Hi all,
I have just complete a GSO dob fan project on my 10" dob via the article posted some years ago by Scott Tannehill on IIS found here
http://www.iceinspace.com.au/63-400-0-0-1-0.html
Everything works extremely well as described in the article, thanks Scott

My only concern is this....
The ring baffle has been crafted to go all the way around the inside of the scope tube 360deg (just above the primary mirror). Thus the air flow does not flow up the tube and out the top as before, to the point where virtually no air can be felt bellowing out any longer.
The question and advice I'm seeking is, should it be left like this or should the ring baffle be crafted to go only half way around the inner tube (for example) and let air flow up and out the tube after crossing the face of the primary mirror?
I don't know if air from the fan needs! to flow up the tube and exit out the top or not for one reason or another. I'd like someone to confirm which method is best to use prior to starting the same project on my 12" dob.
Thanks in advance for any and all replies on this

Cheers
Guy and Linda