His Rubidium-standard atomic ... copper tube frame and a custom fabricated aluminum chassis pan. For the circuit itself [Art] tells us he wanted to build something akin to the old HP nixie ...

Thankfully, this 60-tube Nixie clock bears that mold, and in a big way. The key to [limpkin]’s design is the IN-9 Nixie, which is the long, skinny tube that used to show up as linear indicators ...