Camera, Speckle System

Display Status:

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.

Collection Item Summary:

This suite of objects constitutes the prototype speckle interferometer built by Harold A. McAlister, Regents’ Professor Emeritus of Astronomy & Founder and Director Emeritus of the Center for High Angular Resolution Astronomy (CHARA) Georgia State University, Atlanta, GA. The ensemble includes all the elements employed during an observing session including power supplies and connecting cables.

The technique known as “speckle interferometry” dates from the 1970s and revolutionized many astrometric applications, chiefly the study of very close binary stellar systems. The technique resembles the modern digital technique known as “stacking” but unlike stacking it preserves technical information about the absolute positions of point-source objects. As do modern techniques of active and adaptive optics, it’s primary value is being able to remove the distortion effects of the earth’s atmosphere to provide “diffraction limited” optical performance. Theoretically, when employed on a telescope of 94 inches or larger aperture, speckle provides resolving power equivalent to the Hubble Space Telescope.

In the late 1980s and early 1990s, one of the projects engaged by the Smithsonian's Sloan Videohistory program focused on how speckle interferometry revolutionized double star observing at the Naval Observatory. The instrument employed there is a direct descendant of this instrument.