American Astronomer Joel Stebbins Pioneered Photoelectric Photometry

Summary: American astronomer Joel Stebbins pioneered photoelectric photometry as a technique for precisely measuring an astronomical object's color and magnitude.

Joel Stebbins with photoelectric photometer on 12-inch refractor telescope, University of Illinois at Urbana: Friends of the University of Illinois Observatory, via Facebook Oct. 29, 2010

Twentieth-century American astronomer Joel Stebbins pioneered photoelectric photometry as a technique for the precise measurement of the colors and magnitudes of astronomical objects.

Stebbins was born July 30, 1878, in Omaha, Nebraska. He succumbed to leukemia March 16, 1966, in a Palo Alto, California, hospital.

Stebbins was awarded his Doctor of Philosophy (Ph.D.) in May 1903 as the University of California's third Astronomy doctoral recipient, according to his 1978 biography by American astronomer and physicist Albert Edward Whitford (Oct. 22, 1905-March 28, 2002) for the National Academy of Sciences (NAS). His dissertation considered the spectrum of Omicron Ceti (ο Ceti; Omicron Cet, ο Cet; traditional name: Mira). The Astrophysical Journal, the science journal of astronomy and astrophysics, published Stebbins' dissertation in its December 1903 issue. Whitford stated that Stebbins' published dissertation was consulted as the principal source for information on long-term variable spectra for "almost twenty years" (page 296).

Immediately after completing his Ph.D., Stebbins assumed an instructorship in astronomy at the University of Illinois, in Urbana, Champaign County, east central Illinois. He became Assistant Professor in 1904 and then Professor and second Director of the University Astronomical Observatory in 1913, according to his 1984 biography in science textbook author David Abbott's The Biographical Dictionary of Scientists: Astronomers (page 148).

At the University of Illinois, Stebbins initiated a program for measuring the magnitudes of double stars via a visual polarizing photometer on a 12-inch refractor telescope. The online database of the University of Illinois Observatory Collection describes the visual polarizing photometer used by Stebbins as an instrument that measures stellar magnitudes via the polarizing properties of doubly-refracting crystals. The instrument assesses double stars with known magnitudes for one of the pair.

In his 1957 reminiscences of "Early Photometry at Illinois," Stebbins credited his wife, May Louise Prentiss Stebbins (June 12, 1875-Oct. 10, 1970), with inspiring his search for electronic methods for photometry. As recorder, she found the process slow, what with one magnitude necessitating a hundred readings. After Stebbins shared with her that one day electricity would accelerate the process, his wife kept questioning when the change to electricity would take place (page 507).

Shortly thereafter, Stebbins became aware of selenium cell experiments conducted by University of Illinois physicist Fay Cluff Brown (1881-1968). Stebbins and Brown collaborated on designing a selenium-celled photometer as an attachment for the observatory's 12-inch refractor telescope. Their first attempted application of their invention was directed, unsuccessfully, at gas-giant Jupiter. Stebbins promptly detached the selenium cell from the telescope and exposed it to the moon, which was visible through a window. Their invention's galvanometer (electromechanical instrument for detecting and measuring electric current) immediately responded.

With Stebbins on the telescope and Brown on the galvanometer, the team devoted June, July and August to measuring phase variations in moonlight. They published their results in the December 1907 issue of the Astrophysical Journal. Their findings determined the full phase's brightness as approximately nine times that of the half phase. Their phasal light curve constituted the first such study since research published in 1866 by German astrophysicist Johann Karl Friedrich Zöllner (Nov. 8, 1834-April 25, 1882).

By 1913, Stebbins sought further finesses of photometry via a photoelectric cell developed by Swiss-born American-naturalized theoretical physicist Jakob Kunz (Nov. 3, 1874-July 18, 1938). Planning to spend summer 1915 in California, Stebbins decided to test Kunz's instrument under the optimal conditions prevailing at the University of California's Lick Observatory. He arranged to transport Kunz's instrument and the University of Illinois Observatory's 12-inch refractor telescope to the observatory's location on Mount Hamilton. Stebbins took measures of Beta Lyrae (β Lyrae; Beta Lyr, β Lyr; traditional name: Sheliak) over 34 nights between Sunday, June 20, and Friday, July 30. Stebbins biographer Whitford describes Beta Lyrae as ". . . a prototype example of an eclipsing binary with marked ellipsoidal distortion of the components" (page 299). He published the eclipsing binary's light curve in the March 1916 issue of the Lick Observatory Bulletin.

Stebbins continued to advance photoelectric photometry for the next five decades. Within four decades, the photoelectric technique was becoming universally recognized as the standard method of astronomical photometry (Whitford, page 308).

The takeaway for American astronomer Joel Stebbins as photoelectric photometry's pioneer is that Stebbins' interests in the colors and magnitudes of astronomical objects impelled his measuring technique trajectory from usage of a visual polarizing photometer beginning in 1903 to collaborative development of selenium cells with physicist Fay Cluff Brown and then of photoelectric cells with physicist Jakob Kunz at the University of Illinois at Urbana.

photoelectric photometer cell, developed by Jakob Kunz for Joel Stebbins, on 12-inch refractory telescope, University of Illinois at Urbana: Friends of the University of Illinois Observatory, via Facebook Oct. 2, 2014

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Joel Stebbins with photoelectric photometer on 12-inch refractor telescope, University of Illinois at Urbana: Friends of the University of Illinois Observatory, via Facebook Oct. 29, 2010, @ https://www.facebook.com/U.of.Illinois.Observatory/photos/a.127528800635930/128326157222861/?type=3

photoelectric photometer cell, developed by Jakob Kunz for Joel Stebbins, on 12-inch refractory telescope, University of Illinois at Urbana: Friends of the University of Illinois Observatory, via Facebook Oct. 2, 2014, @ https://www.facebook.com/U.of.Illinois.Observatory/photos/a.137983869590423/716636338391837/?type=3

For further information:

Abbott, David. The Biographical Dictionary of Scientists: Astronomers. New York NY: Peter Bedrick Books, 1984.

