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How does ZWO cools its sensors?

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#1 moxican

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Posted 20 May 2019 - 09:46 PM

I am trying to understand this. Well most of the sensors nowadays have their electrical board right on top of them. This is how they are manufactured. I happened to know that the ASI071 (IMX071) is one those sensor yet ZWO manages to cool it down pretty effectively. Same thing with the ASI183. But with the back illuminated ASI294 it is problematic based on what I have read here on CN.

So how do you cool your sensor when you do not have unobstructed access to it?



#2 orlyandico

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Posted 20 May 2019 - 10:17 PM

IMX183CLK sensor is 118 pin LGA (land grid array). So it is bonded to the PCB.  With sufficiently robust through-holes from the front to the back of the PCB, you can use those PCB through-holes as cooling conduits so even if you cool the back side of the PCB, it will still effectively cool the sensor.

 

This is much less effective with a DIL package (dual in line) like a KAF8300 because there are much fewer pins and they are at the edges of the chip rather than across the back.


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#3 petert913

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Posted 20 May 2019 - 10:18 PM

Peltier cooler,  no?


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#4 sg6

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Posted 21 May 2019 - 01:36 AM

Peltier somewhere, just where is the question.

If sufficent holes I suppose they could sit the board+sensor on the cool side and so drag heat away. Alternative could be like a dew heaterand wrap a ribbon around the internal casing.

 

The cool side is maybe the easy bit, that has to be close in effect to the sensor. The hot side would seem to be the problem as that need to have access to a heat sink and the heat has to be isolated from the camera body as you want to get that heat away.

 

I can envisage a metal cylinder that slides over the camera unit that is thermally isolated on the outer surface and lower end with a peltier acting as a capping unit at the "top".

 

That way the camera is assembled, the cooling unit slid over the sensor unit and a heat sink added to the hot end of the peltier. Peltier cools the cylinder, cylinder isolated from camera body and heat from the sensor is transferred.



#5 moxican

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Posted 21 May 2019 - 07:01 AM

All right, but how is that effective cooling. If the peltier cooled unit is not in immediate contact with the sensor itself?

 

Say that there are sufficient through wholes, whatever they may be, they are not the metal (copper or aluminum I guess) from the cooling element. Thus reducing heat (cold) transfer to the sensor. If it menages cooling only around the edges, wouldn't that result in uneven sensor temp. Either way, matching dark frames will be almost impossible. So, how do they go around this?



#6 Zebenelgenubi

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Posted 21 May 2019 - 08:14 AM

All right, but how is that effective cooling. If the peltier cooled unit is not in immediate contact with the sensor itself?

 

Say that there are sufficient through wholes, whatever they may be, they are not the metal (copper or aluminum I guess) from the cooling element. Thus reducing heat (cold) transfer to the sensor. If it menages cooling only around the edges, wouldn't that result in uneven sensor temp. Either way, matching dark frames will be almost impossible. So, how do they go around this?

The sensor's Si substrate itself has a high thermal conductivity and the thermal path length to the cooler is small.  Unless lots of power is dissipated in the sensor array (not the case) the thermal gradients will be very small.  I am convinced that this uneven cooling stuff is a red herring.


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#7 jdupton

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Posted 21 May 2019 - 10:43 AM

Gusztav,

 

I am trying to understand this. Well most of the sensors nowadays have their electrical board right on top of them. This is how they are manufactured. I happened to know that the ASI071 (IMX071) is one those sensor yet ZWO manages to cool it down pretty effectively. Same thing with the ASI183. But with the back illuminated ASI294 it is problematic based on what I have read here on CN.

So how do you cool your sensor when you do not have unobstructed access to it?

 

   I have never seen the detailed specifications for the Sony IMX071 sensor. Since it seems to have been developed and marketed for the DSLR market, I can see why it might be supplied on a "board" (presumably FR4 / Fiberglass-Resin or derivative).

