Atmospheric refraction Atmospheric refraction is considered in measuring the position of both celestial and terrestrial objects. Astronomical or celestial refraction causes astronomical objects to appear higher above the horizon than they actually are. Terrestrial refraction usually causes terrestrial objects to appear higher than they actually are, although in the afternoon when the air near the ground is heated, the rays can curve upward making objects appear lower than they actually are. Refraction not only affects visible light rays, but all electromagnetic radiation, although in varying degrees. For example, in the visible spectrum, blue is more affected than red. This may cause astronomical
A-135 anti-ballistic missile system 350 km and altitudes of 50 km. A-135 anti-ballistic missile system The A-135 (NATO: ABM-3 Gorgon) anti-ballistic missile system is a Russian military complex deployed around Moscow to counter enemy missiles targeting the city or its surrounding areas. It became operational during 1995. It is a successor to the previous A-35, and complies with the 1972 Anti-Ballistic Missile Treaty. The A-135 system attained "alert" (operational) status on February 17, 1995. It is operational although its 51T6 (NATO reporting name: SH-11) component was deactivated in February 2007. A newer missile (PRS-1M) is expected to replace it. There is an operational test