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Frank Reed wrote:

Let's consider two cases:
1) You have no timepiece, not even an ordinary watch. In a case like this,
you would shoot your lunar and your time sight simultaneously. That is, the
altitude of the Sun is used to clear the lunar *and* to generate Local Apparent
Time. This requires lunars where the Sun is well away from the meridian. And
you're basically limited to using the Sun, but that was by far the prefered
"other body" for lunars in any case.

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Yes, but not the only option. During the twilight, you can e.g. take three 
altitudes of the Moon and Regulus and three distances between those two 
bodies without even marking the time. Average both sets of altitudes and the 
set of the distances. You then have the distance and altitudes for the same 
moment. Now from the cleared distance you have GAT and from the altitude of 
the Regulus (if not being too near to the meridian) you will find LST (using 
the DR latitude); change it to LAT and gain the longitude from LAT - GAT. You 
don't need any clock, you can limit yourself to the sandglass for ringing the 
bell and cooking eggs.

I only repeat the procedure from Thompson's tables (1828).


Jan Kalivoda

   

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