Moravian Instruments C2-5000A Colour CMOS Astrophoto Camera with SONY IMX250 Sensor for 12-bit LONG EXPOSURE
Moravian Instruments C2-5000A Colour CMOS Astrophoto Camera with SONY IMX250 Sensor with 12-bit Digitisation ONLY for LONG EXPOSURE
Sony IMX CMOS 2464 x 2056 pixels, 8.50 x 7.09 mm sensor size, Built-in Tilting Platform, USB 3.0 interface
Ideal for imaging deep-sky objects as its main field of usage, but can be used for other tasks as well (i.e. planetary, lunar, solar etc.).
The ACTIVELY COOLED C2 series CMOS cameras are equipped with SONY IMX GLOBAL SHUTTER CMOS detectors with 3.45 x 3.45 μm square pixels. All used sensors utilize global electronic shutter. This means every pixel within the image is exposed at the same time, as opposed to rolling shutter sensors, 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.
One of the benefits of the C2 series is the MECHANICAL SHUTTER function, so that you don't have to close the telescope to be able to take darks. This is especially handy and important if you are running a remote controlled telescope.
The 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 a vast range of telescope adapters, off-axis guider adapters, internal or external filter wheels, Camera Ethernet adapters, guiding cameras etc.
With proper image calibration, C2 cameras provide surprisingly good results in deep-sky imaging. The used CMOS sensors response to light is linear up to very close to saturation point, so, C2 cameras can be used for scientific applications like variable star research, too.
C2 cameras with Sony IMX sensors supporting 12-bit digitization only:
As the 12-bit read mode is always used for long-exposure applications (astronomical photography, scientific research) and all other parameters being the same (sensor size, resolution, pixels size, noise, …), lower price of these cameras may be then very attractive.
Developed and manufactured in Europe to highest standards.
Sensor: Sony IMX250 Monochrome CMOS
Colour filter: Bayer mask
Resolution: 2464 x 2056 pixels
Pixel Size: 3.45 x 3.45 µm
Imaging Area: 8.50 x 7.09 mm
Diagonal size: 11.07mm
Interface: USB 3.0
Download time: appr. 0.05s with USB3.0 host
Cooling: active cooling, max. ~42 °C below ambient
Internal Mechanical Shutter: yes, blade shutter
Internal Filter Wheel: Optional
External Filter Wheel: Optional
Compatibility with OAG & Standard Adapters: yes
Autoguider Port: No
Available on back order. Usual delivery time: appr. 2 - 3 weeks
C2 Camera Overview
C2 camera head is designed to be easily used with a set of accessories to fulfill 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.
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 D27 mm (or 1”) filters.
C2 camera with Internal filter wheel (left) and with External filter wheel attached (right)
There are two sizes of the External filter wheels, each capable to accept multiple sizes of filters, available for the C2 cameras:
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.
Small “S” size wheel for 7 unmounted D50 mm or 2" filter or filters in 2” threaded cells.
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.
Components of C2 Camera system include:
C2 camera head with Internal Filter Wheel (5 or 6 positions)
C2 camera head capable to control External Filter Wheel
External Filter Wheel “XS” size (7 or 8 positions)
External Filter Wheel “S” size (10 or 12 positions)
C1 guider camera
Remark: 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 cameras can share the Moravian Camera Ethernet Adapter with up to 3 other Cx cameras to be accessed over TCP/IP network.
Off-Axis Guider with M48 × 0.75 thread
Off-Axis Guider with M42 × 0.75 thread (T2)
Thick adapter base, compensating EFW thickness to achieve proper back focal distance for cameras without filter wheel
1.75” dovetail rail for G2 camera head
Gx Camera Ethernet Adapter (x86 CPU)
Gx Camera Ethernet Adapter (ARM CPU)
Remark: Moravian 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.
5-positions internal filter wheel for 1.25”/D31 mm filters
6-positions internal filter wheel for 1”/D27 mm filters
8-positions external filter wheel “XS” for 1.25”/D31 mm filters
7-positions external filter wheel “XS” for D36 mm filters
12-positions external filter wheel “S” for 1.25”/D31 mm filters
10-positions external filter wheel “S” for D36 mm filters
7-positions external filter wheel “S” for 2”/D50 mm filters
M42 × 0.75 (T-thread) or M48 × 0.75 threaded adapters, 55 mm BFD
Remark: Other standard adapters are available, for instance threaded 2" barrel adapter etc.
Canon EOS bayonet lens adapter
Nikon bayonet lens adapter
C2 camera models are equipped with Sony IMX global shutter CMOS detectors with 3.45 × 3.45 μm square pixels. Individual models differ in resolution only.
All used sensors utilize global electronic shutter. This means every pixel within the image is exposed in the same time, as opposed to rolling shutter sensors, 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.
Two lines of C2 cameras are available depending on the available dynamic range (bit-depth of the digitized pixels):
C2 cameras with Sony IMX sensors 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.
C2 cameras with Sony IMX sensors 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 time 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 these cameras may be then very attractive.
C2 camera models with 8- and 12-bit digitization:
|Model||CMOS sensor||Resolution||Pixel size||Image area|
|C2-3000||IMX252||2064 × 1544 pixels||3.45 × 3.45 μm||7.12 × 5.33 mm|
|C2-5000||IMX250||2464 × 2056 pixels||3.45 × 3.45 μm||8.50 × 7.09 mm|
|C2-12000||IMX253||4112 × 3008 pixels||3.45 × 3.45 μm||14.19 × 10.38 mm|
C2 camera models with 12-bit digitization only:
|Model||CMOS sensor||Resolution||Pixel size||Image area|
|C2-3000A||IMX265||2064 × 1544 pixels||3.45 × 3.45 μm||7.12 × 5.33 mm|
|C2-5000A||IMX264||2464 × 2056 pixels||3.45 × 3.45 μm||8.50 × 7.09 mm|
|C2-12000A||IMX304||4112 × 3008 pixels||3.45 × 3.45 μm||14.19 × 10.38 mm|
Remark: Cameras limited to 12-bit read mode are marked with letter A, following the model number. For instance, if C2-12000 marks camera with both 8- and 12-bit read modes, C2-12000A denotes camera model with only 12-bit read mode. All other parameters (sensor size, pixel resolution) are equal.
