The first asteroid found from North America

In 1854 the asteroid count passed 30 — and for the first time, a discovery came from the other side of the Atlantic.

Published 2026-10-23

By 1854, about thirty asteroids were known, all found by observers in Europe. On September 1 of that year, James Ferguson changed that.^[2]

Who was James Ferguson?

Ferguson (1797–1867) was a Scottish-born American astronomer and engineer, credited with the first discovery of an asteroid from North America.^[3]

A hard target

Euphrosyne is large — about 267 km across — but its surface is very dark, with a geometric albedo near 0.05.^[1] It also sits near the outer edge of the main belt. Even at its best oppositions it reaches only around magnitude +10.2, fainter than any of the thirty asteroids discovered before it.^[2] Finding it by eye at the telescope was a real achievement.

A graceful name

The asteroid was named for Euphrosyne, one of the Charites. In Hesiod’s account the Graces were Aglaia, Euphrosyne and Thalia, daughters of Zeus and Eurynome. They have little mythology of their own and usually appear attending other gods, especially Aphrodite.^[4]

Still giving surprises

More than 160 years after its discovery, Euphrosyne revealed a small moon in 2019, which let astronomers measure its mass properly for the first time.^[2]

Numbered citations link to the sources list on the Euphrosyne overview page.