Computation with a true central obstruction of 75mm, allowing for refocus shift

Computation with a true central obstruction of 75mm, allowing for refocus shift

This page summarizes the results of a first preliminary study for finding an appropriate cell design for my primary mirror. These studies would noat have been possible without the assistance of PLOP, a free simulation tool for computing mirror deformations by means of finite elements analysis.

The cell designs included in this first study are a mix of readily available designs and other designs I created (either they were described but without a PLOP input file, or they were not described at all).

Date: Thu, 11 Mar 1999 23:31:29 -0800
From: Anthony J. Cook
To: Olivier Biot
Subject: Serrurier Truss

Olivier,

Introduction

This page is an attempt to gather most of the formulas used with telescopes. I do not grant that all formulas here are correct, but I’ve been using most of them when building my own scope. Please always use the same units. I prefer working with millimeters. Some formulas are only applicable when one parameter is given in a certain unit that is then written next to the dimension, between square brackets, as in : D[mm].

General formulas

• Definitions