 

   However, the Sony IMX294 is a different animal. It is supplied as a 268 pin LGA (Land Grid Array) with a ceramic package. That ceramic package has flat pin contact points arranged around the outside. (The pins for an LGA package are supplied by a socket or other mechanism on the electronics card rather than the chip.) The LGA packages like this generally  have an open area in the center beneath where the sensor chip sits. The pin contact points are arranged in rows around the periphery of the LGA. There is no FR4 material between the silicon sensor chip and the outside (bottom) of the first level package. A TEC would be able to be connected to the bottom of the ceramic LGA package directly.

 

   See the following link for a information on the IMX294 and its packaging:

https://www.sony-sem...94CJK_Flyer.pdf

 

   Typically, since the LGA package has no pins, the chip would be mounted into a camera using a socket. I could not find a 268 pin LGA socket but did find a 257 pin LGA socket which is probably very close the the one required by the IMX294. See that LGA Socket at this link:

https://www.mouser.c...a8eqoBcrrYP/A==

 

   In a camera, the LGA socket would be mounted to the electronics board and then the sensor chip would be clamped into the socket around the periphery. I have not taken my camera apart to see exactly how that is done.

 

   In any case, there would be a rather large open area below the sensor for direct contact with the cooling element (cold finger?) which is attached to the TEC.

 

All right, but how is that effective cooling. If the peltier cooled unit is not in immediate contact with the sensor itself?

 

Say that there are sufficient through wholes, whatever they may be, they are not the metal (copper or aluminum I guess) from the cooling element. Thus reducing heat (cold) transfer to the sensor. If it menages cooling only around the edges, wouldn't that result in uneven sensor temp. Either way, matching dark frames will be almost impossible. So, how do they go around this?

 

   I am not aware of any commercial camera where the cooling is in direct contact with the sensor. There are always going to be a first level (silicon sensor to carrier) package, a second level (chip package to electronics card or assembly carrier) package, and sometimes a third level package (assembly carrier to electronics card). Only in custom-built scientific cameras would you be likely to find a Peltier directly bonded to a silicon sensor. The best we can do with commercial cameras is to get a ceramic first level package and connect that to the TEC.

 

   There are some compromises or trade-offs with using a BSI (back-side illuminated) sensor. You generally get an increase in light sensitivity since there can be fewer structures blocking the light from hitting the photodiode area of a pixel. However, depending on the construction of the silicon sensor and its SoC (System on Chip) control circuitry, there can be a thermal bottleneck in the physical mounting of the silicon sensor to its (ceramic) first level package -- the LGA.

 

   The main difference is not really in the absolute amount of cooling that can be delivered. Rather, it is in the time it takes that cooling to "soak through" the thermal path. A sensor mounted via an FR4 carrier is one example of a thermal bottleneck. Another is BGA (Ball Grid Array) Flip-Chip packaging between the silicon and the LGA in some BSI sensors.

 

   In both cases, even cooling is simply a matter of allowing the system to reach equilibrium and then keeping it there. (Ultimately, reaching equilibrium also depends on the overall thermal design of the camera.) If you blindly turn on maximum cooling and start shooting, you may find that the sensor takes a while to start responding consistently. Allowing plenty of thermal soak time after reaching the desired temperature set-point will go a long way to improving results.

 

   In my opinion, thermal stability control has a greater effect on results than the set-point temperature chosen. I am a proponent of running these CMOS (and CCD for that matter) cameras at reasonable TEC Power settings. Think about how much control you have if you are running at 98% of maximum TEC power and the chip warms up slightly. How long will it take to bring the chip back to temperature? On the same note, think about how much control you have when running the TEC at 5% of its maximum power. If the chip cools too much, how long will it take to warm back up? I have always thought running the TEC in the 30% to 70% range of maximum power will give the best (stable) control for cooling.

