QHYCCD

Astronomy Equipment => Astronomy equipment Discussion board => Topic started by: bfontaine on November 02, 2018, 12:26:49 PM

Title: QHY 42 First evaluation
Post by: bfontaine on November 02, 2018, 12:26:49 PM
I got a QHY42 camera in april 2018, expecting interesting results in my field of interest : exoplanets transit computation.
I tried first to test the camera itself and measures its essential parameters, as literature is very weak for this camera.
This is the part 1, enclosed
Second part, is testing the camera "first lights", also enclosed.
I think many of you could be interested by this experience return !!
In summary, I do not regret having bought this camera with two remarks :
- software acquisition could be improved with several recurring bugs (not fatal, but annoying !)
- to get the best of the camera, it is necessary to change the approach concerning long pose acquisition : typically, changing 60 seconds poses by 30 times 2 seconds poses for instance.
Do not hesitate to contact me for further details !
Bruno
Title: Re: QHY 42 First evaluation
Post by: Wandering Sand on November 12, 2018, 12:32:39 AM
Dear Sir/Madam:

Thank you for your detailed test. We will study the question that you have propose.

Firstly, about the thermal noise, we will study the reason.
The thermal noise (3e) is large in the test data. According to the document the thermal noise should be 0.1e when the temperature is -15 ℃. So, we guess that the Thermal Electronic Cooler is out of touch with the cmos chip.

Secondly, about the full well charge, we will update a new FPGA version. It will support HDR output (Double channel 12bit output). By this way, dynamic range insufficiency can be solved.

Thirdly,about some improvement, we have drawn up a plan.
Single frame shooting delay problem: The reason is that the current single frame shooting is obtained from continuous video, this method will lead to the delay. In the new version we will add truly single frame shooting.
RBI problem: We will fix it. And did you use the latest version? Because the earliest did not set the Glow Inhibition Function open.

Best Regards!
zy
Title: Re: QHY 42 First evaluation
Post by: xs_man on November 15, 2018, 12:58:55 PM
Many thanks Bruno for this analysis of new QHY 42   :)

For short exposure deepsky imaging and VA observation, this camera
is a must have !

But the price is too high. I really hope that in the future Gpixel could find a
solution to decrease  greatly the price of their sensor. Only a dream ??

Please Bruno, could you show us 1, 2 and 5 seconds raw images  on a classical
target as M27 or M57 or M1 or M82 or M45 or  others ?
Is it possible to have raw images ?

Alb?ric
Title: Re: QHY 42 First evaluation
Post by: bfontaine on November 17, 2018, 09:30:08 AM
@ZY : thank you for your answer : I am glad if my post can improve this superb camera
Thermal  noise : I think from your answer there is nothing to do on my camera
Same for full well charge : changing the FGPA is far out my competence !!!
For the software improvements, thank you very much : I will test along you implement them
True single frame shooting is a must
For RBI problem, I think I used the latest version but I well check

@xs_man : Yes the price of the QHY42 is quite high (9090 USD for a class 2 BSI cooled) but not so much compared to other camera (FLI 11002 or 16002) and the result is really impressive
I try to send you 1,2, 5 secs raw images of some well known targets as soon as the weather is clear (terrible for months in France right now !!)
Title: Re: QHY 42 First evaluation
Post by: bfontaine on November 18, 2018, 08:39:48 AM
@ZI For drivers, I use : QHY5IIISeriesDriver 80425 2018/04/26
and for ASCOM : QHYCCDASCOM-Captire-StarSenseSCI V0.1.51.18 2018/08/10
It seems the latest versions
I dont see any glow inhibition function (attached is the set up with ASCOM)

Title: Re: QHY 42 First evaluation
Post by: xs_man on November 19, 2018, 12:58:14 PM
Quote
@xs_man : Yes the price of the QHY42 is quite high (9090 USD for a class 2 BSI cooled) but not so much compared to other camera (FLI 11002 or 16002) and the result is really impressive
I try to send you 1,2, 5 secs raw images of some well known targets 

Many thanks Bruno !
For me RAW images says more than any stacked image.
I hope that I will be possible to compare to the next QHY 2020.

Quote
as the weather is clear (terrible for months in France right now !!)

