Mirror

There have been volumes written on mirror making so my intention here is to simply highlight my experiences in making my first mirror. I'll leave the technical stuff to the experts.

Well, here is where it all started. The 1998 Mason-Dixon Star Party. We hauled the grinding machine along to have something extra to do during the day. That's me on the left and Todd Olvany on the right. This is definetly the way to "hog out" a mirror. The grinding machine was built by Ron Newman using two heavy duty motors from a MRI Unit. The machine was used from rough grinding all the way through to polishing.

Here is a picture of the tile tool used in grinding. If you look closely, you can see one of the three holes drilled into the side of the pyrex blank. The purpose of these holes is for mounting the mirror in the cell without having to place clips on the surface of the mirror. The holes were drilled before rough grinding began.

A new tool ready for the Gugolz pitch squares to be applied.

Applying the squares of pitch. The squares were made by pouring pitch into a grid made from small wooden strips lined with aluminum foil. After the pitch hardened, the squares were removed and trimmed with a hot knife. Heat was applied to the squares with a torch and then were placed on the tool.

The almost completed pitch lap.

Pressing the new pitch lap with the mirror and some additional weight.

After polishing out the mirror with pads, I took this photo of the mirror's surface. Pretty scary huh? Not to worry though, the mirror came out fine. It was my first so I'm not about to claim any fantastic wave front error. Suffice it to say that I am very pleased with the images it supplies and that is what is most important anyway. It took me a year to complete. I should have listened to those of you who advise starting with a smaller aperature.

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