The History of the Telescope

achromatic amateur aperture ratio appeared Astr astronomers bright British Crown copyright camera Cassegrain Cassini cast centre century coelostat colour concave construction convex corrector curvature diameter disk Dollond double stars Dreyer equatorial eyepiece feet focus focal length Fraunhofer Galileo glass Greenwich Grubb Guinand Hale Herschel Huggins Huygens Ibid inches aperture instrument invention John Dollond later lens lenses light lines London magnified meridian metal method micrometer minutes of arc moon motion Mount Wilson Mount Wilson Observatory nebulae Newtonian object-glass objective observations obtained optical opticians parallax Paris Observatory Peter Dollond Phil photographic planets plate polar axis polishing prism quadrant Ramsden reflecting telescope reflector refracting refractor right ascension Ritchey Rosse rotated Royal Society satellites Schmidt Science Museum Simms slit solar spectra spectrograph spectroheliograph spectrum specula speculum spherical aberration stellar surface Swasey temperature Trans Troughton tube Tulley Vide Ref visual Yerkes