Speckle imaging
Videos
Speckle imaging comprises a range of high-resolution astronomical imaging techniques based on the analysis of large numbers of short exposures that freeze the variation of atmospheric turbulence. They can be divided into the shift-and-add method and the speckle interferometry methods. These techniques can dramatically increase the resolution of ground-based telescopes, but are limited to bright targets.
Lucky imaging images of Jupiter at 5 µm, using stacks of individual Gemini Observatory frames each with a relatively long 309-msec exposure time, illustrate the principle that coherence time τ0 increases with wavelength.
Adaptive optics
Videos
Adaptive optics (AO) is a technique of precisely deforming a mirror in order to compensate for light distortion. It is used in astronomical telescopes and laser communication systems to remove the effects of atmospheric distortion, in microscopy, optical fabrication and in retinal imaging systems to reduce optical aberrations. Adaptive optics works by measuring the distortions in a wavefront and compensating for them with a device that corrects those errors such as a deformable mirror or a liquid crystal array.
Adaptive thin shell mirror.
A laser beam directed toward the centre of the Milky Way. This laser beam can then be used as a guide star for the AO.
GRAAL is a ground layer adaptive optics instrument assisted by lasers.