Oui, je vois de quoi vous voulez parler !  ;)

Alb?ric
Title: Re: QHY 42 First evaluation
Post by: Wandering Sand on November 19, 2018, 08:24:08 PM
Hi,

You should use the SHARPCAP software.

Best Wishes!
zy

@ZI For drivers, I use : QHY5IIISeriesDriver 80425 2018/04/26
and for ASCOM : QHYCCDASCOM-Captire-StarSenseSCI V0.1.51.18 2018/08/10
It seems the latest versions
I dont see any glow inhibition function (attached is the set up with ASCOM)
Title: Re: QHY 42 First evaluation
Post by: Wandering Sand on November 20, 2018, 08:57:42 PM
Hi,

Sorry for the last reply. The latest ASCOM version glow inhibition function is default open.

Best Wishes!
zy

Hi,

You should use the SHARPCAP software.

Best Wishes!
zy

@ZI For drivers, I use : QHY5IIISeriesDriver 80425 2018/04/26
and for ASCOM : QHYCCDASCOM-Captire-StarSenseSCI V0.1.51.18 2018/08/10
It seems the latest versions
I dont see any glow inhibition function (attached is the set up with ASCOM)
Title: Re: QHY 42 First evaluation
Post by: Wandering Sand on November 20, 2018, 09:05:13 PM
Hi,

For the thermal noise, can you take some photos in some certain gain value and exposure time? And tell us your parameter. We will take some by using your parameter. Then we will compare yours and ours to judge the reason.

Best Wishes!
zy
Title: Re: QHY 42 First evaluation
Post by: bfontaine on November 21, 2018, 12:24:59 PM
dear ZY,

I have redone thermal noise measures and I get :
at -10?C G=7 Offset=100 dark Noise = 3.4 e-/sec
at -10?C G=4 Offset=100 Dark Noise = 3.8 e-/sec

I will send you some photos (files are two large to be upload on the forum)

My main concern is not so much  the thermal noise, but with the acquisition software. As it is based upon a continuous image transfer, this has some (bad) consequences :
- it is not possible to get images exposure under 0.5 - 0.3 second. Under this number, the system freezes
- it is then impossible to get more than 4 or five bias frames
- the image taken at a given time is not the image which is shown and eventually store in a file. Then, the fits header data of the image are incorrect. The time for instance is wrong, as the filter name if the filter wheel changes at each image !

Besides, there are some annoying bugs :
- the setup camera setting procedure needs to be done each time when launching Maxim DL, and need to be redone in the camera control panel to be effective
- the setting procedure in the camera control panel can be done only once
- trying to disconnect the camera generates an error
- same if quitting the program (this is true for nay software : EZCAP-QT, SharpCap)

I understand that it may be not your priority but it would be nice to develop a good single shot software (Ascom based) ( and get rid of the annoying bugs) so that the QHY 42 owners could get the maximum value of this superb camera

thank you very much in advance
regards


Title: Re: QHY 42 First evaluation
Post by: bfontaine on November 21, 2018, 01:02:44 PM
dear ZY, images to download :
Bias -10?c G=4 Offset=100
https://tomco.wimi.pro/shared/#/file/b3357a0414aec57b49f442d6140c8dc5

Dark -10?C 2 sec G=4 Offset=100
https://tomco.wimi.pro/shared/#/file/4a9caf4cc7259c6a28461cb45312f157

Dark -10?C 10 sec G=4 Offset=100
https://tomco.wimi.pro/shared/#/file/8447133a3b9ab78a37515df3b1a46fef

Bias -10?c G=7 Offset=100
https://tomco.wimi.pro/shared/#/file/2f9e860a6c5a71b15cfa095df418aec7

Dark -10?C 2 sec G=7 Offset=100
https://tomco.wimi.pro/shared/#/file/2f9e860a6c5a71b15cfa095df418aec7


Dark -10?C 10 sec G=7 Offset=100
https://tomco.wimi.pro/shared/#/file/3718fb360eb6468b5e81fb232b3c7b87

Regards
Title: Re: QHY 42 First evaluation
Post by: bfontaine on November 21, 2018, 02:56:46 PM
@xs_man :
Three images of M33 at 1, 2 and 10 seconds
and a 150 x 2 sec stacked (5 min)

