Mars and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System. The smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan. There are ongoing investigations
Olympus OM system the film plane. The combination of on-lens aperture control and the generous 'flange focal distance' make OM lenses adaptable (with limited functionality) to a variety of other camera systems – including Canon EOS models – by using a mount-specific adapter. Manual Zuiko lenses that were never marketed: Being a system, Olympus made numerous accessories for professional portrait, photo journalism, sport photography and scientific photography. Olympus OM system The Olympus OM System (O = Olympus, M = Maitani) was a line of 35mm single-lens reflex cameras, lenses and accessories sold by Olympus between 1972 and 2002 (some accessories were sold until