Loewy's equatorial coude telescope, 1882.
© Science Museum / Science & Society Picture Library
Model (scale 1:5) of the coude (elbow) telescope built for the Paris Observatory in 1882. Designed by French astronomer Maurice Loewy (1833-1907), this compound telescope used a main lens in conjunction with two mirrors. As this arrangement allowed the eyepiece to remain stationary, the observer could work in a separate heated room while the telescope was open to the sky. It also had greater stability and could measure larger angles than a conventional equatorial. When not in use, the telescope was protected by a large moveable shed which was simpler and cheaper to produce than a conventional observatory dome. Supplied by the Parisian model maker Digeon, this model was commisioned because it was thought that telescopes would evolve this way in the future.