Parallax also offers Classical Cassegrain and Dall-Kirkham Cassegrain telescopes in 10", 12.5", 14.5", and 16" apertures. The Classical Cassegrain offers a very long focal length in a relatively compact tube. They are excellent instruments for high magnification planetary and double star work. The Dall-Kirkham Cassegrain with its F/20 focal ratio and smaller central obstruction is perhaps the ultimate high magnification visual planetary telescope.
Classical Cassegrain Telescopes
Dall-Kirkham Cassegrain Telescopes