Amateur telescope making (ATM) was once a means by which almost anyone could have a telescope capable of showing the magnificence of the night sky without breaking the bank. Time was when quality telescopes were beyond the pockets of many. Folks tinkered away with glass, wood and metal to contrive their unique optical concoctions with which to enjoy the wonders of the night sky. Nowadays, the market place has been flooded with cheap telescopes, many of which are more than capable of revealing the splendours of the night sky. Why should amateur astronomers waste time making telescopes when they can buy ready made instruments at bargain prices? As a result of this amateur telescope making (ATM) had been in decline until recently, so what happened to change things? One man, John Dobson, is often credited with starting a revolution in the way we think about telescope design. Dobson championed large aperture low cost minimalist telescopes. The mirrors where made from old portholes (plate glass), and the tube and mount were wood or some other readily available material.
The modern Dobsonian telescope is a favourite with many amateur astronomers who enjoy the art of observing at the telescope. The large apertures and ease of use of these telescopes has made them very popular. The design of modern telescopes of this type has undergone much evolution from the original quite crude instruments made by Dobson and his contemporaries. Many amateurs prefer to buy the optics for their telescopes, choosing to make the mount and tube only. Many are of the opinion that making the optics for their telescope is too difficult; in fact making a telescope mirror is achievable as many who have attempted it have discovered. There are many excellent resources available on the internet, tutorials and videos, all of which provide a lot of help to anyone considering making there own optics. Indeed, making optics today is certainly a lot easier than it was before the advent of the World Wide Web.
I would like to encourage people to make their own optics, not as a means of saving money, because as mentioned cheap decent quality telescopes are readily available, but rather as a fulfilling activity in its own right. For me, one of the joys of astronomy is to look outside of the box of everyday experience. To observe even the craters of the moon, reminds us that our everyday existence is a very small part of a much bigger picture. The testing of a telescope mirror, even with crude apparatus, reveals the wonders of the nature of light and enables us to see errors smaller than one thousandth the thickness of a human hair on the surface of the glass. I would encourage anybody thinking of grinding and polishing their own optics to have a go; it is an absorbing and deeply satisfying process. In order to encourage potential telescope makers I have produced a series of short articles on various aspects of telescope making, mainly related to optics, which I hope will be of interest to those wishing to make there own telescope optics.
Here are some pdf files covering various aspects of telescope mirror making:
Here is a link to my Stargazers lounge thread on making a 12 inch mirror: