The Michelson stellar interferometer is one of the earliest astronomical interferometer

Astronomical interferometer

An astronomical interferometer is an array of telescopes or mirror segments acting together to probe structures with higher resolution by means of interferometry....

s built and used. The interferometer was proposed by Albert Michelson

Albert Abraham Michelson

Albert Abraham Michelson was an American physicist known for his work on the measurement of the speed of light and especially for the Michelson-Morley experiment. In 1907 he received the Nobel Prize in Physics...

 in 1890, following a suggestion by Hippolyte Fizeau

Hippolyte Fizeau

Armand Hippolyte Louis Fizeau was a French physicist.-Biography:Fizeau was born in Paris. His earliest work was concerned with improvements in photographic processes. Following suggestions by François Arago, Léon Foucault and Fizeau collaborated in a series of investigations on the interference of...

.

The first such interferometer built was at the Mount Wilson observatory

Mount Wilson Observatory

The Mount Wilson Observatory is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a 5,715 foot peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles...

, making use of its 100 inch (~250 centimeters) mirror. It was used to make the first-ever measurement of a stellar diameter, by Michelson and Francis Gladheim Pease

Francis Gladheim Pease

Francis Gladheim Pease was an American astronomer.He joined the Yerkes Observatory in Wisconsin, where he was an observer and an optician. There he assisted George W. Ritchey who built many of America's first large reflecting telescopes. In 1908 he became an astronomer and instrument maker at the...

, when the diameter of Betelgeuse

Betelgeuse

Betelgeuse, also known by its Bayer designation Alpha Orionis , is the eighth brightest star in the night sky and second brightest star in the constellation of Orion, outshining its neighbour Rigel only rarely...

 was measured in December 1920. The diameter was found to be 240 million miles (~380 million kilometers), about the size of the orbit

Orbit

In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...

 of Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

, or about 300 times larger than the Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

.

See also

• History of astronomical interferometry
• Fizeau interferometer
  Fizeau interferometer
  A Fizeau interferometer is similar to a Fabry–Pérot interferometer in that they both consist of two reflecting surfaces. In a Fizeau interferometer, however, the two surfaces are usually much less than totally reflecting , so that secondary reflections don't contribute greatly to the fringe...
  
  
• Michelson interferometer
  Michelson interferometer
  The Michelson interferometer is the most common configuration for optical interferometry and was invented by Albert Abraham Michelson. An interference pattern is produced by splitting a beam of light into two paths, bouncing the beams back and recombining them...