¿ Astronomy Picture of the Day [1]Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2021 February 10 [2]See Explanation. Clicking on the picture will download the highest resolution version available. Firing Lasers to Tame the Sky Image Credit & Copyright: [3]Juan Carlos Muñoz / [4]ESO; Text: [5]Juan Carlos Muñoz Explanation: Why do stars twinkle? [6]Our atmosphere is to blame as pockets of slightly off-temperature air, in constant motion, distort the light paths from distant astronomical objects. Atmospheric turbulence is a problem for astronomers because it [7]blurs the images of the sources they want to study. The telescope featured in this image, located at [8]ESO's [9]Paranal Observatory, is equipped with [10]four lasers to combat [11]this turbulence. The lasers are tuned to a color that excites atoms floating high in [12]Earth's atmosphere -- [13]sodium left by passing meteors. These [14]glowing sodium spots act as artificial stars whose twinkling is immediately recorded and passed to a [15]flexible mirror that deforms hundreds of times per second, counteracting atmospheric turbulence and resulting in [16]crisper images. The [17]de-twinkling of stars is a developing field of technology and allows, in some cases, [18]Hubble-[19]class [20]images to be taken from the ground. This technique has also led to spin-off applications in [21]human vision science, where it is used to obtain very sharp images of the retina. Tomorrow's picture: open space __________________________________________________________________ [22]< | [23]Archive | [24]Submissions | [25]Index | [26]Search | [27]Calendar | [28]RSS | [29]Education | [30]About APOD | [31]Discuss | [32]> __________________________________________________________________ Authors & editors: [33]Robert Nemiroff ([34]MTU) & [35]Jerry Bonnell ([36]UMCP) NASA Official: Phillip Newman [37]Specific rights apply. [38]NASA Web Privacy Policy and Important Notices A service of: [39]ASD at [40]NASA / [41]GSFC & [42]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2102/AoLasers_Munoz_3648.jpg 3. https://twitter.com/astro_jcm 4. https://www.eso.org/public/ 5. https://twitter.com/astro_jcm 6. https://en.wikipedia.org/wiki/Astronomical_seeing 7. https://www.youtube.com/watch?v=or1A4g14_jM 8. https://www.eso.org/ 9. https://www.eso.org/public/teles-instr/paranal-observatory/ 10. https://www.eso.org/public/teles-instr/paranal-observatory/vlt/vlt-instr/4lgsf/ 11. https://apod.nasa.gov/apod/ap000725.html 12. https://www.nasa.gov/sites/default/files/images/463940main_atmosphere-layers2_full.jpg 13. https://en.wikipedia.org/wiki/Sodium_layer 14. http://sguisard.astrosurf.com/Pagim/M42-4LGS.html 15. https://www.youtube.com/watch?v=gDGvNyVApgg 16. https://www.eso.org/public/images/eso1824b/ 17. https://en.wikipedia.org/wiki/Adaptive_optics 18. https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-the-hubble-space-telecope-58.html 19. https://apod.nasa.gov/apod/ap201206.html 20. https://apod.nasa.gov/apod/ap181009.html 21. https://www.alpao.com/adaptive-optics/ophtalmology.html 22. https://apod.nasa.gov/apod/ap210209.html 23. https://apod.nasa.gov/apod/archivepix.html 24. https://apod.nasa.gov/apod/lib/apsubmit2015.html 25. https://apod.nasa.gov/apod/lib/aptree.html 26. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 27. https://apod.nasa.gov/apod/calendar/allyears.html 28. https://apod.nasa.gov/apod.rss 29. https://apod.nasa.gov/apod/lib/edlinks.html 30. https://apod.nasa.gov/apod/lib/about_apod.html 31. http://asterisk.apod.com/discuss_apod.php?date=210210 32. https://apod.nasa.gov/apod/ap210211.html 33. http://www.phy.mtu.edu/faculty/Nemiroff.html 34. http://www.phy.mtu.edu/ 35. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 36. http://www.astro.umd.edu/ 37. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 38. https://www.nasa.gov/about/highlights/HP_Privacy.html 39. https://astrophysics.gsfc.nasa.gov/ 40. https://www.nasa.gov/ 41. https://www.nasa.gov/centers/goddard/ 42. http://www.mtu.edu/