A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Brad Morris
Date: 2015 Nov 12, 11:06 -0500
Network Time Server Protocol
Is one way. Your computer, assuming it is internet connected, may send a time request, to which it receives the correct time. Naturally, it is adjusted by your computer for the time zone in your settings.
It is by this method that many apps (for example ClockSync on Android) will find the correct time. Quite useful for CelNav, in that the web provides you with a very accurate time.
(Your computer's internal clock will skew with respect to true time. Over long intervals, the time on your computer will not match true time due to the exact frequency of the crystal. In general, the time difference is not noticeable, except over long intervals or detailed analysis. NTSP was developed to keep things synchronized)
I just happened to be up at 2AM last Sunday morning and thought it would be fun to watch the time change on various sites purported to give local time. To my surprise, my computer clock did not go back an hour for who knows how long (I went to bed), several websites reporting our local time also did not skip back. This is something that might happen on Halloween, but..... Actually, I don't know what keeps my computer's clock synced, so I really should have had no expectations. Next morning, everything was normal.