Exam Review: Ancient Rome and the Scientific Revolution |
On April 15, 1672 , the Journal de Scravans published an excerpt of a letter from a M. de Berce describing a telescope design proposed by a M. Cassegrain. It had a large (primary) concave mirror which reflected light onto a smaller (secondary) convex mirror which then reflected the light back through a hole in the primary mirror to an eyepiece. The diagram that was used to illustrate the device is shown below. Variations of this type of design would dominate the construction of research telescopes from the start of the twentieth century onward. In spite of the importance of the design, the true identity of this M. Cassegrain would not be known for more than three centuries, when it was discovered in 2000. There was a good reason for this obscurity. By the end of 1672, there would be no-one who would want to be this M. Cassegrain or take ownership of the design.
This author has the dubious honour of receiving a very public humiliation for his design from two of the greatest scientists of all time, Isaac Newton and Christian Huygens. Christian Huygens was especially caustic. Isaac Newton predicted that the design would never be of any use. You see therefore, that the advantages of this design are none, but the disadvantages so great and unavoidable, that I fear it will never be put in practise with good effect [_7_] . Both the great scientists were wrong. The Cassegrain design is the basis for many of the most famous twentieth century telescopes including the Hubble Space Telescope and the 200 inch Hale Telescope on Mt. Palomar. The identity of M. Cassegrain was finally discovered in 2000. He was Laurent Cassegrain, a French Catholic priest from the region around Chartres, France. He was a teacher at a lycee (high school). There is an interesting irony here. A common theme in popular literature is the clash between religion and science. The history of the telescope does not do much to support this. Most of the history of astronomical telescopes has been dominated by either Keplerian refractors or Cassegrainian reflectors. The Cassegrain telescope was proposed by a priest. The Keplerian telescope was first proposed by Johannes Kepler, but first built by the Catholic priest, Christopher Scheiner.
0 Comments
Leave a Reply. |