The astronomical telescope, 1611-1650 / Albert van Helden.
Abstract:
This paper traces the development of the telescope consisting of two convex lenses, the so-called "astronomical" telescope, from its first theoretical description by Kepler in 1611 to its general adoption for astronomical research in the 1640s. First used in the study of sunspots, this instrument offered a much needed larger field of view with higher magnification in the 1630s. Francesco Fontana, who claimed to have made "astronomical" telescopes since 1608 (a claim which is examined here) made these instruments popular in Italy in the late 1630s. North of the Alps they did not become popular until after 1645 when Rheita published his Oculus Enoch et Eliae, in which he described "astronomical" telescopes in detail
Annali dell'Istituto e Museo di storia della scienza di Firenze A. 1, fasc. 2 (1976), p. 13-36