Astrometric reflector

The US Naval Observatory at Flagstaff, Ariz., has acquired a new telescope for determining the distances of very faint stars by measuring their heliocentric parallax. The new $2.3 million, 61‐inch Astrometric Reflector is the first large reflecting telescope designed specifically for this purpose, and is capable of detecting the apparent motion of stars as distant as 100 light years and of a magnitude as faint as 18.5. Of particular interest are the red dwarfs, white dwarfs, and subdwarfs—all stars of unusual properties whose energies cannot be evaluated until their distances are known.