QHY268M Pro
QHY268M Pro
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The QHY268M Pro I is a scientific CMOS camera meticulously designed for scientific applications, boasting advanced features and exceptional performance. Let’s delve into its specifications:
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Sensor and Resolution:
- The QHY268M Pro I houses a Sony IMX571 APS-C format CMOS sensor with 26 megapixels.
- This sensor is back-illuminated, enhancing its sensitivity to light.
- With a native 16-bit ADC, it ensures high-resolution sampling across its full well capacity.
- The quantum efficiency (QE) reaches an impressive 91%, and the readout noise is as low as 1.1e.
- Despite its compact pixel size of 3.76 μm, it boasts a substantial full-well capacity of up to 75,000 electrons1.
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Low Thermal Noise and Zero Amplifier Glow:
- The QHY268M Pro I exhibits an exceptionally low thermal noise of 0.0005e/pixel/sec at a cooling temperature of -20°C.
- Its amplifier glow performance is virtually nonexistent, ensuring clean and accurate images even during long exposures1.
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High Frame Rate:
- At 16-bit full resolution, this camera achieves a maximum frame rate of 6.8 FPS.
- Whether you’re capturing planetary details or deep-sky objects, the QHY268M Pro I delivers smooth and precise results1.
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Additional Features:
- True RAW Data: Unlike some cameras that apply noise reduction or hot pixel removal to their RAW output, the QHY268M Pro I provides true RAW image output. This means the image comprises only the original signal, allowing maximum flexibility for post-processing and scientific applications.
- Optical Fiber Interface: The camera supports both USB 3.0 and 2x10 Gbps optical fiber interfaces.
- Memory Buffer: It features a 2 GB DDR3 memory buffer for efficient data transfer.
- GPIO Port: The 6-pin GPIO port allows complex trigger-in and trigger-out signals.
- GPS Timestamp: You can connect the QHY268M Pro I with the QHY GPS-BOX to obtain high-precision GPS timestamps for your images.
- Monochrome Model: Currently, the standard model available is the monochrome QHY268M Pro I. If you require a color version (QHY268C Pro), customization options are available1.
In summary, the QHY268M Pro I combines cutting-edge technology, low noise, and impressive sensitivity, making it an excellent choice for scientific imaging and astrophotography applications. You can find more information about this camera on the QHYCCD website.
Accessories:
PCIE Kit
PCIE Card
Fiber Module (1x)
Fiber Optic 20m（1x）
Level Convertor Board Kit
Large Desiccant Tube
QHY268M Pro I has SONY IMX571 APS-C format CMOS sensor inside. 26mega pixels, Back-illuminated, native 16BIT ADC. QE is up to 91% and readout noise is as low as 1.1e Even with a 3.76um pixel size, it has a big full-well up to 75ke. It has extremely low thermal noise 0.0005e/pixel/sec @ -20C, ZERO amplifier-glow performance, It has a maximum frame rate of 6.8FPS@16bit full resolution.
*PCIE Card Kit is NOT included in QHY268Pro product.
A Pro grade scientific grade camera has the following interfaces or functions.
USB3.0 is a very popular interface and very easy to use. USB3.0 can not support a transfer distance of more than 3meter. If you want to get a long-distance under USB3.0, QHYCCD supplies the optional 5meter and 10meter USB3.0 extender cable with a built-in amplifier.
The built-in 2*10Gbps fiber socket can work with the QHYCCD PCIE2.0x8 data grabber card. The fiber interface is for the requirement of the professional obs. It will give the following advantages than the USB3.0 interface. Then what is the benefit of the Fiber Interface?
- Higher data rate. One 10Gigabit Fiber can transfer maximum 10Gbps data. The actual data rate can get about 800MBytes/s. While the USB3.0 is 5Gbps and the actual data rate is about 350MByte/sec. Use the two 10Gigabit fiber can get about 1.6GBytes/s speed. The IMX455 sensor has the high-speed mode like the 10FPS 14bit full resolution mode and 30FPS 8K VIDEO mode. The data rate of these modes is much more than USB3.0.
