Having previously become accustomed (primarily) to reflectors not exceeding f/6, the smaller fields provided by my acquisition of a f/10 (Ritchey–Chrétien) Meade were a sacrifice I was grudgingly willing to accept. I have in the meantime, of course, experimented with the use of various telecompressors to widen my instrument’s ‘scope’, with mixed levels of success.
This new Baader lens system, designed by no less than Roland Christen (the founder of American premium telescope manufacturers Astro-Physics) based on the style of focal reducers developed by the late twentieth century optical designer Alan Gee, shrinks f/10 to f/5.9. Its unique design positions the telecompressor well within the telescope’s baffle tube, making it suitable for both visual and photographic use, plus allowing its deployment with all manner of supplementary accessories further along the optical path. It is even possible to use it in conjunction with bino-viewers, making possible spectacular binocular (large aperture) wide angle observations.
For more information: baader-planetarium.uk.com