The QHY533M/C is a new generation of back-illuminated CMOS cameras with 3.76um pixels. The QHY533M/C uses the similar series of sensors as the flagship models QHY600 and QHY268, featuring low noise.
*Price shall be slightly different among countries and regions; Shipment expenses, customs, or other taxes are not included.
QHY533M (mono) and QHY533C (color) have different interface designs to be more flexible to deal with different applications.
QHY533M can be directly connected to the QHYCFW3S-SR without removing any part of the filter wheel (like the filter container). This provides a very short back focal length and that’s easy to fix! Besides, QHY533M + QHYCFW3S-SR combination can be easily connected to a DSLR lens, with only one additional adapter (sold separately).
Both QHY533M/C comes with an additional adapter for tripod interface. This makes it easier to shoot with DSLR lens.
Features
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.
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
Compare to the last generation’s astrocam for beginners, like QHY183 or QHY 163, QHY533M has much better amplify control.
QHY533M Dark Frame, 300s
QHY183M Drak Frame, 300s
QHY533M Drak frame, 600s, with highest gain (170) and strech–only very slight amplify can be detected at the corner.
Design
QHYCFW3S Adjustment for QHY533M
In order to let all astrophotographers easily use 533M’s threaded interface to connect filter wheel without removing any part of the filter wheel (like the filter container), since 2022, QHYCFW3-SR won’t be loaded with this adapter (below). This adapter is used to connect QHY163 or QHY183 while QHY533M doesn’t need it. Therefore, if you want to get a QHY533M, we recommend you choose QHYCFW3S-SR for the best experience.
By the way, this adapter is still contained in CFW3S-SR’s package. You can still use CFW3S-SR with QHY183 or QHY163.
QHY533M parallel position adjustment
The QHY533M is connected to the QHYCFW3S by using threads， so the sensor may not parallel to the filter wheel when the threads are fully rotated. In this case you can adjust the front part of the 533M to the right angle of the sensor.
QHY533C Design
A free Adapter Kit E will be provided with QHY533C. The adapters can be directly connected to the 55mm BFL M48 interface MPCC, or Nikon / Canon DSLR lens (need to purchase another DSLR lens adapter). At the same time, the C-port thread can be provided with the QHY533C and you can directly mount the C-port lens.
Dual Stage TEC cooler:
– Long exposures (> 1 second) typically -35℃ below ambient
– Short exposure (< 1second) high FPS, typically -30℃ below ambient（Test temperature +20℃）
Optic Window Type
AR+AR High Quality Multi-Layer Anti-Reflection Coating
Telescope Interface
533M: Support C-Mount or M48 (with adapter)
533C: Support M42 or M48 (with adapter)
QHY533M external use of threaded interface can be directly connected to the small filter wheel. This time we will launch a special standard small filter wheel version together with the 533M, which can be assembled directly by the user externally without removing the disc. When the QHY533M + filter wheel combination is connected to a DSLR lens, only an additional DSLR lens adapter ring (sold separately) is required to complete the focus.
Kits & Adapters--QHY533C
Adapter Kit E1 can be directly connected to the 55mm BFL M48 interface MPCC, or Nikon / Canon DSLR lens (need to purchase another DSLR lens adapter).
E1 is designed for QHY533C, 294C, 163C, 183C, 174C. Of course, if you use 163M/294M/183M/174M while a filter wheel or OAG is not needed, you can use E1 as well.
The camera requires an input voltage between 11V and 13.8V. If the input voltage is too low the camera will stop functioning or it may reboot when the TEC power percent is high, causing a drain on the power. Therefore, please make sure the input voltage arrived to the camera is adequate. 12V is the best but please note that a 12V cable that is very long or a cable with small conductor wire may exhibit enough resistance to cause a voltage drop between the power supply and the camera. The formular is: V(drop) = I * R (cable). It is advised that a very long 12V power cable not be used. It is better to place the 12V AC adapter closer to the camera.
First connect the 12V power supply, then connect the camera to your computer via the USB3.0 cable. Make sure the camera is plugged in before connecting the camera to the computer, otherwise the camera will not be recognized. When you connect the camera for the first time, the system discovers the new device and looks for drivers for it. You can skip the online search step by clicking “Skip obtaining the driver software from Windows Update” and the computer will automatically find the driver locally and install it. If we take the 5IIISeries driver as an example (shown below), after the driver software is successfully installed, you will see QHY5IIISeries_IO in the device manager.
