Aluminizing The Mirror
Making a 4.25 Inch Dobsonian Reflector Telescope
For uses other than sun viewing, for which you will need a sun filter, and moon viewing, you will need to have your mirror coated with a reflective surface. The modern coating material is aluminum. You can silver the mirror yourself, although I recommend against it unless you are a chemist. There are also more exotic coatings that promise a higher reflectivity. Aluminum is about 90% reflective so spending money involves quickly diminishing returns. There are many places you can find on the web that you can ship your mirror to and have the process done. If you are in the Bay Area, you should consider bringing it down to Bob Fies in San Carlos. He will coat your mirror while you wait if you wish, and engage you in a fascinating discussing of telescope making, mirror coating, or whatever subject you want.