The ATM session on 12/10 was productive. Charlie got some ideas for the lower pole clamps for his 13" f9 project. Jay brought pictures of an observing chair that he would like to make, it is a good looking design. I believe he got the image from the internet somewhere, perhaps he will post the link for that image. He also brought a propane heater which really took the chill off the garage! Josh had done some figuring on his 8" mirror and so we tested it and indeed, the Foucault test shows that the central hill is reduced. It is still around an 1/8th wave mirror, which is good, but I have a feeling he is aiming to improve that. We discussed strokes to work a high area around the 85% zone. He then started grinding the back flat on his 4" project (finder for a future 18" scope). The knife edge tester that Josh has made is by far the best I have ever seen. I am now officially envious. I continued polishing one of my 6" f8 mirrors on the machine. I still need to get the technique down for machine polishing because the mirrors come out very "zony" after polishing. To avoid the zoniness, I finish polishing by hand for around an hour which results in a good sphere with no zones. But would rather have the mirrors come out nice right off the machine. Glad to know there are still things I need to learn about making mirrors! Mat P.S. Not sure when the next ATM session will be because I am going to be on-call the weekend I would normally have it. Once I get it figured out, I will post the date. ---------------------------------------------------------------------------- This message and any included attachments are from Siemens Medical Solutions and are intended only for the addressee(s). The information contained herein may include trade secrets or privileged or otherwise confidential information. Unauthorized review, forwarding, printing, copying, distributing, or using such information is strictly prohibited and may be unlawful. If you received this message in error, or have reason to believe you are not authorized to receive it, please promptly delete this message and notify the sender by e-mail with a copy to Central.SecurityOffice.Healthcare@siemens.com Thank you