I have been using specialized astronomical cameras for more than 10 years now and keep an eye on new matrices. During this time, sensors with small pixels, low noise and different diagonals appeared. One of the significant breakthroughs occurred in 2014 with the advent of the Sony IMX224 color sensor, which is characterized by very low read noise and high sensitivity to near-infrared radiation. Moreover, in the visible range, this sensor operates in color mode, and in the near-infrared range, color microfilters “leak” and at a wavelength of 850 nm or more, the matrix begins to operate in full monochrome mode.
As of August 2020, the imx224 sensor has been discontinued. It was replaced by the IMX385 and IMX290 sensors, but in 2019 the IMX462 color sensor appeared with even higher IR sensitivity and very low reading noise (from 0.5e). Soon the first astronomical cameras based on this sensor appeared.
The near-infrared region is of great interest to me for a number of reasons.
1. Photographing Jupiter at 850 nm and especially in the CH4 methane line (890 nm) shows completely different atmospheric details that are not available in the visible range.
2. The ability to reduce atmospheric turbulence when photographing the Moon, planets and the Sun by moving to the long-wave region of the spectrum. At the same time, the resolution of the telescope will decrease, so when photographing the Moon, I still try to use a red or 685 nm filter, and in a very calm atmosphere, a green filter. But if the atmosphere is too unstable, and you want or need to shoot, then infrared photography (850 nm +) will be the only solution to the problem of turbulence by amateur means.
3. Photographing deep space objects in infrared rays allows you to “look” through gas and dust and detect faint, cold stars. Also, the 850 nm filter helped me capture details of the surface of Mars even in the midst of Martian storms.
It was the shooting of Jupiter in CH4 that pushed me to buy an astronomical camera with an IMX462 matrix, since with the existing monochrome camera QHY5III178m (IMX178 matrix) I have to set the shutter speed too long (100-200ms) at the highest gain. And in October 2020, I became the owner of the QHY5III462C camera.
There are two options for cameras on IMX462 – from ZWO and QHY.
The price of the ZWO ASI462MC is higher, the shape is a classic “puck”, but the camera can work with CS-mount security lenses (lens and adapter ring are not included). You also need to purchase a separate IR-cut filter for it. The kit includes a camera, a USB 3.0 cable, an ST4 cable for autoguiding, a T2-1.25″ adapter, a protective cover and instructions. It is possible to add 850 nm and CH4 filters, but such a set will be more expensive. The camera comes in a cardboard box.
The QHY5III462C camera is noticeably cheaper and comes with a richer package. The camera is supplied in a metal box. The shape of the camera is with a 1.25″ fit. Includes IR-cut and 850 nm filters, an adapter ring for C-mount lenses, a USB 3.0 cable, an ST4 cable for autoguiding, a parfocality ring and a warranty card. The camera is supplied in a metal box. Possible option with an additional set of CH4 filter, adapter for CS lenses and a wide-angle 2.5 mm f1.2 lens.There is also a monochrome version QHY5III462M with a b/w sensor.
The QHY5III462C comes standard with C-mount lenses ONLY. With CS-mount lenses you won’t be able to focus to infinity. The DELUXE package also includes an adapter for CS-mount lenses with a built-in IR-cut filter, a 25 mm f/1.2 CS lens and an IR890 nm methane filter.
To shoot in full resolution at high frame rates (from 50 frames per second and higher), you may need a computer with a USB 3.0 port and a high-speed SSD drive (writing speed of at least 300 megabytes per second). A fast multi-core processor is also desirable.
QHY5III462C CAMERA SPECIFICATION
|QHY5III462C (Color and Enhanced Near Infrared)
|SONY IMX462 CMOS
|2.9um x 2.9um
Effective Pixel Area
1920 x 1080
AD Sample Depth
12-bit (output as 16-bit and 8-bit)
Typical 1/2.8 inch
|Full Frame Rate
|Full Resolution 135 FPS@8-bits (USB3.0 Port）
|ROI Frame Rate
Higher rates at selected fields of interest (Supports any region ROI)
|Exposure Time Range
|Electronic Rolling Shutter
|Optic Window Type
|Changeable 1.25-inch filter as optical window
(Includes free 1.25-inch UV/IR cut filter and free 1.25-inch IR850 filter)
Back Focal Length
The camera body is completely metal. The form factor is like an eyepiece, that is, with a 1.25″ inch fit. In the front part there is a thread for an M28.5 light filter. On the body there is a ribbed heatsink. In the rear part there are USB 3.0 ports, as well as a non-standard autoguiding port. On one side on the cable there is a round port for connecting to the camera, on the other end there is a standard RJ11 connector with the following pinout:
To record data from the camera, I use SharpCap version 3.2 (for Windows 10).
