1The telescope was invented by a Dutch optician four centuries ago.
2Before that, it was believed the Earth was the center of everything.
3The theory that it actually revolved around the sun was discounted.
4In the hands of Italian astronomer Galileo, the telescope brought reality into focus.
5Modern telescopes are light years ahead of those early versions.
6And through their eyepieces, the universe continues to unfold.
7A reflecting telescope bounces and concentrates light with mirrors.
8Production begins with the machining of cylindrical metal parts.
9These are baffles, and when screwed together, they'll block stray light
10that would interfere with the telescope's operation.
11More tools transform a solid aluminum disc into a ring with spokes.
12This part, called the spider, is a framework for supporting the telescope's secondary mirror.
13After coating the metal parts with the protective oxide,
14they plunge them into a vat of black dye.
15The dye soaks into the oxidized pores and seals the surface of the parts.
16Next, this molded disk of thick low-expansion glass will become the telescope's primary mirror.
17A diamond edge tool rotates on a calculated tilt to make the glass slightly concave.
18To improve the concave profile, a worker coats the glass with abrasive.
19He adds a weight to a precisely curved cast iron disc and spins it.
20The weighted iron disc bears down on the abrasive-coated glass to fine-tune its curvature.
21A worker then examines the finely ground surface for scratches.
22And using a calibrated gauge, he measures the radius of the disc
23to confirm that the concave profile is precisely what it needs to be.
24The glass now spins
25while a cylindrical cutter aims dead center to cut out a hole.
26This center hole is sized to accommodate the baffles we saw earlier.
27And it will also enable the mirror to be held securely in the telescope.
28Next, the glass disk oscillates
29as an automated tool rubs a compound against it to polish it.
30A worker then applies some of the compound onto a polishing disc.
31He works the surface of the glass against it repeatedly.
32This hand polishing improves the surface considerably.
33In the laboratory, a technician compares the primary mirror glass to a grid
34to verify that the dimensions are accurate.
35He aims a laser at the glass.
36A computer analyzes the reflected light.
37If the angle is off by one thousandth of the width of a hair,
38the telescope's image could be blurry.
39The glass is now ready for its mirror finish.
40They lock it face down in a vacuum chamber.
41They add small amounts of titanium oxide, silicon monoxide, and aluminum.
42They close the chamber tightly, encasing the contents.
43And then they pump out most of the air, creating a partial vacuum inside.
44They activate a 6000-volt electrode.
45This sparks a glowing discharge of ions onto the now-rotating glass disc.
46These ions blast any lingering contaminants from the glass to give it a serious cleaning.
47They heat the aluminum, titanium, and silicon pellets, which evaporate into a cloud of vapor.
48Atoms condense, landing on the surface of the glass to form a glossy mirror surface.
49It takes just minutes for this highly reflective coating to be applied.
50This telescope mirror is now ready to reflect light from the stars and planets in the sky.
51Next, a technician screws lenses into the metal housing for the primary mirror.
52He adds a mount mechanism for the eyepiece, complete with knobs for focusing.
53He flips over the assembly and slides that precision-made mirror onto the housing.
54A cork ring cushions the mirror so a retaining ring can be installed without a scratch.
55The telescope's primary mirror is now secured to the housing.
56He pieces together the three-part baffle.
57Then he screws it to the lens holder protruding from the center of the telescope mirror.
58He joins the baffle and mirror assembly to the telescope tube.
59The tube has already been equipped with a secondary mirror
60that will bounce reflected images from the primary mirror back for magnification and viewing.
61It's taken about six weeks to build this telescope.
62And now it's ready to help unravel the mysteries of the universe.