High Resolution Speckle Methods For Overcoming Image Degradation Caused By The Atmosphere And Telescope Aberrations

Abstract

We discuss various high resolution speckle methods that can overcome image degradation caused by the atmosphere and telescope aberrations. All methods yield diffraction-limited resolution, for example 0.03" for a 3.6m telescope. We show speckle interferometric observations of asteroids, Pluto/ Charon, double stars, and the gravitational-lens triple quasar. True diffraction-limited images can be reconstructed by speckle interferometry if there is a point, source in the isoplanatic neighborhood of the object (holographic speckle interferometry). Speckle masking is a triple-correlation method that yields diffraction-limited images of general astronomical objects. A point source near the object is not required. We describe an application of speckle masking to the central object in the giant HII region NGC 3603. Speckle spectroscopy is a speckle method that yields diffraction-limited objective prism spectra. It is also possible to apply speckle masking to multiple-mirror interferometers or long-baseline interferometers on the ground or in space. True images of very high angular resolution can be obtained by these techniques. Computer simulations are shown for illustration.