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Cooling back stabilized for DSI...
To solve the problem of condensation.
Read this page in english...
A very beautiful accessory was developed for cameras MEADE DSI, by Steve Mogg: a stabilized cooling back.
Some technical information...
This acessoire is very quite carried out and adapted perfectly its use has... which is "the temperature control" and not pure and hard cooling.
Explanations: The DSI and the DSI pro to be strictly accurate do not need to be cooled because of their original mode of operation and even less with the new version of the software "Considers". But on the other hand the problem which installation is that of the application of the darks. The result is very sensitive to the temperature. On the one hand at the temperature of capture of the dark and on the other hand to that of capture of the image to which the dark is applied.
It is thus very interesting to be able to guarantee the equality of these two temperatures. Some solve the problem by constituting series of darks at various temperatures...
But the solution is obviously the regulation of a temperature of instruction. And thus the cooling back "Steve MOGG"
The assembly of this accessory is simple... but its use induced to guard itself against an adverse effect of cooling... Mist! ... or worse, white frost on the window of sensor CCC.
I present my solution here. It applies to a DSI-Pro and is based on the use of a not very common part: the tube adapter of a camera ST4 unfortunately deceased prematurely.
Naturally everyone does not have this object;o) Cependant the idea seems to me easily adaptable to, for example an adapter "T", that it is bought for the occasion or recovered on a DSI. Concerning Dsi-c the problem is much easier to solve. The adapter "T" and filter IRB easily which can "be sealed".
The "tunnel" of the door filters of the DSI-Pro is dismounted and modified to be adjusted perfectly... good, say "as much as possible", at piece-rates which will make "tight room". Here famous adapter ST4. That Ci inclu a "port-hole" clear and seals, as well as an O ring in its base (two reasons which made me choose this part). One sees here the throat which receives this joint.
I was obliged to envisage the passage of the fastening screws of the "tunnel" on the front face of the camera. With an adapter "T" celà would not be necessary. in the same way the modification of the "tunnel" would be simpler... seems it.
These two images show the two parts which imbricate one in the other. To pass the cursor on that of right-hand side for better seeing this assembly....
The "tunnel" will be machined in order to exert a pressure on the basis of other part in order to crush the O ring (visible on the image of left) and to ensure the sealing thus.
Here the whole of the components before assembly.
One notices filter IRB recovered of Dsi-c, cut out and stuck in a tight way in front of the sensor.
CAUTION: before doing this not to forget to very carefully clean the window of the sensor AND the interior face of the filter.
One can always clean them afterwards, but it will be necessary "to pass by the interior"... and thus to open the camera
Here the assembled unit.
One notices on the images that the tube 1"1/4 of the tight part was shortened not to exceed the bottom of the net Ø42 this makes it possible to preserve the possibility of screwing the adapter provided with the camera.
Thus modified the sensor is isolated from the surrounding air by two tight "rooms".
As for the filter drawer... it will have naturally to be replaced by does not coil with filter...
... if however there is the use of it...
Is necessary it "to seal" the whole of the case?
The question can make debate, but in what relate to me I do not think it.
The sensor being isolated from the interior of the camera by a joint which rests against the internal face of the case, provided this joint is correctly placed, the air can pass from the interior towards the tight "rooms" only we contituées...
What is checked in practice since in spite of relative humidities "tropical" and a temperature of 10° on the sensor (with 25°C ambient) no mist is formed.
As indicated in the beginning of this page and as it is very often the case, this modification is obviously not applicable "just as it is"... I think however that the idea can be easily adapted.
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