Jean-Louis started as the janitor. Yup. Then The Directors of the Observatory of Marseilles gave him lessons in astronomy. He learned and quickly.
On July 11, 1801 he discovered his first comet.
From Scientific Itineraries in Tuscany:
For these achievements, he was named adjunct astronomer and later vice-director of the Observatory. In 1819, he was called to Lucca by Duchess Maria Luisa of Bourbon (1782-1824) to direct the Marlia Specola [Observatory]. In 1824, after the closure of the facility, Grand Duke Leopold II of Tuscany (1797-1870) appointed Pons director of the Observatory attached to the Museo di Fisica e Storia Naturale of Florence, where he remained until his death.