(This book was originally published prior to 1923, and rep...)
This book was originally published prior to 1923, and represents a reproduction of an important historical work, maintaining the same format as the original work. While some publishers have opted to apply OCR (optical character recognition) technology to the process, we believe this leads to sub-optimal results (frequent typographical errors, strange characters and confusing formatting) and does not adequately preserve the historical character of the original artifact. We believe this work is culturally important in its original archival form. While we strive to adequately clean and digitally enhance the original work, there are occasionally instances where imperfections such as blurred or missing pages, poor pictures or errant marks may have been introduced due to either the quality of the original work or the scanning process itself. Despite these occasional imperfections, we have brought it back into print as part of our ongoing global book preservation commitment, providing customers with access to the best possible historical reprints. We appreciate your understanding of these occasional imperfections, and sincerely hope you enjoy seeing the book in a format as close as possible to that intended by the original publisher.
https://www.amazon.com/Researches-Stellar-Photometry-During-Years/dp/B00AP65162?SubscriptionId=AKIAJRRWTH346WSPOAFQ&tag=prabook-20&linkCode=sp1&camp=2025&creative=165953&creativeASIN=B00AP65162
John Albert Parhurst was born on September 24, 1861 in Dixon, Lee County, Illinois, United States. His parents were Sanford Britton and Clarissa J. (Hubbard) Parkhurst. After the death of his mother, when he was five, he was adopted by Dr. and Mrs. Abner Hagar, his uncle and aunt, of Marengo, Illinois.
John Adelbert Parkhurst attended the public schools at Marengo and entered Wheaton College in 1880. At the end of his sophomore year he left college and taught in the public school of Lombard, Illinois. For a year, then entered the Rose Polytechnic Institute, Terre Haute, Indiana, where he graduated in 1886 with the degree of Bachelor of Science in mechanical engineering. In 1897 the degree of Master of Science was conferred on him by the same institution, and in 1906 Wheaton College gave him the degree of Bachelor of Arts as of the class of 1885.
After graduation, John Adelbert Parkhurst spent two years as instructor of mathematics at Rose. The death of his uncle made it necessary for him to return to Marengo, where he was engaged in business for the next ten years. His interest in astronomy had been stimulated by reading the works of Thomas Dick, and while in Terre Haute he had bought a small lens and fashioned his own telescope. As soon as possible after returning to Marengo he bought and set up a modern 6-inch reflector by J. A. Brashear, and during his ten years there contributed some fifty articles to astronomical periodicals, chiefly on variable stars. During a part of this time he acted as a non-resident computer for the Washburn Observatory. The opening in 1897 of the Yerkes Observatory of the University of Chicago at Williams Bay, Wisconsin, within thirty miles of his home, was an important event in his career. He was a frequent visitor there, and during the summer of 1898 he was a volunteer research assistant, assigned to the 12-inch telescope.
In 1900 he was appointed assistant and from then on devoted his entire time to astronomy. He was made instructor in 1905, assistant professor in 1912, and associate professor in 1919. His first piece of work at the Yerkes Observatory was The Spectra of Stars of Secchi's Fourth Type, in collaboration with George E. Hale and Ferdinand Ellerman. His chief work, however, was in photometric research, the measurement of the brightness of stars, both visually and photographically. In 1906 the Carnegie Institution of Washington, which had made special grants toward his salary during his first five years at Yerkes, published his Researches in Stellar Photometry.
During the years 1894 to 1906, made chiefly at the Yerkes Observatory. His "Yerkes Actinometry, " published in the Astrophysical Journal, on October 1912, contained the results of many years of painstaking work in determining the visual and photographic brightness, color indices, and spectral types of all stars not fainter than magnitude 7. 5, located within seventeen degrees of the north pole. Parkhurst, for Yerkes, also cooperated with the Harvard, McCormick, and Lick observatories in a campaign to extend the scale of brightness of the bright stars to the faint ones. He also collaborated with Father J. G. Hagen, of the Vatican Observatory, on the latter's Atlas Stellarum Variabilium. Another important piece of work was his posthumously published determination of magnitudes in one of the zones of Kapteyn's "Plan of Selected Areas".
Other photometric researches of importance were carried on by his many graduate students. He took part in three eclipse expeditions with the chief object of measuring the brightness of the corona. Although exceedingly modest, he had unusual ability in imparting his knowledge to his students.
John Adelbert Parkhurst was a distinguished astronomer. He made the most important work in the specialty of photometry. He participated in three solar eclipse expeditions to measure coronal brightness, but only enjoyed clear seeing conditions on the last (1925). During his career, he published about 100 papers on astronomy.
(This book was originally published prior to 1923, and rep...)
John Adelbert Parkhurst was an active member of the Congregational Church.
John Adelbert Parkhurst was a member of the British Astronomical Association, of the Astronomische Gesellschaft of Hamburg, and was a fellow of the Royal Astronomical Society.
John Adelbert Parkhurst was never physically strong, he adhered to a strict discipline of body and mind which enabled him, in spite of bodily ills, to accomplish a full lifetime of work. Although exceedingly modest, he had unusual ability in imparting his knowledge to his students.
On November 21 1888, John Adelbert Parkhurst married Anna Greenleaf of Terre Haute, Indiana. Their only child died in infancy.
