Royal Harwood Frost (25 February 1879 – 11 May 1950) was an American astronomer, born in Salem, Massachusetts to Albinus Finney Frost and Emma Jane Richardson, the fourth son of a family of ten.
Frost was an astronomical assistant at the Harvard College Observatory from 1896 to 1908, under the directorship of Edward Charles Pickering.
From 1902 to 1905 he worked at the Arequipa station in Peru using the 24-inch f/5.6 Bruce photographic refractor, made by Alvan Clark & Sons and completed in 1893.
His observations of nebulae (following DeLisle Stewart) using four-hour plates were published in the Harv.
When moving the Bruce telescope to Boyden Observatory in Bloemfontein, South Africa in 1926, Harvard offered him a job, but he did not go.