Canon 350D Peltier Mod

[MarkS]

John,

Yes I have one of those (a DIY version) but I was using it on the other camera.  I will have to make another then I can keep the camera sealed.

I'm also waiting for some 2mm sheet copper to arrive so I can make a Mk2 of my mod.

My earlier Orion subs were all OK - I'll process them at the weekend 'cos I'm busy finishing off Thursday's presentation on digital imaging noise.

Mark

[mickw]

I'm busy finishing off Thursday's presentation on digital imaging noise.

....................... and the perils of cooling 

[Fay]

I have got one of those adaptors Mark

[The Thing]

I've just taken delivery of the Astronomiser power adaptor. Nicely made.

[MarkS]

I'm now the proud owner of a sheet of copper.  Very shiny!   

[Carole]

Thursday's presentation on digital imaging noise.

Looking forward to it Mark.

Carole

[MarkS]

I performed the MkII mod yesterday. 

Here's the copper strip I soldered together and cut to shape:



I've made the strip wider than the previous piece of copper pipe.  That and the double thickness means it transfers the heat much better.  Since it is completely flat it gives excellent thermal contact.

I had to then do a bit of extra shaping so it would not collide with other components:



In position in camera:



Here are two 15minute subs before and after cooling (same scaling on both) - all done at room temperature.




The cooling is so dramatic that I can't meaningfully measure the noise reduction - I'll have to do 60min subs to measure it.  It's well over 30C of cooling.  The "after" picture is almost indistinguishable from a bias frame except in the amp glow areas.  I really need to do an amp-off mod as well to get rid of it.

Mark

[Mac]

Looking good,

I'll probably start mine in the new year.
I'm busy untill then, Birthday, Degree, Concerts, and that thingy some where around the 25th

I really need to do an amp-off mod as well to get rid of it

Is there such a mod?
also is it necessary?

i know it would reduce the amp glow

but, , what would the length of time be to fill the wells up?
considering their depth.

if this is only say 9 mins, what is the effect of the amp glow after this time?

Mac.

[mickw]

Once again, impressive stuff.

How does this compare with the Mk1 mod for an exposure of the same length ?

Have you just tack soldered the outside edges or did you "tin" one or both surfaces ?
Tacking may introduce an air gap (a very small air gap)

[Mike]

That is an impressive difference Mark. I can't wait to see this camera used in anger.

[MarkS]

Mick,

The 15min darks with Mk2 are very similar to the 5min darks with Mk1.  I'll have more acurate figures later today.

I coated the internal surfaces with plumbing flux (makes the copper very shiny), clamped it together, heated it and then introduced plumbers solder at the join until it was "sucked" into the gap.  I carried on adding solder until I could see it appearing at all the edges it had internally flowed to.

Mark

[MarkS]

what would the length of time be to fill the wells up?
considering their depth.

It's not a question of how long the wells take to fill up.  The problem is that those brighter areas contain greater noise.  The brightness can be subtracted with a dark but it leaves the extra noise behind and this extra noise drowns the faint details in your image.

It's a shame you missed my talk - I explained it all there.

Mark

[The Thing]

Great results. Payback for all your hard work on this.

Don't suppose you made a template of the copper strip for next time? I got my second 350d back and hope to start Ha modding one as soon as I can get some Edmunds glass or a Baader pane ordered. Since the cooling is so impressive that will have to follow shortly after!

[MarkS]

I've now done a couple of cooled 60min darks at room temperature.

The standard deviation of the pixels in the difference image between the two is 8.9ADU.
Compare this with a standard devation of 6.9ADU for a diffence image between two 1/4000s bias frames.
I'm pretty happy with this 

35C is the estimate I have for the cooling (vs approx 24C for the MkI version) - this is the difference in CCD temperature between cooled and uncooled.

Roughly speaking this means the cooled CCD temperature is approx 28C below ambient.

Duncan, I've made a template - I just need to transfer it to squared graph paper for repeatability and ease of use.

Mark

[RobertM]

Have you had any more problems with keeping the moisture (and hence ice) out ?