[Orion Nebula]

Arcetri 1876

pencil drawings, 340×260 mm, 165×125 mm

INAF-Arcetri Astrophysical Observatory, Historical Archives, Donati fond

The drawings shown here represent two parts of the Orion Nebula observed by Tempel with the Amici-I telescope of the Arcetri Observa-tory. Before the observations, Tempel had marked on the paper the position of the stars as given by the micrometric measurements of G.P. Bond. Using these stars as reference, he drew the nebula during several nights of observation, from January to March 1876. The spectroscopic observations of this nebula conducted by Huggins showed the emission line spectrum typical of gases (see Fi. 05); today we call nebulae these large clouds of interstellar gas in our own Galaxy, the Milky Way. Tempel instead shared the traditional view that all nebulae were composed of stars and almost despised spectroscopic works, which he considered a kind of fad. The Irishwoman Agnes Clerke, chronicler of the development of the nascent astrophysics, criticized this attitude of Tempel (defining it “neither philosophic nor just”) in an otherwise benign review of his work on Nature.

Bibl.: BOND 1867, HUGGINS 1865, BRÜCK 2002, CLERKE 1886 (anonymous review, attributed thanks to a letter sent by the writer to Tempel on 11/12/1886; State Archives of Florence, Fondo Nobili, 20/d, n. 570).