Orion Nebula, captured in 1901 by American astronomer George Ritchey

August 20, 2019

Orion Nebula

This image of the Orion Nebula was featured as NASA's Astronomy Picture of the Day on August 17, 2019.

By the turn of the 20th century advances in photography contributed an important tool for astronomers. Improving photographic materials, long exposures, and new telescope designs produced astronomical images with details not visible at the telescopic eyepiece alone. Remarkably recognizable to astrophotographers today, this stunning image of the star forming Orion Nebula was captured in 1901 by American astronomer and telescope designer George Ritchey. The original glass photographic plate, sensitive to green and blue wavelengths, has been digitized and light-to-dark inverted to produce a positive image. His handwritten notes indicate a 50 minute long exposure that ended at dawn and a reflecting telescope aperture of 24 inches masked to 18 inches to improve the sharpness of the recorded image. Ritchey's plates from over a hundred years ago preserve astronomical data and can still be used for exploring astrophysical processes. 

​The image was produced through a partnership with the University of Chicago Library to digitize a subset of historic glass photographic plates archived at the Yerkes Observatory. Led by Professor Rich Kron, a team of undergraduate interns from the Department of Astronomy and Astrophysics is developing code for analyzing high-resolution image files made from the photographic plates in order to extract astrometry and photometry data from them. The research goal is to assess the scientific usefulness of a sample of plates and to make the images available for research. The undergraduate interns are William Cerny, Olina Liang, Jason Lin, Michael Martinez, Elisabeth Medina, Blake Moss, Buduka Ogonor, MaCheaux Ransom, and Jorge Sanchez.

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