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 January 2 [2]See Explanation. Clicking on the picture will download the highest resolution version available. 21st Century Wet Collodion Moon Image Credit & [3]Copyright: Mike Smolinsky Explanation: In the mid 19th century, one of the first photographic technologies used to record the lunar surface was the [4]wet-plate collodion process, notably employed by British astronomer [5]Warren De la Rue. To capture an image, a thick, transparent mixture was used to coat a glass plate, sensitized with silver nitrate, exposed at the telescope, and then developed to create a negative image on the plate. To maintain photographic sensitivity, the entire process, from coating to exposure to developing, had to be completed before the plate dried, in a span of about 10 to 15 minutes. This modern version of a wet-plate collodion [6]image celebrates lunar photography's early days, reproducing [7]the process using modern chemicals to coat a glass plate from a [8]21st century hardware store. Captured last November 28 with an 8x10 view camera and backyard telescope, it faithfully records large craters, bright rays, and dark, smooth mare of the [9]waxing gibbous Moon. Subsequently digitized, the image on the plate was 8.5 centimeters in diameter and exposed while tracking for 2 minutes. The wet plate's effective photographic sensitivity was about ISO 1. In your smart phone, the camera sensor probably has a photographic sensitivity range of ISO 100 to 6400 (and [10]needs to be kept dry ...). Tomorrow's picture: northern lights __________________________________________________________________ [11]< | [12]Archive | [13]Submissions | [14]Index | [15]Search | [16]Calendar | [17]RSS | [18]Education | [19]About APOD | [20]Discuss | [21]> __________________________________________________________________ Authors & editors: [22]Robert Nemiroff ([23]MTU) & [24]Jerry Bonnell ([25]UMCP) NASA Official: Phillip Newman [26]Specific rights apply. [27]NASA Web Privacy Policy and Important Notices A service of: [28]ASD at [29]NASA / [30]GSFC & [31]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2101/WetCollodionLunar112820SMO.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://en.wikipedia.org/wiki/Collodion_process 5. https://en.wikipedia.org/wiki/Warren_De_la_Rue 6. https://www.metmuseum.org/art/collection/search/786096?&exhibitionId=%7b1db98082-524d-46fe-93ee-3ba6436c0acb%7d&oid=786096&pkgids=578&pg=0&rpp=20&pos=23&ft=*&offset=20 7. https://unblinkingeye.com/Articles/WPC/wpc.html 8. https://www.pbs.org/wgbh/americanexperience/features/eastman-wet-plate-photography/ 9. https://svs.gsfc.nasa.gov/Gallery/moonphase.html 10. https://www.wetplateday.org/galleries/ 11. https://apod.nasa.gov/apod/ap210101.html 12. https://apod.nasa.gov/apod/archivepix.html 13. https://apod.nasa.gov/apod/lib/apsubmit2015.html 14. https://apod.nasa.gov/apod/lib/aptree.html 15. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 16. https://apod.nasa.gov/apod/calendar/allyears.html 17. https://apod.nasa.gov/apod.rss 18. https://apod.nasa.gov/apod/lib/edlinks.html 19. https://apod.nasa.gov/apod/lib/about_apod.html 20. http://asterisk.apod.com/discuss_apod.php?date=210102 21. https://apod.nasa.gov/apod/ap210103.html 22. http://www.phy.mtu.edu/faculty/Nemiroff.html 23. http://www.phy.mtu.edu/ 24. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 25. http://www.astro.umd.edu/ 26. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 27. https://www.nasa.gov/about/highlights/HP_Privacy.html 28. https://astrophysics.gsfc.nasa.gov/ 29. https://www.nasa.gov/ 30. https://www.nasa.gov/centers/goddard/ 31. http://www.mtu.edu/