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Magic of Glass - Part 3

The Magic of Glass
Part 3

In the Last part of the series, we looked at Refractor telescopes. In this part we put the spotlight on the Reflector Telescope. In most people’s opinion, the Reflector telescope is nothing less than a boon to modern amateur Astronomy; I would list two main reasons of why reflectors sometimes score over refractors in the field of Amateur Astronomy.

Let’s look at the history of reflector telescopes.
As we all have made note of from previous parts, Galileo was the first person to look at the heavens with a telescope of his own handiwork, we have all seen telescope evolve from that period, although it should not surprise the reader that the idea, that someone could use mirrors instead of lenses was probably older than the invention of the telescope, but after the invention of the telescope, the idea of replacing the lens with the mirror, slowly but steadily started to brew in the intelligentsia of the  scientific community, more so with those closely related with Astronomy. The answer eluded most, for long, people tried various experiments with mirrors and the results were mostly unsatisfactory, until it was the great Isaac Newton, the father of Physics and the inventor of the Calculus who came to their rescue with the World’s first completely working model of the Reflecting telescope.


It is to him, that we credit the construction of the Reflecting Telescope, and rightly christen the design as the “Newtonian Reflector”( Although in terms of scientific accuracy, it is duly noted that he did not come up with the idea on his own, but brought into existence a instrument  no doubt, though persistent efforts and gave the world a gift, one of the many he has given. Why he was interested and what prompted him to build this contraption is a story for another time). The design of the Newtonian was so simple yet so elegant that it was a overnight success. Suddenly mirrors could be used instead of expensive lenses and the size of the telescopes could grow, in turn gathering more light than ever before, gone were the days of the small handheld telescopes using lenses, it is probably right to say that the Astronomers of the time were gripped with “aperture fever” (A feeling common among amateurs who have grown out of their relatively small telescope and want a larger telescope to see more of the heavens).

newton first reflector

Newton's first reflector telescope

The design of the Reflecting telescope is pretty straight forward, you have 2 mirrors doing the most work, the primary and the secondary, the primary mirror is a parabolic mirror (concave in simple terms) which “collects” the light and focuses it on the secondary mirror which then transmits it to the eyepiece where one can view it at ease.  The simple design of the telescope makes it a winner, what’s more, because it uses mirrors and not lenses, the images are virtually free of chromatic aberration (the effect explained in the article on refractors).

reflector working large
Working of reflector telescope

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