Primary Mirror Fan

[davidpretorius]

bunnings sell sheets of aluminium at .6mm thick. I would try that first. My little cordless palm drill drills it, a pair of snips cuts it easy.

Easiest way to get a rough template. Cut a hole in the middle, drill holes for the screw to secure the fan. Also maybe a hole for the temp sensor, but my dob has a hole in the cell to poke the sensor wire thru???.

Once happy, leave the aluminium or use it to cut a more permanent piece out of wood or perspex or whatever.

[matt]

Dave

I think you misunderstood, or didn't read closely enough OR BOTH

I've already got the back plate to affix the fan and speed controller to, so I don't need the aluminium sheet.

I've already amrked out the places where I have to cut to allow access to collimation screws and where the fan's going to go. I'll figure out the controller units pozzie after that.

What size fan and where do I get a variable speed unit?

What about vibration dampening? Power considerations?

Got any pics of where you attached the temp sensor on your primary? It'd need to be out of the direct line of fire of the fine, wouldn't it?

[Starkler (Geoff)]

Originally Posted by matt

Those pre-made mrror cooling units on Pat's website look great.

Mine doesnt look as flash but i bet it works better
Check it out here

[matt]

Looks good Geoff!

How do you go as far as vibration's concerned? Does the foam weather sealing strip gasket work as a dampener? Can you keep the fan running while observing/imaging?

Nice work

[Starkler (Geoff)]

Well on a night of better than average seeing and stable air temp viewing Saturn at 200x I couldnt detect a difference between the fan being on or off. The fan had been running for a couple of hours previous to that.

For a definitive test I really need excellent seeing, but that doesnt happen here very often

[matt]

you star tested with the fan on?