cameras can be equipped with GPS receiver module (see the Optional Accessories chapter). The primary purpose of the GPS receiver is to provide precise times of exposures taken with the camera, which is required by applications dealing with astrometry of fast-moving objects (fast moving asteroids, satellites, and space debris on Earth orbit, ).

The GPS module needs to locate at last 5 satellites to provide exposure timing information. Geographic data are available if only 3 satellites are visible, but especially the mean sea level precision suffers if less than 4 satellites are used.

The camera SDK provides functions, allowing users to access precision exposure times as well as geographics location. The SIPS software package main imaging camera control tool window contains the “GPS” tab, which shows the state of the GPS fix.

Determination of exact exposure time is quite complicated because of the rolling-shutter nature of the used sensors. Camera driver does all the calculations and returns the time of the start of exposure of the first line of the image. Still, users interested in precise exposure timing need to include several corrections into their calculations:

  • Individual image lines are exposed sequentially. The time difference between start of exposure of two subsequent lines is fixed for every sensor type:

    • C5A-100M line exposure takes 40.944μs

    • C5A-150M line exposure takes 45.833μs

  • If the image is binned, single line of resulting image contains signal from multiple added (or averaged) lines, each with different exposure time start. The exposure start of individual lines of the binned images differs by the single line time difference, multiplied by the vertical binning factor.

  • If only a sub-frame is read, it must be considered that the sensor imposes some restrictions to the sub-frame coordinates. If the required sub-frame coordinates violate the sensor-imposed rules, camera driver enlarges the sub-frame region to fully contain desired sub-frame and then crops it by software. The provided start exposure time then concerns the first line actually read from the camera, not the first line of the resulting (software cropped) image.

    For instance, the y-coordinate of the sub-frame must not be lower than 25 lines. If a sub-frame with lower y-coordinate is asked by the user, whole frame is read and cropped by software. Note the camera SDK offers function AdjustSubFrame, which returns the smallest sub-frame, fully containing the requested sub-frame, but also fulfilling the sensor-imposed sub-frame coordinate restriction. If adjusted sub-frame is read, no software cropping occurs and image exposure time concerns the first line of the image. The SIPS software offers the “Adjust Frame” button, which adjusts defined sub-frame.


Please note the precise exposure timing is properly handled in the camera firmware version 7.10 and later.

Always use the latest camera drivers (ASCOM or Camera SDK DLLs in Windows, INDI or libraries in Linux) available on the web. Also, always update the firmware in the Moravian Camera Ethernet Adapter if the camera is connected over Ethernet.

Cooling and power supply

Regulated thermoelectric cooling is capable to cool the CMOS sensor up to 45C below ambient temperature. The Peltier hot side is cooled by fans. The sensor temperature is regulated with 0.1C precision. High temperature drop and precision regulation ensure very low dark current for long exposures and allow proper image calibration.

The C5 camera air intake is located on the top side of the camera head; hot air output vents are on the camera back side.

The C5 camera air intake is located on the top side of the camera head; hot air output vents are on the camera back side.

The cooling performance depends on the environmental conditions and also on the power supply. If the power supply voltage drops below 12V, the maximum temperature drop is lower.

Sensor cooling Thermoelectric (Peltier modules)
Cooling ΔT 45C below ambient regulated
48C below ambient maximum
Regulation precision 0.1C
Hot side cooling Forced air flow

Chip cooling specifications

C5A-100M cameras reaching -45C below ambient sensor temperature

C5A-100M cameras reaching -45C below ambient sensor temperature


Maximum temperature difference between the 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 keeping 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.

Overheating protection

The C5 cameras are equipped with an overheating protection in their firmware. This protection is designed to prevent the Peltier hot side to reach temperatures above ~50C sensor cooling is turned off to stop heat generation by the hot side of the Peltier TEC modules.


Please note the overheating protection uses immediate temperature measurement, while the value of camera temperature, presented to the user, shows temperature averaged over a longer period. So, overheating protection may be engaged even before the displayed camera temperature reaches 50C.

