The secondary mirror is the heart of a newtonian telescope. In terms of cost there isnt really a significant advantage to making your own mirror over buying one already made when you factor in the cost of your own labor and time. In terms of quality there can be a world of difference. You can make a much better mirror then you can buy commercially. Most commercial telescope mirrors are good enough-but a mirror you make yourself has the potential to be near perfect. As near perfect as you have time, knowledge, and determination to make it. For me, while Im very attracted to the possibility of attaining excellence in mirror performance, grinding and polishing a mirror means putting part of myself into the mirror. When I look at a mirror I feel like Im looking at a bit of magic. We have the ability to extend our senses and minds across vast distances in space and even in time. I find that amazing regardless of whether Im observing with a 4.5 inch telescope or a 20 inch telescope. A disk of glass, a bit of grit, a spray of water and a whole lotta wonder. As I work this mirror Ill put pictures of it and different aspects of the process of turning it from a glass blank into a mirror. Im planning still pics as well as video of the process. I also plan to add different projects Im working on and volunteering with including Pixo's Linux Astronomy Project. I ran this page thru babelfish and back out again and if my guess is right-at least in French, this site makes about 50% sense compared to the original in English. Until I can do better for translations-Im afraid those who wish to see this page in another language may have to rely upon a service like babelfish. Nothing against the fish-I like and use it frequently-but it really chooses some strange words sometimes-like about half the time. Thank you, Pixo, for the webspace :)