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DIY peltier on asi178mm


Fieldsy
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10 hours ago, Fieldsy said:

Hi all has anyone tried a peltier on a asi cam ?

If so has the fan produced any vibrations?.

Thanks

You can get low vibration fans, look for magnetic bearings. But I would use a water block with flexible 6mm/4mm pipe to a PC water cooling radiator. But to be honest you are limited in how far you can cool them due to the sensor chamber not being sealed (the sensor will frost up). It might cause more issues than it solves. 

The other thing is that at this time of year with temperatures hovering around zero at night you will not get very much benefit from that sensor being further cooled looking at the dark current chart (it has the same pixel design as the 183 and is likely to have the same dark current) as by the time you are approaching 0c its already got quite a low dark current.

At 0c the dark current for the 178 is 0.01e/pix/second. So with a 60 second exposure that is only 0.6e of thermal noise per pixel, that is insignificant to be honest. At -10c you get down to 0.004e/pix/second so you might be able to do longer exposures but it wont give you much more and you will have a hard time doing 5 min exposures with a 130PDS on a EQ5 mount without guide errors. As things are with a temperature of about 0c you could do 120s exposures no problem.

Your images are good, they just lack total integration time. If you want to step it up then 30 mins per channel is not going to give you the most impressive results, 6hours is the least I do per channel.  

Adam

Edited by Adam J
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I have an ASI178MM in my All Sky Camera and use Peltier TEC to cool the camera casing with water cooling of the hot side and reach -20°C with good results and no misting or frosting of the optics.  The camera has a thermal jacket and insulation to separate it from the outer casing and hot side of the Peltier TEC.  Though it might seem complicated, water cooling is very efficient and doesn't rely on drawing damp air through a fan.  The water cooling radiator, reservoir with pump etc. are inside my observatory with the ASC mounted outside on the roof.

Edited by Gina
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2 hours ago, Gina said:

I have an ASI178MM in my All Sky Camera and use Peltier TEC to cool the camera casing with water cooling of the hot side and reach -20°C with good results and no misting or frosting of the optics.  The camera has a thermal jacket and insulation to separate it from the outer casing and hot side of the Peltier TEC.  Though it might seem complicated, water cooling is very efficient and doesn't rely on drawing damp air through a fan.  The water cooling radiator, reservoir with pump etc. are inside my observatory with the ASC mounted outside on the roof.

Oh Gina please post a pic I would love to see that.

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3 hours ago, Gina said:

I have an ASI178MM in my All Sky Camera and use Peltier TEC to cool the camera casing with water cooling of the hot side and reach -20°C with good results and no misting or frosting of the optics.  The camera has a thermal jacket and insulation to separate it from the outer casing and hot side of the Peltier TEC.  Though it might seem complicated, water cooling is very efficient and doesn't rely on drawing damp air through a fan.  The water cooling radiator, reservoir with pump etc. are inside my observatory with the ASC mounted outside on the roof.

But is the camera sealed within a small clear dome limiting the amount of moist air around the cooled sensor?

Edited by Adam J
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1 hour ago, Fieldsy said:

Oh Gina please post a pic I would love to see that.

The latest version is not quite finished but there are pics of earlier versions on here and I shall certainly be posting pics of this one when it's finished.

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9 hours ago, Gina said:

I have an ASI178MM in my All Sky Camera and use Peltier TEC to cool the camera casing with water cooling of the hot side and reach -20°C with good results and no misting or frosting of the optics.  The camera has a thermal jacket and insulation to separate it from the outer casing and hot side of the Peltier TEC.  Though it might seem complicated, water cooling is very efficient and doesn't rely on drawing damp air through a fan.  The water cooling radiator, reservoir with pump etc. are inside my observatory with the ASC mounted outside on the roof.

Gina I have done a little googling and water cooled seems very effective, but water cooling a scope on a mount seems very problematic, I have enough trouble with cables being tidy (ocd) the thought of water pipes and a tank with a pump is a little to freaky for me.

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  • 2 weeks later...

Here is a retro fitted pettier cooler on a 178, all engineered by @Tomatobro. It can get to sub zero temperatures but as the cooler is working on the external camera body there is a lot of external icing and some water droplets were evident on the sensor window when imaging at the zenith. A ZWO retro fit heating tape has since been fitted, along with temperature control to deal with this.

It has a quality fan so no issues with vibration.

It should hopefully get some more use when Galaxy season rolls around, but to date has taken the attached image of M51, using 30 sec subs.

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  • 5 months later...
On 05/12/2019 at 11:12, Fieldsy said:

So my peltier items have arrived looking good but it's just a small one to see how it goes 🤞🏻

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I am going to guess that heat sink will be too small but it really depends on how many watts that peltier is. A water block is a better bet, unless your going to enginear it like tomato above. Too heavy is a problem too as it will cause tilt...its a small sensor mind you.

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1 hour ago, Adam J said:

I am going to guess that heat sink will be too small but it really depends on how many watts that peltier is. A water block is a better bet, unless your going to enginear it like tomato above. Too heavy is a problem too as it will cause tilt...its a small sensor mind you.

Have a larger heat sink now.

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Well using that heat sink and fan with a 7.4v nimh battery that I found in my old rc car box it takes it 5degrees below Ambient on testing ,so all connected and charged for first night testing while imaging 🤞🏻 nothing goes wrong

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Edited by Fieldsy
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Low voltage battery only 7.4v so not running at max .I do have a control unit but will prob only use if needed (12v) i tried it last night and it only took camera temp down to 11.6 degrees that was 5 below ambient.  But going to image tonight and just see how it goes .🤞🏻 If it goes well then a good tidy up and lagging will be next.

Edited by Fieldsy
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29 minutes ago, Fieldsy said:

Low voltage battery only 7.4v so not running at max .I do have a control unit but will prob only use if needed (12v) i tried it last night and it only took camera temp down to 11.6 degrees that was 5 below ambient.  But going to image tonight and just see how it goes .🤞🏻 If it goes well then a good tidy up and lagging will be next.

I'd be interested to know which fan, heatsink and peltier unit you used. And where you got it from?? If you don't mind sharing. 

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21 minutes ago, Bobby1970 said:

I'd be interested to know which fan, heatsink and peltier unit you used. And where you got it from?? If you don't mind sharing. 

U want me to see if it works first lol

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3 minutes ago, Bobby1970 said:

Can do I guess, but I'm sure it will. Interested in the dimensions of the heatsink and fan tbh. 

I have a bigger fan and heat sink but want to keep weight down.

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The 7.4v battery couldn’t cool below 17 degrees (Ambient) so  I will have to wait until I get the 12v power supply sorted And a bracket and larger sink fitted .😩 this Astrophotography def test your patience.

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Haven't considered running a Peltier TEC off a battery (other than something like a car/caravan battery).  I have cooled the astro camera in my ASC - an ASI178MC, using a good quality Peltier TEC - Peltier Module, 54.6W, 4.4A, 20V, 40 x 40mm.  Running this off my 13.8v main observatory supply and using water cooling of the hot side, I can get the camera temperature down to -12°C with an ambient temperature of 15°C.  The TEC draws around 2.5A.

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