Hexagonal Star Test - Ideas??

I had a chance to get out with my newly reconfigured 13.1" scope last night ( http://www.indytel.com/~rnabholz/index.htm )and did some testing.

The star test is showing a clear hexagonal shape at high power and I could use your ideas as to how to diagnose the problem.

Some stats first.

13.1" f4.5 mirror
1 1/8th" thick
9 point cell as spec'd by Plop
3.1" secondary attached by silicone



Arguments in Favor of improper support by Cell

1. Thin Mirror, maybe 18 point would be a better choice?

2. Hexagonal Pattern suggests pattern that would result from 3 outer pad sets and 3 spaces between.


Arguments against improper support by cell

1. Previous Coulter Tail Gate cell was a 9 point with no observed problem.


Arguments in Favor of Secondary as cause

1. Silicone mounting could have stressed secondary

2. Previous Coulter mounting was 2.5" square double sided tape, Better support?

3. One of the 3 silicone pads shows concave sides instead of convex, Maybe the culprit?


Arguments against Secondary being the cause

1 Trouble visualizing how a secondary mounting with 3 pads would cause the hex pattern.



Well you have my thoughts, What do you think?

Thanks

Rod

Hi Rod
I'm a novice about mirrors, but is it possible that the mirror was not supported correctly during the refigure?

Buck

Thanks for your thoughts Bill.

The scope uses a "two vane" V shaped spider configuration yielding an x shaped diffraction pattern.

I will check the clips, although they are positioned 1/8 to 1/4 inch above the mirror and don't hold the mirror down. I don't think it could be stressing the mirror, but anything is possible and I will take a look.

Thanks

Rod