Timestamp issue w/QHY174GPS

watan_rockhand
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Timestamp issue w/QHY174GPS

Post by watan_rockhand » Tue Jun 30, 2020 12:09 pm

Hello

I purchased the QHY174 GPS this week and have confirmed its operation.
Therefore, the time stamp is displayed as "0001 01 01 00:00:00:0000000" under certain conditions. This is reproducible.
The version of SharpCap that I use is 3.2.6377 -64bit.
The conditions that occur are
1920x1200, Binning1x1, USB Traffic 0,
In MONO16
<12.9msec
In MONO8
37.1 - 99.8msec
720x480, Binning1x1, USB Trafic 0
In MONO16
<5.45msec
In MONO8
<4.46msec
Please let me know if something similar happens to others.

Regards,
watan_rockhand
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MONO8_50msec_zoom-up.PNG
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admin
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Re: Timestamp issue w/QHY174GPS

Post by admin » Tue Jun 30, 2020 8:03 pm

Hi,

not a problem that I've seen before – have you validated that the calibration is correct when you are taking these measurements? SharpCap now performs approximate calibration automatically based on experiments that uses here on the forums have done to work out the relationship between camera settings and calibration parameters. As far as we know those relationships apply to all cameras, but we can't be sure. Usually you will need to perform a small amount of adjustment to the calibration after changing exposure/binning/bit depth/resolution/usb speed.

Thanks, Robin

procyon12
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Re: Timestamp issue w/QHY174GPS

Post by procyon12 » Tue Jun 30, 2020 10:51 pm

Hi,

the timestamp "0001 01 01 00:00:00:0000000" is shown if you have no GPS lock / Bad Data with GPS on. Have you checked whether the camera temporarily loses its GPS lock? (see e.g. GPS-log file, and/or GPS status window).

In order to reproduce your problem, I would need to have your full settings (capture profiles and ...CameraSettings.txt files) and the hardware used for recording. (Incidentally, I am familiar with the SEXTA device shown ...).

Cheers

Christian

watan_rockhand
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Re: Timestamp issue w/QHY174GPS

Post by watan_rockhand » Wed Jul 01, 2020 1:00 pm

Hello Robin, Christian,

Thank you for reply.
I did some additional testing and as you said, the GPS was not Locked and the timestamp was "0000 00 00 00:00:00.0000000" with BadCalibrationReduceEndPos.
The table of test results is as attached.
What I learned from that was
1. It occurs when the exposure time is short or the USB transfer speed is limited. (Light blue part)
2. It occurs in a specific range of MONO8. (Yellow part)
About 1 is acceptable, but I think there is concern about 2.
I will attach the MONO8 camera setting at 50msec and the information of my PC.

Best Regards,
Hiroyuki Watanabe
watan_rockhand

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Attachments
Capture_00001.CameraSettings.txt
(788 Bytes) Downloaded 2 times
Capture_00001.jpg
Capture_00001.jpg (106.69 KiB) Viewed 186 times
Calib_List.xls
(15 KiB) Downloaded 3 times
BadCalibrationReduceEndPos_50msec.png
BadCalibrationReduceEndPos_50msec.png (691.59 KiB) Viewed 186 times

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Re: Timestamp issue w/QHY174GPS

Post by admin » Wed Jul 01, 2020 3:46 pm

Hi,

if you are getting the BadCalibrationReduceEndPos status then you need to do just that – reduce the end calibration position value until that status goes away. This is an error condition with the camera that SharpCap detects and fights for you – for some reason under certain conditions of bad calibration values the camera will claim that it is locked but returned the same time stamps with every frame. SharpCap flags this up to avoid you collecting bad data without noticing that something is going wrong.

Cheers, Robin

procyon12
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Re: Timestamp issue w/QHY174GPS

Post by procyon12 » Wed Jul 01, 2020 5:05 pm

Hello Hiroyuki,

I tested 3 cases from your table (see attachment) and got always a lock. I think the key is, that you must calibrate both Start and EndPos.

I hope this helps. (If I may ask: I see that your camera is FW upgraded. Did you buy your camera with this upgrade done by QHY or was it made later - as in my case?)

Christian
Attachments
Calib_List_1.xls
(32.5 KiB) Downloaded 6 times

procyon12
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Re: Timestamp issue w/QHY174GPS

Post by procyon12 » Wed Jul 01, 2020 6:58 pm

Hi Robin,

sorry that I overlooked your above post.

In the 3 cases I tested with Hiroyuki's settings your (and SC's) recommendation

"if you are getting the BadCalibrationReduceEndPos status then you need to do just that – reduce the end calibration position value until that status goes away"

was insufficient, I had to tune the StartPos too (by a very little amount, see the excel file) - means I made a complete calibration. In this respect Hiroyuki is right in his statement.

I think, that is not a big problem, however, a user can run here into difficulties. Maybe BadCalibrationReduceEndPos should be renamaed a little ?

Cheers

Christian

watan_rockhand
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Re: Timestamp issue w/QHY174GPS

Post by watan_rockhand » Wed Jul 01, 2020 10:41 pm

Hello,

Thanks for the advice, Robin, Christian.
I bought a new camera from QHY at the end of last month.
I haven't updated anything on the camera.
The SharpCap Calibration value is the default.
I attach a photo of my camera.

Regards,
Hiroyuki
Attachments
81B37628-8B41-4F5B-8A87-140E63C9D3D4.jpeg
81B37628-8B41-4F5B-8A87-140E63C9D3D4.jpeg (247.48 KiB) Viewed 164 times

procyon12
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Re: Timestamp issue w/QHY174GPS

Post by procyon12 » Thu Jul 02, 2020 6:20 am

Hello Hiroyuki,

many thanks. I asked this question because so far all QHY174GPS cameras had reduced GPS data output. There was a complicated way to upgrade the firmware, see viewtopic.php?f=28&t=2802#p14626, to get more GPS data, especially for minor body occultation observations.

Good luck with your camera.

Cheers

Christian

watan_rockhand
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Joined: Sat Jun 27, 2020 11:20 am

Re: Timestamp issue w/QHY174GPS

Post by watan_rockhand » Thu Jul 02, 2020 1:16 pm

Hello,Robin, Christian,

Please let me know about LED Calibration.
MONO16,1920x1200,1x1,SER,20ms,USBTrafic=0 When LEDCalibration is performed, it becomes "CSP=4224, CEP=10916", which is close to "CSP=4190, CEP=10930" on the QHY website. ..
However, Exp. in GPS status became 89.2us.
On the other hand, the default value of SharpCap is "CSP=6301, CEP=1504297", which is greatly different from the LED Calibration value, but the Exp. value in GPS status is 19971.2us, which is close to the indicated value of 20ms.
Is Manual LED Calibration No Longer Needed?

You taught me to change the CSP or CEP if I got "BadCalibrationReduceEndPos", but under the same exposure conditions I would have to do this every time. Could you let me know how to save a new CSP, CEP?

Regards,
Hiroyuki
Attachments
MONO16_1920x1200_1x1_SER_20ms_USBTrafic_0.png
MONO16_1920x1200_1x1_SER_20ms_USBTrafic_0.png (1004.68 KiB) Viewed 121 times

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