Turning the overheating protection on results in a drop in cooling power, a decrease in the internal temperature of the camera and an increase in the temperature of the sensor. However, when the camera cools its internals down below the limit, cooling is turned on again. If the environment temperature is still high, camera internal temperature rises above the limit an overheating protection becomes active again.


Please note this behavior may be mistaken for camera malfunction, but it is only necessary to operate the camera in the colder environment or to lower the desired sensor delta T to lower the amount of heat generated by the Peltier modules.

The overheating protection is virtually never activated during real observing sessions, even if the environment temperature at night reaches 25C or more, because camera internal temperature does not reach the limit. But if the camera is operated indoors in hot climate, overheating protection may be activated.

Power supply

The 12VDC power supply enables camera operation from arbitrary power source including batteries, wall adapters etc. Universal 100-240V AC/50-60Hz, 120W “brick” adapter is supplied with the camera. Although the camera power consumption does not exceed 60W, the 120W power supply ensures noise-free operation.


The power connector on the C5 camera head differs from the 5.5/2.5mm power plug, used on other Cx camera lines, because of the higher power draw of the C5 cameras. New power connector also ensures safer connection.

Camera power supply 12VDC
Camera power consumption <9W without cooling
60W maximum cooling
Power connector 4-pin plug
Adapter input voltage 100-240 V AC/50-60 Hz
Adapter output voltage 12VDC/10A
Adapter maximum power 120W

Power supply specification


Power consumption is measured on the 12VDC side. Power consumption on the AC side of the supplied AC/DC power brick is higher.

The camera contains its own power supplies inside, so it can be powered by unregulated 12 V DC power source the input voltage can be anywhere between 10 and 14V. However, some parameters (like cooling efficiency) can degrade if the supply drops below 12 V.

C5 camera measures its input voltage and provides it to the control software. Input voltage is displayed in the Cooling tab of the Imaging Camera control tool in the SIPS program. This feature is important especially if you power the camera from batteries.

12 V DC/10 A power supply adapter for C5 camera

12 V DC/10 A power supply adapter for C5 camera

Mechanical Specifications

Compact and robust camera head measures only 154נ154נ76mm (approx. 6נ6נ3inches).

The head is CNC-machined from high-quality aluminum and black anodized. The head itself contains USB-B (device) connector and 4-pin 12VDC power plug, no other parts, except a “brick” power supply, are necessary. Another connector on the camera head allows control of optional external filter wheel. Integrated mechanical shutter allows automatic dark frame exposures, which are necessary for unattended, robotic setups.

Internal mechanical shutter Yes, blade shutter
Camera head dimensions 154mmנ154mmנ76mm
Camera head weight 1.9kg (without filter wheel)
2.8kg (with the “XL” external filter wheel)

Mechanical specification

Camera head front view

C5 camera head interface for filter wheel or tiltable adapter base

C5 camera head interface for filter wheel or tiltable adapter base

Filter wheels or tiltable adapter base are attached to the camera head using six M3 screws around the 70mm diameter ring.

Camera with M85נ1 threaded adapter

C5 camera head with M85נ1 adapter front view

C5 camera head with M85נ1 adapter front view

C5 camera head with M85נ1 adapter side view with back focal distance

C5 camera head with M85נ1 adapter side view with back focal distance

C5 camera with External Filter wheel with M85נ1 adapter Back Focal Distance

C5 camera with External Filter wheel with M85נ1 adapter Back Focal Distance

The stated back focal distances (BFD) include corrections for all optical elements in the light path (cold chamber optical window, sensor cover glass, ...), fixed in the camera body. So, stated values are not mechanical, but optical back focal distances. However, no corrections for filters are included, as the thicknesses of various filters are very different.


Note the M85נ1 adapter is also equipped with eight M3 threaded holes arranged around the 91mm diameter circle. These threaded holes provide alternative mean of camera attachment to the optical system.

