Telescope Project

As a last hurrah to our undergraduate studies we've decided to each build a telescope in the next few months! Mine (Matt's) will have an 8-inch mirror, with an F-5 focal ratio (less magnification but more light-gathering) for looking at nebulas, galaxies, and star clusters. Cam's will have a 6-inch mirror with an F-9 focal ratio (more magnification but less light-gathering), and will be ideal for planetary and lunar observation. Cam's mirror will actually be made out of old ship porthole glass (picture at left)! This the only really cheap source of thick glass, but at only 3/4-inches it is still really not thick enough for large mirrors. The glass came with 10-inch diameter, but Joe has offered to trepan two 6-inch blanks out of the original portholes. One will become the mirror, and the other will serve as a grinding tool. Because an F-9 is much easier to grind than an F-5, I've gone ahead and started on mine even though Cam doesn't have her glass trepanned yet.

My glass was a gift from Joe. He bought (at a good deal) a mirror kit which included an 8-inch pyrex blank, and an 8-inch plate glass blank. The plate glass was intended to be the grinding tool, but he built a tile tool instead and gave me the glass to use as my own mirror blank (he also made for me a tile tool to use for grinding).

Rather than the traditional method of grinding atop a large barrel or a plywood pedestal, I've employed a workspace which can be pushed under the couch when not in use. This also allows me to watch shows on the Internet while I work. Here is a picture of me just before I marred the flat smooth surface of my mirror blank by grinding. Hopefully the next time it is that smooth it will also be in the shape of a parabola.