 

   This post is already too long so I will cut the opinions and conjecture off here. I will just mention that there are some things about cooling in the latest generation of CMOS cameras that bother me. I have an experiment in mind that I need to run to characterize the relationships between TEC Power, Set-Point Temperature, and Ambient Temperature. I just need to get time to run it and take real data. With the amount of rainy / cloudy days we have had for the past 10 months, I cannot image so I may as well experiment.

 

 

John

 

[Edit] PS: All of our guessing aside, the best way to know how ZWO actually implements its cooling system attachment between the TEC and sensor package is take the camera apart and look. I have had no reason to do that but there may be someone out there with a dead ASI294MC-Pro that document a tear-down and show us what the cooling system involves.

 

I vaguely recall seeing some images here of an ASI camera that was partially disassembled to replace a vibrating fan (I think). I could not find those images via a search here.


Edited by jdupton, 21 May 2019 - 11:47 AM.


#8 orlyandico

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Posted 21 May 2019 - 11:48 AM

I think this is a red herring. A lot of power IC's sink through their pins. It's well established technology, and sensors don't dissipate much heat.



#9 moxican

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Posted 21 May 2019 - 03:09 PM

John, thanks for the wealth of info. But here is another thing then...

 

What is all that talk here on CN about "don't modify your DSLR, rather save up money and by an astro-dedicated camera". I am not arguing that an astro-camera is a better option, that is not why I started this thread. But based on the info here it seems like they have no better access to the sensor then I would if I take apart, say... a Nikon D5100, which has the same IMX071 sensor than the ASI071. 

 

So what is the difference between me cooling it or they cooling it? I thought that they have special access or equipment for cooling. Something I have no access to.


Edited by moxican, 21 May 2019 - 03:14 PM.


#10 jdupton

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Posted 21 May 2019 - 03:50 PM

Gusztav,

 

   That is a good question.

 

   I have not seen any photos of the IMX071 sensor alone in order to know just how it is packaged. As you pointed out in your first post, many sensors made for the DSLR market are supplied on an FR4 carrier with some number of other components. It's possible that there are multiple packaging flavors of the IMX071 sensor other than what may have been (or be) supplied for Nikon's use.

 

   The main reason many advocate for a dedicated astro camera has to do with cooling. Even if the Nikon D5100 has access to the back of the sensor to some extent, that doesn't mean they would ever add cooling to a DLSR camera. While the sensor in an astro camera may be exactly the same as the sensor in the 5100, the addition of cooling still makes it much better for long exposure photography. If you have the means to modify a DSLR to add cooling that is just as effective as what a dedicated astro camera can attain, then there would be no significant difference in the hardware.

 

   Hardware aside, a DLSR will have certain firmware methods that are likely very different from the firmware that runs an astro camera. Unless you have knowledge of Nikon's interface circuitry to the sensor and can hack the firmware, there will likely always be some differences present that may still tilt the decision towards the astro camera.

 

   I am going to guess that the IMX071 sensor is available as a leaded QFP-like or TSOP-like package. If you look at the tear-down photos on the Web for the Nikon D5100, you will that the carrier contains a lower level package for the chip. (See the photos at Step 13 at the following Website).

https://www.ifixit.c...0 Teardown/5271

 

   If you wish to add cooling to that card, you will have to do so through the attached FR4. If the astro camera makers can obtain just the dark leaded sensor portion, they would probably have an advantage in getting more efficient cooling to the sensor.

 

 

John



#11 jhayes_tucson

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Posted 21 May 2019 - 04:52 PM

John, thanks for the wealth of info. But here is another thing then...

 

What is all that talk here on CN about "don't modify your DSLR, rather save up money and by an astro-dedicated camera". I am not arguing that an astro-camera is a better option, that is not why I started this thread. But based on the info here it seems like they have no better access to the sensor then I would if I take apart, say... a Nikon D5100, which has the same IMX071 sensor than the ASI071. 

 

So what is the difference between me cooling it or they cooling it? I thought that they have special access or equipment for cooling. Something I have no access to.

