Cooled astro camera design flaw?

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D. Jung avatar


Bought this cooled CMOS camera (and returned it).
In the image you can see the holes behind which the fan for the heat sink of the pet cooling sits.
You can also see that there are one or two PCBs, likely managing the data transfer and control of the camera. Those PCBs are completely unprotected and if you get dew or just high humidity, it can easily reach the PCB.

My question, is this a common design?
On my Newtonian, the holes would face upwards and I do get some nights with heavy dew, where a layer of water can form on my equipment. So this didn't seem like a long life product to me and I returned it. 
I wonder why you would make astro equipment that is not even splash proof. Maybe there are people doing indoor astronomy and this is in fact an indoor astro camera?
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Maria Pavlou avatar
Agreed is pretty poor for the price we pay for these things new!
Bruce Donzanti avatar
How about making the cameras so that the sensor is orthogonally aligned to the camera casing?!…..  my new pet peeve.
Dsmith79 avatar
I agree,  that seems to be a design oversight. In the case of imaging with newts though, you can turn the OTA so that the draw tube hangs down. I've seen this as pretty standard practice, as it also relieves any torque from having the long drawtube/coma corrector train hanging out to the side.
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Stuart Taylor avatar
D. Jung:


Bought this cooled CMOS camera (and returned it).
In the image you can see the holes behind which the fan for the heat sink of the pet cooling sits.
You can also see that there are one or two PCBs, likely managing the data transfer and control of the camera. Those PCBs are completely unprotected and if you get dew or just high humidity, it can easily reach the PCB.

My question, is this a common design?
On my Newtonian, the holes would face upwards and I do get some nights with heavy dew, where a layer of water can form on my equipment. So this didn't seem like a long life product to me and I returned it. 
I wonder why you would make astro equipment that is not even splash proof. Maybe there are people doing indoor astronomy and this is in fact an indoor astro camera?

The colour looks suspiciously like a ZWO, but I would hope not, as I have two of them.

What is 'indoor astronomy'? Is there such a thing? If you mean EEA then the camera still has to be outside (as it's attached to the scope). Only the laptop is indoors.
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andrea tasselli avatar
Some times I get shorts by high humidity when touching the casing and yet the camera never ever flinches a bit. Besides, shouldn't it be rather warm with the fan and Peltier running full blast? Admittedly my ZWO hasn't got such features.
D. Jung avatar
It's not a zwo, it's the Altair equivalent to the asi 2600mm.
I got super annoyed that for the price of the camera, they pretty much send me a cabriolet of camera.

Sorry, I should have held up my sarcasm sign when writing about indoor astronomy, thought that was implied smile

Sure, when the camera runs, it might get a bit warmer so no dew forms, but what if I get a power cut or after I stop the imaging? I usually leave my stuff out over night.

Maybe it's just me, but for ~3000$ hard earned dollars, I expected a bit more…
Tommy Blomqvist avatar
I did check my budget ZWO-camera (ASI533MC-PRO) and noticed that the PCB for power and USB-hub is unprotected.
Even if I always have my camera mounted downward on my Newt (when in home position) it still doesn't feels optimal.
But I've never noticed any real problems even in very humid conditions...

Michel Makhlouta avatar
This is common, the sensor is protected in a different "chamber" but the PCB doesn't need to be protected, those are usually treated when produced, there are different methods like lamination and coating, etc… I dismantled my ZWO on several occasions, the back of the camera has the pcb, fan and heatsink, and it's all exposed, so is your laptop and most of the your electronics that are air cooled. It was never an issue for me, and I live a couple hundred meters from the sea.
Björn Arnold avatar
I don’t consider it a design flaw.

1. To get something hermetically sealed isn’t that easy. If, for whatever reason, water gets inside, it’s tough to get it out again and that’s trouble.
The typical option is to coat the whole electronics for protection. If that’s the case with the astro electronics? I don’t know.

2. Dew is practically free of any minerals and hence electric conductivity is low. 

If dew builds up, it can also evaporate quickly.
Steven avatar
I don't know how much of a problem it would be.  It's in a cooled camera, and the parts are probably hot enough to prevent dew from forming on them. Or, there is enough airflow to prevent it from forming. There are many people that leave these kinds of things outside 365 days of the year, covered by a small cover and a little dehumidifier-bag. So I'm sure it can take a night outside just fine.

Equipement like this is design to be used outside. But, given that the nature of the hobby requires good weather and cloudless nights, there isn't a huge need to spend the extra time/cash/research etc to make it water/splashproof.  And I doubt you'll find this to be any different in any other brands, so returning it to go for a different brand might not make a huge difference. 

Either way, it's also probably best to flip/rotate your newtonian to have the camera pointing down, towards the mount. this also has the benefit of lowering the center of gravity (and preventing dew by having the ports facing downwards.)
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Stuart Taylor avatar
D. Jung:
Sorry, I should have held up my sarcasm sign when writing about indoor astronomy, thought that was implied


Oops! Yes, re-reading it, it's pretty obvious you were being sarcastic. Now where is the facepalm emoji....?
Björn Hoffmann avatar
Two comments:
  • Typically, such outdoor electronics will have a conformal coating covering the complete PCB. Thus, humidity cannot reach the solder joints.
  • Since the electronics get a little warm when running, they will stay above the dew point. So even if you are in a very humid environment, humidity will only condensate on cold surfaces (like our telescopes, front lenses, car roofs, etc.)
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Linwood Ferguson avatar
Yeah, I think it would be tough to design so you had good airflow for the cooler and also keep high humidity air out.  But if you keep power on dew isn't going to form inside, it stays pretty warm.  

I just leave the cooler and dew strips on my rig on when it parks at dawn, so it's still staying dry in the important areas even if the tripod and mount are drenched from dew.   I think I could warm the camera and it would stay hot enough without the cooler running, but not sure as I think that stops the can also (dew also will not form with good airflow, generally).  I say "think" as it comes on with power initially applied, but I think it turns off if you turn the cooler off in the driver (yet the cooler isn't on by default on power up, rather confusing, so safer just to keep it on). 

Since I shoot flats later in the morning after I wake up, having the camera already cool is useful.