OK. Having decided to get a QHY8 from Peter Tan, I thought I better read up on it a bit. Yes the wrong way round I know, but its not called berserk for nothing.
Seems lots of people have had problems with reflections, and then with the sensor icing up due to the modifications required to get rid of the reflections.
Is this a good camera to buy? Are the issues of the niggle kind, or more like the tear your hair out, throw the camera as far as you can out into the field at a dark-sky site kind?
Is there a better choice of camera for similar money?
It is a great camera, and ages ago I took sourced mine from him, as there was no local dealer. He will look after you, but I have to be honest why not give your local seller a try first.
I had issues with mine, nothing major, and mostly operator error, and your local dealer was the guy who got me through, even though he didn't sell it to me.
At least ask, or have you already done this?
Gary
Peter Tan is NOT an authorized QHY dealer, and what he sells are "Second Hand" NOT new.
You are also buying ex repaired, and old stock that he buys from anywhere.
You have NO warranty from QHY, as Peter Tan is NOT authorized to do any warranty, so he has to do it secretely thru another fake name.
He buys the cameras in a shady method, and QHY has had many complaints about his dealings. As did i, and as you will now to return the camera back to him.
There is a reason why his cameras a cheap. You have unfortunately just found out one of them.
I hope he comes thru with your issues. The camera is a good camera, but it needs to be in correct operating condition.
Just to clarify I haven't as yet bought the camera.
I am in the process of getting prices shipping costs for a few items, the camera being one of them.
What I am most interested in are the issues that others seem to have had with them, and whether I should consider something else instead.
Theo, I notice that you have the QHY8L on your website. Have you had any feedback regarding internal reflections with these? Are they a big jump in quality or performance over the old model?
Here's an example of reflections from a qhy8. I found moving the front glass window further from the sensor calmed down the reflections a lot but then again they only showed up on bright stars.
I tried just putting a normal nosepiece on the front of the camera with an 2" astronomiks ir filter on the end. It worked reasonably well but you would need to seal the filter glass to the filter holder and the nosepiece to the camera to keep air out in the long term.
I believe all these problems where solved in the newer cameras, qhy8 pro, qhy10 etc. Theo would know more about that.
Adam,
I have a used QHY8Pro that was originally sourced from Theo. After some initial problems with USB-based cooling instability, it is now a nice reliable camera.
Since I often loosen the IR nosepiece (accidentally), I have had some problems with condensation recently. Theo's plastic bag solution works just fine. I happened to do it yesterday and "soaked" the camera in the argon-filled bag until this afternoon, then reattached the nose inside the bag and ran the camera for a few hours. Just FYI, the cooler seems to reduce the sensor temp by about 45C.
I ran it until 10.30 tonight in the obs and noticed that it looked like I was still seeing some condensation effects. On checking, it turned out I still had condensation on the external side of the IR filter, (about 15mm diam) but nothing internal. The CCD was at -17.5C. (Hot humid night).
So the bag will fix internal condensation, but I'm still thinking about a solution for the external stuff. I'll keep you updated.
Mike, have you got one of those heaters that scew onto the nose piece? I have one here if you wanna try it.
My qhy9 decided to ice up tonight as well. It is hot and humid tonight. I just took the nose off and hit the guts with a hair dryer and screwed the nose back on. Been fine since then ....
Hi Adam, The QHY-8 is an obsolete camera now, and is only being sold until old stock is gone.
The replacement is the QHY-8L, and although its a single TEC cooled camera, it still does a very good job cooling. But best of all, its controlable.
All the new QHY cameras have a new thicker front glass filter. This was was two reasons.
1, it helped the reflection issues by the extra AR coating.
2, made thicker so as to help prevent condensation appearing on the outside. Because of the extra glass mass, the condensation was slowed down.
Although its near impossible to prevent condensation on humid nights, regardless of manufacturer, every little bit helps.
These new thicker front filters are available for the older QHY-8, or any camera with a M42 thread. It comes with the Tip Tilt adapter, so you can also align the CCD to the focal plane. Heres the link to it.
If you wish to learn more about it, maybe a personal message, as its getting close to hitting the "TOS"...
A..... I have had some problems with condensation recently. Theo's plastic bag solution works just fine. I happened to do it yesterday and "soaked" the camera in the argon-filled bag until this afternoon, then reattached the nose inside... .
Hi Mike...can I ask...why Argon...why not "dry nitrogen"? Maybe you have an Argon gas canister for welding? .
edit:
Ah..never mind just read the SBIG frosting posts.
The reason I ask why argon?... is that dry nitrogen (not std nitrogen... it must be the dry nitrogen) is readily available. We used to use it for hermetically purging F111 instruments....back in the stone age!
