40 replies to this topic

[Campos]

Good news, according to QHY's the USB2 dowload issues are solved for good, some testing has been done and looks like is't stable now with no "hiccups"

 

Good to know QHY is quick addressing some issues reported on the forum, thumbs up on that!

 

Now, off to try this new version...if the skies clear that is...

 

Cheers,

Edited by Campos, 12 January 2017 - 04:56 AM.

[gotak]

Latest from the qhy forum seems the new drivers maybe doing something strange with exposure. And the resolution changed with the new driver which is completely wrong. Still points to a lack of attention. Sure it's great to get fixes out but if you introduce other problems then it sort of make the fix moot.

[Campos]

Latest from the qhy forum seems the new drivers maybe doing something strange with exposure. And the resolution changed with the new driver which is completely wrong. Still points to a lack of attention. Sure it's great to get fixes out but if you introduce other problems then it sort of make the fix moot.

I made a quick test yesterday (was too tired...) and yes I can confirm the the vertical resolution drops 100 pixels comparing to the previous version...there's also something strange goin on with USB traffic as the amp glow increases with higher USB traffic.

 

Glad i'ts all cloudy here now...

[Cyclop_si]

Luis,

On QHY Forum there is explained why amp glow increase with increased USB traffic settings. I am not very technical to understand details, but explanation still sounds well formulated.

Regards,

Daivd

[Campos]

Hi David,

 

Just checked it, ok it makes sense, so in theory we should use as low as possible (maybe 5 or 10) with no download hangs and stick with it for callibration and aquisition, so it all callibrates properly.

 

Cheers

[gotak]

Hi David,

 

Just checked it, ok it makes sense, so in theory we should use as low as possible (maybe 5 or 10) with no download hangs and stick with it for callibration and aquisition, so it all callibrates properly.

 

Cheers

Actually it makes no sense unless their hardware design's terrible or their software engineers are the type I'd never hire, which I am starting to suspect could be both.

 

They have a DDR buffer. In theory the buffer should just be as it says on the can: a buffer. The hardware should take care of all the exposure and downloading of data from the sensor into the buffer. After which the data is transfer out to the computer over the USB connection at whatever rate's possible on the computer. The DDR buffer is digital so once data is in there there should be no impact no matter how slow the USB connection is.

 

What it actually sounds like now is that QHY actually designed the HW or firmware around timing on the USB connection. Since USB and your windows PC in general is not designed to guarantee any tight timing (we find at work the best resolution we can get with a windows timer is about 15ms) that would be a terrible design. This would explain why some folks were having strange exposure issues on slow USB connections. If all the exposure stuff happens based on USB commands, random delays to commands due to USB being slow could change your exposure randomly.

 

I understand these things are built to a price but it just seems there a lot of bad decisions in either the HW or how they structured the SW.

 

And slightly off topic, I am not too surprised. I have worked with engineers from China before (FYI that applied to me, I am Chinese.) some are amazing, and some you just wonder how they graduated from university. A few years ago I got a question about why a board design didn't work using our chips. No amount of hand holding on debugging the chip seems to made a difference to them. So I asked for a schematic of their design. Once I had it, it took 1 glance to realize they design a 5 volt power supply for a chip that max out at 3.3. Max 3.3 was on the first page of the chip's datasheet.

 

As a small company I don't know if QHY has the name or money to attract the good talents they need to make these issues resolved internally. Even now working at a large french conglomerate with little name recognition outside of Europe we find it hard to attract the good talent in North America. Sometimes I have decided to hire folks who I am not 100% happy with because of time constraints and also well they aren't the perfect resource but they'll get the job done. And on a daily basis that has lead to having to remind myself not to get too upset if someone did something that causes me to do a face->palm. Hiring good people is very very hard. At one point in the past a place I worked for had a 1st interview pass rate of something like 1 out of 200, but boy were the folks there smart.

Edited by gotak, 15 January 2017 - 11:36 AM.

