What Size Reflector

The purchase price of such an instrument of professional make is necessarily high,
and many an amateur feels compelled to do without it. But if he is possessed of some ingenuity and craftsmanship, and is willing to devote a few hours a week to the task, he can in a relatively short time build the telescope in its entirety, for a small fraction of that price. Of course, many amateurs feel that their mirrors are inferior to the professionals', but this is not necessarily true.

It has been frequently demonstrated that mirrors of professional make will seldom stand up to a test, because it is impossible for the professional optician to spend sufficient time on the mirror without losing money, whereas the amateur can, if he will, devote all the time and care necessary to produce a mirror of admirable figure.

In the following account, the amateur astronomer will be introduced to the optician's art of grinding and polishing spherical surfaces on glass. He will learn how to alter the concave spherical surface to a paraboloid, an achievement that baffled the world's opticians for 50 years, from Newton to Hadley. He will learn
how to make and test an optically plane surface. He will find out why and how to make an equatorial mounting. He will take pride in his telescope, and derive profound pleasure from using it, because it will be a good one, and because he made it himself.

Chapter 2 Material and Equipment