Introduction

Experience astrophotography at its finest with the QHY268M-PH, a high-resolution monochrome camera designed to deliver precise imaging of celestial wonders. Unleash the true potential of your astrophotography with this advanced camera system that captures stunning details of galaxies, nebulae, and other celestial objects with exceptional clarity.

At the heart of the QHY268M-PH lies a high-performance CMOS sensor, optimized for monochrome imaging. This combination of high resolution and monochrome sensitivity ensures that each image is captured with utmost precision, allowing you to reveal the subtlest features of the cosmos.

The QHY268M-PH excels in capturing faint celestial objects with unparalleled accuracy. Its advanced sensor technology minimizes noise, providing you with clear and detailed images of even the most elusive targets in the night sky.

Monochrome imaging provides astrophotographers with greater control over their images. With the QHY268M-PH, you can use narrowband and LRGB filters to capture specific wavelengths and create stunning, true-color astrophotos that showcase the beauty of the universe in extraordinary detail.

Whether you are a dedicated astrophotography enthusiast or a seasoned professional, the QHY268M-PH is the ideal tool to elevate your imaging experience. Its user-friendly interface and advanced features cater to photographers of all levels, empowering you to capture breathtaking celestial images effortlessly.

Upgrade your astrophotography gear with the QHY268M-PH and witness the universe like never before. Embrace the precision and clarity of monochrome imaging and embark on a journey to explore the cosmos in unprecedented detail.

After Adjusting the USB Traffic to avoid the periodic horizontal noise.

1GB DDR3 image buffer

In order to provide smooth uninterrupted data transfer of the entire 26MP sensor at high speed, the QHY268 has 1GB DDR3 image buffer. The pixel count of the latest generation of CMOS sensors is very high resulting in greater memory requirements for temporary and permanent storage. The QHY268 has adopted a large-capacity memory of up to 1GB. Data throughput is doubled. This large image buffer meets the needs of high-speed image acquisition and transmission of the new generation of CMOS, making shooting of multiple frames smoother and less stuttered, further reducing the pressure on the computer CPU.

Internal Humidity Sensor

QHY268M has a unique internal humidity sensor (while QHY268C doesn’t). The Blue curve shown below represents humidity.

Native 16 bit A/D: The new Sony sensor has native 16-bit A/D on-chip. The output is real 16-bits with 65536 levels. Compared to 12-bit and 14-bit A/D, a 16-bit A/D yields higher sample resolution and the system gain will be less than 1e-/ADU with no sample error noise and very low read noise.

BSI: One benefit of the back-illuminated CMOS structure is improved full well capacity. This is particularly helpful for sensors with small pixels. In a typical front-illuminated sensor, photons from the target entering the photosensitive layer of the sensor must first pass through the metal wiring that is embedded just above the photosensitive layer. The wiring structure reflects some of the photons and reduces the efficiency of the sensor. In the back- illuminated sensor the light is allowed to enter the photosensitive surface from the reverse side. In this case the sensor’s embedded wiring structure is below the photosensitive layer. As a result, more incoming photons strike the photosensitive layer and more electrons are generated and captured in the pixel well. This ratio of photon to electron production is called quantum efficiency. The higher the quantum efficiency the more efficient the sensor is at converting photons to electrons and hence the more sensitive the sensor is to capturing an image of something dim.

Zero Amplify Glow: This is also a zero amplifer glow camera.

TRUE RAW Data: In the DSLR implementation there is a RAW image output, but typically it is not completely RAW. Some evidence of noise reduction and hot pixel removal is still visible on close inspection. This can have a negative effect on the image of astronomy such as the “star eater” effect. However, QHY Cameras offer TRUE RAW IMAGE OUTPUT and produce an image comprised of the original signal only, thereby maintaining the maximum flexibility for post-acquisition astronomical image processing programs and other scientific imaging applications.

Anti-Dew Technology: Based on an almost 20-year cooled camera design experience, The QHY cooled camera has implemented fully dew control solutions. The optic window has a built-in dew heater and the chamber is protected from internal humidity condensation. An electric heating board for the chamber window can prevent the formation of dew and the sensor itself is kept dry with our silicon gel tube socket design for control of humidity within the sensor chamber.

Cooling: In addition to dual-stage TE cooling, QHYCCD implements proprietary technology in hardware to control the dark current noise.

Advanced Functions

Multiple Readout Modes

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.

Random change thermal noise suppression function

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 Protection

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.

Optimizing USB Traffic to Minimize Horizontal Banding

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.

Reboot the camera by power off and on

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.

Specifications

model	QHY268M	QHY268C
CMOS Sensor	SONY IMX571 M	SONY IMX571 C
Mono/Color	Mono	Color
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 Port: Full Resolution 6.8FPS @8BIT 6FPS @16BIT 2048lines 13.6FPS @8BIT 11.5FPS@16BIT 1080lines 25.4FPS @8BIT 19.5FPS@16BIT 768lines 35FPS @8BIT 25FPS@16BIT 480lines 50FPS @8BIT 34FPS@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
Recommend Gain*	30 (PH Mode， or Extended Full Well Mode) 56 (High Gain Mode) *With the improvement of the CMOS technology, For these 16bit CMOS cameras, even in the lowest gain it has beyond the requirement of unit gain (less than 1e/ADU due to sufficient samples). Learn more at the “Readout Modes” part of this page.
Amp Control	Zero Amplifier Glow
Firmware/FPGA remote Upgrade	Fully support via Camera USB port
Shutter Type	Electronic Shutter
Computer Interface	USB3.0
Built-in Image Buffer	1GByte DDR3 Memory
Cooling System	Two-stage TEC cooler Less than 1S lower than ambient temperature -30C in continuous mode More than 1S continuous mode or lower than ambient temperature -35C in single frame mode （Test temperature +20°）
Optic Window Type	AR+AR High-Quality Multi-Layer Anti-Reflection Coating
Anti-Dew Heater	Yes
Humidity Sensor*	Yes	No
Telescope Interface	Support M54 or M48 (Combined with adapters )	Support M54 or M48 (Combined with adapters )
Back Focal Length	QHY268M: 12.5mm* *If companies with the QHY filter wheel, the BFL consumed is counted as 12.5mm. The actual BFL (the intercept from the CMOS chip to the top of the camera) is 14.3mm (±0.3). Since most users will match CFW with monochrome cams, please take 12.5mm as a major reference.	QHY268C: 14.3mm（±0.3）* *Since 2023, the top part of QHY268C is the same as 268M.
Weight	About 810g	About 810g

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