Raw images after calibration :
One second :
https://tomco.wimi.pro/shared/#/file/db2f52be868b8f70cdb6d987da4d22ce

2 seconds :
https://tomco.wimi.pro/shared/#/file/b7c99c25e27ddf932be7568cdb9f125d

10 seconds :
https://tomco.wimi.pro/shared/#/file/ca5e2088692858e7e9fecf82066bbd56

150X2 seconds :
https://tomco.wimi.pro/shared/#/file/180001090c457bd679f1e92e61e0b996


Title: Re: QHY 42 First evaluation
Post by: xs_man on November 22, 2018, 12:36:25 PM
Many thanks Bruno !  ;)

The problem about read noise is annoying.
I really hope that it will be solved quickly because there is a gap between 1.7 e- and
3.4/3.8 e- ! A part of background may be lost.

To my opinion, what would be really interesting to compare this camera with a QHY 290 M.
The best Sony sensor for short exposure deep sky imaging.
Of course, main difficulty would be to compare equaly the 2 sensors. 

Many thanks.

Alberic
Title: Re: QHY 42 First evaluation
Post by: bfontaine on November 22, 2018, 01:08:30 PM
It is not the read noise, but the thermal noise
For 2 seconds shots, it is completely neglectible
Title: Re: QHY 42 First evaluation
Post by: Wandering Sand on November 22, 2018, 09:04:57 PM
Dear Sir,

Thank you for your reply. We will handle this problem as soon as possible.

For your recommend , I will transfer to Mr.Qiu.

Thank you for your support!

Best Regards!
zy
Title: Re: QHY 42 First evaluation
Post by: bfontaine on November 23, 2018, 10:02:03 AM
Thank you very much for your answer and taking into account my feedback

Sincerely

Title: Re: QHY 42 First evaluation
Post by: xs_man on November 23, 2018, 04:44:00 PM
It is not the read noise, but the thermal noise
For 2 seconds shots, it is completely neglectible

Ah yes you're right, I apologize,  I read too quickly  !

Alb?ric
Title: Re: QHY 42 First evaluation
Post by: bfontaine on December 19, 2018, 11:37:38 AM

Enclosed is the third and last set of measures of the QHY42, devoted to exoplanet transit measurement.
In summary, the approach of taking 2500 4 seconds image (which is the limit of the full well saturation), and then to reduce to 160 mean images of 60 seconds, allow to produce high quality
results, often better than those produced by more conventional camera and "long pose" approach.
Even if this camera is not always easy to use, it is possible to take advantage of its very high QE and broad spectrum, especially in the near IR.
bonne lecture !
Title: Re: QHY 42 First evaluation
Post by: QiuHY on December 24, 2018, 09:30:47 PM
Hello,

     Thank you very much to share the test results of the exoplanet transit measurement. That's very nice and detailed data.

     Now we are developing the QHY42PRO. To add the HDR output and the native Single Frame readout.(The QHY42 driver is taking a frame from video streaming so it is not the native single frame mode, the native single frame readout will be no the one frame delay problem and it should be easy to use in some conditions).

     When the QHY42PRO release. The QHY42 can be upgrade to QHY42PRO free.

Best regards,
Qiu Hongyun
   

   
Title: Re: QHY 42 First evaluation
Post by: bfontaine on December 30, 2018, 01:28:10 PM
Hello,

Thank you Dr QIN and it is a great new, because the present single frame implementation has many severe drawbacks for DSO astronomy

Do you think it will be necessary to send the camera back to China to update it, or will it be possible to do it remotely ?

Thanks again to take my feedback into account
Bruno

Title: Re: QHY 42 First evaluation
Post by: QiuHY on January 07, 2019, 03:12:22 AM
Hello,

        When our codes finished. I think you can send to our oversea service center to do this upgrade. Maybe faster than send back China.

Best regards,
Qiu Hongyun
Title: Re: QHY 42 First evaluation
Post by: bfontaine on January 13, 2019, 05:52:27 AM
Hello Dr QIN

OK and thank you very much for your answer and the attention you pay to increase the performance of the camera, which is a bit difficult to use but incredibly fast and sensible.

I just wait your signal when the code is finished and that you telle me where I can send the camera.

