(12-24-2015, 02:24 AM)stargazer Wrote: How do you all note the time to the second when operating alone? Glance at watch and subtract a second, then read the angle?
Your CG taught method of finding the horizon is well known.
Yes, time is recorded first and then angle.
As to time recording; when shooting any celestial body I wear my $12 chronometer on my left wrist. At the immediate instance of the sight I count "1-2-3" at an interval equivalent to one second of time between the numbers. In that period of time here's what I've done;
At "1"- taken the sight- the body is on the horizon.
At "2"- lowered my sextant which hangs around my neck on a line of Dynema.
At "3"- Looked at my watch and noted the seconds of time and minutes of time. (in a few seconds from "3" I write the hours:minutes:seconds on an index card)
The counting of "1-2-3" spans a period of time of 2 seconds because I count "1" at the very instance of the sight. So, only two seconds must be subtracted from the time on my watch.
It's very easy and quite mechanical if you were watching me do it.
Some people use stop watches and start the stop watch at the instance of sight and then casually record the time based on the difference between elapsed time of the stop watch and the current time.
There was a stop watch, I don't remember the exact name of it...something like "911 stoptime", that when the button was pressed it froze the exact UTC time of the button pressing.
When recording the time I make no allowance from "CE"- chronometer error as my watch is always set to the correct UTC before any observations are made. So many books and sight reduction forms waste pages talking about CE and the need to note it. For me, it seems elementary and pointless to discuss it further than make sure your chronometer is correct BEFORE you take a sight and if it's not then know what the CE is and record the corrected time of sight when you make the sight.
But, with all of the concern for precise to-the-second" time, a 4 second error in time will only equal 1 nm error in position.
Larry