light-concentration

Updated: May 21, 2025

Frank McClean; at Potsdam, at Meudon, at Paris, at Alleghany, engines for light-concentration have been, or shortly will be, erected of dimensions which, two generations back, would have seemed extravagant and impossible. Perhaps the finest, though not absolutely the greatest, among them, marked the summit and end of the performances of Alvan G. Clark, the last survivor of the Cambridgeport firm.

Agnes M. (Agnes Mary) Clerke - A Popular History of Astronomy During the Nineteenth Century: Fourth Edition

The satisfactory nature of its performance is vouched for by the observations made with it upon Jupiter's new satellite in December, 1892. This instrument, to which a Newtonian form has been given, had no rival in respect of light-concentration at the time when it was built. It has now two the Paris 50-inch refractor and the Yerkes 5-foot reflector.

Agnes M. (Agnes Mary) Clerke - A Popular History of Astronomy During the Nineteenth Century: Fourth Edition