Max Wolf and the photographic hunt for asteroids

How a Heidelberg astronomer turned the camera into the main tool for discovering asteroids, Herculina among them.

Published 2026-10-23

Herculina was found in 1904, when asteroid hunting had already changed completely. The person most responsible was its discoverer, Max Wolf.^[3][2]

From the garden to the chair

Wolf was born in Heidelberg in 1863. His father built him an observatory in the family garden, and from there he found his first discovery, comet 14P/Wolf, in 1884.^[3] He earned his PhD at Heidelberg in 1888 and stayed for almost his whole career, becoming chair of astronomy and director of the new Heidelberg-Königstuhl observatory in 1902.^[3]

Photography changes everything

Earlier discoverers compared the sky with charts by eye. Wolf pioneered astrophotography for this work: long exposures reveal a moving asteroid as a short trail among point-like stars. Other astronomers found that photography let them discover far more asteroids than would have been feasible visually.^[7][3]

Beyond asteroids

With his friend and rival E. E. Barnard, Wolf used photography to show that dark nebulae — long thought to be “holes in the sky” — are actually huge clouds of fine, opaque dust.^[3] He also used the Bruce double-astrograph, built to hunt dim asteroids, to measure the motions of faint stars, publishing a catalogue of more than a thousand in 1919.^[3]

A mystery name

Many of Wolf’s discoveries around 1904 were named after opera characters, but nobody recorded why Herculina got its name.^[2]

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