rumples riot
Carpal Tunnel
Reged: 07/01/04
Posts: 2262
Loc: South Australia
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Several months ago I posted a link to SCP about cooling my C14 with peltier coolers.
I have now done a how to and the link can be found in my signature. It has all the images and detail that I could think of.
I hope that those of you with SCT's will consider this option. Mirrors can be brought to temperature quickly and efficiently doing this modification.
I also urge people with newtonians to investigate Bird's site and his excellent article on mirror cooling. It is his invention. I just merely adapted it to suit my C14. To the best of my knowledge it will work with a C11, however I am not sure if it will work with a C9.25. Although smaller parts may make this posible.
I might also work on Meade 12" and 14" LX200R scopes. You will have to negotiate the mirror locking system for this though.
Best of luck. Please consider this as an option.
Paul Haese
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EARTH AND COSMOS
My Solar System Imaging BLOG
How to peltier cool a C14 SCT
SOUTH CELESTIAL POLE
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David Rivas
Carpal Tunnel
Reged: 05/29/04
Posts: 2000
Loc: Lima, Peru
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Thank you very much Paul for such an excellent, detailed and brave link!
I homemade a cat-cooler myself , it works well for my humble 8 incher... but I guess it's not as effective and swift as having the coolers built in... something to consider indeed... it seems to be so easy when one reads your splendid link...
Best regards,
David
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gazerjim
Postmaster
Reged: 02/12/04
Posts: 7630
Loc: San Angelo, TX
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Paul, Thanks for the work and for so generously sharing your results!  I firmly believe you and Bird have started a lasting trend.
Still lumbering along on my Peltier project. It's looking like something from a child's old toy box, but it should work. It's now mostly a matter of a few more nylon screw attachments and wiring. At least I think so. 
Thanks again for the info and motivation.
Jim
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Jim Fisher
If you're not part of the solution, you're part of the precipitate.
Henry J. Tillman
Edited by gazerjim (11/20/07 06:06 AM)
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rumples riot
Carpal Tunnel
Reged: 07/01/04
Posts: 2262
Loc: South Australia
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Hey Jim it is Paul not Mike. I wrote the article and did the mod.
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EARTH AND COSMOS
My Solar System Imaging BLOG
How to peltier cool a C14 SCT
SOUTH CELESTIAL POLE
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gazerjim
Postmaster
Reged: 02/12/04
Posts: 7630
Loc: San Angelo, TX
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Paul, Apologies and error corrected.
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Jim Fisher
If you're not part of the solution, you're part of the precipitate.
Henry J. Tillman
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rumples riot
Carpal Tunnel
Reged: 07/01/04
Posts: 2262
Loc: South Australia
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Thanks Jim, accepted. Do you have some images of your setup too? Why not put it in here. The more people doing this the better.
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EARTH AND COSMOS
My Solar System Imaging BLOG
How to peltier cool a C14 SCT
SOUTH CELESTIAL POLE
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Bird
Carpal Tunnel
Reged: 08/07/03
Posts: 2621
Loc: Canberra, Australia
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Nice writeup Paul, and also a spectacular Jupiter image as well :-)
We can't control the seeing, but we can control pretty much everything else...
cheers, Bird
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Deep Sky Optics 13.1" f/5.5 newtonian,
PGR Dragonfly Express, PGR Dragonfly 2
RedHat Linux + Coriander
http://www.acquerra.com.au/astro/
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rumples riot
Carpal Tunnel
Reged: 07/01/04
Posts: 2262
Loc: South Australia
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Thanks Anthony, if we can control everything else, we have got a half way decent chance at getting a really nice image.
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EARTH AND COSMOS
My Solar System Imaging BLOG
How to peltier cool a C14 SCT
SOUTH CELESTIAL POLE
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gazerjim
Postmaster
Reged: 02/12/04
Posts: 7630
Loc: San Angelo, TX
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It's not pretty. But here is progress so far on my Peltier cooling cap.
Liberal use of duct tape is due to the plastic cracking while being drilled.  If the concept works, I may use the old plexiglass as a pattern to make one from lexan.
The peltier unit is mostly hidden under the heat sink, which is bolted to the plexiglass with nylon screws. I'm hoping they do not soften overmuch due to heat.
Hanging the external fans from bungees is not aimed at vibration control as I don't expect to image with the peltiers running anyway. I originally planned to bolt the fans, heat sinks, and peltiers in place with one set of long nylon screws and so sized the heat sinks for the fans. This went awry when I couldn't find nylon screws long enough. I'll try to post a pic when complete to show the whole gizmo with much smaller internal fan on standoffs.
As I said earlier, if this works it should prove that
almost anyone can build a Peltier cooler. 
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Jim Fisher
If you're not part of the solution, you're part of the precipitate.
Henry J. Tillman
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gazerjim
Postmaster
Reged: 02/12/04
Posts: 7630
Loc: San Angelo, TX
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Another view,
--------------------
Jim Fisher
If you're not part of the solution, you're part of the precipitate.