 

 

Cooling isn't the only reason that a dedicated astro-camera has an advantage over a modified-cooled DSLR.  DSLRs have deep red filters that block Ha, they have anti-aliasing filters that essentially blur the image, and they are not available with mono sensors.  The mirror box on a DSLR chews up space in the image train and introduces severe vignetting with some optical configurations.  Finally, if you look at the cost, you can get dedicated astro-cameras with the same large format OSC sensors used in high-end DSLR cameras for less than what a modified version of the same camera costs--and it will have better cooling specs, dedicated control software, and factory support.  Many years ago, there were good reasons to modify a DSLR because that was the only option; but in my view, modified, cooled DSLRs no longer make any sense.

 

John


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#12 moxican

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Posted 21 May 2019 - 05:11 PM

Ok, hypothetical situation. I've read up about this so I know lol.gif

 

Nikon D5100, dark current hack, IMX071 sensor (same as ASI071), can be bought for $200 (ASI071 is $1500), anti alising and Ha filter can be removed easily, and let's leave the mono sensors out of the game, I am interested in how dedicated astro cameras cool the sensor, regardless of color, size, design or bubble gum flavor. I guess some vignetting could still exist though, but I had astro cameras before and depending on set up I still had vignetting many times.

 

So If I do all that to a Nikon D5100, technically I end up at the same point where the ASI071 is in terms of image quality? If ZWO cools its sensor the same way I would cool the D5100... then what is that great difference then? Again I am not trying to badmouth the company, I am trying to understand their method.



#13 OldManSky

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Posted 21 May 2019 - 05:19 PM

So If I do all that to a Nikon D5100, technically I end up at the same point where the ASI071 is in terms of image quality? If ZWO cools its sensor the same way I would cool the D5100... then what is that great difference then? Again I am not trying to badmouth the company, I am trying to understand their method.

If you do all that, you wind up with a cooled DSLR.  I personally don't think that's the "same point" as the ASI071 in terms of image quality or much else.  There are some advantages, of course -- easier mounting of DSLR lenses, for example.  There are downsides, too.

 

Don't forget, it's not *just* the Peltier that makes up the cooling system.  The dedicated astro cams have temperature sensors, regulating circuitry, cooling fans, support electronics, etc.  All of which is controllable through ASCOM so you can cool the sensor slowly, warm it up slowly, and maintain a darn accurate constantly-held temperature. And the dedicated sensors are in an isolated chamber with dessicant, to help avoid condensation.  And more...

 

Cooling the sensor helps reduce noise.  No question.  But cooling the sensor isn't all that the dedicated astro cams do smile.gif


Edited by OldManSky, 21 May 2019 - 05:20 PM.


#14 jdupton

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Posted 21 May 2019 - 06:03 PM

Gusztav,

 

   I understand your point on the hardware. You could come extremely close if not exact to duplicating the hardware between a dedicated astro camera and a modified DSLR.

 

   However, as I mentioned before, you will still be left the firmware and how that might affect "image quality". In order to get the data from the sensor in the modified camera, you still have to work through the firmware of the camera. All DSLRs have "image processing chips" with attendant firmware that massage the data before transferring it from the sensor the storage area (either internal or external).

 

   That processing is what can give the DSLR an advantage in "normal" low light photography. With an astro camera, you get out pretty much what the sensor puts out. With a DSLR, even operating in "RAW" mode, many (or most?) will do noise reduction, white point adjustment, and who knows what else. An astro camera's image compared to that of a DSLR's image will likely still be different even when the shooting conditions and target are exactly the same.

 

   With an astro camera, you get to do the processing with pretty much "pure" sensor data (sometimes scaled linearly to a different number base such as 14 bit to 16 bit for storage). With an extensively modified DLSR, even under the exact same conditions, you get data has passed through some level of changes from the time it left the sensor. What those changes are and whether they matter to you is effectively the only difference.

