University of Valencia Observatory-- 156mm/
2300mm First light in 1909, restored in 2002
If you asked most astronomers to give the name of a well-known, family run telescope manufacturing company of the nineteenth or twentieth centuries, most would mention Alvan Clark without having to give much thought. No doubt Clark's fame among astronomy buffs, at least in the United States, was due the 40" Yerkes, the largest refracting telescope ever built, as well as the superb refractor still in every day use by the U.S. Naval Academy. Then, too, there was the legendary quality of the Clark lenses. Alvan Clark was a craftsman of unusual talents, an optical engineer with the ability to see flaws in glass that escaped the eyes of everyone else.
But, before Clark and his sons, came Thomas Grubb, who, along with his son, Howard, contributed at least as much to the world of astronomy as anyone in the nineteenth century and beyond. In one incarnation or another, their company produced telescopes for roughly 150 years, beginning in 1833 and ending in 1985 when Grubb Parsons produced the optics for their last telescope, the 4.2m William Herschel Telescope, largest of the Isaac Newton Group at the Canarian Observatories. It was, in fact, the largest telescope in western Europe. It was not the first time they had achieved that status.
By the end of the nineteenth century, the design innovations of men like Thomas and Howard Grubb had put Ireland at the very heart of astronomical discovery. William Parsons, the Third Earl of Rosse, built the famous 72 inch reflecting telescope that was, for seventy years prior to the Mt. Wilson and Palomar observatories in California, the world's largest telescope. The spiral structure of galaxies were first observed through this instrument. Coincidentally, one of the Earl's neighbors, Thomas Grubb, was also interested in large telescopes.
The Grubb telescope company was founded by Thomas Grubb, born in 1800, an Irish engineer from Waterford who made a living producing printers and other machinery. He always had a personal interest in astronomy and optics, and built a private observatory, which included a small reflector. But he was more interested in larger instruments, and, as he became familiar with the processes involved, his observatory and workshop grew, along with his reputation.
Then, in 1833, Thomas received his first order when Edward Cooper presented him with a 13.3 inch objective lens with a focal length of 25 feet. He had purchased the optics in Paris two years before, and comissioned Thomas Grubb to build what would at the time be the world's largest refractor, to be installed, equatorially mounted, in his observtory in Markree Castle. Next, a 15 inch reflector was ordered for the Armagh Observatory. In building this reflector Grubb introduced new features that would become standard, such as clock-driven equatorial mounts and eyepieces situated at the rear of a telescope, the light coming to focus after traveling through a hole in the center of the primary mirror.