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[ATM] New home built 12" ultralight dob

Rod,
  Thanks!  It has been fun.
  The mirror cell has been one of the most successful parts of the project.  
To give credit, it came from a friend in the local astronomy club, Jim 
Lawrence from TAAS.  I didn't believe that it would be a good cell either, 
but he finally convinced me.
  I searched all over creation on the net, and finally found a web site that 
had this double sided sticky tape, with properties.  From what I can tell, I 
am at the upper acceptable working strength of the tape per square inch.  
So, theorie is satisfied.  When I pull the screws in the bottom, I just 
invert the mirror box, and the mirror hangs.  It has never given me any 
reason to worry yet.  And finally, the secondary is stuck on with double 
sided sticky tape also - and it has been hanging from that tape since 
October 2004.  Often, I have a sock or plastic bag around it for additional 
weight/protection.  So, I feel safe saying that the tape works and works 
well if you have enough surface area.
  The mirror mount has also surprised me with it's quality.  I used results 
from plop to figure out where to put the center of the screws, and the 
results have been good.  I could see NO astigmatism when driving the scope 
at 381 power, and stars looked fine.  Saturn was FABULOUS.  I do find that I 
have to columnate it VERY well to get these images, but that is another 
issue.
  I also think that this cell will have pretty good cooling properties.  I 
have noticed thermal issues late at night, however, so also plan on 
installing a fan.  These thermal issues crop up at high magnification, with 
an unfocused star, with motion in the aire disk.

alan

>Hi Alan,
>
>It's a very impressive looking instrument.  I was particularly intersted 
>because I have just completed a >partial re-build of my 12 inch F5.  I was 
>interested in your mirror cell design.  I am planning something >similar 
>but I was going to use silicone.  Have you had any problems with the double 
>sided tape?  I >would worry about it holding the mirror securely.
>
>I have cool down issues with my mirror too: it is 2 inches thick.  My next 
>project will be to install fans.
>
>Rod Brackenridge
>Mount Martha
>AUSTRALIA
>--

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