Photographic charts of the main phases of the Moon

made at the Collegio Romano Osservatory in the year 1858
[Angelo Secchi]
[s.l., s. d.]
478 x 340 mm
Historical archives of INAF-Astronomical Observatory of Rome, Monte Porzio Catone (Rome)

The first attempts of application of the photographic technique to astronomy were made by Angelo Secchi in 1851 on the occasion of the solar eclipse of 8 July. He was aware, almost surely, about the experiences conducted by William Draper and Samuel Morse in 1840 and about the ones carried on in the following ten years by William C. Bond and John A. Whipple who, thanks to the daguerreotype technique, obtained images of the Moon. Moreover, in 1843 Father De Vico, Director of the Roman College Observatory, tried to photography the Moon employing daguerrotipes, although with questionable results.
In 1857 Secchi, employing the humid collodion technique, decided to create an Atlas of the Moon with all its phases. With the collaboration of the Roman pharmacist Francesco Barelli, photograph amateur, he realized a series of positive images on albumine, from which ”negative stubs to multiply the copies on the phases on paper” were acquired. In this way the first ever photographic Atlas of the Moon was realized, and then presented in Paris, on 28 August 1858 at the Academié des Sciences, and in London later, at the Greenwich Observatory. Moreover, some of the blow-ups of the pictures were exhibited in Florence in 1861 at the National Exhibition of the newborn Italian Kingdom and had such a success to the point that Francesco Barelli obtained a prize, and he was appointed with a mention to the scientific merit. The album contains an introduction and 8 tables showing the phases of 4°, 5°, 6°, 7°, 8°, 10°, 12°, 14° or full moon. The photographs were took with the Merz equatorial telescope of the Roman College and were obtained by replacing the ordinary eyepiece of the telescope with a small dark room, in which the image of the Moon formed by the lens of the telescope was received on a frost glass.
The frost glass was then replaced by a collodion plate, and through the automatic movement in right ascension and an appropriate movement in declination given by hand, the telescope could track the lunar motion.
Not many copies of the Moon Atlas of Secchi do exist. The preparation of this section was possible thanks to the helpfulness of the colleagues from the Rome Astronomical Observatory who retrieved and made accessible the copy preserved in the historical archive of the Observatory.

Antonella Gasperini, INAF-Osservatorio Astrofisico di Arcetri

Bibliography
A. Secchi, “Atlas photographique lunaire”, Comptes Rendus de l’Académie des Sciences, XLVII, pp. 362-364; “Sulla fotografia della luna; lettera del Padre Secchi al Prof. Matteucci”, Il Nuovo Cimento : giornale di fisica, di chimica e scienze affini compilato da C. Matteucci e R. Piria, tomo VII, 1858, pp. 263-267; A. Secchi, “Fotografie lunari e degli altri corpi celesti”, Memorie dell’Osservatorio del Collegio Romano, n. 20, 1859, pp.158-160; L. Gasparini, “Padre Angelo Secchi e l’applicazione della fotografia nelle osservazioni astronomiche”, Fotologia, vol.12, 1990, pp.34-48.