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QHY268M Manual (Reediting)
2021 年 02 月 20 日
QHYCCD Cooling CMOS Camera QHY268M
User’s Manual 


0.0 Before Using
1.0  Hints for using the camera
2.0  Description of Camera Connections
3.0  Camera Driver Installation and ALL-IN-ONE System Pack
4.0  Using with SharpCap Software
5.0  Using with ASCOM supported Softrware
6.0  Using with EZCAP_QT Software
7.0  Using with N.I.N.A. 64-bit Software
8.0.  Troubleshooting FAQs
9.0  Camera Maintenance

0.0 Before Using

0.1 Included Accessories
please confirm that the package contains the following items:


*Note: According to the characteristics of USB3.0, the maximum supported cable length of USB3.0 is about 3 meters, and the transmission stability cannot be guaranteed above 3 meters. In order to ensure the image quality, the standard USB cable length of QHY is 1.8 meters. Please use the standard cable to connect the camera to the computer.
If you need to extend the USB cable, please inform the dealer. QHY options provide an active USB extension cable (with signal amplifier) as shown in the figure. The USB extension cable number is 030028 (5 meters), 030029 (10 meters) .

Connect QHY268M with Filter Wheel

Connect QHY268M, Filter Wheel, OAG with 55mm M48 MPCC

1.0  Hints for using the camera

How to reboot the camera
The QHY600 is designed to use the +12V to reboot the camera without disconnecting and reconnecting the USB interface.  This means that you can reboot the camera simply by shutting down the +12V and then powering it back on.  This feature is very handy for remote controlling the camera in an observatory.  You can use a remotely controlled power supply to reboot the camera.  There is no need to consider how to reconnect the USB in the case of remote control.

What are the readout modes of the QHY600?
The QHY600 now has three readout modes. The different readout modes provide different timing settings in the CMOS driver. These different readout modes have different performance characteristics, like different full well, read noise and dynamic range.  Since each readout mode has its advantages and disadvantages, we allow user to set these different readout modes. Currently both the ASCOM driver and SharpCAP support this option. 

Image Area Layout 
The QHY600 can output the whole active area of the sensor, including the optically black pixels and the overscan area. The total image size including the optically black area area is 9600 x 6422 pixels. The optically black area is on the left of the image and the overscan area is on bottom of the image. 

The difference of optically black area and overscan area is that the optically black area includes the dark current during a long exposure while the overscan area does not include the dark current during an exposure.

Neither the optically black area nor the overscan area respond to light, so they are regarded as the "non-effective" area of the sensor. 

In the bottom of the overscan area you may find some vertical series of dots in single frame that can become vertical lines after stacking. One of the reasons for this is that the FPN calibration results represented in the overscan area can’t be found in the effective image area.

The following picture is the left bottom corner of a 300 second dark image. You can see these dots in the overscan area.

The optically black level area and overscan area are usually used for precise calibration of an image and for calibration of an image without using a bias frame or dark frame, or for some scientific applications.  Because the optically black and overscan areas are not part of the effective image area, QHYCCD does not guarantee the signal quality in these areas.  If you do not use these areas, you can select the option "Ignore overscan area" in the ASCOM driver or select a ROI of effective area in SharpCAP.

Input Voltage Requirements
The QHY600 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.  There 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.

64-bit Software 
A full resolution image from the QHY600 is 120MBytes. It takes a significant amount of processing power and memory to capture, buffer, display and process.  We therefore suggest using 64-bit software with the QHY600, for example, SharpCAP x64 , N.I.N.A x64. etc.  Although the camera has 4GB of internal memory, 32-bit software will run within this memory area and the remaining memory may be not sufficient for normal operation.


2.0  Description of Camera Connections

On the back plate of the QHY600 you will find the USB 3.0 port, 4-pin QHYCFW port, 12V power input port and two 10 Gigabit Optic Fiber ports (the optical fiber ports are only found on the Professional version and Early Bird version).

One side of the camera body, near the front of the camera there is a desiccant tube socket. Normally this it is plugged with a screw and o-ring.  If the CMOS sensor chamber accumulated moisture and needs to be dried, you can connect the desiccant tube filled with silica gel for about 24 hours to dry the chamber.  If you are using loose silica gel that is not in a package, you must install a small piece of cotton first to prevent the silica dust from contaminating the chamber and the sensor. 

3.0  Camera Driver Installation and ALL-IN-ONE SYSTEM PACK

All-in-one Pack (Windows) is for all QHYCCD USB3.0 devices, including all Cooling CMOS cameras, QHY5III and QHY 5II series, QHYCFW3. We recommend you choose "Stable Version" as usual.
In this pack there are:
1. System driver. It must be installed to make devices work.
2. EZCAP_QT: it's developed by QHYCCD which could be used in QHY devices tests, simple capture tasks, and above all, the management of updates. So even if you won't use EZCAP_QT as your main capture software, we suggest you install it to get the latest information of QHY drivers/SDK updates.
3. Ascom driver: Ascom Platform is supported by most astronomy devices which connect to Windows.
4. SDK: SDK is the file of ".dll" format. With this the device can be identified in other capture software.
5. SkyX Plugin: special support for SkyX.

