Thread by @mcnees

Astronomer Milton La Salle Humason was born #OTD in 1891. He dropped out of the eighth grade and had little formal education, but a knack for difficult observations helped him collect much of the data used to establish what we now call Hubble’s Law.
Image: Emilio Segrè Archives

Humason was born in Minnesota, but moved to California with his family as a teenager. At 14 they sent him to a summer camp on Mount Wilson. He loved life on the mountain, and it was an exciting time to be there. Preparations were already underway to build a new observatory.

Humason asked his parents to let him take a year off and work on the mountain. He never went back. His last year of school was 8th grade. He took a job leading wagons up the mountain. Drawn by mules, they carried lumber for buildings and parts for the massive 100" telescope.

Humason worked there for 5 years. After marrying Helen Dowd, the daughter of the observatory's chief engineer, he took a job as a ranch hand. But he missed the mountain and observatory, and when the opportunity arose he took a job there as janitor.

From there he applied for a job as "night assistant." He helped the astronomers run the equipment and dome, and he became very good at it. In fact, he was so good at running the equipment that George Hale, the observatory's director, promoted him to scientific staff.

Some of the staff protested. After all, Humason had never made it past 8th grade, and now he was a member of the scientific staff?? It was an outrage! But Hale recognized a rare talent in Humason, and ignored the staff's complaints.

In just three years, Milton Humason went from janitor of Mount Wilson Observatory to a member of the scientific staff.

Did I mention that he dropped out of 8th grade and never went back to school?

Humason had a knack for difficult measurements and became an expert at establishing the redshift of distant galaxies. He measured the redshifts of over 600 galaxies, data that Hubble used in his work on the relationship between distance & radial velocity.

Here's the velocity-distance plot from Humason’s 1931 paper with Hubble. The dots near the origin are the data used in Hubble's 1929 paper.
Ref: ui.adsabs.harvard.edu/abs/1931ApJ...…

(Hubble relied on Humason's expertise to obtain the data for the 1929 paper as well, though he was the lone author on that one. Imo it’s proper to credit them both for that work.)

Besides working with Hubble, Humason collaborated with Fritz Zwicky, Allan Sandage, and many other noted astronomers.

Humason also famously *missed* discovering Pluto eleven years before Clyde Tombaugh! He captured it on four plates in 1919 but didn’t realize a tiny planet was sailing across his photographs.
articles.adsabs.harvard.edu/cgi-bin/nph-ia…

Humason was widely considered by his peers to be an outstanding observer, and was responsible for the data behind what is arguably the most famous result of 20th century astronomy. Not bad for a kid who quit school at 14 to go live on a mountain.