Rome, June 21 1868

INAF – Rome Astronomical Observatory, Hystorica Archive

This letter illustrates the exchange between Respighi and the Munich instrument builders Ertel and Merz, regarding the making of a large prism to be placed before the objective of Respighi’s telescope. The mechanical part was realized by the Ertel workshops, whereas the optics were assigned to the famous Merz company. In the letter it can be noted the drawing, handmade by Respighi, of the metal stand for the prism. Although priority of invention for the objective prism must be given to Respighi, it was Secchi who made a systematic use of it for his research on spectra. [i.c.]

Bibl.: Chinnici in Altamore & Maffeo (eds.) 2012, pp. 71-79.