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).
The sensors used in C2 cameras shows 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.
C2-3000 (IMX252) response to light
As already noted, there are two lines of C2 camera series, differing in the used sensor. The first series 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
Remark: 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 C2 cameras offers only single read mode:
12-bit fast mode with ~132 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.
Remark: 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.
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.
Sensors used in C2 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.
Remark: Note the C2 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.
Generally, many sensor characteristics depend on the used gain. Hence, we provide two lists of parameters for both minimal and maximal gain.
Camera/sensor parameters for minimal gain 0 dB (1×):
|Full well capacity||9000 e-|
|Conversion factor||2.2 e-/ADU|
|Read noise (12 bit)||1.8 e- RMS|
Camera/sensor parameters for maximal gain 24 dB (15.9×):
|Full well capacity||820 e-|
|Conversion factor||0.2 e-/ADU|
|Read noise (12 bit)||1.2 e- RMS|
Remark: Please note the values stated above are not published by sensor manufacturer, but determined from acquired images. Results may slightly vary depending on particular sensor and other factors (e.g. sensor temperature), but also on the software used to determine these values.
C2 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).
Regulated thermoelectric cooling is capable to cool the CMOS sensor up to 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.
The camera head contains two temperature sensors — the first sensor measures directly the temperature of the CMOS sensor package. The second one measures the temperature inside the camera shell.
Back side of the C2 camera head contains vents for a fan, cooling Peltier hot side
The cooling performance strongly depends on the amount of heat generated by a sensor used in the camera:
In general, lower resolution sensors generate less heat and thus reaches lower temperature.
The “A” version cameras, using sensors with limited read modes, also generate less heat and reaches lower temperature.
The cooling performance also 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 Δ T||~42 °C below ambient|
|Regulated cooling Δ T||40 °C below ambient (90% cooling)|
|Regulation precision||0.1 °C|
|Hot side cooling||Forced air cooling (fan)|
Sensor cooling specifications
Remark: The stated values are valid for C2-12000A camera. As noted above, maximum ΔT of lower resolution sensors (C2-5000A, C2-3000A) is higher, but ΔT of corresponding non-A camera versions is lower.
Maximum temperature difference between CMOS 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.
C2-12000A camera reaching -40°C sensor temperature below ambient
The 12 V DC power supply enables camera operation from arbitrary power source including 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 40 W, the 60 W power supply ensures noise-free operation.
|Camera power supply||12 V DC|
|Camera power consumption||15 W without cooling|
|40 W maximum cooling|
|Power plug||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 supply specification
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 other than the supplied power source is used.
Remark: Power consumption is measured on the input (AC side) of the supplied power adapter. Camera consumes less energy from 12 V power supply than stated here.
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 14 V. However, some parameters (like cooling efficiency) can degrade if the supply drops below 12 V.
C2 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/5 A power supply adapter for C2 camera
Compact and robust camera head measures only 114 × 114 × 65 mm (approx. 4.5 × 4.5 × 2.6 inches). The head is CNC-machined from high-quality aluminum and black anodized. The head itself contains USB-B (device) connector and 12 V DC power plug. Integrated mechanical shutter allows streak-free image readout, as well as automatic dark frame exposures, which are necessary for unattended, robotic setups.
Bottom side of the camera without filter wheel (left) and with internal filter wheel (right)
Camera head with integrated Internal filter wheel is 77.5 mm thick. Filter wheel offers 5 positions for standard 1.25-inch threaded filter cells. A variant of filter wheel with 6 positions for unmounted D26 mm filters is also available.
|Internal mechanical shutter||Yes, blade shutter|
|Shortest exposure time||125 μs (electronic shutter)|
|Longest exposure time||Limited by chip saturation only|
|Internal filter wheel||5 positions for 1.25" threaded filter cells or for D31 mm unmounted filters|
|6 positions for 1" or D26.5 mm unmounted filters|
|Head dimensions||114 mm × 114 mm × 77.5 mm (with internal filter wheel)|
|114 mm × 114 mm × 65 mm (without filter wheel)|
|Back focal distance||33.5 mm (base of adjustable adapters)|
|Camera head weight||1.00 kg (without filter wheel)|
|1.15 kg (with internal filter wheel)|
|1.70 kg (with “XS” external filter wheel)|
|1.95 kg (with “S” external filter wheel)|
Remark: Back focus distance is measured from the sensor to the base on which adjustable adapters are mounted. Various adapters then provide back focal distance specific for the particular adapter type (e.g. M48 threaded adapter back focal distance is 55 mm).
Stated back focal distance already calculates with glass permanently placed in the optical path (e.g. optical window covering the sensor cold chamber).
When the adjustable adapter base, intended for camera with Internal filter wheel, is mounted on camera without filter wheel, the resulting back focal distance is only 21 mm.
C2 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 acquire dark frames, necessary for proper image calibration.
Mechanical shutter in the C2 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 approximately 1 second while the shutter is open (this means after a light image exposure), camera firmware closes the shutter to cover the sensor from incoming light.
C2 camera head front view dimensions
C2 camera head with Internal Filter Wheel side view dimensions
C2 camera head with External filter wheel front view dimensions
C2 camera head with External filter wheel side view dimen