viernes, 14 de agosto de 2020

QHYCCD 367C camera review

Hello everyone, I am going to carry out an analysis of the new specialized camera for Astrophotography from the manufacturer QHYCCD, it is the COLDMOS QHY367 model, color "one shoot color" (OSC) and Full Frame with a resolution of 36 Megapixels. Using the same clip as used on the Nikon 810 camera.
  • CMOS Sensor: Sony IMX094 Color CMOS
  • CMOS Size: 36mm * 24mm full frame
  • Pixel Size: 4.88um * 4.88um
  • Resolution 5.984x3.366
  • Full Well: 56ke-
  • Shutter: Electric rolling shutter
  • Exposure Time: 60us-3600 sec
  • Max Frame Rate (for both 8bit and 14bit): 3.2FPS@Full Resolution.
  • AD Convert: 14BIT
  • Readout Noise: 3.2e @Low gain. 2.4e@unity gain
  • Maximum Dynamic Range: More than 17000.> 14 STOP
  • Mechanical Interface: M54 / 0.75 female thread
  • Optic window heater: Yes
  • TEC 2-stage TEC: -35C below ambient
  • Optic Glass Window: AR + AR Clear glass
  • Silicon gel socket: Yes
  • Weight (Camera only): 788g
The evolution of technology CMOS sensors cooled, are beginning to have better performance, exceeding in many cases traditional CCD in size, readout noise, Fullwell (ability to capture photons) and lower cost, with excellent photographic results   also Manufacturers are incorporating  more advanced electronics that incorporate intermediate DDR3 buffer memories that speed up full downloads in less than 1 second and at lower power consumption, as occurs in this QHY367C.

ONY IMX094
UNBOXING

Coming directly from Hong Kong, the courier took 3 days for the perfectly packed package. Inside was the characteristic white QHYCCD box illustrated with constellations. The camera body is cylindrical with an excellent finish and quality,   in which the full frame sensor vision (24x36mm) stands out. The cylindrical body is oriented for use in Hiperstar systems in catadrioptic telescopes, although logically it can be mounted and used in any optical system.

The following items came in the box:
  • QHY 367C camera
  • Cover for camera
  • Rotator ring adapter.
  • M54 adapter to 2 "barrel.
  • USB 3.0 cable
  • Cable and 6A 12V power supply to connect it to 220V AC.
  • Extension cable with double DC Jack type connector, one of them with thread. for the camera.
  • Desiccant tube with silica bag.
A metal cover is missing to protect the sensor for when it is already mounted with the OAG

                                                                QHYCCD BOX
 
36X24MM FULL FRAME SENSOR IS APPRECIATED


QHY 367C BODY 

I also requested that the following accessories be supplied to me.
010094 QHYOAG-M 
  • 020079 Spacer M54 (F) Medium with 6 holes.
  • 020076 Spacer to install 2 "filter M56 Part A
  • 020077  Spacer to install 2" filter M56 Part B
THE OAG is an  accessory that is used to mount a QHY5II, QHY5LII type tracking camera, using the same optical axis of the main telescope, 

Spacers are used to ensure the distance required by the telescope's reducer / flattener and to prevent spherical aberrations from occurring. They are composed of 6 spacers of different thicknesses to use those necessary to ensure the correct distance. The last two adapters are used to place in the middle of the two a 2 "filter, IR / IV type, anti contamination, narrow band.

Installation to the telescope is done using the M54 (H) thread

QHY 367C, QHY OAG INSTALLED. TMB 780/780 SCOPE , y TTAKAHASHI MOUNT
CLOSER VIEW
PERFORMANCE 

Phase 1: Analysis of the Bias / darks 

Taking a Bias take at -10º bin1 the result is the one I attach.

Uniformity of the distribution without gradients
Low reading noise.
                                                        QHY 367C BIAS -10ºC

Similarly, the Dark at. -10ºC, 900 seconds Bin1 has the same characteristics of low noise and uniformity, detecting a small Amp Glow on the left.

QHY 367C DARK -10ºC  900 SEG.

