John Byrne (telescope maker)

John Byrne started as an apprentice for the telescope maker Henry Fitz in 1847. He worked with him until Fitz's death in 1863. Byrne worked most of his life correcting lenses made by others. He began making his own personal telescopes in the 1870s and 1880s that he signed. In the late 1860s, at the beginning Byrne's telescopes resembled Fitz's and were signed in script undated on the faceplate above the focuser. In the 1870s and the early 1880s he signed in script in the lens cell. Later in the 1880s he signed by engraving his name, place of manufacturing, and date in script on the faceplate. A refracting telescope he made for Carleton College in Northfield, Minnesota in 1878 is signed in block letters "John Byrne, New York, 1878" and is mounted on a wooden tripod.
Byrne came up with unique technology for his telescopes of which a six foot one with a 5-inch aperture telescope of "f"/15 focal length he made was used by the astronomer Edward Emerson Barnard to discover his first comment in 1881 with additional ones that followed later. Barnard bought the telescope for a discounted price of $330 in 1877 (), which represented two thirds of his yearly income at the time. It was endorsed by professor Lewis Morris Rutherfurd of New York City.
Byrne opened a telescope shop at 314 East 21st Street in New York City in 1883 and made objective lenses for amateur astronomers. His "Short focus and brilliant light" telescopes were "f"/8.9 to "f"/10.5 focal length. Starting in 1892, he made objective lenses for tubes made by Gail & Lembke and signed undated on the lens cell. An example of one put together by Byrne is a 4.5-inch aperture telescope which Governor Levi K. Fuller purchased and gave to Vermont Academy in 1894. The telescope had a magnifying power of 400 diameters on a clear day. That brought the moon within an apparent distance of 600 miles. The telescope showed the planet Jupiter 1300 times the size of earth. Jupiter's four moons could be seen. The rings of the planet Saturn could be seen with the telescope as could six of its eight moons.