 

 

John


Edited by jdupton, 21 May 2019 - 06:07 PM.


#15 moxican

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Posted 21 May 2019 - 10:24 PM

If you do all that, you wind up with a cooled DSLR.  I personally don't think that's the "same point" as the ASI071 in terms of image quality or much else.  There are some advantages, of course -- easier mounting of DSLR lenses, for example.  There are downsides, too.

 

Don't forget, it's not *just* the Peltier that makes up the cooling system.  The dedicated astro cams have temperature sensors, regulating circuitry, cooling fans, support electronics, etc.  All of which is controllable through ASCOM so you can cool the sensor slowly, warm it up slowly, and maintain a darn accurate constantly-held temperature. And the dedicated sensors are in an isolated chamber with dessicant, to help avoid condensation.  And more...

 

Cooling the sensor helps reduce noise.  No question.  But cooling the sensor isn't all that the dedicated astro cams do smile.gif

Those are all fair points Paul. It is true that all that could be controlled through ASCOM. But, I could also include an arduino mini board and do the same thing. 

Again, I am not trying to compare astro cam vs modified DSLR. I am trying to understand how the companies cool their sensor and if it is bottom line the same thing that I could so, why people say that there is a significant difference, that is as long as we are talking about OSC cameras. 

I have modified a Canon 450D once, and although I did not have the sealed chamber, I did not need to. I just simply included a little heating element for the front glass and that was it. Never had condensation, not once. Isn't that also something astro camera manufacturing companies employ nowadays?



#16 moxican

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Posted 21 May 2019 - 10:41 PM

 

 

   That processing is what can give the DSLR an advantage in "normal" low light photography. With an astro camera, you get out pretty much what the sensor puts out. With a DSLR, even operating in "RAW" mode, many (or most?) will do noise reduction, white point adjustment, and who knows what else. An astro camera's image compared to that of a DSLR's image will likely still be different even when the shooting conditions and target are exactly the same.

 

   

John, this statement would be right, except it is not, well... not necessary. There are readily available hacks for both Canon and Nikon DSLRs. 

 

Here is a thread on CN dedicated to testing DSLR camera dark frames in terms of what processing they go through after capture. The attached image is post# 64 of that thread talking about a hacked Nikon D5100.

 

 

Untitled.jpg

 

 

So, on the list of the features here that an astro camera has, peltier cooling seems to be the most substantial difference, the most difficult to achieve. If you do a search on modifying or cooling a DSLR pretty much everywhere you will see comments saying that it is difficult to regulate sensor temp on a DSLR due to the lack of heat transfer between the sensor and the cold finger. But if an astro camera has the same mechanics and contact between the cold finger and sensor, how come they can achieve that?



#17 OldManSky

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Posted 22 May 2019 - 08:04 AM

Those are all fair points Paul. It is true that all that could be controlled through ASCOM. But, I could also include an arduino mini board and do the same thing. 

Again, I am not trying to compare astro cam vs modified DSLR. I am trying to understand how the companies cool their sensor and if it is bottom line the same thing that I could so, why people say that there is a significant difference, that is as long as we are talking about OSC cameras. 

I have modified a Canon 450D once, and although I did not have the sealed chamber, I did not need to. I just simply included a little heating element for the front glass and that was it. Never had condensation, not once. Isn't that also something astro camera manufacturing companies employ nowadays?

Yes, you could include an Arduino mini board and a temp sensor.  And write an ASCOM driver for your mini board.

And you can add a heating element for the front glass (yes, some dedicated astro cams do that or have it as an option.  Others like StarlightXpress use sealed chip cambers filled with argon.  Etc.).

 

So ultimately the only thing keeping you from turning your DSLR into "the same thing" as a dedicated astro cam is time, money, hardware, software...and the existing hardware of the DSLR, which doesn't let you have full/direct access to the sensor itself.