[microstar]

That's not the way I read the QHYCCD Forum post. Sounded to me like the old drivers weren't using the DDR buffer (seems odd) but rather were trying to control the problem by reducing download speed via the USB Traffic setting. If your download is slower then there's going to be more amp glow. The new driver uses the DDR so now you want to set the USB Traffic as low as possible (testers are reporting good results with USB Traffic set at 1 or 0). So download as fast as possible to the DDR to minimize amp glow and let the DDR handle the USB 2 traffic. Is that what others got out of the QHY forum discussion?
...Keith

[hfjacinto]

I think what Keith says is correct. I currently have the USB traffic to 5 but I'm going to set it to 1 after my imaging session.

[Campos]

For what I understood it seems that the previous drivers were not using the buffer (go figure...) and were relying intirely on the USB transfer speed.

 

Now, I've been doing quite a bit of imaging, we had very clear skies over the whole weekend, appart from the big moon it was perfect

 

Gotak makes a good point over the erratic exposure behavior, I've noticed this and in fact discussed it over the QHY forum, see here an excert of the topic:

 

"Hi all,

Got my 163M about two weeks ago, but when giving some real use to the camera I stumbled across some issues:

 

1. When aquiring my light frames I see an erratic exposure behavior, it's like the camera is changing the gain during exposures, some exposures are correct but others apear underexposed, at first I thought it was due to thin high clouds during capture but after successive nights of imaging with perfect seeing the issue remains, some subs have the correct exposure and some seem to have a different exposure setting.

 

2. This behavior is also noticed on the bias aquisition, by looking at the histogram there is an erratic exposure fluctuation between frames, it's like they are taken at different exposure settings again, I'm using an exposure of 0.001 secs. and gain:20 offset 75, same as my lights and use APT for aquisition because this is the only program stable enough for me to use on my old usb2 laptop, all other crash or hang on dowload (SGP, EZCAP)..."

 

The camera now seems to work fine regarding the USB2 issues, but on my particular case, I'm still not interely convinced of the following:

 

-I continue to see an unusual amount of black (dead) pixels on my images, especially noticed on the bias frames

 

-Exposure fluctuation, easy to see on the bias histogram when acquiring the subs and also on the lights (will check this in more detail now that I have quite a good amount of data for analisys)

 

Appart from these things the camera works extremelly well for narrowband imaging, the amp glows are reduced from the previous SW versions, and loosing 100 pixels on vertical resolution is ok with me, if this is needed to further refine the camera behavior.

 

On my little SW ED80 with 0.8X reducer I was abble to get very nice images with 300 sec subs at Gain 20 and Offset 100, with usb traffic speed 5, with incredible detail for only 480mm f/l, now I need to process my data and see what I can pull out

 

Cheers,

Edited by Campos, 16 January 2017 - 06:06 AM.

[hfjacinto]

Luis,

 

One thing I noticed on the QHY is that the standard deviation is very minimal sometimes less than 40. Could those dark pixels not really be dark, but below the standard deviation?

[Campos]

Hi Helder,

 

I´m not sure...but also I don't know what to expect as I don't have any experience with this sensor

Do you mind if I send you a raw single bias so you can compare with yours at the same gain / offset settings?

 

Another thing I'm still noticing is the exposure random changes, it´s suble but it's there, do you noticed this behavior with yours? I've been doing a session on the horse head nebula and yesterday I compared two frames from this same session with same exposure time and settings, there are in fact these exposure random fluctuations, once I've gathered all relevant info I'll check this with Qiu over QHY forums.

 

Appart from this the camera is now working nice, very happy now  

 

Many thanks,

Edited by Campos, 18 January 2017 - 04:33 AM.

[Marco Prunotto]

my small contribution: spectroscopically the camera is amazing with a very big sensitivity in the blue region (all Hydrogen Balmer series visible). An amazing tool for spectroscopy: more to come.

[StarMike8SE]

I am thinking about this camera.  It has been a month since the last post.  Are most of the issues resolved?

[hfjacinto]

Only issue I had was with USB2, i've been working well for over a month, so I will say yes.

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[StarMike8SE]

Only issue I had was with USB2, i've been working well for over a month, so I will say yes.

Thanks.  And great image!  

[Aenima]

i would still count the microlens reflections as an issue, but after the tests i've seen and some i've done myself the problem doesn't really have a solution apart from avoiding bright stars. :/