When Robert Baker arrived he continued a photoelectric photometry program focusing on variable stars.
He continued to use the 12-inch refractor until 1927 when a new photometer was constructed and attached it to the 30-inch reflector telescope in the Observatory annex .
He supervised two graduate students who worked on this equipment in the early 1930s.
On May 27, 1933 the star Arcturus provided light which fell onto a photo cell in the observatory's annex and sent a signal to open the Chicago World's Fair.

The Great Depression was soon in full swing.
and the department budget fell from $1000 to a mere $200.
 It was during this time that Dr. Baker authored a number of books.
Baker was an extremely gifted writer whose clear simple work helped him explain what was going on up there to an entire generation.
In 1930, he authored the textbook Astronomy, followed in 1932 by The Universe Unfolding, and his revision of Simon Newcomb's Astronomy for Everyone.
In 1934 Baker described an imaginary trip to the moon in When the Stars Come Out.
His second textbook, An Introduction to Astronomy also appeared in 1934.
Introducing the Constellation was published in 1937 and, with the help of Howard Zim in 1951, Stars: A Guide to the Heavens.
His textbooks were used across the entire country for undergraduate astronomy courses and praised as classics.

After two sabbaticals to Harvard, Baker's interest moved from photometry to the Milky Way.
In 1939 the 30-inch reflector was replaced with a Ross photographic telescope and for more than ten years after that, 1939 through 1951 Baker used the observatory's photographic telescope to help count the stars in the Milky Way and determine their distribution as part of Harvard's Star Counting Circuit.
This would be the primary research until Baker's retirement in 1951.
The 12-inch refractor was only used for instruction, public open houses and for visiting school groups.
When Robert Baker arrived he continued a photoelectric photometry program focusing on variable stars. He continued to use the 12-inch refractor until 1927 when a new photometer was constructed and attached it to the 30-inch reflector telescope in the Observatory annex . He supervised two graduate students who worked on this equipment in the early 1930s. On May 27, 1933 the star Arcturus provided light which fell onto a photo cell in the observatory's annex and sent a signal to open the Chicago World's Fair.
The Great Depression was soon in full swing. and the department budget fell from $1000 to a mere $200.  It was during this time that Dr. Baker authored a number of books. Baker was an extremely gifted writer whose clear simple work helped him explain what was going on up there to an entire generation. In 1930, he authored the textbook Astronomy, followed in 1932 by The Universe Unfolding, and his revision of Simon Newcomb's Astronomy for Everyone. In 1934 Baker described an imaginary trip to the moon in When the Stars Come Out. His second textbook, An Introduction to Astronomy also appeared in 1934. Introducing the Constellation was published in 1937 and, with the help of Howard Zim in 1951, Stars: A Guide to the Heavens. His textbooks were used across the entire country for undergraduate astronomy courses and praised as classics.
After two sabbaticals to Harvard, Baker's interest moved from photometry to the Milky Way. In 1939 the 30-inch reflector was replaced with a Ross photographic telescope and for more than ten years after that, 1939 through 1951 Baker used the observatory's photographic telescope to help count the stars in the Milky Way and determine their distribution as part of Harvard's Star Counting Circuit. This would be the primary research until Baker's retirement in 1951. The 12-inch refractor was only used for instruction, public open houses and for visiting school groups.
Astronomical Observatory (University of Illinois at Urbana–Champaign)