The homemade CAT cooler up the guts & the peltier cooler parked right behind it, in theory sucking in colder than ambient air & exiting it out of the OTA thus cooling the optics quicker than just using the CAT cooler.
I have the dual thermometer setup & taking readings.
Good idea Asi, looks like a winner to me. Remember that it will take a while for the mirror to equalise after you turn off the cooling. Give it 10 or 15 minutes at least before you judge the image.
Hmmmmm after seeing you work on that fix for your computer problem, are you sure thats not some kind of bomb as Houghy mentions will condensation be a problem? could you use those mositure removeal type bags that come with some things you buy? (dont know what they are called) looks good, how about some before and after cooling shots.
Condensation will only form if the air temp inside the OTA drops to its dew point, so the humidity of the air entering the OTA will determine the factor of when that happens.
In the few hours I ran the peltier I saw no condensation forming on the optics.
This idea is hardly quick enough to keep up with the falling ambient in any case.
Problem 1: The peltier runs heaps colder with a 240VAC to 16V 2A DC converter rather than 12V DC off a car battery that I'm using at the moment.
Problem 2: is the obvious falling of the ambient air & the system not keeping up.
It's still better than using the CAT cooler by itself though.
Quote by Joe: ' how about some before and after cooling shots '
I guess you mean astrophotography shots? The weather here is crap ATM so I can't do any as yet.
if the OTA is fully sealed (it is isent it? never seen a cat up close, have to get out more ) wouldent it be better to have some vent holes near the front of the tube, stand the OTA up so the mirror is on the bottem and pump in the cold air. that way the hotter air exscapes through the vents at the top, when its cooled enough close the vents ?
Great Idea, patent pendeing ?,,But how about this,,,having nearly finished all of the major parts for the observatory, and yes I appreciate your gear is portable..I thought if I install a kick bottom Air con in the dome, Set at anticipated nightime temp, timed to turn on late afternoon, will that work, ? your input would be appreciated. Or shall I post this in its own thread.
Joe
And yes most are fully sealed, the commertial cat coolers have slots in the slide in tube to allow inside to escape....and the vent holes in the tube are directed back toward the primary...
some of the Larger SCT aside, they have fans and filters built in..
Joe when using a CAT cooler, the OTA is no longer 'sealed'. The air is blown into the OTA via a smaller tube than the baffle tube, the air then circulates in the OTA & exits out up the baffle tube past the CAT cooler inlet tube if you know what I mean. I'll take a pic for you if you don't..
Excellent idea Shawn, thats what I was doing until my aircon. cashed its chips in! I just stuck the whole kit & caboodle in the lounge room turned on the aircon mid afternoon, come back at sundown..
My next idea was to make a peltier cooled box (an esky actually) to house the OTA in & keep it at a regulated temp. (in effect, keeping the bloody thing in a frost free fridge lol) But 1 peltier was not enough to do any good in this area. http://www.iceinspace.com.au/forum/s...ead.php?t=9940
Not sure Dave, I've never thought about that idea (well I kind of have)......That go's back to ONE of my ideas to have the whole OTA in this 'esky', with CAT cooler up the guts & with just the peltier cold plate in the lid of the esky (heatsink outside the lid)....
as Houghy mentions will condensation be a problem? could you use those mositure removeal type bags that come with some things you buy? (dont know what they are called) looks good, how about some before and after cooling shots.
) wouldent it be better to have some vent holes near the front of the tube, stand the OTA up so the mirror is on the bottem and pump in the cold air. that way the hotter air exscapes through the vents at the top, when its cooled enough close the vents ? 