Camera with M68נ1 threaded adapter

C5 camera head with M68נ1 adapter front view

C5 camera head with M68נ1 adapter front view

C5 camera head with M68נ1 adapter side view with back focal distance

C5 camera head with M68נ1 adapter side view with back focal distance

C5 camera with External Filter wheel with M68נ1 adapter Back Focal Distance

C5 camera with External Filter wheel with M68נ1 adapter Back Focal Distance

Camera with C5-OAG with M85נ1 thread

C5-OAG is designed to be used with the XL-sized External filter wheels only.

C5 camera with External Filter wheel with C5-OAG

C5 camera with External Filter wheel with C5-OAG

C5 camera with External Filter wheel with C5-OAG Back Focal Distance

C5 camera with External Filter wheel with C5-OAG Back Focal Distance

Filter distance to sensor

It is necessary to know the distance of the filter entrance aperture from the sensor to calculate possible vignetting (partial shielding of the sensor edge parts from the incoming lights). In the case of C5 cameras, this is technically not an “aperture”, as the filters are squares. So, instead of comparing filter aperture diameter to sensor diagonal, filter hole linear dimension must be compared longer side of the sensor.

Distance of the filter wheel entrance pupil from the sensor

Distance of the filter wheel entrance pupil from the sensor

The 7-positions filter wheel for 50נ50 mm filters entrance dimension is 48mm, 5-positions filter wheel for 65נ65 mm filters entrance dimension is 63mm. The C5A-100M sensor longer side measures 43.86mm, while the C5A-150M sensor longer side measures 53.42mm.

Optional accessories

Various accessories are offered with C5 cameras to enhance functionality and help camera integration into imaging setups.

External filter wheels

The C5 camera contains electronics and an 8-pin connector on the camera head to control filter wheels. As the mechanical interface of the C5 cameras, intended to attach filter wheels, differs from the interface on the C3 or C4 cameras (see the chapter Camera head front view of the Mechanical Specification section for details), C5 cameras are not compatible with the “M” or “L” external filter wheels intended for C3 or C4 lines. New “XL” size external filter wheel is designed especially for the C5 series.

C5 camera with the “XL” filter wheel attached

The XL filter wheel housing can accommodate two filter wheels:

  • 5-positions filter wheel for 65נ65 mm filters

  • 7-positions filter wheel for 50נ50 mm filters


Note the 50נ50 mm filters are suitable for C5A-100M cameras only, as the filter would partially shade sides of the large sensors of the C5A-150M camera.

Telescope adapters

There are basically only two types of telescope adapters, available for C5 cameras:

  • M85נ1 threaded adapter, intended for both C5A-100M and C5A-150M camera models. This adapter is also equipped with eight M3 threaded holes arranged around the 91mm diameter circle, providing alternative possibility to attach the C5 camera to the optical system.

  • M68נ1 threaded adapter, suitable for C5A-100M camera only due to limited aperture, possibly causing vignetting of the large sensor of C5A-150M camera.

Both adapters have adjustable tilt and both can be mounted either on the adapter base on the camera head or on the External filter wheel front plane.


Note the Back Focal Distances of these adapter are slightly different because of differences in mechanical design. BFD also varies for adapter mounted directly on the camera head or on the filter wheel. Refer to the Mechanical Specification chapter for exact BFD values, please.

Off-Axis Guider adapter

C5 camera can be optionally equipped with Off-Axis Guider Adapter. This adapter contains flat mirror, tilted by 45 to the optical axis. This mirror reflects part of the incoming light into guider camera port. The mirror is located far enough from the optical axis not to block light coming to the main camera sensor, so the optics must be capable to create large enough field of view to illuminate the tilted mirror.

Position of the OAG reflection mirror relative to optical axis

Position of the OAG reflection mirror relative to optical axis

The C5-OAG offers the M85נ1 thread on the telescope side. The back focal distance is 61.5mm.