Please note that the input voltage cannot be lower than 11.5v, otherwise the device will be unable to work normally.
Install "All-In-One" System Pack
All-in-one Pack supports most QHYCCD models only except PoleMaster and several discontinued CCD cameras.
Since most of the contents of All-in-one package are plug-ins that support third-party software, the third-party capturing software that you want to use must be installed before the All-in-one package. Otherwise the program will report an error.
ALL-IN-ONE Pack contains:
System Driver, which is necessary for the camera operation and must be installed.
WDM Broadcast Driver, which can provide a live signal to Obs and other live software, you can install it if you have such needs like opeing a live show.
EZCAP_QT , which is developed by QHYCCD and can be used in QHY devices tests, and management of updates. So even if you won’t use EZCAP_QT for capturing, we suggest you install it.
Ascom driver, which is necessary for the camera used in Ascom (the latest version of Ascom is 6.6).
The two sorts of Ascom CFW Drivers correspond to two methods of controling the filter wheel: USB control and camera serial control. It is recommended that both drivers should be installed if you have a filter wheel.
CP210X_VCP is a serial driver. Some computers come with the driver, but the computer without the driver may be failed of controling the filter wheel.
SDKs for Third-party Software: Just pick and install the corresponding SDK according to the software you want to use. Don’t forget to check whether the software you are using is 32-bit or 64-bit and select the right SDKs.
SHARPCAP is also included in the pack, you can choose 32-bit or 64-bit to install. This is authorized by SHARPCAP.
QT LIB is a plug-in to ensure that 64-bit software can exeuate normally on some computers with poor compatibility.
Difference between Stable version and Beta Version: Beta version is the latest version, which gives priority to support for the latest products (the stable version may not be compatible with those yet), and has some of the latest optimized ,but experimental features. The stable version is older than the beta version but more stable, so it is recommended for beginners who are not using the latest products.
Don’t let the camera connect to the computer during the All-in-one pack installation process; connect it to the computer after all the installation is complete.
Connect DSO Imaging Software (e.g. NINA)
Before using software, make sure you have connected the cooling camera to the 12V power supply and connected it to the computer with a USB3.0 data cable. If it’s an uncooled camera, 12V power is not needed. We recommend 64-bit Software, like SharpCAP x64 , N.I.N.A x64. etc., especially when you’re using 16bit cameras.
In NINA, you can select the device to connect to QHY Camera directly without ASCOM driver.
If connecting to the camera via ASCOM is desired, first make sure you have installed both the QHYCCD ASCOM Drivers and ASCOM Platform. Then you would select the appropriate camera driver under the ASCOM section. Then click the Connect icon. Here we take NINA as an example, but it’s similar to other software packages supporting ASCOM, like MaxDL, The SkyX, etc.
Launch SharpCap. If the software and drivers mentioned above are installed successfully, the video image will appear automatically about 3 seconds after the software loads. You will also see the frame rate in the lower left corner of the software window as shown below.
If you have already started the SharpCap software before connecting the camera, in order to open the camera, click on the “camera” in the menu bar and then select the device.
Offset adjustment. When you completely block the camera (i.e., like taking a dark frame) you may find that the image is not really zero. Sometimes this will reduce the quality of the image contrast. You can get a better dark field by adjusting the offset. You can confirm this by opening the histogram as indicated in the figure below.
If you want to enter the 16-bit image mode, select the “RAW16” mode.
By selecting the “LX” mode you can expand the exposure setting range and take long exposures.
After cooling devices connected to the 12V power supply, the temperature control circuit will be activated. You can control the CMOS temperature by adjusting the settings in the figure below. Basically, you can control the temperature of CMOS by either adjusting “Cooler Power” or clicking “Auto” and setting “Target Temperature”. You can also see the CMOS temperature at the lower-left corner of the software window.
Camera Maintenance
Drying the camera CMOS chamber
There are holes in the two sides of the camera near the front plate that is normally plugged by a screw with an o-ring. If there’s moisture in the CMOS chamber that causes fog, you can connect the desiccant tube to this hole for drying. There would better be some cotton inside to prevent the desiccants from entering the CMOS chamber.Please note that you may need to prepare desiccants yourself, because for most countries and regions desiccants are prohibited by air transport. Since QHY always deliver your goods by air, sorry that we can’t provide desiccants for you directly.
