The 91-centimetre telescope at Lick Observatory first used

Background. Lick Observatory was constructed between 1876 and 1887 from a bequest of $700,000 from James Lick, equivalent to $25,100,000 in 2025. The observatory is named after James Lick, who donated the funds for its construction. Lick, the wealthiest man in California at the time of his death, left the majority of his estate to social and scientific causes, and in his last deed he chose the site atop Mount Hamilton.

Instrument. The 91-centimeter (36-inch) refractor was the largest in the world at the time. Its lens manufacturing took until 1885, with delivery on December 29, 1886. The telescope saw first light on January 3, 1888, retaining its status as the world's largest refractor until Yerkes Observatory was built in 1897.

Institutional Transfer. In May 1888, the observatory was turned over to the Regents of the University of California, becoming the Lick Astronomical Department. This transfer established it as the first permanently occupied mountain-top observatory in the world, solidifying its institutional status following the initial use of the telescope.