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.
At Botany Bay Dagelet undertook calculations on map position of Botany Bay, carried out astronomical observations and met with William Dawes at Port Jackson.
Dawes volunteered for service with the First Fleet and sailed on the Sirius.
From February 1788, he was employed on shore to build an observatory at Dawes Point.
Following this meeting Dagelet sent a letter to Dawes (1762-1836) with advice to Dawes on setting up his observatory, recent work on the fluctuations of the Earth's magnetic field and calculations on maps positions of Botany Bay.The island of Dagelet, named in his honour, is now known by its Korean name, Ulleungdo.