Cyclic Drying: The front end of the camera body is equipped with two drying interfaces with M5 threads, which are used in conjunction with drying tubes and circulation pumps for drying treatment inside the sensor chamber. The position of the drying interface is indicated by the red circle in the figure below (take the QHY600 as an example):Under the vacuum pump, the gas inside the sensor chamber is drawn out through one drying interface, enters the drying tube, and then undergoes filtration. It is then reintroduced into the camera through the other drying interface, circulating back and forth for drying.
Note:1.Do not reverse the order of the intake and exhaust ports
2.Before circulating drying, it is necessary to turn off the refrigerator, and then turn on circulating drying after the temperature returns to normal temperature. Only by following this step can the water vapor in the sealed chamber be effectively removed. If the cooler is turned on, the cooler inside the camera will absorb water vapor, causing more water vapor to condense inside the camera instead of being absorbed by the desiccant.
Cleaning the CMOS sensor and optical window
If you find dust on the CMOS sensor, you can first unscrew the front plate of the cam and then clean the CMOS sensor with a cleaning kit for SLR camera sensors. Because the CMOS sensor has an AR (or AR/IR) coating, you need to be careful when cleaning. This coating can scratch easily so you should not use excessive force when cleaning dust from its surface.
Preventing fogging of the CMOS chamber
All QHY cooling cameras have built-in heating plates to prevent fogging. However, If the ambient humidity is very high, the optical window of the CMOS chamber may have condensation issues. Then try the following:
1. Avoid directing the camera towards the ground. The density of cold air is greater than of hot air. If the camera is facing down, cold air will be more accessible to the glass, causing it to cool down and fog.
2. Slightly increase the temperature of the CMOS sensor .
3. Check if the heating plate is normally working. If the heating plate is not working, the glass will be very easy to fog, the temperature of the heating plate can reach 65-70 °C in the environment of 25 °C. If it does not reach this, the heating plate may be damaged. Please contact us for maintenance.
TE Cooler Maintenance
Please avoid thermal shock during use. Thermal shock refers to the internal stress that the TE cooler has to withstand due to the thermal expansion and contraction when the temperature of the TEC suddenly rises or falls. Thermal shock may shorten the life of the TEC or even damage it.
Therefore, when you start using the TEC to adjust the CMOS temperature, you should gradually increase the TEC power rather than turning the TEC to maximum power. If the power of the TEC is high before disconnecting the power supply, you should also gradually reduce the power of the TEC and then disconnect the power supply.
Appendix 1: How to Set Gain and Offset
Unity Gain of Some Models
Unity Gain
600M/C
25 (Extended Full Well Mode) *
268M/C
30 (Extended Full Well Mode) *
294Pro
1600 (11MP Mode)
2600 (47MP Mode)
410C
90 (Low gain)
40 (High gain)
367C
2800
247C
2200
128C
3300
168C
10
183M/C
10
163M/C
120
174GPS
17
550P
85
Gain Setting
For beginner, we recommend that you set the gain to “unit-gain”. Unit-gain is the gain when system gain is 1 (1e/ADU). This number is shown in the table above, like the unit-gain of QHY168C is 10. In fact, increasing or decreasing a bit doesn’t make a big difference.
You could increase or decrease Gain according to the condition. For example, if your optical system is fast, like F2.2 to F5, or long exposure for more than 5 minutes without narrowband filters, then you can decrease GAIN to achieve a higher dynamic range and make better use of full well capacity. By doing so you can avoid overexposure.
If you use narrowband filter on a slow optical system like F6 to F10, or short exposure time, the amount of photons received will be less. In this case you can increase GAIN to make better use of characteristics of low read-out noise in high GAIN value.
OFFSET Setting
There is no fixed “best value” for OFFSET. To set OFFSET, you should take the bias frame and dark frame at a certain GAIN value, then check the histogram of the frames.
The histogram distribution is a peak-like curve. While changing the OFFSET value, the histogram will move left or right. We need to guarantee the range of the whole curve won’t be chopped off at the end. At the same time, we need to keep a little residue on the left side, just over 0 a bit.
Pay attention that under different GAIN values, the width of this peak varies. The higher the GAIN is, the wider the distribution will be. So OFFSET value at low GAIN is not suitable for high GAIN because the curve is easily to be chopped off.