Alvan Clark & Sons. "Visual Polarizing Photometer." University of Illinois Observatory Collection.
Available @ https://uiobservatory.omeka.net/items/show/2

Brown, F.C.; and Joel Stebbins. "Some Studies on the Change of Electrical Resistance of Selenium Cells." Physical Review, (Series I) vol. 26, issue 4 (April 1, 1908): 273-298.
Available @ https://journals.aps.org/pri/abstract/10.1103/PhysRevSeriesI.26.273

Consolmagno, Guy; and Dan M. Davis. Turn Left at Orion. Fourth edition. Cambridge UK; New York NY: Cambridge University Press, 2011.

Friends of the University of Illinois Observatory. "December 31, 1913. In 1913 Dr. Joel Stebbins earned the Rumford Award for his work on the selenium cell photometer which is now located in the University Archives. His grandson Robert Stebbins donated the award to the university several years ago." Facebook. Nov. 1, 2012.
Available @ https://www.facebook.com/U.of.Illinois.Observatory/photos/a.137983869590423/421142501274557/?type=3

Friends of the University of Illinois Observatory. "Inside the shelter. A galvanometer (center right) was read by the reading telescope to measure the current produced by the photoelectric cells." Facebook. Oct. 16, 2014.
Available @ https://www.facebook.com/U.of.Illinois.Observatory/photos/a.137983869590423/723046997750771/?type=3

Friends of the University of Illinois Observatory. "Joel Stebbin's work on the 12-inch was noted in this month's Sky & Telescope!" Facebook. Feb. 8, 2019.
Available @ https://www.facebook.com/U.of.Illinois.Observatory/posts/2002912819764176

Friends of the University of Illinois Observatory. "Joel Stebbins at the eyepiece of his photometer, about 1923." Facebook. Oct. 29, 2010.
Available @ https://www.facebook.com/U.of.Illinois.Observatory/photos/a.127528800635930/128326157222861/?type=3

Friends of the University of Illinois Observatory. "TBT: One of the earliest photographs of the photoelectric cell photometer on the 12-inch telescope. Taken about 1913. Notice the wires for the lights in the dome were two bare wires, no conduit." Facebook. Oct. 2, 2014.
Available @ https://www.facebook.com/U.of.Illinois.Observatory/photos/a.137983869590423/716636338391837/?type=3

Genet, Russell M. "Joel Stebbins: Pioneer of Astronomical Photoelectric Photometry." International Amateur-Professional Photoelectric Photometry, Communication, No. 6 (November 1981): 1-3.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/full/1981IAPPP...6....1G

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Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/full/seri/ApJ../0027//0000187.000.html

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Available via JSTOR @ https://www.jstor.org/stable/40673265

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Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/full/1939PA.....47..117S

Stebbins, Joel. "The Light-Curve of δ Cephei." Astrophysical Journal, vol. XXVII, no. 3 (April 1908): 188-193.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/full/1908ApJ....27..188S

Stebbins, Joel. "A Method of Determining the Heights of Migrating Birds." Popular Astronomy, vol. XIV, no. 2, whole no. 132 (February 1906): 65-70.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/full/1906PA.....14...65S

Stebbins, Joel. "Observations of the Crater Linné During the Lunar Eclipse of February 8, 1906." The Astronomical Journal, vol. XXV, no. 587, no. 11 (July 18, 1906): 87-88.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/full/1906AJ.....25...87S
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/pdf/1906AJ.....25...87S

Stebbins, Joel. "A Study of β Lyrae With a Photo-Electric Photometer." Lick Observatory Bulletin, vol. VIII, no. 277 (issued March 18, 1916): 186-193.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/full/1916LicOB...8..186S
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/pdf/1906AJ.....25...87S

Stebbins, Joel; and Edward A. Fath. "The Use of Astronomical Telescopes in Determining the Speeds of Migrating Birds." Science, vol. 24, issue 602 (July 13, 1906): 49-51.
Available @ https://science.sciencemag.org/content/24/602/49

Stebbins, Joel; and F.C. Brown. "A Determination of the Moon's Light With a Selenium Photometer." Astrophysical Journal, vol. XXVI, no. 5 (December 1907): 326-340.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/full/1907ApJ....26..326S
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/pdf/1907ApJ....26..326S

Svec, Michael. "The Many Transformations of the University of Illinois Observatory Annex." Journal of Astronomical History and Heritage, vol. 21, issue 1 (March/April 2018), 81‒93(2018).
Available via NARIT (National Astronomical Research Institute of Thailand) @ http://old.narit.or.th/en/files/2018JAHHvol21/2018JAHH...21...81S.pdf

Whitford, A.E. (Albert Edward). Joel Stebbins 1878-1966: A Biographical Memoir. Washington DC: National Academy of Sciences, 1978.
Available @ http://nasonline.org/publications/biographical-memoirs/memoir-pdfs/stebbins-joel.pdf

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Available @ https://onlinelibrary.wiley.com/doi/10.1002/asna.18660661502