Images taken with ground based telescopes are subject to the blurring effect of atmospheric turbulence (seen to the human eye as the stars twinkling). Many astronomical imaging programmes require higher resolution than is possible without some correction of the images. Lucky Imaging is one of a number of approaches to reducing atmospheric blurring (see also adaptive optics, speckle interferometry).

Lucky Imaging uses a high-speed camera with exposure times short enough (100ms or less) so that the changes in the atmosphere during the exposure are minimal. From these images, those (typically around 10%) least affected by the atmosphere are chosen and combined into a single image, yielding much higher resolution than would be possible with a single, longer exposure which includes all the frames.

Both amateur and professional astronomers have begun to use this technique. Modern webcams and camcorders have the ability to capture rapid short exposures with sufficient sensitivity for astrophotography, and these devices are used with a telescope and image stacking software to achieve previously unattainable resolution. The recent development of EMCCDs has allowed the first high quality Lucky Imaging of faint objects.

Used at a 1% selection or less Lucky Imaging can reach the diffraction limit of even 2.5m aperture telescopes, a resolution improvement factor of at least five over standard imaging systems.

Other approaches that can yield resolving power exceeding the limits of atmospheric seeing include adaptive optics, interferometry and space-based telescopes such as NASA's Hubble Space Telescope.

External links

Amateur Lucky Imaging

The Cambridge University Institute of Astronomy Lucky Imaging group website

Lucky Imaging with the 2.6m Nordic Optical Telescope