Henry J. Tillman
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rumples riot
Carpal Tunnel
Reged: 07/01/04
Posts: 2262
Loc: South Australia
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Looking good Jim, once you get it going, you can mod it at some point. Make sure you seal the unit in place to prevent warm air making it into the tube.
More pics please.
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EARTH AND COSMOS
My Solar System Imaging BLOG
How to peltier cool a C14 SCT
SOUTH CELESTIAL POLE
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Aaron Worley
member
Reged: 10/21/05
Posts: 12
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This is really cool stuff. After looking at the back of my C9.25, I don't think there's room to do a mod like this unfortunately. Would there be any benefit to installing a peltier cooler on the side of the OTA tube instead? I've seen this done for newts, but never on an SCT.
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rumples riot
Carpal Tunnel
Reged: 07/01/04
Posts: 2262
Loc: South Australia
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Aaron, you could install it on the side, maybe right near the corner of the actual back and where it heads up to join the tube. There is just enough room to put a fan on the inside near that spot. One on each side would work well. Lateral thinking, well done. I wish I had thought of that at the time I owned a C9.25.
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EARTH AND COSMOS
My Solar System Imaging BLOG
How to peltier cool a C14 SCT
SOUTH CELESTIAL POLE
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davidpretorius
professor emeritus
Reged: 09/25/05
Posts: 574
Loc: Tasmania, Australia
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Quote:
Looking good Jim, once you get it going, you can mod it at some point. Make sure you seal the unit in place to prevent warm air making it into the tube.
More pics please.
spot on, you want to recirculate the cooling air over and over again.
great piece of work there Jim
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Davo
10" peltier cooled Next with dob driver II, Lu075 camera
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gazerjim
Postmaster
Reged: 02/12/04
Posts: 7630
Loc: San Angelo, TX
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Thanks, guys, for comments and suggestions. I'm trying to view this as a prototype--another term for for messy first run. But it should work as long as the fans keep the heatsinks cool enough.
I've sketched out a simple schematic that uses two 20 amp switches so that the inside fan can be run by itself but will always be running whenever the peltiers are on. No biggie.
Quote:
Would there be any benefit to installing a peltier cooler on the side of the OTA tube instead?
Aaron, Are you talking about the side of the OTA (curved) or the back plate? No doubt a 9.25 with active cooling would be a real planet killer.
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Jim Fisher
If you're not part of the solution, you're part of the precipitate.
Henry J. Tillman
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Aaron Worley
member
Reged: 10/21/05
Posts: 12
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Hi Jim, I'm not sure yet. I'm looking at putting the fans and coolers on either the curved sides of back plate (roughly where you attach the finder scope), or on the sides of the steel OTA tube.
I'm not sure either arrangement will cool the scope as well as the way Paul has his fans, blowing right on the back of the mirror. But I'm going to take a crack at it as an experiment, I'll report back.
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gazerjim
Postmaster
Reged: 02/12/04
Posts: 7630
Loc: San Angelo, TX
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Sounds interesting. The peltiers pretty much need to seat on a flat surface. But maybe there is a technique for mounting on curves. Anyway, looking forward to seeing pics of your progress.
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Jim Fisher
If you're not part of the solution, you're part of the precipitate.
Henry J. Tillman
Edited by gazerjim (11/23/07 10:43 PM)
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Aaron Worley
member
Reged: 10/21/05
Posts: 12
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An update on my C9.25 peltier concept. It was pretty much a non-starter, since upon further inspection there's no clearance on the inside of the OTA tube for fans. Any internal fans on the side of the OTA will stick out into the light path, and possibly bump into the primary when focusing, depending on where you place it.
On to Plan B. Since I haven't figured out how to affix the peltiers, I'm going to test out a fan-only system. I've put an external, 12v fan on my OTA that blows outside air into the tube, across the face of the mirror. Once I get a clear night here (might be a while) I'll post some results and photos.
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gazerjim
Postmaster
Reged: 02/12/04
Posts: 7630
Loc: San Angelo, TX
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Aaron, Seems like if you are going with a fans only system a Lymax cooler might do just as well.
Only solution I can imagine without mounting a fan inside the OTA might be to blow in chilled and filtered air by way of a small duct or tube. Don't ask me how. 
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Jim Fisher
If you're not part of the solution, you're part of the precipitate.
Henry J. Tillman
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asimov_1
sage
Reged: 06/17/07
Posts: 343
Loc: Bundaberg Queensland Australia
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I've tried bolting a peltier to a Catcooler; it failed to get it to ambient.
The next best thing to do is what I do with my C11. I house it in a tote & add ice bricks from the freezer 6 or 7 hours before commencing imaging. It's a bit of a guessing game but with a bit of trial & error,it works well.
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CS's
Asi
CGE1100XLT - DMK 21AU04.AS USB version
http://southcelestialpole.org.au/forum/index.php
http://asimovjohn5.googlepages.com/home
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