Robert Blair - A Famous Scottish Inventor And Astronomer
Robert Blair (1748 - 1828) was born in Garvald in East Lothian and, like many other Scottish intellectuals, his father was a minister of the kirk. After he finished his education Blair practiced as a surgeon. In 1785 he was appointed the first Regius Professor of Astronomy at Edinburgh University. In 1786 he wrote an unpublished paper that gave a systematic treatment of the Newtonian kinematics of light, taking into account in the absolute space of Newton the motion of the light source, that of the observer, and the velocity of the corpuscles of light.
Blair investigated ways in which to reduce aberrations and secondary spectra found in lenses of the time. He developed a hollow lens and investigated the effects of using different liquids in them and in comparison to the flint glass used at the time. His research into the effectiveness of reflecting telescopes led him to invent (and name) the aplanatic telescope. The Aplanatic lens, which maintains a very small focused spot, and allows for much higher energies at the focal point, does not suffer from spherical aberration.
Although Robert Blair developed many widely acclaimed telescopes of several inches it is for his Aplanatic lens that he remains most famous for. Sir David Brewster (a contemporary) greatly admired Blair's work and, as Brewster was well known for wanting greater collaboration amongst intellectuals, it is highly likely that scientific matters were discussed between the two of them which may have helped both in their respective studies.