CLICK HERE to read installation method

4.0  Using the QHY600 with SharpCap Software:
CLICK HERE for more information


5.0  Using the QHY600 with ASCOM supported Softrware

Currently the QHY600 only supports normal ASCOM still image operation ASCOM VIDEO operation is not supported.  Please note that the QHY600 always transfers the maximum bit depth in ASCOM for best deep space imaging performance.  The image format is 16-bit width and patch zero on low bit.

CLICK HERE for more information

6.0  Using the QHY600 with EZCAP_QT Software

EZCAP_QT is software developed by QHYCCD. This software has basic capture functions for QHYCCD deep sky cameras.  
7.0  Using the QHY600 with N.I.N.A. 64-bit Software


8.0.  Troubleshooting FAQs

8.1. How to avoid the camera hanging  

If your camera hangs (stops downloading images and does not respond to commands) it may be caused by a number of things. Check the following: 
8.11. In some computers with a VIA chipset and some types of motherboards, running the camera with SharpCap will not produce an image. But in ASCOM it works well. In this case, you need enable the DDR buffer of the camera.
8.12. Is there a leak for your mount or computer? If so, the leaking current may be transferred from computer to the camera via the GND. This may affect the USB transfer and cause data packet loss, hanging the camera. In this case you need to make sure that the computer and mount are well grounded.

8.13. Is the USB port voltage sufficient? The voltage of some computers' USB ports is sometimes less than +5V. This may cause the camera to hang. In this case you can use a powered USB 3.0 HUB to connect camera, which will ensure that the camera gets +5V power.

8.14. Is your CPU utilization is too high? If your computer's CPU utilization is too high, it will cause many frames to be lost and may cause the camera to hang. You can change the USB
traffic value to reduce the FPS and get more stable video transfer.

8.15. Is the USB cable connection is secure enough?  Sometimes a connection issue with the USB cable to camera or USB cable to computer will cause some signal loss and may cause the camera to hang, particularly when you move the cables. In this case you can try to add a little silicon oil into the USB connector and socket. This can make the connection more stable.

8.16. Avoid the static electricity. Static electricity from the human body can cause the camera to hang. To ground yourself, touch the external metal case of the computer to discharge any static electricity before touching the camera.
8.17. Are you using the front USB port on your computer?  The USB port on the front of some computers is not adequate for high-speed transfer because it is connected to mainboard by a cable which weakens the signal integrity. If you find that the camera always hangs when using the front USB port, try using a USB port on the rear panel of the computer instead. This will connect the camera to the chipset on the mainboard directly.   

8.18. When the USB selective pause function is enabled in the system, it may cause the camera to hang during long hours of work. Follow the steps below to turn off this option.
Windows power setting steps: 1. Click "Start button" and click "Settings". 2. Click "Power and Sleep", and click "Other Power Settings". 3. Click "Change Power Plan". 4. Click "Change advanced power settings". 5. By default, the "USB Selective Suspend" function is enabled. (This may cause the image to freeze, the frame rate too become low, the video to become unsmooth, the image fail to refresh, and so on.) 6. Disable this function.

8.19. When you encounter a situation where the camera cannot output the usual frame rate after updating Sharpcap software, please download the All-In-One installation package and select the Sharpcap option during installation. The installation package will automatically update the QHY SDK in Sharpcap. Restart the sharpcap software after completion.

8.20.  According to the characteristics of USB3.0, the maximum supported cable length of USB3.0 is about 3 meters, and the transmission stability cannot be guaranteed above 3 meters. In order to ensure the image quality, the standard USB cable length of QHY is 1.8 meters. Please use the standard cable to connect the camera to the computer.
If you need to extend the USB cable, please inform the dealer. QHY options provide an active USB extension cable (with signal amplifier) as shown in the figure. The USB extension cable number is 030028 (5 meters), 030029 (10 meters) .

8.2. How to clean the CMOS sensor and optical window

If you find dust on the CMOS sensor, you can first unscrew the front plate of the QHY600 and then clean the CMOS sensor with a cleaning kit for SLR camera sensors. Because the QHY600's CMOS sensor has an AR 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.

8.3. What is the camera's built-in DDR buffer? What are its advantages?

The QHY600 has a built-in 1GB(8Gbit)/ 2GB(16Gbit)DDR3 image buffer. It has two advantages:  It can buffer the entire image to avoid loss during USB transmission. Because the CMOS sensor is continually exposed, as soon as it starts working, the image will be output without stopping. However, the computer will pause the USB transfer because of the multitasking characteristics of the operating system. If the pause time is too long, a buffer with a small storage capacity in the USB will be full, resulting in the loss of the upcoming data. It is also possible to cause partial data loss of one frame to form a bad frame. For short exposures, this may not cause too many problems, but for long exposures, this means losing a long exposure image. The 1GB(8Gbit)/ 2GB(16Gbit)DDR3 buffer can solve this problem by storing and transmitting the entire frame of images. Even if the USB transfer is paused for a long time, no data will be lost.

