Baader Planetarium has designed a new optimized telecentric system for use with Solar Spectrum H-Alpha systems. A telecentric system is used to convert shorter focal ratio telescopes to the desired f/25 or greater beam needed by the rear mounted Solar Spectrum filter. More than a barlow lens or barlow lens based system, the Baader telecentric ensures that the output beam maintains a consistent normal incident angle across the full filter width. The result is a consistent bandwidth and high image contrast across the field of view.
This lens system has been optimized to maintain an exceedingly high optical quality for dedicated solar use (>99% strehl at 656.3nm). Simpler barlow or barlow-based systems are not able to produce this level of accuracy or telecentricity. Hard Dielectric IR coatings further help to reject IR energy and protect the rear etalon from excessive heat energy.
This version effectively extends the focal length by a factor of 4x (2x version also available separately). Baader part # TZ-4 or 2459256. Item weight = 10.5oz.