Telescope Making

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Mirror Cell Design

Written by Toshimi Taki
November 22, 2003


When I started tackling the problem of mirror cell design in 1993, there was little information about number and location of mirror support points for amateur telescope makers. The mirror design had not been based on science but experience.

I was interested in number of support points necessary to support a mirror without harmful deformation. I developed a finite element analysis program (FEA for short), "Plate" to analyze deformation of a mirror under its own weight. I have enough knowledge of FEA because my background is structure engineering. My analysis was limited to existing cell designs, 3-point, 9-point and 18-point support floating cells. Optimization of location of support point was beyond the reach of my analysis.

After my articles on mirror cell design were published in Sky & Telescope magazine in 1994 and 1996, Professor David Lewis of Tronto University extended my work by developing mirror support point optimization software "Plop" based on my FEA program, "Plate". Plop enables us to find out the most effective cell design for a particular mirror. (Plop is available at David Lewis's Home Page).

Mirror Cell Design Data

Mark D. Holm investgated many cell designs using "Plop" and summarized the results in his home page. The data is very useful for telescope makers.

See Mirror Cells for Amateur Telescope Makers by Mark D. Holm.

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