Degree of difficulty 2 (of 5)

Minimum aperture Naked eye

Designation NGC 1960

Type Open cluster

Class I3r

Distance 4300 ly (K2005) 4240 ly (CMD, 2000)

Size 15 ly

Constellation Auriga

R.A. 5h 36.1min

Decl. +34° 8′

Magnitude 6.0

Surface brightness –

Apparent diameter 12′

Discoverer Hodierna, 1654

History M 36 was discovered before 1654 by the Sicilian observer Giovanni Batista Hodierna as a “nebulous patch.” However, his observations were soon forgotten and his notes were rediscovered only in 1984. For this reason, le Gentil must be considered a true independent discoverer of this cluster, which he found in 1749. Messier made his observation on the 2nd of September 1764, and wrote: “Cluster of stars in the Charioteer, with a simple refractor of 3½ foot the stars are barely discerned, the cluster does not contain any nebulosity. 9′ diameter.”

John Herschel called M 36 a “very pretty object which fills the field.” Smyth described it as “the device of a star whose rays are formed by very small stars.” D'Arrest must have had a similar impression when he wrote: “extremely rich and pretty cluster. Originating from the center, many stars are arranged in three thin spirals.”

Leo Brenner recommended the observation of M 36 to his fellow amateur observers, about 100 years ago, with the words: “very large, rich and bright, consisting of somewhat scattered stars of 8th to 10th magnitude, which include the double star Σ 737 of 8th and 9th magnitude stars, separated 10.6". A rewarding object even for 3-inch telescopes and low magnifications.”

Astrophysics M 36 is the least rich of the three Messier clusters in Auriga. Only 178 stars are regarded as physical cluster members. The brightest star (magnitude 8.8) is a blue giant with the early spectral type B2 and 360 times the solar luminosity.