vintage diagram showing the principle of the equatorial coude 1900s

1874 1891 1900s 1930s 1939 1940s bring conceived constant coude coudé council curved designed diagram electromagnetic elements employing enabling encyclopaedia equatorial fatigue focus gather harmsworth immobile instrument its large lenses light loewy maurice mirrors model more objects observation observatory observer observing one optical original other presented principle purpose radiation reduce remain remote showing telescope telescopes that two use vintage was work