Dobsonian and Newtonian
Fig. 17: Two newtonians of different constructions. In the front a Dobsonian and in the back a classic Newtonian tube on an equatorial mount. Telescope meeting, Ahornalp. — EXIF: Nikon D3; Δt=1/10 s; f=50 mm; f/4.0; ISO 200; 2009-05-22 21:33:29