 

Hey, I love to build stuff (just finished the PnP focuser project, building my own ASCOM-controlled motorized focuser).  And tear stuff apart.  It's just that in the case of a DSLR, by the time you do all the modifications, you've spent as much as a dedicated cam would cost anyway, you have something that isn't as good as the dedicated cam (you could get darn close, but not the same), and you don't have the support of a company that makes thousands of them.  I think some self-builds/modifications make total sense.  I don't think this one does.  You might think it does -- that's great.  Go for it!  Don't let me dissuade you! :)



#18 moxican

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Posted 22 May 2019 - 01:58 PM

 

 you have something that isn't as good as the dedicated cam (you could get darn close, but not the same), 

This is what I do not understand why. This is what I am trying to get at.



#19 moxican

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Posted 22 May 2019 - 02:05 PM

 

  It's just that in the case of a DSLR, by the time you do all the modifications, you've spent as much as a dedicated cam would cost anyway, 

This is very inaccurate. I have read this on CN on quite a few places and that is absolutely not the case. I already modified a DSLR once. The only thing that is difficult about it is time. I bought my D5100 for less than $200. All the hardware that it needs is in the cost of a few dollars online. I I wanna be generous I say extra hardware is another $200. So about $400 more or less. How is that the same price as an ASI071 for $1500?

 

And if I may throw this in here... not everyone is so "lucky" to be born/live in north america. It might be the same for you but I assure you there are many people around the world who are doing/interested in astronomy and $400 vs $1500 is a no brainier decision.



#20 OldManSky

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Posted 22 May 2019 - 05:46 PM

This is very inaccurate. I have read this on CN on quite a few places and that is absolutely not the case. I already modified a DSLR once. The only thing that is difficult about it is time. I bought my D5100 for less than $200. All the hardware that it needs is in the cost of a few dollars online. I I wanna be generous I say extra hardware is another $200. So about $400 more or less. How is that the same price as an ASI071 for $1500?

 

And if I may throw this in here... not everyone is so "lucky" to be born/live in north america. It might be the same for you but I assure you there are many people around the world who are doing/interested in astronomy and $400 vs $1500 is a no brainier decision.

Don't really want to argue, but I think you're understating the cost of additional hardware.  And you've given your time no value.

And you still will have a cooling system that's not designed/attached to the sensor's architecture in the optimal way.  And you'll still have Nikon's software messing with the RAW files before they're saved.  And...well, a lot more.

 

Like I said above, don't let me dissuade you.  Go for it.  Let us know how it turns out.  Keep track of what it actually costs you, and let us know that too.  You might have a workable, lower-cost option people can use.  That would be great (whether someone lives in North America or not).  Or it might not.  Somebody needs to do the full set of mods, keep track of time and costs, do the imaging tests, and find out.  You sound like you want to do that -- so go for it.  :)



#21 spokeshave

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Posted 22 May 2019 - 06:50 PM

Ok, hypothetical situation. I've read up about this so I know lol.gif

 

Nikon D5100, dark current hack, IMX071 sensor (same as ASI071), can be bought for $200 (ASI071 is $1500), anti alising and Ha filter can be removed easily, and let's leave the mono sensors out of the game, I am interested in how dedicated astro cameras cool the sensor, regardless of color, size, design or bubble gum flavor. I guess some vignetting could still exist though, but I had astro cameras before and depending on set up I still had vignetting many times.

 

So If I do all that to a Nikon D5100, technically I end up at the same point where the ASI071 is in terms of image quality? If ZWO cools its sensor the same way I would cool the D5100... then what is that great difference then? Again I am not trying to badmouth the company, I am trying to understand their method.