Phase 2: Analysis in Black and White

In this phase I wanted to exploit the capabilities in black and white, for this I rely on using the Bin2 format. If it is true that with this format I will have 1/4 of the resolution of the sensor format, which together with the Bayer matrix, another 1/4 we would have 2.3Mpx instead of 36.7 Mp, but I want to find out the performance in sensitivity, resolution and thermal noise of this sensor. In this Bin2, being a color camera with a Bayer Matrix RGGB configuration, when Debayerized it becomes directly black and white photography. I want to exploit the details and the appearance of artifacts, in black and white they are better appreciated.

The astronomical target for the test has been intentionally a faint nebula with high Ha emissions, in order to detect the limitations of the camera on very faint objects, specifically    NGC7822, an emission nebula. The exposure data is: 13  exposures of 10 minutes to Bin2. That is, 2.5 hours of effective exposure time, well below the more than 4 hours needed at least in a monochrome camera for similar results. EQUIPMENT
  • Takahashi EM200 Temma2
  • TMB Superpochromatic 130/780 CNC II with 585mm reducer.
  • Pixinsight 1.8 processing

The result of the image once processed highlights:
  • Even being a photograph to Bin 2, it has a high resolution without pixelation or loss of details.
  • The stars appear punctual, better even to experience with monochrome cameras.
  • A very high sensitivity is to BIn2, we will have to see the results to Bin1 and color.
  • A high depth of field.
  • Complete elimination of artifacts in any part of the photograph, so it has not required aesthetic modifications.
  • In the processing, the noise elimination has been very slight
  • Complete absence of Amp Glow noticeable in the photograph.
  • Calibrated with Darks, Bias, Flats with flat image results without residual gradients.
  • The high performance in black and white makes the use of narrow band filters type Ha, Oiii, SII very viable.
Phase 3: Color results analysis

Finally I present the final results  made in another shooting session to Bin1, that is to say in full color and of the same object, slightly varying the frame. 11 exposures of 15 minutes, 2 hours and 45 minutes total capture, the team is the same.


  • No artifacts, dead spots, or hot spots are detected in the entire photo.
  • The color balance is very exact, a few light calibrations have been needed with a natural balance of colors.
  • Very smooth color transitions.
  • The processing has been much simpler by eliminating the combination of RGB and luminance channels.
  • Please note that the color calibration must be done with the stacking result without stretching.
  • As can be seen, the detail is enormous, with no difference to the results on a monochrome CCD.
CONCLUSIONS 

I have owned and used several monochrome cameras, SBIG ST8300, SBIG STT8300, SBIG STL11000, QHY 16200A, ... and from what experience I have, I can objectively compare the results with this camera ..

The QHY 357C is in color with 36Mpx resolution, using a Bayer Mask, which means that from the start the resolution of a final color photograph drops to 1/4 of 36Mpx, that is, to 9Mpx the equivalent of a monochrome camera. The results obtained have been a pleasant surprise to me because the resolution and resulting details are enormous !!!, with a high quality of colors, very soft, without gradients or artifacts. The historical discussion between astrophotographers about the pros and cons of color cameras (OSC) versus monochromatic ones makes it meaningless in this case, the high resolution of the QHY367C makes the final results, resolution, details, color balance are similar or even superior, adding more ease of use, cost and weight 

I think that the experience gained after many years of using monochrome cameras has created a prejudice of opinion in front of OSC cameras, but I was wrong. I can confirm that the COLDMOS QHY 367C is an excellent product, highly recommended for those astrophotographers who want more simplicity, without the complexity of adding a filter wheel, LRBG channel processing, longer capture and processing time.

PROS
  • High resolution
  • Low reading noise
  • Low electricity consumption.
  • Great course, full fame
  • Great light gathering capacity.
  • Fast download to the computer (approx. 1 second a 70Mb photo.
  • Simplicity.
  • Shorter capture and processing time.
TO IMPROVE
  • The price is high, comparatively less than a monochrome camera with a filter wheel.
  • Careful bayerization is necessary to obtain good results.
  • As an improvement aspect, it would incorporate a handle for easy handling and old-fashioned security.
  • Although the takes must be increased in time, it is compensated by the absence of captures in each LRGB channel, time is saved and the total time required is less.
  • It cannot be used for Astrometry.
  • Limited for narrow band captures. Usable but loses resolution.

Author : Rafael Rodríguez Morales