Innovative Mirror Cell
Each of our mirror cells are initially designed by utilizing David Lewis’ aberration saving program, PLOP. For our 8” scopes, a three point mirror cell is used. Rather than using large 1” furniture pads as our cell’s contact points, we remain as true to PLOP as possible by utilizing actual “points”. That’s why you’ll find we use very small nylon acorn nuts. The rounded profile provides the continuous point needed for contact with the back of the mirror. As our 8 inch mirrors weigh only a few pounds, we use a simple single point edge support system that utilizes support points every 120 degrees. This 3-point mirror cell is very lightweight at just over a pound, yet it keeps the 8” mirror properly supported with zero collimation drift from zenith to horizon.
Our 12.5” telescopes use a 6-point flotation cell. We were surprised that PLOP showed the six point cell to outperform a nine point cell for this size mirror, but nonetheless, it does. To keep the 12.5” as lightweight as possible, we employ aluminum and Baltic birch to build these mirror cells.
The three flotation bars have 2 nylon acorn nuts that come in contact with the back of the mirror. They can only pivot up and down, so true flotation is achieved, and they never slide out of position. The often overlooked edge support is given important consideration as well. We use an edge bearing support system that is positioned precisely at 90 degrees from the center of the mirror. Because the 12.5 inch mirror cell moves with the mirror during collimation, the mirror is always properly supported, both underneath and on its edge.
Finally, on our 16” and 20” scopes, we fabricate a custom welded steel 18 point flotation mirror cell with steel cable edge support, but with a twist:
New Moon Telescopes implements an adjustable sling that keeps the mirror supported at its true center of gravity, yet compensates for the up/down motions upon initial collimation, by sliding on 2 linear bearings where the cable is connected.
This ensures that the mirror is always being supported at its true center of gravity, but also that the sling stays in one plane. With this design, typical aberrations (namely astigmatism) clearly seen in inferior mirror cells, are completely negated. You can observe knowing that your mirror is performing to its fullest potential.
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