INTO
I wanted a sensitive guide camera for my CG-5 mount.
The problem was that i needed a small light camera to keep the weight down since the CG-5 mount isn´t rated for more than 35 lbs.
By adding an ED80 scope mith my DIY electronic focuser, DIY side by side bar, guide scope, camera, finder scopes and whatnot, i figured why not get a small, lightweight, very sensitive guidecamera?
On second thought, get a small lightweight camera that can double as an imager.
hmmm, how about a cooled small lightweight camera, autoguide imaging doubling camera?
After much deliberation, adding to the ever growing list of requirements i realized there aren´t many cameras that can do all this and don´t require me to become a professional hardened criminal.
Thus this idea came to me, thinking ofcourse that this was the only sane way going about the whole extremely nessesary need for a camera that has everythink and costs nothing.
Ready Steady .....GO!
Let us begin by examining what needs to be undone to get to the insides, remove all 4 screws and using whatever tool you fancy allthough i recoment the 4mm hex head variant. Now simply put your camera with the chip facing down on the workbech and lift up the back side. Don´t hold it in your hands while opening becouse the insides are not held in place with any glue or screws so they can fall out.
Remove the guts by taking hold of the USB connector and simply lift it out.
Put the electronics in a sealed container.
Next we need to get rid of the porcupine looking spikes on the backside of the housing.
I taped up the open end of the housing to keep the small metal particles from entering while i worked them of.
You choose your own method of destruction but after 30 minutes of this,removing 4 spikes.
I changed my method into,
giving quite satifsying results in a lot shorter time, leaving just enough left for me to work with using
Next order of business is modifying the new heat exchanging watchamacallit we´re putting in to replace the peculiar spikes.
I got hold of a CPU aluminum cooling watchamacalit. Usually they have this centered flat spot on the back, ideal for drilling two small holes into, providing us with the means to secure the wachamacallit to the now flat side of the imager.
Aligning the watchamacallit to the place where i was going to put the unit i marked the location of the holes, drilled 3,2 mm holes into the backside clam of the imager and put some 4mm threads using my 4mm threader tap
I had a can of Gold spray paint staring me in the eye so i left a couple coats of paint sticking to the horribly looking piece of metal i had been dismembering.
If painting is to be done remember to put a piece of tape where the peltier element will be placed so you won´t have to scrape the paint of later.
Then it´s time to sandwich the Peltier element between the Watchamacallit and back side of the imager.
I put some heat transfering goo between all the components, just a drop will do, more does not mean better here, only messy and possible something will break if goo is leaking inside the peltier.
It´s very easy to figure out what´s up and what´s down on the peltier, just put some 12 volts on the vires while holding the peltier between your fingers and 2 seconds later you know.
Now put the side that became cold facing the imagers backside and the hot side facing the watchamacallit. Screw the items together using one turn at each screw until you feel it´s getting a little stiffer, don´t overdo it just enough so the contact is good and it´s not wiggling. I used a litle common sense and it worked.
VOILA
Now flip it over and cut any screw part extruding from the cavity, at this stage i really wished i hadn´t left my Dremel tool at home when i went to the workshop.
Back home the glue i used for the glass sealing the CCD champer with the IR block filter removed from the 1000D conversion had settled nicely, notice the fine handycraft workmaship utilizing the glue hahaha.
Needless to say but anyway, it´s really not good putting glue in the path of the light. So badly looking glue job was a 100% success. This needed to be done so i wouldn´t have to use the flimsy wobbly slide bar filter holder. And then filling up the holes left by absent filter slide bar with pipe insulating sponge material.
I put the temperature sensor on the left side of the cavity on the backside, do not put it on the right side, there is a capacitor on the electric circuit board that does not agree with sharing it´s space.
I found a cheap pen and cut of a suitable piece to be used as housing for the temperature gauge that could be glued into place using the two component epoxy glue.
You can see i put a piece of heat shrink tube on the gauges cord to act as a stopper if the cord got pulled on.
Next you really don´t want to glue your fingers stuck like i didn´t do.
Now for the final part i cleaned of the inefficient white paste Meade used and replaced with high quality expensive looking goo on the finger and sandwiched all together.
I put some heat shrinking tube on the wires coming from the peltier and fan, that can be seen on the second picture at top.
HokusPokus
Testing at 24°c
starting with hot imager and imaging 1 second images during test
19:15 Start temp 28
19:17 temp 22
19:19 temp 19
19:21 temp 17
19:23 temp 16
19:25 temp 15
19:27 temp 14.5
19:29 temp 14
19:34 equalization 13.5
I did a test by insulating and further 8°c are at hand by doing this, not bad me thinks.
I spent 70 $ in parts at my local geek electronic component store.
Further adjustments are to be done, cutting the heat exchanging watchamacallits fins in half, no need for them to be so big since my peltier is only 29 watts, and putting a smaller fan, therefore cutting the total weight by some grams.
The 29 watt peltier draws a whopping 3 amps of current i therefore added a 2,2 ohm 25 watt resistor in series with it to reduce the power consumption and prolonging the lifetime of my batterypack.
Here is what i used to control the cooling, http://fadisel.com/cebek-electronic/thermostats_P_285.aspx
Items, I-8 (-10-60°c), 12 volt dc relay thermostat
And PROBE for I-8, I-81 and I-108 modules CEBEK
Please leave a comment if you stuck with me this far.
Nonni.
UPDATE!
Im currently adding a control box for the cooling that will also indicate the voltage of the system letting me know when to shut of the cooling before everything runns out of juice.
