"Tis with our Judgments as our Watches none Go just alike yet each believes his own" - Pope, An Essay on Criticism,1711

Generally, noon was used to reset a clock or watch.

There were many almanacs with sunrise, noon and sunset published.

Try looking at the approach outlined in the middle of page 20 of:

Time's Telescope for 1816 or A Complete Guide to the Almanack

https://books.google.com/books?id=bF8NAAAAYAAJ

To adjust a watch clock . . .

Then there is the earlier (1731):

An Explanation of the Nature of Equation of Time and Use of the Equation Table for Adjusting Watches and Clocks to the Motion of the Sun

https://books.google.com/books?id=fOlbAAAAQAAJ

In part, this noon fixing of time caused the naval day to start at noon, rather than midnight. - R