Best regards

Bruno Fontaine

Title: Re: QHY 42 First evaluation
Post by: QiuHY on February 12, 2019, 04:34:13 AM
Hello Bruno,

         I make a test image of the QHY42PRO in HDR mode. Could you please to have a check and how about the readout noise etc?  I have put the test image at http://note.youdao.com/noteshare?id=be405ee3023a82b36225e758ba7208ba  it has includes the bias, dark and flat frames. I want to do a compare with the STD mode to see if there is anything need to be fine-tune.

Best regards,
Qiu Hongyun
Title: Re: QHY 42 First evaluation
Post by: bfontaine on February 19, 2019, 11:53:25 AM
Hello Dr QIN,

I just loaded the images
I have a look next days
Bruno
Title: Re: QHY 42 First evaluation
Post by: bfontaine on February 20, 2019, 12:23:25 PM
Hello Dr Qiu, I have measured the QHY42PRO parameters with your data enclosed  :

QHY 42PRO measurements :
Right High Gain Channel :
Gain : 0.0602 e-/ADU (16bits)   0.96 e-/ADU (12bits)  (?quivalent to G=4 setting on my own camera) Full well : 4000 e-
Read Noise : 37.7ADU = 2.3e-
Dark noise : 1.8 e-/sec (attention : 30 seconds dark frames : some pixel are saturated, not usable )

Left Low Gain Channel :
Gain : 2.02 e-ADU (16bits)  32.4 e-/ADU (12bits)
Read noise : 23.4 ADU (which is equivalent to 47 e- ! with the gain, but ADU is more significative : 23.4 compared to 37.7)
Dark noise : 3.5 e-/sec

STD mode :
Gain : 0.1 e-/ADU (16bits) 1.6 e-/ADU (which is equivalent to G=2 on my own camera - Full well : 6500 e-)
Read noise : 1.3 e-
Dark noise : 0.7 e-/sec (rather better than today )

Discussion :
With this setting, the High gain channel goes from 0 to 65000 ADU (16bits) for 0 - 4000e- and then get saturated
The low gain channel would start from  2000 ADU (4000e- ) to 65000 ADU (130000 e-, but the full well of the chip (90000e- ?) would saturated at about 45 000 ADU
May be setting the low gain channel to something like 1.4 e-/ADU (instead of 2) would give better precision with the same full well constraints ?


Hope it helps !

Title: Re: QHY 42 First evaluation
Post by: bfontaine on March 15, 2019, 01:06:43 PM
Hello Dr Qiu

It seems that the new version QHY42PRO is not available (documentation on the web site)
If it is, would it be possible to upgrade my QHY42 to the PRO Version ??
Title: Re: QHY 42 First evaluation
Post by: isoplut on March 16, 2019, 11:38:21 AM
Dears,

I just measured data in STD mode using Basic CCD Parameters script in Pixinsignt:

(http://irydeo.com/data/contents/resources/tests/qhy42t1.png)

My question is, taking into account that gain is set to a very low value, why Full-well capacity is so limited? 

Regards.
Title: Re: QHY 42 First evaluation
Post by: bfontaine on March 21, 2019, 12:50:32 PM
The gain of 0.097 e-/ADU is the gain in a 16 bit range (0-65535); the ADC (analog to digital converter) inside the camera is 12 bits long only (due to fast acquisition in video mode) and the value captured by the camera is 4 bits left shifted (multiplied by 16)  before being transmitted to the interface. The "real" 12 bits gain is then 0.097 * 16 = 1.552 e-/ADU 12bits. As there is only 2**12 (4096) ADU in a 12 bits register, the saturation (of the ADC not of the pixel in the camera) is reached as soon as 4096 * 1.552 = 6356 ADU (CQFD!) Of course, it is the same if you multiply the 16 bits gain by 65635 : 0.097 * 65535 = 6356 but it is less clear for the physical interpretation.

