Actually doing some telescope making

I worked on the 6" f/5 mirror for about 5-7mins using the W-stroke and with plenty of Cerium Oxide. I am hoping that this is enough to bring the mirror close to 1/4th wavelength from the 1/2 that it was. I have not tested the mirror after this work. BTW, before working on the mirror, I made sure that the mirror and the pitch tool were in a good contact. I placed the mirror on the pitch tool and then placed 10-12lbs weight on top of the mirror. I had the weights remain on the mirror for about 24hours and then for another 24hours I had just the mirror on the tool without any weights. Both times, I had plenty of Cerium Oxide so that the mirror and the tool do not stick together. With the dry winter weather, I had to make sure that the Cerium Oxide did not dry out. Plenty of Cerium Oxide solution (Cerium Oxide and water) had to be regularly used. I plan to test this mirror sometime soon.

On another note, I have also started working a 12" mirror. Very first day I noticed that the tool had a small but deep depression (about 4mm deep and having a diameter of approx 9"). I tried working on the mirror with #80 Silicon Carbide grit however the depression did not seem to be going away. Then I decided to take some drastic action and started using the #36 Silicon Carbide grit. This is very powerful and has a strong cutting action. The central depression on the tool is not much shallower (1mm or so) and also only a small central circle of about 5" diameter is now the problem area. This is the only part where the mirror and the tool are not in complete contact. I am hoping that 1-2 sessions of 1hour each with the #36 grit should bring both the surfaces in complete contact. Only after that can the actual process of grinding the mirror can begin.

I am hoping to do at least 3-4 hours of actual mirror grinding per week. Thats one of my New Year's resolution for 2008. I am planning to do approx 4-5 grinding sessions of 45mins each per week.