The C5-OAG is designed for cameras using the XL-size external filter wheel. The guiding camera will not be able to reach focus is the OAG is mounted directly to the camera head.

C5-OAG adapter (left), OAG on then C5 camera with External filter wheel (right)

OAG guider port is compatible with C0 and C1 cameras. It is necessary to replace the CS/1.25 adapter with short, 10mm variant. Because C1 cameras follow CS-mount standard, (BFD 12.5mm), any camera following this standard with 10mm long 1.25 adapter should work properly with the C5-OAG.

GPS receiver module

The C5 cameras can be equipped with an optional GPS receiver module, which allows very precise timing of the exposure times. Geographic location data are also available to the control software through specific commands.

The used GPS receiver is compatible with GPS, GLONASS, Galileo and BeiDou satellites.

The GPS receiver can be attached to the back side of the camera head. If the GPS module is removed, the GPS port is covered with a flat black cover.

Spare desiccant containers

The C3 cameras are supplied with silicagel container, intended to dry the sensor cold chamber. This container can be unscrewed and desiccant inside can be dried in the oven (see the camera User's Manual).

The whole desiccant container can be baked to dry the silica-gel inside or its content can be poured out after unscrewing the perforated internal cap and baked separately

The whole desiccant container can be baked to dry the silica-gel inside or its content can be poured out after unscrewing the perforated internal cap and baked separately


This is why the container itself does not contain any sealing, which could be damaged by high temperature in the owen. The sealing remains on the sensor cold chamber instead.

New containers have a thin O-ring close to the threaded edge of the container. This O-ring plays no role in sealing the sensor cold chamber itself. It is intended only to hold possible dust particles from entering the front half of the camera head with the sensor chamber optical window, shutter and possibly internal filter wheel. While the O-ring material should sustain the high temperature during silica-gel baking, it is possible to remove it and put it back again prior to threading the contained back to the camera.

Container shipped with the camera by default does not exceed the camera head outline. It is equipped with a slot for tool (or for just a coin), allowing releasing and also tightening of the container. Containers intended for enhanced cooling cameras are prolonged as the camera thickness is greater in the case of this variant.

It is possible to order spare container, which makes desiccant replacement easier and faster. It is possible to dry the spare container with silicagel and then only to replace it on the camera. Spare container is supplied including the air-tight cap.

Spare container can be supplied also in a variant that allows manipulation without tools. But this container is longer and exceeds camera outline. If the space behind the camera is not critical, this container can make desiccant exchange even easier.

Optional cap, standard and tool-less container variants

Optional cap, standard and tool-less container variants

Moravian Camera Ethernet Adapter

The Moravian Camera Ethernet Adapter allows connection of up to 4 Cx cameras of any type on the one side and 1Gbps Ethernet on the other side. This adapter allows access to connected Cx cameras using routable TCP/IP protocol over practically unlimited distance.

The Moravian Camera Ethernet Adapter device (left) and adapter with two connected cameras (right)

Moravian Camera Ethernet Adapter devices are described in detail here.

Software Support

Powerful SIPS (Scientific Image Processing System) software, supplied with the camera, allows complete camera control (exposures, cooling, filter selection etc.). Also automatic sequences of images with different filters, different binning etc. are supported. With full ASCOM standard support, SIPS can be also used to control other observatory equipment. Specifically the telescope mounts, but also other devices (focusers, dome or roof controllers, GPS receivers etc.).

SIPS also supports automatic guiding, including image dithering. Both “autoguider” port hardware interface (6-wire cable) and mount “Pulse-Guide API” guiding methods are supported. For hi-quality mounts, capable to track without the necessity to guide at last during one exposure, inter-image guiding using the main camera only is available.

SIPS controlling whole observatory (shown in optional dark skin)

SIPS controlling whole observatory (shown in optional dark skin)

But SIPS is capable to do much more than just camera and observatory control. Many tools for image calibration, 16 and 32bit FITS file handling, image set processing (e.g. median combine), image transformation, image export etc. are available.