Comments : those new BSI camera are very sensitive in a broad spectrum but the saturation arrived very rapidly. It is perfect to detect and to measure very low signals (star photometry) but inadequate for contrasted images like a wide angle DSO image.
That is why FLI and now QHYCCD with the PRO version of the QHY42, have implemented the possibility to have a dual channel mode : in STD mode, it is like now with a high gain adjustable image, but in HDR mode, you get simultaneously two images : one high gain on the right and one low gain on the left in the example below. In that mode, two gains are fixed (see discussion above).
The first example below shows a low illumination level (where right image is interesting) and the second example shows a more illuminated image where the right image is saturated and the left image is interesting. It is  possible then to produce a composite image by a formula like lowgain (12bits) * k + highgain (12bits) on a higher (16 or more bits wide)
Hope it is clear (it took me some time to understand!)
Title: Re: QHY 42 First evaluation
Post by: bfontaine on March 21, 2019, 12:53:12 PM
Sorry for the mistake for my post of te availability of the PRO version of the QHY42
As it seems NOW available, can I have mine updated to the PRO version in your european facility ??
Title: Re: QHY 42 First evaluation
Post by: isoplut on March 22, 2019, 05:28:41 PM
Hi Bruno, thanks a lot for your explanations,

coming from years and years using 16 bits CCD... this is a quite new for me :)

It is clear that these cameras are not good for classic DSO imaging, but great to detect  and measure faint objects.

Kind regards!
Title: Re: QHY 42 First evaluation
Post by: bfontaine on March 31, 2019, 11:20:03 AM
Below is a composite image of M33 : 360 x 10 seconds in L,R,G, B
So it is possible to make DSO images also with the QHY42 !
Title: Re: QHY 42 First evaluation
Post by: bfontaine on April 19, 2019, 12:58:58 PM
" Hello,

        When our codes finished. I think you can send to our oversea service center to do this upgrade. Maybe faster than send back China.

Best regards,
Qiu Hongyun "


Hello Dr Qiu,
Do you think the code is finished now and that it would be possible to update my QHY42 camera ?
Thank you very much in advance for your answer
Bruno
Title: Re: QHY 42 First evaluation
Post by: Wandering Sand on April 21, 2019, 08:34:10 PM
Hi,

We have finished the code. Now we will ensure the oversea center can complete the update process. When we affirm it we will post you the information as soon as possible.

Best Wishes!
zy


" Hello,

        When our codes finished. I think you can send to our oversea service center to do this upgrade. Maybe faster than send back China.

Best regards,
Qiu Hongyun "


Hello Dr Qiu,
Do you think the code is finished now and that it would be possible to update my QHY42 camera ?
Thank you very much in advance for your answer
Bruno
Title: Re: QHY 42 First evaluation
Post by: bfontaine on April 22, 2019, 12:55:36 PM
Thank you very much
Bruno
Title: Re: QHY 42 First evaluation
Post by: bfontaine on July 03, 2019, 10:27:06 AM
Hi,
any news on the possibility to upgrade my QHY42 to QHY42 PRO by your overseas center ??
Title: Re: QHY 42 First evaluation
Post by: QiuHY on August 12, 2019, 12:14:52 PM
Hi,
any news on the possibility to upgrade my QHY42 to QHY42 PRO by your overseas center ??


Hello, Yes, we can do this at any time.  You can contact Mr.Jan Soldan in Czech.

Best regards,
Qiu Hongyun .
Title: Re: QHY 42 First evaluation
Post by: bfontaine on February 22, 2020, 11:21:47 AM
My camera has been finally upgraded from QHY42 to QHY42 PRO
Thank you to QHYCCD and especially to Jan Soldan for having successfully done it (for free !)
The very good surprise (additionally to the specification of QHYCCD) is that the software works perfectly and all bugs have been removed (including in ASCOM driver which supports the dual mode - STD and HDR)
Single frame support (very important for me) works perfectly
Thank you to all
Title: Re: QHY 42 First evaluation
Post by: isoplut on March 12, 2020, 10:47:25 AM
I acquired this camera several months ago and works great.

I fully recommend it for scientific works, is easy to reach magnitude 19-20 under a very light polluted sky in a few minutes, with a 12" telescope and stacking short exposures (~5 seconds).

As example, a mag ~18 NEO is clearly visible stacking 16 images of 5 seconds:

(http://irydeo.com/data/works/asteroids/2017BM123/tycho-processed.png)

or a supernova of mag ~19 in a stack of ~10 minutes:

(http://irydeo.com/data/works/supernovas/AT2020cqn/AT2020cqn-2.png)

Kind regards.