Hobbies And Interests
Significance
Although Newton did not conceive of the idea of a reflecting telescope, he did successfully take the idea from the drawing board stage to the realm of actual existence. This accomplishment is huge, especially considering that much of Newton's basic design is still used in reflecting telescopes today. He was able to convert James Gregory's ideas concerning the use of a curved surface to overcome the problems of distortion and thus create a working and well-made apparatus.
Prior Interest
The idea of a reflecting telescope had actually been floating around the scientific communities of Europe for several decades before Newton created a working model in 1668. Over the years Newton gradually refined his primitive scope, producing models with larger mirrors and better optics. The diameter of the mirror in the first telescope was only 1.5 inches The fact that Newton made a functioning device years after the concept first appeared gives, as much credence to his engineering skill, as it does to his scientific mind. Galileo Galilei, among others, had discussed the idea and even made some theoretical sketches. Then in the year 1663 the British scientist James Gregory correctly theorized that a reflecting telescope could be made from a part of a sphere and that this kind of optical device would not have some of the technical problems, such as color and shape distortion that occurred in a refracting telescope. However, all of this was just conjecture until Newton was successful in 1668.
Features
The telescope that Newton built in 1668 had a small curved, or parabolic, mirror that was made from a combination of tin and copper. Of crucial importance was the reflector and eyepiece that Newton added in front of the mirror, so that one could look at the celestial images from the side. Newton's creation looked more like a complicated spyglass than a device for gazing into the heavens, but still the craftsmanship of Newton's optical device is quite evident even from photographs of the antique piece of equipment.
What He Could See
Newton could see Jupiter and several of its moons, along with the different phases of Venus. One must keep in mind that Newton's original mirror was less than an inch and a half in diameter, a very small scope indeed by modern standards. Still, for that day and age the sight of the moons of Jupiter must have been quite an event. For the first 50 years Newtonian telescopes were rather primitive affairs. That all changed in 1721, when John Hadley of Great Britain came up with a slightly more functional and much larger reflecting telescope.
Effects
Astronomy took off as a science after the reflecting telescope was invented. The acceleration of scientific observations over the years is staggering. Today space probes that we put into space such as the Hubble use technology that is partly derived from the simple little device that Isaac Newton made in 1668. The intergalactic imagery that is available today is in many ways indebted to a small cadre of inquisitive scientists scattered across the European continent in the seventeenth century.