SIPS handles FITS files, supports image calibration and processing

As the first “S” in the abbreviation SIPS means Scientific, the software supports astrometric image reduction as well as photometric processing of image series.

SIPS focuses to advanced astrometric and photometric image reduction, but also provides some very basic astro-photography processing

SIPS software package is freely available for download from this www site. All functions are thoroughly described in the SIPS User's Manual, installed with every copy of the software.

Drivers for ASCOM standard as well as native drivers for third-party software are also available (e.g. TheSkyX, MaxIm DL, AstroArt, etc.). Visit the download page of this web site for current list of available drivers, please.

Also INDI drivers for 32bit and 64bit Linux running on x86 and ARM are available. Also drivers for TheSkyX package running on macOS are supplied with the camera.


Make sure to always use the latest versions of available software and drivers. Minimal versions or the respective software packages, supporting the C5 cameras, are:

  • SIPS version 3.33

  • Moravian Camera Ethernet Adapter firmware version 53

  • ASCOM drivers version 5.13

  • INDI drivers in Linux version 1.9-2

  • Linux libraries version 0.7.1

  • macOS libraries version 0.6.1

  • TheSkyX drivers version 3.5

  • AstroArt drivers version 4.3

Automatic guiding

SIPS software package allows automatic guiding of the astronomical telescope mounts using separate guiding camera. Proper and reliable automatic guiding utilizing the computational power of Personal Computer (e.g. calculation of star centroid allows guiding with sub-pixel precision) is not simple task. Guiding complexity corresponds to number of parameters, which must be entered (or automatically measured).

The SIPS Guider tool window

The SIPS “Guider” tool window

The “Guiding” tool allows switching of autoguiding on and off, starting of the automatic calibration procedure and recalculation of autoguiding parameters when the telescope changes declination without the necessity of new calibration. Also swapping of the German Equatorial mount no longer requires new autoguider calibration. There is also a graph showing time history of guide star offsets from reference position in both axes. The length of graph history as well as the graph range can be freely defined, so the graph can be adjusted according to particular mount errors and periodic error period length. Complete log of calibration procedure, detected offsets, correction pulses etc. is also shown in this tool. The log can by anytime saved to log file.

An alternative to classic autoguiding is the inter-image guiding, designed for modern mounts, which are precise enough to keep tracking with sub-pixel precision through the single exposure, and irregularities only appear on the multiple-exposure time-span. Inter-image guiding then performs slight mount position fixes between individual exposures of the main camera, which eliminates “traveling” of the observed objects through the detector area during observing session. This guiding method uses main imaging camera, it does not use another guiding camera and naturally does not need neither OAG nor separate guiding telescope to feed the light into it.

Inter-image guiding controls in the Guiding tab of the Imager Camera tool window

Inter-image guiding controls in the Guiding tab of the Imager Camera tool window

Shipping and Packaging

C5 cameras are supplied in the foam-filled, hard carrying case containing:

  • Camera body with a user-chosen telescope adapter.

  • A100-240VAC input, 12VDC output “brick” adapter with 1m long power cable.

  • 2m long USB3.0 A-B cable for connecting camera to host PC.

  • USB Flash Drive with camera drivers, SIPS software package with electronic documentation and PDF version of User'sManual.

  • Aprinted copy of camera User'sManual

Image Gallery

Example images captured with C5 cameras.

Object M7 star cluster
Author Patrick Winkler
Camera C5A-150M
Filters L, R, G, B
Exposure 66, 40, 40, 40min
Telescope ASA H400, 400mm f/2.4

Object M42 “Orion” nebula
Author Patrick Winkler
Camera C5A-150M
Filters R, G, B
Exposure 45min (15min per color)
Telescope ASA H400, 400mm f/2.4

Object NGC3372 “Carina” nebula
Author Patrick Winkler
Camera C5A-150M
Filters R, G, B
Exposure 45min (15min per color)
Telescope ASA H400, 400mm f/2.4

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