Hi Roland,
I'd be interested in your take on something. I see that you sometimes drop in on this forum.
I've got a project going on right now to build a newtonian reflector. I'm using an aluminum tube, and will be using some computer fans to pull air out the back of the mirror cell.
I've read lots of discussion on these forums (and other places) with opinions on the best ways to finish aluminum tubes in order to manage heat. I know that there are several issues to deal with such as: radiation of heat to the outside of the tube, the inside of the tube & optics, formation of dew etc. I'm sure that whatever design choice is made will have some trade-offs.
Some propose leaving the tube bare aluminum on the outside, and using an insulating material on the inside (such as cork or flocking paper). I read one article proposing that it is best to paint the tube black on the outside, and white on the inside first before coating with flat black.
I've seen you make some comments on thermal management before. And you obviously know the subject well. Just observing, I see that you use white paint on the exterior of your tubes.
If you were going to build a newtonian in an aluminum tube (and I realize that is probably a real stretch), how would you finish the tube?
I'd be interested in your take on something. I see that you sometimes drop in on this forum.
I've got a project going on right now to build a newtonian reflector. I'm using an aluminum tube, and will be using some computer fans to pull air out the back of the mirror cell.
I've read lots of discussion on these forums (and other places) with opinions on the best ways to finish aluminum tubes in order to manage heat. I know that there are several issues to deal with such as: radiation of heat to the outside of the tube, the inside of the tube & optics, formation of dew etc. I'm sure that whatever design choice is made will have some trade-offs.
Some propose leaving the tube bare aluminum on the outside, and using an insulating material on the inside (such as cork or flocking paper). I read one article proposing that it is best to paint the tube black on the outside, and white on the inside first before coating with flat black.
I've seen you make some comments on thermal management before. And you obviously know the subject well. Just observing, I see that you use white paint on the exterior of your tubes.
If you were going to build a newtonian in an aluminum tube (and I realize that is probably a real stretch), how would you finish the tube?
Rushby Craig
Centerville, UT
8" f6 reflector
Takahashi FS-128 Fluorite Apochromatic Refractor
EQ6 Synscan GEM