- Very long transfer distance. The fiber is hundreds of times longer than USB3.0. USB3.0 can only transfer 3meter to 5meter. For longer distances, it needs the extender cable but can just get 10meter to 15meter. While the Fiber can transfer 300meter directly by default optic module; with the long-distance optic module, it can transfer up to 40km.
- Solid stable and no affected by EMI. One major factor that causes the camera to hang is the EMI issue. The USB3.0 transfer maybe gets effect by the EMI in the transfer patch. Like the static and other high-power device emitted. The EMI will cause the transfer data packet to get a CRC error and cause the image loss. A long USB cable is easier to get this problem. Light can not be affected by the EMI. So with the fiber transfer, it will get everything very stable.
There is a 6pin GPIO socket on the camera backside. It can be configured into different modes, or customized as the user requests to meeting more complex timing by re-programming the FPGA.
Compared with air cooling, liquid cooling has the following important advantages. If any interest, please contact QHYCCD in advance for customization.
No vibration. Air-cooling requires the use of a fan inside the camera that may induce small vibrations. Even the highest quality fan cannot avoid some effect on the FWHM (full width at half maximum) of stellar images on certain telescopes. Long focal length optical systems are more sensitive to this effect. However, water cooling achieves temperature reduction through the slow flow of water. There is no moving mechanical component to cause vibration of the camera, eliminating any negative effect on the image.
Multiple Readout Modes are special for QHY 16-bit Cameras (QHY600/268/461/411). Different readout modes have different driver timing, etc., and result in different performance. See details at “Multiple Readout Modes and Curves” Part.
You may find some types of thermal noise can change with time in some back-illuminated CMOS cameras. This thermal noises has the characteristic of the fixed position of typical thermal noise, but the value is not related to the exposure time. Instead, each frame appears to have its own characteristics. The QHY600/268/461/411 use an innovative suppression technology that can significantly reduce the apparent level of such noise.
UVLO (Under Voltage Locking) is to protect the electronic device from damage caused by abnormally low voltages.
Our daily life experience tells us that the actual operational voltage of an electrical device must not significantly exceed the rated voltage, otherwise it will be damaged. For such precision equipment as cameras, long-term work at too low input voltage can also be detrimental to the working life of the camera, and may even make some devices, such as power manager, burn up due to long-term overload. In the all-in-one driver and SDK after 2021.10.23 stable version, the camera will give a warning when the input voltage of the camera is below 11V.
It is common behavior for a CMOS sensor to contain some horizontal banding. Normally, random horizontal banding can be removed with multiple frame stacking so it does not affect the final image. However, periodic horizontal banding is not removed with stacking so it may appear in the final image. By adjust the USB traffic in Single Frame mode or Live Frame mode, you can adjust the frequency of the CMOS sensor driver and it can optimize the horizontal banding appeared on the image. This optimized is very effective to remove the periodic banding in some conditions.
A typical Periodic Horizontal Noise under certain USB_TRAFFIC values.
After Adjusting the USB Traffic to avoid the periodic horizontal noise.
The camera is designed to use the +12V to reboot the camera without disconnecting and reconnecting the USB interface. This means that you can reboot the camera simply by shutting down the +12V and then powering it back on. This feature is very handy for remote controlling the camera in an observatory. You can use a remotely controlled power supply to reboot the camera. There is no need to consider how to reconnect the USB in the case of remote control.
Multiple Readout Modes are special for QHY 16-bit Cameras (QHY600/268/461/411). Different readout modes result in different performance. These readout modes are currently supported in the QHYCCD ASCOM Camera Driver, SharpCap and N.I.N.A.
Readout Mode #0 (Photographic DSO Mode). This mode is suitable for most DSO imaging situations. Since there is a drop in the noise between Gain 25 and Gain 26 (unity gain), we recommend it as default gain setting; however, gain0 is also good enough for a 16-bit sensor.
Readout Mode #1 (High Gain Mode). This mode is something like double native iso of some new digital cameras, whose dynamic range can greatly increase at the very high iso value, like iso800, iso3200, etc. The high gain mode provides such improvement for QHYCCD 16bit cameras. We recommend you choose this mode when you have to capture at high gain, for example, a vary dark object. Please note the switch point of HGC/LGC of QHY600/268/461 is 56. That means you must set Gain 56 to make the best of it.
