Re: Innovative sundials?
Most good analogue watches use Luminova these days - it absorbs solar radiation and uses a phosphor to make the hands visible for several hours. Tritium used to be the norm*, and this had the advantage of working even after a month in a cave. However, it was banned* because of fears of exposing watch repairers to a radioactive dust.
* Any watch with ' T Swiss Made T' is one that used tritium, but the half life is such that the luminosity is reduced after about ten years. Plus, the tritium's energy eventually degraded the phosphor into dust - not good for the delicate gear cogs.
** A loophole used by some watches is that 'tactical equipment' can use tritium, but it needs to be contained within little glass vials
Biting the hand that feeds IT
