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Second Light with the QSI - NGC7822... another

Sp@ce_d

By Sp@ce_d
in Imaging - Deep Sky

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Sp@ce_d

Sp@ce_d

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Well, so desperate was I to try this camera on this target, last night found me shooting this one under the Moon. Thought I'd compare it with my other bicolour from the 314L+ I posted the other day... still being a WIP.

After loosing the firsts hours worth of subs due to what looks like icing up I salvaged an hour an a half's worth to play with.

Oh.. did I say I'm liking this camera a lot.. :grin:  oh yes..

Esprit80

Astrodon 5nm

6x900

Roll on some proper clear dark skies...

post-11176-0-71616800-1446165291_thumb.p

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Sp@ce_d

Sp@ce_d

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I've had my QSI a long time and have been delighted with it. What was icing up, the QSI? Have you bought it new?

Hi Martin

Yes a week old.. so maybe finger trouble from the user perhaps.. I posted examples over here.. http://stargazerslounge.com/topic/255824-qsi-advice-anyone-ice-or-debris/

Hasn't done it since I switched to -10 but not tried it back at -20 yet either. Assuming it needs a staged cooling cycle to reduce shock.

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Physopto

Physopto

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I have had a 583 for several years and it never iced up. It was operated at -20 deg C all the time with cooling in one stage to that temp. It never iced up, ever! I now have the 683 same as yours. It also never has iced up. If yours has then something is wrong. Check it out carefully. It is the warming up that needs care to avoid shock to the chip.

Derek

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MartinB

MartinB

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QSI cameras are purged with argon which should completely prevent icing up.  The argon leaks out over time and the camera (if it's like the 5 series) then relies on it's dessicant.  My argon is long gone so I periodically have to cook the dessicant otherwise I do start to get icing.  

I wouldn't be happy having a new QSI icing up.

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Physopto

Physopto

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Have a look here on page 16 of the QSI manual which states:

"When using forced-air cooling the body of the camera and the window of the CCD chamber can be up to 12ºC warmer than the surrounding ambient air temperature. By definition, the camera will be above the dew point (or frost point) and condensation will not form. When using the LHX there is the opportunity to drive the enclosure of the camera and the CCD chamber window significantly below ambient temperature if the recirculating water is colder that the surrounding environment. If the relative humidity is high enough, this action could drop the camera below the dew/frost point and condensation will form."

http://www.qsimaging.com/docs/QSI%20User%20Guide%202.0.pdf

This is more for liquid cooling but states that the camera body under normal cooling should be above ambient temperatures and so not ice up. I would guess that the cavity window is not actively heated, just passively. As I said so far I have never had an icing problem so far. As it is a new camera it should ne still nitrogen filled.

By the way Argon filling does not prevent icing up as such, it just replaces air which has contaminants and so is an aid to help prevent heat conduction. Hi purity Argon is slightly worse at heat conduction and has no moisture content to speak of. Only a vacuum can prevent conducted heat as there is no, (very few, depends upon the vacuum pressure), carrier atoms present. Heat radiation still can take place across the void from window to CCD chip and from the surrounding casing. Also any internal connections can still conduct heat to the chip.

Derek

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Sp@ce_d

Sp@ce_d

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Hmm thanks for pointing that out.

So that suggests I shouldn't have met the criteria for dew to form anyway. Certainly the camera body was warm to the touch, there was no dampness on any of the gear at all. So, the other things I noticed. I had disconnected from Maxim & done a visual check. Restarted the camera and it came up with fans full blast. That I've not noticed before on power up (or since). I was unable to see the drivers loading under dev/manager. I reseated the usb. Still nothing. Meantime the lights on QSI indicated it had booted up (solid green led state). Fans still high. So I went through a complete system/Obsy reboot/restart. At which point I set cooling to -10 & away it went for the rest of the night looking ok. I left it around 2am under the control of ACP.

Now, bear with me this gets a bit long winded... Since I've had the QSI I've also had about 3 or 4 occasions where Maxim v6.09 has stopped responding during acquisition (not download, but it does also pop a not responding message up in the title bar of the CCD window for a second or so when downloading. I'm assuming this is a download timeout setting somewhere i've yet to find).

No, after about an hours worth of 15min subs windows itself comes up with the "application has stopped responding" message. Only way out of that is to kill Maxim. I've tried different USB ports & cables with same results. CCD is now direct to dedicated PC port using QSI supplied cable. This is a big issue with automation as its hanging the system & in danger of not being able to park scope & close roof!

I've gone back to Maxim V5.24 and have not had this issue over 3 automated nights so far. This points to instability with Maxim V6 to me. So could it have been Maxin causing an issue with frosting. How do I know that the reported temperature was right & it hadn't set it to max? Why do I suspect this?.. Because they broke the temp control with the Atik driver in v6.09. I have to use the Ascom driver to get it to work. Just a thought. So I'm going to set the temp back to -20 using Maxim V5.24 and see how that goes. Not sure I really need to run it at -20 anyway but of course I want to find root cause with this, it's not a light investment!

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Physopto

Physopto

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I have had the same "windows not responding" type messages before. I get it regularly when downloading, but only whilst it is downloading for a few seconds. I am using Maxim DL version 6.10. I think that windows does this for several programs at times with no ill effects. I did have a Maxim DL crash several times a while ago  but it was possibly an earlier version of Maxim or before windows updated. It has not happened for a good while. It may be because I reinstalled Windows again as it was causing other problems.

