BSI
One benefit of the back-illuminated CMOS structure is improved full well capacity. This is particularly helpful for sensors with small pixels like the QHY533M. 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.
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 for astronomy such as the “star eater” effect. However, QHY Cameras offer TRUE RAW IMAGE OUTPUT and produces 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 almost 20-year cooled camera design experience, The QHY cooled camera has implemented the fully dew control solutions. The optic window has 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.
Amplify Control
QHY533M Dark Frame, 300s
QHY183M Dark Frame, 300s
QHY533M Dark frame
600s, with highest gain (170) and strech–only very slight amplify can be detected at the corner.
Compare last generation’s astrocam for beginners, like QHY183 or QHY 163, QHY533M has much better amplify control.
| Model | QHY533M | QHY533C |
| COMS Sensor | SONY IMX533 M | SONY IMX533 C |
| Mono/Color | Mono | Color |
| FSI/BSI | BSI | |
| Pixel Size | 3.76um x 3.76um | |
| Effective Pixel Area | 3008*3028 (includes the optically black area and overscan area) | |
| Effective Pixels | 9MP | |
| Sensor Size | 1 inch | |
| A/D Sample Depth
|
Native 14-bit A/D | |
| Full Well Capacity (1×1, 2×2, 3×3) | 58ke- | |
| Full Frame Rate | USB3.0 Port: Full Resolution 26.5FPS @8BIT 20FPS @16BIT2160Lines 37FPS @8BIT 28.5FPS@16BIT1080Lines 71.5FPS @8BIT 55FPS @16BIT768Lines 97FPS @8BIT 76FPS @16BIT480Lines 152FPS @8BIT 117FPS @16BIT240Lines 280FPS @8BIT 215FPS@16BIT |
|
| Readout Noise | 1.3 to 3.4e- | |
| Dark Current | -20C，0.0005e- /pixel/sec | |
| Exposure Time Range | 30us-3600sec | |
| Unity Gain | 68 | |
| 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 | |
| Telescope Interface | – | Support M48 (with adapter) |
| Back Focal Length | Actual Back Focal Consumed: 14 mm (Combined with CFW)
Standard BFL: 17.5mm（±0.5） |
17mm |
| Weight | 845g | 845g |