Readout Mode#2 (Extended Fullwell Mode). With a pixel size of 3.76um, these sensors already have an impressive full well capacity of 51ke. Nevertheless, QHYCCD has implemented a unique approach to achieve a full well capacity higher than 51ke- through innovative user controllable read mode settings. In Extended Fullwell Mode, the QHY600 can achieve an extremely large full-well charge value of nearly 80ke- and the QHY268 can achieve nearly 75ke-. Greater full-well capacity provides greater dynamic range and large variations in magnitude of brightness are less likely to saturate.
Mode-2CMS
Based on the three basic modes above, 2CMS mode can greatly reduce readout noise by secondary sampling while keeping the same full well value and system gain. We prefer 2CMS modes than basic modes in astrophotography. By the way, the recommend gain values are the same as their basic modes.
Currently QHY600 and QHY461 Series support Extended Fullwell Mode-2CMS (Mode#3), and QHY268 Series support Photographic DSO Mode-2CMS (Mode#4) and High Gain Mode-2CMS (Mode#5). Mode#4 and Mode#5 require Allinone version 20230412 or higher.
| Model | QHY268M PRO I |
| COMS Sensor | SONY IMX571 M |
| Mono/Color | Mono Only |
| FSI/BSI | BSI |
| Pixel Size | 3.76um x 3.76um |
| Effective Pixel Area | 6280*4210 (includes the optically black area and overscan area) |
| Effective Pixels | 26MP |
| Sensor Size | APS-C |
| A/D Sample Depth | Native 16-bit (0-65535 greyscale) A/D |
| Full Well Capacity (1×1, 2×2, 3×3) | 51ke-
75ke- or above in extended full well mode |
| Full Frame Rate | USB3.0 Mode
6.7FPS@6280*4210 8Bit 6.5FPS@6280*4210 16Bit 13.6FPS@2048*2048 8Bit 12.7FPS@2048*2048 16Bit 25.4FPS@1080*1080 8Bit 21.8FPS@1080*1080 16Bit 12BIT High Speed Mode 14.5FPS@6280*4210 8Bit 29FPS@2048*2048 8Bit 52.5FPS@1080*1080 8Bit PCIE Mode 6.7FPS@6280*4210 8Bit 6.7FPS@6280*4210 16Bit 14FPS@2048*2048 8Bit 14FPS@2048*2048 16Bit 25.4FPS@1080*1080 8Bit 25.4FPS@1080*1080 16Bit |
| Readout Noise | 1.1e- High Gain,
3.5e- Low Gain (5.3e- to 7.4e- in extended full well mode) |
| Dark Current | -20C，0.0005e /pixel/sec
-10C，0.001e /pixel/sec |
| Exposure Time Range | 30us-3600sec |
| Unity Gain* | 0*（PH Mode）
30（Extended Fullwell Mode） *With the improvement of the CMOS technology, the 16bit CMOS camera has been released, like QHY600/268/411/461. For these cameras, even in lowest gain it has beyond the requirement of unit gain (less than 1e/ADU due to sufficient samples) So you can directly set gain0 as start. Please note QHY600/268C/411/461 has extend full well mode. In this mode you still need to find out the unit gain position.
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| Amp Control | Zero Amplifier Glow |
| Firmware/FPGA remote Upgrade | Fully support via Camera USB port |
| Shutter Type | Electronic Shutter |
| Computer Interface | USB3.0 and 2*10Gbps Fiber interface |
| Built-in Image Buffer | 2GB DDR3 Memory |
| Cooling System | Two-stage TEC cooler
Air Cooling Version Typical -30C below ambient in short exposure time (exposure time < 10sec) Typical -35C below ambient in long exposure time (exposure time > 30sec) （Test temperature +20°） Water Cooling Version Typical -45C below ambient in long exposure time (exposure time > 30sec) |
| Recommended flow rates for water-cooled versions | 1.6ml/s |
| Optic Window Type | AR+AR High Quality Multi-Layer Anti-Reflection Coating |
| Anti-Dew Heater | Yes |
| Humidity Sensor* | Yes |
| Telescope Interface | Support M54 and M48 (with standard adapters ) |
| Back Focal Length | 14.5mm* |