Argon because (a) Theo said so . Actually, seems to me any dry relatively inert gas would do, even dry air.
Argon for me is convenient in that there's a welding shop nearby and the gas is guaranteed to be dry, but I suspect a good load of dessicant in the plastic bag with the camera for a couple of days may do just as well.
However, the bragging rights of casually informing onlookers that "the camera is argon-filled" surely has some value
Argon because (a) Theo said so . Actually, seems to me any dry relatively inert gas would do, even dry air.
Argon for me is convenient in that there's a welding shop nearby and the gas is guaranteed to be dry, but I suspect a good load of dessicant in the plastic bag with the camera for a couple of days may do just as well.
However, the bragging rights of casually informing onlookers that "the camera is argon-filled" surely has some value
I was thinking ...maybe because the Argon has a higher ionisation level?..It is inert dry and displaces air/moisture and is readily availble...but I reckon pure dry nitrogen would be just as effective.
All this is probably best if done in a baking oven lets say 50degrees C.. But since this is not readily available...purge with dry nitrogen. And maybe this is the issue. You probably need to purge with dry nitrogen..not just let it soak in it.
And the bragging rights diminish!..my gas is Argon..whats yours.
Anyway..it's all "black magic"! thanks Mike.
P.S.: I have my greedy eye on the QHY8L but are looking at the reflection issue.
I found the standard heater ring did not work on the qhy8pro because the side of the ring that heats up is pointing away from the front of the camera - towards the coma corrector in my case. A dew heater strap works better. I've tried drying out the guts of the camera by sitting it in a bag with silica gel and had some success however I've still had some internal condensation issues occasionally. It seems to start off ok then condensation forms after 1-2 hours. I can't understand why this would be the case?
To completely purge moisture from instruments we used to heat in an industrial oven at around 50 degrees C for around 3~ 4 hours (depending upon the size & type) and purge/evacuate cycle with dry nitrogen during this process.
We would then open the door, solder seal the purge tube and ice test on the glass with cube of ice, gently rubbing it around the glass rim (bezel) and working to the centre of the glass. Any internal moisture would thus form on the inner of the glass.
We did have a mass spectrometer for leak testing (with dry nitrogen and helium back fill gas) but it was broken, had been for years and the Airforce was too short armed to buy another for this purpose.
Rubbing ice on a hot glass surface used to result in many glass breakages..if you followed the "rubbing it around the bezel 1st" then you would reduce this cold shock and breakage problem. But it did occur..too often.
This "purge" system worked a treat and you could really see the moisture formation, rapidly! It was fascinating to see instruments fail, then after more purging and baking..Pass! This system worked!
But from this you can guess that many hrs of heating and purging is really the only way to go to completely purge an instrument (camera).
A short purge probably doesn't cut it. But obviously owners do not have small industrial ovens and dry nitrogen HP bottles lying around.
I did develop and trial a method of heating nitrogen and passing it thru the instrument..but alas..fail..you need a very large flow rate of gas! The instruments act as a heat sink.
So really not much to suggest apart from variations of placing it in a bag with inert gas to soak purge! I also suggest that some cameras may not be perfect hermetic seals which is exacerbating the moisture issue.
The reason for Argon, is that it is easily found by anyone. There must be a panel repair shop near just about anyone and anywhere.
Nitrogen however, is more task specific, and thus harder to get you hands on.
There is specific Nitrogen that is used to displace water in heavy feeder cable used on large high powered Radio and Television transmitters.
They use it to purge all the moisture out, but again, its not so easy to get a hold of.
Peter, you need to make sure that the surface of the CCD is clean. Use Acetone to revove any residue on the CCD. Even when you think its clean, its not. Acetone will remove this, and dont be afraid to use a large quantity as well. Just make sure its dry before re assembly. There is also desicant strips that stick on inside the camera or anywhere for that matter, and absorb a very large amount of moisture.
If any one opens up a camera, regardless of model, and either doesnt have time or availability of desicants, bags, etc, then i suggest standing in front of a heater/hair dryer etc, while re sealing the camera. This way only hot dry air is blowing over the chamber, and when sealed, the air inside is dry.
My QHY9 is sitting outside on the scope day and night.
I always cool the camera to -20C and never get frost or dew on the camera (glass or otherwise).
As long as the ccd is cleaned and assembled while blowing hot dry air on it, it will not have any problems.
Also place some very thin double sided tape in the ccd chamber so if there is any dust in the chamber it will stick to that and not the ccd.
I haven't opened up or cleaned my QHY9 for almost a year now.
Well sealed and a couple of simple mods make the QHY camera's much better.
QHY8 issues
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. Actually, seems to me any dry relatively inert gas would do, even dry air. 
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