Speckle Interferometry with Small Telescopes

Abstract

Speckle interferometry is a mature technique first utilized by Antoine Labeyrie over a quarter century ago. Unlike conventional interferometry, speckle is filled-aperture interferometry utilizing the turbulence cells of the atmosphere over the telescope to constructively interfere and produce diffraction limited information. Despite an initial flurry of activity, however, work at the present time is limited to a few groups, typically utilizing telescopes of 0.7 to 4.0 meters. Although actual images have been difficult to obtain and are rather expensive (both in computer and telescope time) to produce, speckle interferometry is well suited to simple morphologies, such as relative astrometry of binary and multiple stars. The vast bulk of work done in speckle interferometry is observations of binary stars. These observations can be used to: determine stellar masses (although this is also dependent on the availability of other data, e.g., spectroscopic or parallactic), provide an independent check on proper motions determined for close doubles by other techniques, provide verification or confirmation of close binaries found by other techniques (e.g., Hipparcos), or, due to the rapid operation of most speckle observing, provide information as to the multiplicity characteristics of a large sample of stars over a large regime of p-Δm space. Speckle investigation can also aid in the study of stars in planetary searches by culling from targeted searches stars unlikely to have life harboring planets, or to ensure that “planets” detected spectroscopically are not (due to the sin i dependence) pole-on binary stars. Many of these known binaries in need of investigation can be observed with moderate or smaller sized telescopes.techniquesInterferometryvisual binaries