Pierre-Louis Guinand (1748–1824) was a Swiss lens maker. who in the late 1700s came up with a breakthrough for making better quality and larger glass, and in time went on to teach a young Fraunhofer at Joseph von Utzschneider's (1763-1840) glassworks, and eventually started his own optical glass works. Guinand would supply glass for the Paris Observatory telescopes and also Cauchoix. He was a pioneer in the manufacture of optical glass for microscopes, telescopes, glasses and other optical instruments.
See also Markree Observatory#Pierre-Louis Guinand
References
Bibliography King, Henry C. (1979). The History of the Telescope. New York, NY: Dover Publications, Inc. pp. 176–9, 188–9, 191–2, 196, 204, 252. ISBN 978-0-486-23893-7.