Editing Lucky imaging (section)

==History==

[[File:Gemini North Infrared View of Jupiter.jpg|thumb|upright=1.4|Lucky imaging of Jupiter at 5 μm, using stacks of individual Gemini Observatory frames each with a relatively long 309-msec exposure time]]

Lucky imaging methods were first used in the middle 20th century, and became popular for imaging planets in the 1950s and 1960s (using cine cameras, often with [[image intensifier]]s). For the most part it took 30 years for the separate imaging technologies to be perfected for this counter-intuitive imaging technology to become practical. The first numerical calculation of the probability of obtaining ''lucky exposures'' was an article by [[David L. Fried]] in 1978.<ref>{{Cite journal|doi=10.1364/JOSA.68.001651|title=Probability of getting a lucky short-exposure image through turbulence|year=1978|last1=Fried|first1=David L.|journal=Journal of the Optical Society of America|volume=68|issue=12|page=1651}}</ref>

In early applications of lucky imaging, it was generally assumed that the atmosphere ''smeared-out'' or ''blurred'' the astronomical images.<ref>{{Cite journal|bibcode = 1991A&A...241..663N|title = Recentring and selection of short-exposure images with photon-counting detectors|last1 = Nieto|first1 = J. -L|last2 = Thouvenot|first2 = E.|journal = Astronomy and Astrophysics|year = 1991|volume = 241|page = 663}}</ref> In that work, the [[full width at half maximum]] (FWHM) of the blurring was estimated, and used to select exposures. Later studies<ref>{{Cite journal|doi = 10.1051/0004-6361:20053695|title = Lucky imaging: High angular resolution imaging in the visible from the ground|year = 2006|last1 = Law|first1 = N. M.|last2 = MacKay|first2 = C. D.|last3 = Baldwin|first3 = J. E.|journal = Astronomy & Astrophysics|volume = 446|issue = 2|pages = 739–745|arxiv = astro-ph/0507299|bibcode = 2006A&A...446..739L|s2cid = 17844734}}</ref><ref>{{Cite thesis |last1 = Tubbs |first1 = Robert Nigel |year = 2003 |title = Lucky exposures: Diffraction limited astronomical imaging through the atmosphere |type=PhD thesis |publisher=University of Cambridge |hdl=1810/224517 |hdl-access=free |doi = 10.17863/CAM.15991 |doi-access=free}}</ref> took advantage of the fact that the atmosphere does not ''blur'' astronomical images, but generally produces multiple sharp copies of the image (the [[point spread function]] has ''speckles''). New methods were used which took advantage of this to produce much higher quality images than had been obtained assuming the image to be ''smeared''.

In the early years of the 21st century, it was realised that turbulent intermittency (and the fluctuations in [[astronomical seeing]] conditions it produced)<ref>{{Cite journal|doi=10.1098/rspa.1949.0136|title=The nature of turbulent motion at large wave-numbers|journal=Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences|year=1949|volume=199|issue=1057|pages=238–255|bibcode=1949RSPSA.199..238B|last1=Batchelor|first1=G. K.|last2=Townsend|first2=A. A.|s2cid=122967707}}</ref> could substantially increase the probability of obtaining a "lucky exposure" for given average astronomical seeing conditions.<ref>{{Cite journal|doi = 10.1051/0004-6361:20079214|title = The point spread function in Lucky Imaging and variations in seeing on short timescales|year = 2008|last1 = Baldwin|first1 = J. E.|last2 = Warner|first2 = P. J.|last3 = MacKay|first3 = C. D.|journal = Astronomy & Astrophysics|volume = 480|issue = 2|pages = 589–597|bibcode = 2008A&A...480..589B|doi-access = free}}</ref><ref>{{Cite book|doi = 10.1117/12.671170|chapter = The effect of temporal fluctuations in r<sub>0</sub> on high-resolution observations|title = Advances in Adaptive Optics II|year = 2006|last1 = Tubbs|first1 = Robert N.|series=Proceedings of SPIE |volume = 6272|pages = 62722Y|s2cid = 119391503}}</ref>