The camera allows you to adjust all three color channels – red (R), green (G) and blue (B). By default, the settings are set to white balance 64, 64, 64. This white balance should be used when shooting with infrared filters 850 nm and CH4 (890 nm). In this mode, the camera operates as MONOCHROME.
To use in COLOR mode, you must install an IR-CUT filter. In this case, the white balance must be adjusted based on the histogram. I use the values 66, 56, 106.
When shooting planets and the Moon in color mode with an IR-cut filter, as well as in monochrome mode with an 850 nm filter, I use 8-bit mode (RAW8).
When shooting Jupiter in monochrome mode with a CH4 filter, I use 16-bit mode (RAW16), preferably with subsequent shooting of dark frames and calibration.
When shooting deep sky objects – 16 bit (RAW16) with full calibration.
The supplied 850 nm filter turned out to be defective – the image with it is too dark and red, which should not be the case. Apparently something went wrong during production. It’s good that I had a spare 850 nm filter from ZWO. However, I was able to test another copy of the 850 nm filter from QHY – it works flawlessly. Below is a test of filters using a QHY5III462 camera and a Chinese spectroscope. Yes, this is another interesting application of the camera – testing filters for leakage in the IR range.
I really like the noise character of the imx462 sensor at high gain, it is somewhat similar to “white noise”. I observed a similar noise pattern in the ixm224 matrix. The imx178 and imx183 sensors at high gain work differently and are subjectively worse.
The sensor’s own glow is quite peculiar – the upper right corner glows very faintly, the right side of the sensor, as well as the left side of the frame is slightly lighter than the right. In addition, the QHY5III462C camera has a glow suppression function, it can be activated in the SharpCap settings (Amp Noise Reduction – ON), it further reduces extraneous light.
The QHY5III462C copes well with its main task – lunar-planetary photography, including in the infrared range. Please note that for lunar-planetary photography in the infrared range, it is better to use mirror or mirror-lens telescopes, since lens telescopes are not designed for photography in the infrared range and the image quality in the IR can be significantly worse than in the visible region of the spectrum.
Source videos in ser-format are available here.
For Jupiter, the camera works great, allowing you to quickly capture the planet in both visible and infrared light. Interestingly, the Great Red Spot appears light when photographed in infrared light. It also turned out that with a CH4 filter you can successfully photograph Jupiter even at twilight in a very bright sky. In an unstable atmosphere, you can safely go to the infrared range, where turbulence is much lower. However, keep in mind that due to an increase in the operating wavelength, the resolution of the telescope will drop by about one and a half times. Of course, it is advisable to use derotation in WinJUPOS – this will significantly improve the detail.
When shooting in the 850 nm and CH4 ranges, when processing in Autostakkert, select the monochrome mode (COLOR>GRAYSCALE) to avoid a drop in resolution from debayering.
It’s funny that 3 weeks later the James Webb Space Telescope released a similar image, but, of course, with better detail:
When shooting Saturn, thanks to the high sensitivity of the camera, my equipment was able to achieve a shutter speed of 50 milliseconds at maximum gain and filling the histogram by 75-85%.
-Celestron NexStar 8 SE telescope
-Meade LX85 mount
-Barlow lens cell 2x
-QHY IR-cut filter
Stacking of 2500 frames out of 49000 in Autostakkert, wavelets and deconvolution in AstroSurface.
SHOOTING DEEP SPACE OBJECTS
Despite the lack of cooling, the QHY5III462C camera performed well when photographing deep space objects. High sensitivity, weak amp glow of the sensor, as well as the type of the noise allow you to successfully photograph deep space objects even with short shutter speeds (from 0.5 to 30 seconds, depending on the brightness of the object and the focal ratio of the telescope). Yes, the sensor size is small, but it is quite possible to find objects suitable for it. If you are not chasing megapixels and pictures in a resolution of 1920 x 1080 are enough, then the QHY5III462C is an excellent choice for a beginning astrophotographer. In the future, QHY5III462C can be used as a guider, or for photographing bright planetary nebulae.
Stacking of 50 frames per 30 seconds with processing:
Stacking of 1500 frames per 0.5 seconds:
With CH4 filter (890 nm), also the result of stacking frames:
To use it as an autoguider in the PHD2 program, you must install the ASCOM driver and, when the camera selection dialog appears in PHD2, select QHYCCD-Cameras-Guider (ASCOM) from the list.
An excellent camera for all types of astrophotography. Low noise, excellent sensitivity in the infrared range, good equipment at an attractive price. We haven’t noticed any problems with the camera’s operation; it works stably and without any complaints. The matrix is small, but with the right choice of subject and equipment for shooting, you can get great pictures. I enjoy using it and definitely recommend it!
You can buy the QHY5III462C astronomical camera on Aliexpress using the link.
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