Another advantage is that when using some computers that do not have fast processors or have poor support for USB 3.0, the computer can't transfer high-speed data well, and the data is often lost. The DDR can buffer a lot of image data and send it to the computer. Even if the USB 3.0 transmission frequently gets suspended, it will ensure that data is not lost. There are options in SharpCap to turn DDR buffering on or off. The current version of the ASCOM driver works in DDR mode.

8.4. How to protect the TE Cooler

The QHY600's TE cooler can achieve an ambient temperature difference of nearly 35 °C. You should 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.

8.5. The frame rate drops to 0 after the camera restarts when DDR mode is turned on.

The large file sizes of high-resolution images and fast frame rates will tax computers that are not designed and configured for such high speed, high data rate transfers and display. Some users reported that the frame rate of their cameras with DDR modules dropped to zero after re-running on SharpCap. This problem is caused by the high output rate of the CMOS chip and the slow reception rate of the computer. If the computer suspends USB transmission too much due to the operating system, it will cause the DDR data to overflow, resulting in the continuous generation of bad frames. None of the images entering the DDR are complete, so the frame is implanted with zeros.

The first method is to replace a better computer. For computers with poor performance, we recommend replacing them to ensure that the camera runs normally.
The second method is to turn off the DDR mode in SharpCap, but for computers with poor performance, this method is not necessarily effective due to its slow data transmission speed.

8.6. Optimizing USB Traffic to Minimize Horizontal Banding

It is common behavior for a CMOS sensor to contain some horizontal banding. Normally, random horizontal banding can be removed with multiple frame stacking so it does not affect the final image. However, periodic horizontal banding is not removed with stacking so it may appear in the final image. For QHY600, by adjust the USB traffic in Single Frame mode or Live Frame mode, you can adjust the frequency of the CMOS sensor driver and it can optimize the horizontal banding appeared on the image. This optimized is very effective to remove the periodic banding in some conditions.

A typical Periodic Horizontal Noise under certain USB_TRAFFIC value

After Adjust the USB_Traffic to avoid the periodic horizontal noise

8.7. Partial image loss and image misalignment caused by USB data transmission errors

The picture above is a typical situation where part of the image is lost due to USB data transmission errors and causes image misalignment.
The reason is that due to USB communication quality problems or external interference problems, the data of the USB image data packet being transmitted is wrong and cannot pass the CRC check, so the SDK judges it as a USB transmission error. The SDK will repair communication errors to avoid crashes, but this packet of data will also be lost. Cause this phenomenon.
The check and solution are:
(1) Communication quality problems caused by USB cable damage or poor USB contact: The solution is to replace the USB cable, and check the connection of the USB cable to the computer and whether the connection between the USB cable and the camera is too loose.
(2) Some HUBs with mismatched signals may cause such problems. You can connect directly or try to replace other types of HUB. (It is recommended to use active HUB)
(3) The communication interference problem caused by the leakage of the AC adapter, it is necessary to check whether the AC adapter of each device in the system is well grounded.
(4) Use the SDK and firmware that does not match the version, download the latest installation package (QHY ​​recently released the AllInOne installation package, which can automatically replace the SDK with one click, you only need to check the corresponding software in the installation package), or request QHYCCD technology Support remote assistance.

9.0  Camera Maintenance

9.1. Drying the camera CMOS chamber:
The CMOS sensor is located in the CMOS chamber.  There is a hole in the side of the camera near the front plate that is normally plugged by a screw with an o-ring.  If there is moisture in the CMOS chamber that causes the sensor glass to fog, you can connect the silica gel tube to this hole for drying the chamber. Place an effective silica gel desiccant in the silica tube make sure there is some cotton inside to prevent the silica gel from entering the CMOS chamber.

9.2. Preventing fogging of the optical window of the CMOS chamber window:
If the ambient humidity is very high, the optical window of the CMOS chamber may have condensation problems. The QHY600 has a built-in heating plate to heat it to prevent fogging. In most cases, it is very effective. However, If fogging still persists, try the following:
(1). Avoid directing the camera towards the ground. The density of cold air is greater than the density 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). Increase the temperature of the CMOS sensor. You can increase the temperature of the CMOS sensor slightly to prevent fogging of the glass.

(3). Check if the heating plate is working. If the heating plate is not working, the glass will be very easy to fog. Normally, the temperature of the heating plate can reach 65-70 °C in the environment of 25 °C. If it does not reach this heat, it may be because the heating plate is damaged, you can contact us to replace the heating plate.

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