7 July 2008 Alignment of two mirror astronomical telescopes (the astigmatic component)
Author Affiliations +
The effects of alignment perturbations on the aberration fields of two mirror astronomical telescopes are discussed. It is demonstrated that expressions describing alignment induced field-linear astigmatism, published by McLeod based on the work of Schroeder, can be obtained using nodal aberration theory. Rather than merely providing a different derivation for alignment induced astigmatism, it is shown that nodal theory can provide several insights that are significant for the development of effective alignment techniques. In the example of a specific telescope sited on Mt. Hopkins (Ritchey- Chretien), two approaches to identify misalignments of the secondary mirror are demonstrated. One approach utilizes the eccentricity of defocused star images and their orientation angles to calculate the misalignment of the secondary mirror after axial coma is removed. A second approach based on the location of the two zeros of the astigmatic aberration field is then shown to give equivalent results, but at the same time ensuring a complete model of all possible effects of misalignment on the performance of the telescope.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Tobias Schmid, Tobias Schmid, Kevin Thompson, Kevin Thompson, Jannick Rolland, Jannick Rolland, "Alignment of two mirror astronomical telescopes (the astigmatic component)", Proc. SPIE 7017, Modeling, Systems Engineering, and Project Management for Astronomy III, 70170C (7 July 2008); doi: 10.1117/12.791263; https://doi.org/10.1117/12.791263

Back to Top