Sayre Observatory: Instruments
Sidereal Clock
Sidereal time is a measure of the Earth's rotation with respect to the stars, while solar time, used by our everyday clocks and watches, measures the Earth's rotation with respect to the Sun. The sidereal day is about 4 minutes shorter than the 24 hour solar day. This is due to the fact that the Earth revolves around the Sun while it rotates about its axis. Use of sidereal time permits astronomers to point their telescopes to a given celestial object more easily.
SAYRE OBSERVATORY
Circa 1940 - 1961
Filar Micrometer
Maker: A.LEEMING
The Filar Micrometer is a device using fixed and moveable cross hairs to measure very small angles between stars, usually for visual binary stars in which both of the orbiting stars are visible through a telescope. The orbital periods of visual binary stars range from about a year to centuries or longer.
SAYRE OBSERVATORY
1936 - 1961
Refractor Telescope: 2004
Maker: ALVIN CLARK & SONS
This original telescope was used at Sayre Observatory. It was dismantled and moved away when the Department stopped using Sayre Observatory. Professors Gary DeLeo and George E. McCluskey located it in one of Lehigh's warehouses and the stand was built for this exhibition by Joe Zelinski of Lehigh's Physics Dept.
Refractor Telescope: 1938
Maker: ALVIN CLARK & SONS
This 1938 photograph taken by George Henry Reussner, Jr., Class of 1940, shows the original telescope in Sayre Observatory.
Transit Instrument
This 1900 brass transit instrument was used at Sayre Observatory from around 1910 to 1961. It was made by Buff and Buff Instrument Makers of Boston, MA. This type of instrument could measure vertical angles of heavenly bodies and determine geographic positions.
Clock
This instrument, made by Henry Glover and numbered "599", was one of the finest timepieces of its time.
It was used in Sayre Observatory from around 1920 to 1961.