Building optics - equipment.

Even Twila doesn't really understand how the optics are built, so I'm going to try to make it more clear. This post is about the hardware that's used, and next I'll describe how we use it. We're building two optics, but both are essentially the same.

A machine called a lathe (the NuSTAR webpage says it's a lathe-like tool, but it's really a lathe) holds the optic. Probably some of you don't know what a lathe is, so I'll describe it. First, here is the Wikipedia definition:

A lathe (pronounced /ˈleɪð/) is a machine tool which rotates the workpiece on its axis to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.

I have no idea what that pronunciation thing is. Simply, 'lathe' is pronounced the way it looks, with a long 'a'.

Suppose you have a cylinder of wood that you want to make into a baseball bat or a bed post. You would put it in a lathe, horizontally. The lathe rotates it at a fairly high speed, and then some kind of tool, like a sharp edge, slowly moves down the length of the cylinder, shaving wood off. The carriage, which holds the piece that cuts the wood (or whatever), holds the cutting piece. It can move in and out, depending on the shape that's required. For the NuSTAR optics, the carriage moves in a straight line, and it takes about one hour to travel the entire length of the optic. Here are some photos of our lathe. The photos are clickable, if you want to look more closely.

This photo is kind of blurry - sorry. But you can see that the optic is mounted horizontally. It is spinning. The black thing with the gauge behind the optic is the carriage. It moves from left to right.

This is a view from the end. The optic is on the right, and the carriage on the left. The carriage moves both left and right and forward and backward. It is controlled by a computer. Instead of a cutting tool, the carriage carries a grinding wheel, which spins and grinds the spacers. You can see the grinding wheel just under the white band (a filter) under the gold part of the carriage.

The rest of the equipment is used to apply the spacers to the optic and to measure the results. The glass pieces that form the optic are epoxied to those spacers. I'll talk about that in the next post.