Advanced Settings
For those CMOS less than native 16-bits, the AD sampling accuracy doesn’t match perfectly with the full well capacity. At low GAIN level, the system gain will be couple electrons per ADU. The camera loses the ability to distinguish the strength of the signal because of such sampling error.
When GAIN increases, the system gain will decrease. However, increasing GAIN will limit the full charge of the well. If the system gain is 1 for a 12bit CMOS camera, the pixel will be saturated at only 4096 electrons (full well). Some bright stars will be easily saturated. This problem goes worse under fast optical system or long exposure. Over saturated objects cannot be fixed during post processing (unless you shrink stars, like in PixInsight). Also, the color saturation of the star will be affected. As result, the stars will be huge and white washed. We should decrease the gain value in this case, to gain a higher full well capacity.
Under long exposure or using fast optical system, the pixel will receive more photons. The variation of quantized noise from the photon which you can consider as natural dithering of the light intensity, will be greater than the “noise” from the sampling error. Therefore, the effect of the sampling error will diminish. By averaging multiple exposures, this will compensate the lack of depth of the picture because of the sampling error.
If the number of received photons is limited, like using narrowband filters or short exposures, we can increase the GAIN value. It is because the stars will not be easily saturated. At the same time, we limit the noise from the background cosmic radiation. Under this condition, the readout noise and quantized noise are the major factors that affect the ability to distinguish dim light or objects. By increasing the GAIN value in order to decrease the readout noise and quantized noise from sampling error, this would greatly increase the signal to noise ratio.
Appendix 2: Bayer Sequences of Some Colored Cameras
Cooled CMOS Camera
Bayer
QHY600C/QHY268C/QHY410C/
QHY367Pro/QHY128Pro/QHY294C/
QHY247C/QHY168C/QHY165C/QHY183C/QHY174C
RGGB
QHY533C/QHY178C/QHY290C/QHY224C
GBRG
QHY163C
GRBG
QHY1920C
BGGR
Cooled CCD Camera
QHY8L-C
GBRG
QHY10-C
RGGB
QHY12-C
BGGR
Planetary and Guiding
QHY5III174C
RGGB
QHY5III178C
GBRG
QHY5III224C
GBRG
QHY5III290C
GBRG
QHY5III462C
GBRG
QHY5III485C
RGGB
QHY5L-II-C
GRBG
QHY5P-II-C
GBRG
QHY5III585C
RGGB
QHY5III678C
RGGB
QHY5III715C
GBRG
QHY5III568C
RGGB
Appendix 3: White Balance Adjustment
When SharpCAP starts, it will use the default white balance, which is R:G:B=1:1:1. Therefore, the image you see is greenish (as shown below). Because from the light efficiency curve of the color CMOS chip, the response to green light is the highest. In order to obtain the correct white balance, you need to perform manual white balance adjustment.
For color cameras, SharpCAP will automatically open the progress bar of the white balance adjustment function, and you can make adjustments.
Since white balance is the ratio of light sensitivity between red and green, and the ratio of light sensitivity between blue and green, you can first fix the green value to 128. Then adjust the red and blue.
For example, after adjustment, blue is 255 and red is 161, and now it looks much better. If you need more blue, because the blue has reached 255 and cannot be adjusted upwards, in this case, you can reduce the green appropriately. Then adjust again. In this way, a larger proportion can be obtained.
As we said before. If you are doing planetary imaging you should set the offset value as low as possible. To make the background close to zero. Then you can easy to get correct color balance. Otherwise it will not easy to get it. The The following image shows the offset is good and you can not get good balance.
The reason is that the Color balance is a ratio of the RGB sensitivity difference. So we use a ratio to multiple the RGB value and get it done. But if there is a bias exist. The ratio will not be correct. For example, the G sensitivity is two times than R.
G=2R In order to get white balance. We multiply a ratio of 2 to R
R’=2R= G so we get R=G
When a bias exist. The bias is a constant add to each pixel. So the image you see is:
R’’=R+bias
G’’=G+bias=2R+bias
Now the ratio R”:G”=(R+bias)/(2R+bias) and it is not equ to 1:2. It shows the bias will effect the true value of the R:G. And the ratio of R:G will arious when the image light changed. It is hardly to correct with a fixed ratio.
But for DSO capture, You should keep the offset above zero and avoid the background is cut off. A background from 1000-5000 is a good value(16bit mode) for DSO imaging.
