William Pendry Bidelman ( ; September 25, 1918 – May 3, 2011) was an American astronomer.
Born in Los Angeles, and raised in North Dakota, he was noted for classifying the spectra of stars, and considered a pioneer in recognizing and classifying sub-groups of the peculiar stars.
Bidelman's undergraduate degree was from Harvard College, and his Ph.D. in astronomy was from the University of Chicago under advisor William Wilson Morgan. He was a physicist in the Army during World War II. A professional astronomer for over 50 years, Bidelman taught for ~41 years at The University of Chicago, The University of California,
He co-discovered the class of barium stars with Philip Keenan, the phosphorus and the mercury stars, and was the first to describe the hydrogen-deficient carbon stars.
Born in Los Angeles, California, Bidelman was raised in North Dakota, where he met his future wife of 69 years. He was a father of four and a grandfather. As an Emeritus Professor William P. Bidelman continued working in astronomy after he retired from teaching, and was 92 when he died in Murfreesboro, Tennessee.