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Topics - pmwolsley

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QHYCCD SDK FOR WINDOWS / Questions for V20.11.26
« on: November 18, 2020, 12:55:44 PM »
I noticed in the past few weeks there has been a new QHYCCD SDK released (V20.11.26).  I believe you may have mis-labelled the release notes for this new SDK.  I believe the first release notes listed are for V20.11.26 but they are labelled as if they are for V20.08.26.  You may want to correct this.

One line of these release notes states "294Pro-M/C/485 support and firmware update".  Can you please give some more explanation of what this means.  I own a QHY294C...does this SDK include a firmware update for my QHY294C?  Will this upgrade my QHY294C to a QHY294C-Pro.  What are the improvements contained in this firmware update.

Thank- you


QHYCCD SDK FOR WINDOWS / Feedback for V2020/8/26
« on: September 08, 2020, 10:40:16 AM »
Version 2020/8/26 works very well with my QHY294C
I cannot get it to work with my QHY5II-M
PHD2 uses my QHY5II-M as my guiding camera.  It is able to get an image but the timing of the images is very erratic.  PHD2 will get 3 or 4 images and then it will wait for 3 or 4 seconds before it gets a few more images.
My program uses the LIVE stream mode for the QHY5II-M which does not seem to work...no images.  PHD2 uses the single frame mode which seems to work...but very poor performance.


QHYCCD SDK FOR WINDOWS / Feedback for SDK v20.06.26
« on: July 08, 2020, 10:51:34 AM »
I use a QHY5II-M and a QHY294C.  The last version of the SDK I could use is v20.2.28.  I tried using V20.06.26 and I still cannot use both devices.  Most importantly, I use the QHY5II-M with PHD2 guiding and if I have my QHY294C connected via v20.06.26 then PHD2 has a terrible time using the QHY5II-M.  The PHD2 update rate is extremely slow and erratic.

Do you have some suggestions for me to try?  Perhaps the drivers for the QHY5II-M need to be either updated or revised?


Image Issue Q&A / QHY294C LGC/HGC characteristics
« on: July 01, 2020, 07:23:25 PM »
I have been experimenting with my QHY294C and I stumbled on something that is very confusing to me. I performed a test during the daytime where I pointed my telescope at a wall and took photos at various gains and exposure lengths.  I specifically focused on the LGC/HGC threshold which occurs when the gain=1600.

4 seconds at GN=1599.jpg
This is a histogram of the image. It clearly shows that the green pixels were saturated at 65,535.  The red pixels were not saturated and the blue pixels were the dimmest with a mean value of 36415.

4 seconds at GN=1600.jpg
This is a histogram of the same section of wall where all I changed was the camera gain from 1599 to 1600.  This caused the camera to switch to its HGC mode.  I was shocked to see that the pixel values were now dramatically limited to a mean value of roughly 45,950.  The green and red pixels have all been affected.  The blue pixels slightly increased in value.  Their mean value rose from 36415 to 36,452 which, I believe makes sense because the camera gain was changed by a very small amount.  The limiting of the pixel values to a mean value of 45,950 was not expected.

10 seconds at GN=1600.jpg
This is a histogram where all I changed was the exposure time.  I increased it by a factor of 2.5 which caused all the pixels to now be limited at the same mean value of ~45,950.

10 seconds at GN=2000.jpg
This is a histogram where all I changed was the gain from 1600 to 2000.  All of the pixels are still being limited but now the limiting mean value has rose to ~56,640.

Are these histogram results to be expected?  Is my camera defective?  I have been taking astrophotos and the camera behaves very well at GN=1599.  I have taken astrophotos with the gain at 1600 and at 2200 and the galaxies look correct but the bright stars are bloated and have lost their color.

Please advise,


I am trying to write a program that will focus my telescope using a live stream from my QHY294C.  I can only use USB2. This issue I have is that when I command the focuser to change position it can take several seconds for the live stream from the QHY294C to show the change in focus.  This is also true if I command the mount to move.  The live stream will take several seconds to show the movement. I want the live stream to be fast so I am using a Region Of Interest that is roughly 1/2 of the full image. I am also binning the image 2x2.

-I have tried to turn off DDR memory usage but I believe this ability is not available for the QHY294C. Is this true?

-I have experimented with increasing the USB Traffic which can make the live stream quicker to respond but this seems difficult to repeat. I need to always be certain that the image delay is minimized.

-I have also noticed that sometimes the image will jump erratically.  I suspect this happens when the camera fills the DDR memory and has to wait.

-I suspect that the camera is able to take several images and save them in the DDR memory at a rate that is faster than I can read them using USB2.

What are your suggestions for reducing this image delay and the image jumping erratically?


QHYCCD SDK FOR WINDOWS / Possible Memory Leak in qhyccd.dll
« on: May 19, 2020, 03:33:17 PM »
I am a LabVIEW programmer and I have been writing a program to support my QHY294C.  I can control the camera but when I go to exit my program generates a crash report.  I have contacted LabVIEW support people and they can't figure out why the crash is happening.  They say that LabVIEW works with lots of 3rd party dlls without issue.

I was able to create a very simple LabVIEW demo program that first executes InitQHYCCDResource() and then executes ReleaseQHYCCDResource().  There are no other calls to the dll in this demo program.  There are no errors generated by these functions but the program crashes when it exits.  It's as if not all of the resources are being released or that something that InitQHYCCDResource() does that is not being un-done.  I know that there are many programs written using this dll that don't have this problem but I need some guidance as to what this issue could be.

Please advise


I am developing a LabVIEW program for my QHY294C and I am having some issues. I am using the latest version of the 294C driver (19-11-6) and the SDK (V20200228_0)

  @fn uint32_t GetQHYCCDCameraStatus(qhyccd_handle *h,uint8_t *buf)
  @brief Get the camera statu
  @param h camera control handle
  @param buf camera's status save space
  on success,return QHYCCD_SUCCESS \n
  another QHYCCD_ERROR code on other failures
EXPORTC uint32_t STDCALL GetQHYCCDCameraStatus(qhyccd_handle *h,uint8_t *buf);

I cannot get this function to work...it always returns -1.  Do you have a sample C++ code that shows the correct usage for this function?

When I use the SetQHYCCDParam to set the value for CONTROL_MANULPWM the cooler PWM does respond correctly but if I use GetQHYCCDParam to get the value for CONTROL_CURPWM it returns a bad value.  The value returned is equal to 255 - CONTROL_MANULPWM.

I also need to know how to detect if I have lost communication to my 294C.  If I unplug my 294C's USB cable the GETQHYCCDPARAM functions does not return an error.  What function should I use to determine if I can still communicate to the 294C.

I also need to know how to determine if the 294C is already being used by another application.  If I try to connect to the camera with sharpcap running my LabVIEW program crashes.



Astronomy equipment Discussion board / QHY294C cooling ON at start-up.
« on: February 15, 2020, 09:53:12 PM »
I noticed that when I power up my QHY294C and connect it to my computer that the cooling system comes on immediately.  I don't have any programs running yet!  I have not yet connected the camera to ASCOM.

I want to configure my QHY294C so that the cooling always starts in manual with a cooler power of zero.  I have 10 minutes of work to polar align and calibrate my mount.  I want to use this time to slowly cool the camera.  Your manual for the QHY294C has a section that warns about avoiding thermal shock but your driver makes this impossible.


I have a USB2 system and would like to purchase the QHY294C for DSO imaging.  Because this typically means one image every 2 to 5 minutes, I was hoping that a USB2 connection between my computer and the camera would be sufficient.


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