The icing I think  is a fault of the camera, but also could be as you say a misreading of temperature or temperature control.  I would try it on another computer to check out if it then works OK. I never rely only on one computer. I check everything on up to three before I make any conclusions. I have all programs including Maxim on all of mine as a check for fault finding. QSI ccds are set to stop cooling when the reach -40 deg C. You will not get that cold on air cooling unless in the arctic me thinks.

The reason you could be getting the crash on Maxim is probably due to the QSI camera failing. By this I mean the QSI cameras are very prone to voltage levels. If the voltage falls below (or above) a set level it will give an error message. The led flashes a code and it beeps a code also. The manual will give the error dependant upon the number of beeps/flashes. QSI ccds do not like the voltage above 14 volts. They give an error and although you would think just resetting the correct voltage would be OK they need completely shutting down and restarting and  that means complete  voltage removal as well. Maxim DL has no control over the camera if this happens. The sudden shut down can cause CCD failure by thermal crack!!! Be careful with the shut down procedure, warm up before shut down.  This is something when you get the voltage alarm, that does not happen. I can't remember off hand the lower voltage level. I had al sorts of problems so in the end went with  dc/dc power bricks. ( I can get the make if you want to go down that route.). They output 12.2 volts independent of the input voltages between approximately 10.6 and 15 volts. So far this has sorted out  the shut downs for me, i.e. no more problems so far, crossed fingers. The cameras are so expensive I did not want to take any more chances when I discovered the reason for the shutdowns.

I'll be honest I don't think Maxim is at fault, but I would definitely try the ccd on another  computer set up with the same software to be sure.

I hope this is of some help.

Derek

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Sp@ce_d

Sp@ce_d

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Thats interesting as I've been wondering about the supply tonight. I run the Obsy 12v off one of these set to 13.8 http://www.maplin.co.uk/p/moonraker-375w-switched-mode-dc-variable-voltage-compact-bench-power-supply-n87jn

I had a hang earlier on with v5.24 after a couple of hours running so I've hooked up the supplied QSI psu (yes I know) to see how that goes. Not ideal as I don't like having to strap a wall wart to the mount. I guess there could be noise on the power from the other kit it doesn't like.  It's done another couple of hours on that so far. I'll get the meter out tomorrow & check the levels to compare. I don't have a scope I can look at the noise on the line with any more though.

I'd be interested in hearing a bit more about your supply then. 12.2v is lower than the standard 13.8 from a car battery. I'll need to check the output from my Tracer 22ah as I was hoping to run it from that for trips to dark sites.

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Physopto

Physopto

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I will hunt out the details for you in the morning. I will have to go through the old emails on the main computer. It will be there somewhere. The ones I use are about £14 ish and very good quality. There are some that cost about £40. I put details on another thread here on SGL some time ago. They were initially used for TV supplies in caravans and motor homes as the so called 12 volt TVs cannot take more than about 12.6 volts before damage results. The alternator charging takes the batteries up to 14.4 volts. A good Dec/doc supply will put out about 5amps at 12.2 ish volts. Depends upon the make.

By the way the lower voltage for the QSI is 11 volts.

Depending upon how far you camera is from the supply and the size of the supply cable your 13.6 volts could be quite low when the camera demands high current on full cooling. Bad/poor connections could also loose a bit voltage.

If your QSI power brick from the mains works OK and you don't get any more drop outs you may have cracked the problem, I hope so. QSI state in their instructions that they do not suggest you use other power sources for their cameras other than the supplied power brick. Fat chance in the middle of a field! Low voltage is the safe method, not 240 volts even with an RCD.

Derek

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Sp@ce_d

Sp@ce_d

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Got it

Hunter field Ltd. You can get them off amazon.co.uk 12 volt 5 amp car/ caravan dc/ dc regulated supplies. £10.98 plus postage. I bought. Three of them and they seem really good.

Derek

Excellent.. appreciate your time on this Derek

Cheers Graham

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Sp@ce_d

Sp@ce_d

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This looks like the one. http://www.amazon.co.uk/cigarette-equipments-Hunterfield-distributed-reserved/dp/B008A6GCXK

It comes with a 2.5mm plug I take it you've had no probs with the QSI being 2.1. I can change it if its too loose anyway. Looks like I'll need to stick a cap across the input from the Obsy 12v supply as it's not a real battery.

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Physopto

Physopto

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This looks like the one. http://www.amazon.co.uk/cigarette-equipments-Hunterfield-distributed-reserved/dp/B008A6GCXK

It comes with a 2.5mm plug I take it you've had no probs with the QSI being 2.1. I can change it if its too loose anyway. Looks like I'll need to stick a cap across the input from the Obsy 12v supply as it's not a real battery.

To be honest I cannot remember if I changed the fitting. But I don't connect straight to the camera. All my electronics are in water proof boxes fitted on each side of the scope and then there are sockets to the outside. This includes power and all USB connections. Then leads I made up to the CCD, rotator, focuser, dew heaters etc.

I only image at Star Camps as I cannot at home.

I just hope this helps you as I've gone through several years of fault finding myself.

Derek

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