A compact, grating spectrometer (1A) particularly adapted for visual observation of the sun's spectrum, from the Calcium K line to the Fraunhofer B line, at very high dispersion. The numerical aperture of the spectrometer's collimating mirror is intentionally mismatched to the numerical aperture of the...http://www.google.com.au/patents/US6587198?utm_source=gb-gplus-sharePatent US6587198 - Compact, solar spectrometer with sub-one-third angstrom resolution, faint-light compensation, and infrared and ultraviolet suppression
