Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

QHY600 Pro Fiber Usage

  • Please log in to reply
5 replies to this topic

#1 hmaron

hmaron

    Lift Off

  • -----
  • topic starter
  • Posts: 12
  • Joined: 01 Dec 2020

Posted 23 February 2021 - 03:36 PM

I hope this isn't repetitious but I couldn't find this question previously discussed. Cost aside, who is either utilizing or is considering using the 10gig network connectivity of this offering? I would just love to hear people's thoughts. It's not like USB3.0 is slow. Yes, it is true that it USB can be finicky whereas network is generally quite stable providing one is properly set up for it. The cost differential is substantial. But, again, with cost aside, I would love to hear the thinking. I actually found the feature surprising. I say that because there doesn't even appear to be much buzz as a request nor do I get the impression the competition considering it as a feature in their pipeline.

 



#2 fbzolt

fbzolt

    Vostok 1

  • -----
  • Posts: 137
  • Joined: 03 Apr 2013
  • Loc: Edgewood, NM

Posted 23 February 2021 - 04:00 PM

Hi,

 

  From what I heard, the fiber is not for network use but goes into a frame grabber.  QHYCCD has one available (PCIe I think), but while others make SFP+ fiber frame grabbers, I don't know whether they would work.  We use similar at work converting CameraLink to fiber for transmitting video data in EMI prone systems.  It would be nice to have the data over fiber, but unless your pc can accept an 10Gig SFP+ fiber, you would need to convert it to 1000Base ethernet to use in a standard RJ45 port...then you would not gain much as far as data rates.

 

Thanks,

Frank Z...



#3 dghent

dghent

    Apollo

  • *****
  • Vendors
  • Posts: 1,010
  • Joined: 10 Jun 2007

Posted 23 February 2021 - 04:02 PM

I have this for testing purposes, along with the PCIe capture card.

 

The two SFP+ interfaces on the rear are operated in an aggregated link mode. The summed bandwidth of this arrangement allows the camera to send 4.5fps back to the PC at full sensor resolution and bit depth in any of the 4 main readout modes - Photographic, High Gain, and the two Extended Full Well modes, which are also found on other QHY cameras that have sensors in the same family. The QHY600 Pro model now has a 5th mode that's available only on it, which is a 14 bpp mode that enables a higher 10fps frame rate. Frame rates can also increase with a smaller ROI being specified. 

 

There are use cases for this - occultation studies or other such applications that want a large FOV and a high frame rate. The Pro model is equipped with an accessory port which a QHY GPS receiver can be connected. This can use the timecode portion of the GNSS/GPS signal (every GNSS/GPS sat has a few atomic clocks) to timestamp frames or trigger synchronized exposures with other cameras.

 

So, for long exposure astrophotography, there's not really a compelling use case since you're not going to image at such frame rates. I suppose there could be one if your imaging PC is a distance away and you'd rather run your images over fiber rather than USB, but this is probably a bit overboard since people are putting their imaging PCs on the telescope itself or at least quite near it and remoting in over wifi.

 

The 10Gb interfaces are driven by a RTOS running on a controller inside the camera. I think that QHY is interested in developing a network (as in IP network) capability that streams sensor data over UDP, but I'm not sure how far along they are on this. It's software, so between firmware and any necessary FPGA software updates, existing cameras should be able to gain this functionality should it come to fruition.


  • bortle2 likes this

#4 hmaron

hmaron

    Lift Off

  • -----
  • topic starter
  • Posts: 12
  • Joined: 01 Dec 2020

Posted 23 February 2021 - 08:48 PM

I was having difficulty even speculating on what such an application would require such a high frame rate and you successfully provided one such example.  Pretty darn esoteric, no doubt.

I was wondering if (or rather hoping) folks were flirting with using these frame rates in an attempt to step toward DSO lucky imaging.



#5 TxStars

TxStars

    Vanguard

  • *****
  • Posts: 2,459
  • Joined: 01 Oct 2005
  • Loc: Lost In Space

Posted 23 February 2021 - 09:18 PM

@hmaron,   One could try this, tho it will fill a SSD fairly quick.



#6 dghent

dghent

    Apollo

  • *****
  • Vendors
  • Posts: 1,010
  • Joined: 10 Jun 2007

Posted 23 February 2021 - 09:28 PM

I was having difficulty even speculating on what such an application would require such a high frame rate and you successfully provided one such example.  Pretty darn esoteric, no doubt.

I was wondering if (or rather hoping) folks were flirting with using these frame rates in an attempt to step toward DSO lucky imaging.

Sure, Lucky Imaging is another use I had thought of, but slipped my mind when I wrote my response. I'm sure there could be non-astro uses for these cameras, too, seeing as how crossover from other scientific and medical fields sometimes happens when imaging requirements match up.

 

But with frame rates and frame sizes like this, the pipe between the camera is just one part of the overall contraption. Your physical storage and imaging program would need to be geared towards it. CPU and memory bandwidth, too, if compressing the data on the way to disk is desired.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics