A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2023 Nov 6, 20:18 -0800
Surely someone... at some point in the twentieth century (when celestial navigation by stars became much more popular) made a version of this device for bright navigation stars! Or has anyone encountered instructions for a DIY kit? Seems easy enough to bang together. The principle is quite simple: align the axis with the celestial pole, just like the gnomon of a sundial. Then turn the disk to the proper Sidereal Time, equivalent to the Hour Angle of Aries (determined by date and local mean time pointers, as on a common planisphere). Read the declination of the desired constellation from the disk, and tilt the arrow accordingly. Probably a bit tricky sighting along the arrow and not much use with sprawling constellations like Ophiuchus or Hydra. It seems the idea would actually work much better if limited to a standard set of a few dozen bright stars (like the modern nav star list of 57).
This device, with a patent date from 1910, was apparently intended for backyard starfinding and not for navigators specifically. There's more here at the Smithsonian website: