Joseph Lepaute Dagelet (1751–1788) was a French astronomer, clockmaker and mathematician who accompanied Lapérouse on his scientific circumnavigation, in the course of which he perished in the final shipwreck of the expedition.
Young Dagelet arrived in Paris in 1767, welcomed by his uncles the renowned clockmakers Jean-André and Jean-Baptiste Lepaute, who held the brevet horlogers du Roi.
He presented his observations of the planets and stars to the Académie des sciences and was received as adjoint and then named astronomer to the Academy in 1785, the year he embarked at Brest on the fatal expedition.
After extensively mapping and recording the coastlines of North America, Japan, Korea and Siberia, Lapérouse was directed by the French government to go to Botany Bay to observe the founding of the British Colony by the First Fleet.
The French ships stayed at Botany Bay for six weeks and built a stockade, observatory and a garden for fresh produce on the La Perouse peninsula.