“It was in Bobcaygeon, I saw the constellations reveal themselves one star at a time”
— Tragically Hip
Making a Telescope Featured
The following notes describe the building of a powerful, fast, lightweight telescope. By powerful, I mean it is of sufficient aperture to grab a LOT of light. By fast, I mean that its focal length is aggressively small (below f/3), resulting in a compact, lightweight, telescope that can be easily moved between locations.
A meniscus telescope mirror allows the ATM to make a proportionally lighter mirror for a given aperture, due to the fact that the glass, front and back, are shaped to the necessary curvature determine by the desired focal ratio of the telescope. This allows the glass to be uniformly thick (thin!), to support faster mirrors. And the first step in creating a meniscus mirror is to “slump” the glass blank in a computer-controlled kiln. More
In many respects, the grinding and polishing stages of fabricating a thin meniscus telescope mirror are not different from any telescope mirror. There are lots of resources, online and in print, describing that. This article will focus on the specific issues introduced by working on such a mirror.More
In traditional ATM stages, figuring a sphere into a paraboloid is the last hurdle before having a completed mirror, and that hurdle is really just a speed bump. It is important, to be sure, but it usually only takes a modest amount of time to complete, and is well described online and in print. Figuring a fast meniscus mirror, on the other hand, is a completely different beast, and this post will discuss the issues related to it in depth.More