Celestial background of 1869 eclipse

Kent replies: I’m glad Robert McAdory enjoyed the article . Although I’m not aware of any photos from the 1869 eclipse that show visible stars, there were images on plates from eclipses before 1919. Expeditions from the Lick, Yerkes, Smithsonian Astrophysical, and US Naval Observatories took large-format images of the corona during the 28 May 1900 eclipse, when the star field was similar to that during the 29 May 1919 eclipse. The images taken by Lick and their possible connections to the relativity test are explored in chapter five of Jeffrey Crelinsten’s Einstein’s Jury: The Race to Test Relativity (2006) and chapter two of No Shadow of a Doubt: The 1919 Eclipse That Confirmed Einstein’s Theory of Relativity (2019) by Daniel Kennefick.

The 19th-century searches for an intramercurial planet resulted in many images in which some background stars might be visible. The Lick Observatory Bulletin, number 24 (1902), reported that half of the observatory’s plates from the eclipse of 18 May 1901 included star images. That report also has more specific information about Lick’s capabilities to capture stars in images.

My thanks to Tom English of the Cline Observatory, Jamestown, North Carolina.