I did something similar a few years ago with a Canon 550D. I machined a copper cold finger that cooled the sensor and had a TEC and HSF mounted to it. I immediately had problems with dewing/frosting of the sensor. So, I tore the camera down again, removed the cover glass and installed a very fine nichrome wire heater circuit. That worked well. Then I realized that cooling didn't have much value without setpoint control. So I tore the camera down again, installed a temp probe on the sensor and built a control circuit. That worked well for a few nights until the camera simply died. I tore it down again and it became clear to me that condensation on the control board cause the electronics to short, ruining the whole rig. Undaunted, I bought another camera (they're pretty cheap on eBay) and this time I potted the circuit board with potting silicone. This time, the camera lasted several months before dying again. The problem was the same. Despite what I thought was careful potting, the dew still found its way into the circuitry.

 

So, yeah, it can be done. You can essentially convert a DSLR to a dedicated cooled astro camera. But I learned that just because you can, doesn't mean you should. Cooled astro cameras are engineered to be cooled from the ground up. As a result, they work well. I seriously doubt that someone could engineer a cooling retrofit for a DLSR that would be as foolproof and reliable as a dedicated camera - at least in a cost-effective way. 

 

I won't discourage you from trying it, though, if you have the patience and disposable income to risk destroying a camera. 

 

Tim


Edited by spokeshave, 23 May 2019 - 03:44 AM.

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#22 Jon Rista

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Posted 23 May 2019 - 12:38 PM

All right, but how is that effective cooling. If the peltier cooled unit is not in immediate contact with the sensor itself?

 

Say that there are sufficient through wholes, whatever they may be, they are not the metal (copper or aluminum I guess) from the cooling element. Thus reducing heat (cold) transfer to the sensor. If it menages cooling only around the edges, wouldn't that result in uneven sensor temp. Either way, matching dark frames will be almost impossible. So, how do they go around this?

In practice, ZWO cameras provide rock solid stable regulated cooling. I've been using several of their cameras for years now, with different sensors (not including the 294). I have not noted any meaningful discrepancies between dark frames and light frames at a given temperature. Temperature stability once it is initially reached is superb, and that stability is maintained all night long (which usually means it is cooling throughout the night, so the cooler power drops throughout the night.)

 

The only case where I have noted some issues with cooling ZWO cameras is on particularly warm nights. If the ambient temp is over 80 degrees then I have to cool less...-15C maybe even -10C, instead of -20C, to support proper regulation. But that is simply a matter of physics, and not a matter of whether the cooler "can" work or not. 


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#23 Jon Rista

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Posted 23 May 2019 - 12:43 PM

John, thanks for the wealth of info. But here is another thing then...

 

What is all that talk here on CN about "don't modify your DSLR, rather save up money and by an astro-dedicated camera". I am not arguing that an astro-camera is a better option, that is not why I started this thread. But based on the info here it seems like they have no better access to the sensor then I would if I take apart, say... a Nikon D5100, which has the same IMX071 sensor than the ASI071. 

 

So what is the difference between me cooling it or they cooling it? I thought that they have special access or equipment for cooling. Something I have no access to.

It isn't just about cooling...it is also about sealing. The sensor chamber and the cold side of the TECs must be sealed off from damp outside air. The air inside the sensor compartment must be very dry to avoid condensation issues. While you could disassemble a DSLR and slap a TEC on the back of the sensor PCB, the problem you are going to have is keeping the rest of the camera and the sensor compartment sealed. All but impossible to do, given that DSLRs are interchangable lens designs and there is no real way to actually seal the sensor chamber. 

 

So, the key difference is, with a purpose-designed astro camera with regulated cooling...they deal with sealing and avoiding condensation for you. With a DSLR, there really is no good way to deal with it at all. 


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#24 t-ara-fan

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Posted 06 June 2019 - 01:33 PM

I did something similar a few years ago with a Canon 550D. 

  • So, I tore the camera down again 
  • So I tore the camera down again 
  • I tore it down again  this time I potted the circuit board with potting silicone.
  • This time, the camera lasted several months before dying again.
  • The problem was the same.

 

https://www.youtube....NaXdLWt17A&t=24

 

Never give up!!!




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