Someone else’s project

A clock with red numbers, labelled 'local sidereal time'A few days ago I helped someone at makespace do some laser cutting. I saw a man looking at the laser cutter stock shelves, and he asked me about the stock and one thing led to another and once we managed to post bail, I explained that volunteers to buy stock and get their money back were what made Makespace run. So, he very kindly ordered what we needed as well as what he needed.

His name is Steven, and he’s a radio astronomer, and he was making the front of a clock. But, as he wasn’t yet trained on the laser cutter, he needed someone to do the standing there getting hypnotised by the moving red light. So I did that. He had the file ready, and I just plugged in the cutting speed and power, and pressed Start.

Red light travels least, as I recall dimly from some source or another, which may be why the lights here are red, or it might be that the red light has other properties in radio telescope land, like keeping night vision working, or it might just be that red lighting was cheap. But anyhow, this is now ‘at the Thorrowgood telescope at the Institute of Astronomy, helping astronomers find their stars’.

Sidereal time is to do with where the bit of the earth you are on is pointing, and nothing to do with whether you’re late for work.