[kayakfisherman (Brian)]

Hi all

I am very keen on getting into astronomy, but have a very tight budget, and no interest in buying a toy telescope. I have thought a lot about building my own dob, but the main cost is the mirror, and it doesn't look like its much cheaper to grind your own. This got me thinking about something that has no doubt crossed the minds of many people before me, especially those on a budget, namely why does a mirror have to be made of glass - why not epoxy for example. Obviously if it could be done cheaper, it would have already been done, so there must be a reason, I just can't find one. So either my research skills aren't that crash hot, or my question is too stupid that anyone would even consider addressing the issue!!!

I can only guess that glass is the most stable substance available that can be polished to a sufficient degree of smoothness. If anyone can shed light on this it would be much appreciated.

Cheers
Brian