NavList:

I’m wondering about the potential of a pre-watch technique of roughly measuring elapsed time to about a 1/4 hour while "on the go" (as in traveling on land or sea) by measuring the change in the distance between the moon and a star (or the sun) with a carefully tapered and graduated piece of wood or metal.
I have in mind the early system of the lunar mansions, for example, as key reference points among the stars. Those who were intimately familiar with these would always be aware of the moon's position among them as it completed its sidereal cycle month after month. We know they gauged the passing of days as the moon swept through 13.2 degrees each solar day on its way from one convenient, if somewhat random, reference point to the next. Why then might we not suspect that some also gauged the hours by estimating changes in lunar distances with tapered "sticks" graduated with rings to indicate angular measurement indicating about 1.6 mm changes in diameter for 1/8 degree /15 minutes of time when held at the user's arm length? Wouldn't any two stars near the path suffice as long as the viewer connected a pair more or less perpendicular to the path? This technique would also have facilitated coordination of meeting times between people from widely separated locales. I should add that even though I know very well the ecliptic constellations I have not yet tried my hand at this.

I have a very, very old text in which I thought something like this might be in play, but if there is no analogy for it from any other time in history I may have to leave this part out. Does anything come to mind?

Stephen
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