Duttons, 1934 says:
"Some of the older methods, which still are in use to some extent in the merchant marine will first be presented very briefly. It should be understood that there will be practically no occasion to make use of the theory, nor of the time sight. They are presented merely in order that the naval officer may be acquainted with the terms in use to some extent by merchant officers..."
Of course, flight navigators never used this method since you need sights more often than once or twice a day.
As long as we are discussing time sights I also have a question. You need to take the observation of the sun when it is on the prime vertical. But, during at least half of the year the sun will never be on the prime vertical. Any body who's declination is opposite to the latitude never crosses the prime vertical and that is the
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