Neil's News

Webb Mirror

15 November 2022

The James Webb Space Telescope has an iconic segmented mirror. I'd like a similar mirror for my closet door. Whereas the original cost $10 billion, let's make a scaled replica for just $5.

I started by designing a 1:1 template in Inkscape and printing it on A3 paper. This was used to mark out the dimensions on a piece of scrap Masonite I found in the trash. A bandsaw cut the rough outline, then a belt sander brought it to final dimensions. Banana for scale.

Next, the whole board is spray painted matte black. A series of pin pricks transferred from the template mark out the corners of each hexagon. Speaking of hexagons, a pack of 24 of them have arrived from China.

The quality of the hexagons leaves a bit to be desired. They are not so much 'bestagons', but more like 'chinagons'. Fortunately since we only need 18 of them, I was able to sort though to find the best specimens.

The central hexagon was temporarily placed, without exposing the sticky backing. Then one by one, the surrounding six had their backing peeled off and were carefully pushed into position using toothpicks. As long as one was gentle, they were happy to slide around on the wooden surface. Once all were in the right positions, light pressure anchored them down permanently.

With the outer ring was similarly attached, it was time to affix the mirror to the closet door using double-sided tape. Peeling the protective plastic off the front was very satisfying. I have a mental image of NASA technicians in bunny suits doing the same at a much larger scale.

I'm pretty happy with this little project. If one wants a bigger mirror, one could model the silver mirror of the Keck Observatory in Hawaii. They have one extra ring, bringing the total number of hexagons up to 36. Ideally one would make two such mirrors, since Keck is a twinned observatory

Albert seems unimpressed.

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