2009

Dual-Channel Multi-Purpose Telescope

A dual-channel telescope allows for a wide-field telescope design with a good, narrow field channel of fewer surfaces for shorter-wavelength or planet-finding applications. The design starts with a Korsch three-mirror-anastigmat (TMA) telescope that meets the mission criteria for image quality over a wide field of view. The internal image at the Cassegrain focus is typically blurry due to the aberration balancing among the three mirrors. The Cassegrain focus is then re-optimized on the axis of the system where the narrow field channel instrument is picked off by bending the primary mirror. This now makes the wide-field channel blurry (i.e., the TMA image), and it must be re-optimized while holding the fore-optics fixed. This leaves the tertiary mirror as a variable, as well as a fold mirror strategically placed at the image of the primary mirror (i.e., exit pupil of the telescope). This fold mirror can then be used to compensate for the departure in primary mirror figure used to optimize the narrow field channel. As such, only an aspheric term is needed for this final optimization on this “corrector” fold mirror. This work was done by Joseph M. Howard and David Content of Goddard Space Flight Center. For further information, contact the Goddard Innovative Partnerships Office at (301) 286-5810. GSC-15574-1

White Papers

When Wire Feedthroughs Make Sense
Sponsored by Douglas Electrical Components
A Guide to the MISRA Coding Standard: What you need to know
Sponsored by PRQA
Introduction into Theory of Direction Finding
Sponsored by Rohde & Schwarz A&D
Protecting the Sky
Sponsored by Rohde & Schwarz A&D
How To Make Pressure Switches That Last
Sponsored by Sigma-Netics
Critical Techniques for High-Speed A/D Converters in Real-Time Systems
Sponsored by Pentek

White Papers Sponsored By:

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.