Appendix 4: QHY533M Parallel Position Adjustment
The QHY533M is connected to the QHYCFW3S by using threads. So there might be a small problem that the sensor may not remain parallel to the filter wheel when the threads are fully rotated. In this case you can adjust the front part of the 533M to the angle of sensor correct.
Steps
Remove the front part of the camera. Rotate the front part onto the filter wheel.
Position the camera so that the sensor is parallel to the filter wheel. Then use one screw to fix it.
Remove the filter wheel and fix the other two screws. Finally install the filter wheel.
Appendix: UVLO Function
UVLO（Under Voltage Locking), is primarily intended to protect the electronic device from damage caused by abnormally low voltages. Now only QHY600, QHY268, QHY410, QHY411, QHY461, QHY533 cameras have UVLO Protection.
UVLO warning execution
After a warning is given, the camera firmware will automatically turn off the cooler and will turn on the camera’s TEC protection mode. After the camera is reconnected, it will always work in TEC protection mode (maximum power cooler power will be limited to 70%). Since many times the voltage shortage is caused by the high resistance of the power supply cable itself, resulting in a large voltage drop at high currents, the voltage will usually rise after the power is limited. But limiting the power will affect the cooling temperature difference. Therefore, it is recommended that users first check the power supply cable to solve the problem of excessive resistance of the power supply cable.
If the user has solved the problem of insufficient supply voltage, the TEC protection mode can be removed through the menu of EZCAP_QT.
How to improve the power supply?
Make sure the output voltage of the AC adapter is not less than 12V and the maximum output current can reach 4A or more. Otherwise, the AC adapter itself will not meet the power demand of the camera and it may cause a low voltage problem.
Make sure that the 12V power supply cable connecting the AC adapter to the camera has a low impedance. The impedance of the positive and negative paths should not exceed 0.1 ohms each. Or the total impedance (positive + negative) should not exceed 0.2 ohms. Otherwise, the power supply cable should be thickened.
When using battery power, it is recommended to add a 12V output voltage regulator. If the battery is connected directly, usually the battery voltage reaches 13.8V when fully charged, and will gradually drop during use. It is easy to cause the camera to reach the low-voltage detection threshold.
How to clear the TEC protection status triggered by UVLO?
Once a UVLO event occurs, the camera will automatically memorize it and will work in a protected mode at a maximum of 70% power after reconnection. This memory can be erased as follows:
After you find the system error, you need to turn off the device and check the power supply. After inspecting the problem, open the ezcap software and select “Camera Settings” – “Preferences” – “Reset Flash Code” to reset the error status.
Why does the warning appear even though the power supply voltage is 12 V?
The voltage measured inside the camera is the voltage reaching the camera, not the voltage at the power adapter end. Therefore, the voltage measured at the power adapter end does not reflect the voltage received at the camera end. This is because the power cable has its own resistance. If the resistance is large, it will cause a large voltage drop. The voltage drop can be calculated by U = I * R. So if the power cable has a resistance of 0.2 ohms, it will produce a voltage drop of 3.3 * 0.2 = 0.66V. If the power adapter output is 12 V, the voltage reaching the camera is 12 – 0.66 = 11.34 V. To actually measure the input voltage at the camera end, you can refer to the photo below.
For cameras produced after September 2021, the UVLO is detected by communicating directly with the power manager, and the UVLO code that appears is 9, while for cameras produced before, the indirect detection method is used, and the UVLO code that appears is 3. The indirect detection method will detect UVLO except for the low voltage problem, and any other accident that causes CMOS not to work will also trigger the UVLO=3 alarm, for example, the camera is subject to severe electromagnetic interference, causing registers inside the CMOS not to work. Therefore, if UVLO=3 occurs, it is recommended to contact QHYCCD technical support for further judgment.
Using older versions of drivers and firmware may cause false positives (UVLO=9). Please make sure that ALL-in-one SDK version is out of stable version 2021.10.23 or higher. Please disconnect the 12V power supply during the driver installation.
Others
Technical Support
You can login QHYCCD Help Center for any technical support.
Submit a Ticket: Describe the issue you met while you’re using them. Our technicans will reply you in 48 hours during working days. You don’t have to check the Ticket update everyday—they can receive email notifications and know if there’s any update.
Knowledge Base: Here lists some tips for using your gears, or solutions to issues that you may met. Help your self!
Cooling
