Cooling an MN190...

[fatwoul]

I'm trying to speed up the cooling-down of my MN190. I've made a little fan mount, that screws in place of the plate at the rear of the scope, but there's one thing I'm not really clear on. Do telescope cooling fans blow warm air out of the tube, or suck cold air in? I'm guessing they're supposed to remove air from the tube, only because if they suck air in, they will also suck in lots of unwanted dust and moisture.

So which is it? Suck or blow?

Ta

[fatwoul]

Another thought: If the fan sucks air in, and a CCD is attached at the top, then any dust or moisture that is drawn in might end up on the sensor.

So far I'm thinking the fan should blow.

[Deneb]

I think the general concensus would be the fan is meant to blow cold air onto the primary (someone correct me if im wrong please), then through the scopes baffled tubing, thus reducing cool down time.

So far I have never used it on my scope, I just take the scope out & leave it for 2 - 3hrs before I start my session.

Have you checked out Nick Howes Review in Astronomy Now. Another Review of it would be Andys Shot Glass.

Cheers

Nadeem