QHY42 High QE, Low Noise Back-Illuminated Scientific CMOS
The QHY42-BSI is a cooled scientific CMOS camera with extremely low (1.6e-) read noise and a backside illuminated CMOS sensor with 95% peak QE. We also offer the QHY42-BSI in a UV enhanced version as well as a front illuminated version. The sensor array is 2048 x 2048 with relatively large 11um pixels and 89ke- full well capacity. The QHY42-BSI is capable of high frame rates up to 24FPS at full resolution. Two stage TE cooling lowers the sensor temperature to -40C below ambient. The QHY42-BSI is ideally suited to scientific research, astronomy, biology, UV and low light imaging, and security.
There is three type of the coating of the sensor. TVBIS,UV,VIS. The TVBIS is the most popular type and it has the best QE of 95%. The UV version has a peak QE of 76% on the 275nm. While the TVBIS version has also a high UV QE at 240nm. For UV application. Both TVISB and UV is possible to be use. You can select it according the QE curve. And the TVISB version has lower dark current than UV version. VIS version is not so popular and sometimes the sensor factory does no stock. So if you need the VIS version you need to quote QHYCCD for details.
The first version QHY42 is released in early 2018. And now we will release the enhanced version QHY42PRO. The different of QHY42 and QHY42PRO is that QHY42 only support the single ADC channel output (which called STD mode in the datasheet of Gsense400 , and 24FPS for 8bit/12bit . While the QHY42PRO support both STD mode and the dual channel ADC mode (HDR mode). The dual ADC can work together to sample the same pixels. And output two images. One is high gain and another is low gain. Which can enlarge the dynamic of the output data. The QH42PRO HDR mode will output the 4096*2048 image. Which consist two 2048*2048 image. QHY42PRO also support the remote FPGA upgrade function via USB port. In future if there is any upgrade of the FPGA code, you can upgrade it directly without send back to factory to upgrade.
The information of the QHY42 tester and user for reference
1.Transit Measures with QHY42 Camera by Bruno Fontaine
2.Realtime Imaging with QHY42 and 50mmF0.95 lens on 2017.12.12 by Qiu Hongyun
QHY42 capture of point source meteor or satellite glint in Orion at 24FPS during Geminid Meteor shower in December, 2017. Reference star is Mag. 9.5. Event lasted less than 0.4 seconds
3. 2018.12.16 Testing with QHY42BSI and 50mmF0.95 lens on a dark site
We took the QHY42 (with BSI sensor installed) And 50mm focal F0.95 lens to a dark site near Beijing City to do a testing under the real dark sky. Here is the story of this testing. The 50mmF0.95 lens is a ZhongYi Optic product. The cost is not very high. But the 0.95 big aperture is very nice. The lens is a SONY E type interface. The back focus is 18mm. So it need a special modified camera front part. Otherwise it can not get so short back focal length when use the standard QHY42 front part and the 10mm Nikon adapter (The NIKON adapter can connect the SONY E type interface lens)
Since the Gsense400 sensor has some FPN noise. But it can be completely removed by the dark frame calibration. In order to get this calibration done when during video recording. We use the Sharpcap3.2 PRO . Because the pro version has the realtime dark frame calibration function . (Thanks to Robin Glover, the author of SharpCAP, to give us the license of the pro version for testing).
Here is the original image with with/without calibration. On the un-calibrated image, You will see there is the horizontal and vertical FPN noise. And also you can see a little amplifier glow on top of the image. But in the calibrated image they are removed totally.
In the whole testing, we use about 24FPS speed and about 43ms exposure time.The gain set to the max (includes both analog gain and digital gain). The image is saved to 8bit AVI video format.
We tested the limitation mag from the results. We thin It is more than mag9.5 under this exposure time
We select about 50frames which contains two meteor. You can download from here. The video is *.mp4 file and it is a high quality compressed video. 2048*2048 resolution. The file size is 10MB.
You can also see the following online video. It is best to click full screen playback. This video clip is a 1920*1080 video crop from the original 2048*2048 RAW video. And compressed to MP4 format. The video size is 380MB
4. QHY42 Test Image by Dr.Martin Miller
Der kometarische Nebel ist ein Reflexionsnebel, der sich durch den Aussfluss eine jungen Stern gebildet hat und von diesem angeleuchtet wird. 62 x 30 Sekunden, Gain 2, Offset 20, T= -22°C, 16"Mak, Sternwarte Hö, MartinMiller
The test results shows the high sensitivity of QHY42, especially in Ha wavelength, and the ultra low readout noise. results the high SNR image in short exposure time. Dr.Martin Miller says QHY42 has great potential in professional astronomy imaging. See all of the test image and the parameter at http://avvamhl.xobor.de/g90-Test-der-Scientific-QHY-CMOS-Kamera-p2.html
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