Fogassi's group built on the earlier work by examining how certain mirror cells
respond to the intention behind the actions.
At the mirror-cell end, the threaded rod is fitted with a spherical ball-rod end, which mates to a pin in the outer circumference of the mirror cell's outer ring.
You can read about his double-plate mirror cell at his website, www.garyseronik.com.
Traditionally, mirror cells increase in complexity through a series that includes 3-, 9-, and 18-point supports.
Designing an effective mirror cell requires you to answer two basic questions: How many support points does your mirror need, and how should they be arranged?
For minimal cost and a weekend's effort, you will be rewarded with a mirror cell
that is easy to collimate and lets your primary perform at its best.
Suspecting that the mirror supports might also be responsible, I disassembled the Orion and Bushnell mirror cells. Both proved to be holding the mirrors only at the edges.
With their light, well-ventilated mirror cells and oversize tubes, they were virtually free of tube currents.
Although the ability to optimize mirror cells
was the primary reason for developing Plop, I expected that it would also verify the effectiveness of the standard cell designs.
My recent evaluation of mirror cells
(S&T: September 1994, page 84) sparked a lot of interest, judging by the many letters I received.
The mirrors were mounted in place on three-point, bolt-and-spring mirror cells
. Lock-down bolts on the cells proved essential, since a tiny movement in either mirror will completely ruin the alignment of the two telescopes.
The off-axis design is especially sensitive in this regard, so I used mirror cells
that allow a wide range of adjustment.