star test oddity for optical mavens

Since some of our best minds hang out here I thought I would solicit diagnostic opinions on this optical oddity which has been reported on two Bosma Maks.

Attached Image:

Further notes: there is some speculation that this effect may be related to a screw that protrudes part way out the baffles, but I don't have a clear sense as to placement.

The CN thread is here

http://goo.gl/bXsIv

Greg N

I have a 127mm Orion Mak that shows very similar star test. The problem in mine is a defect in the central zone of primary mirror. The defect is about the size of a dime and resembles a clam shell fracture at the edge of the central hole but it is next to invisible to the naked eye. You can see it if you catch a reflection just the right way.

It doesn't seem to affect images much but is obvious in a star test.

dan