NavList:

Hi Kermit

Aha!  The Nautical Almanac for 4 Aug 1773 states that the declination of the sun is N17d 8m 8s.

You have the declination at N17d 5m 41.8s  That is a ~3minute difference.

Without knowledge of the internals of Frank’s calculator, I cannot be sure which value he uses.  Perhaps he will help us when he next returns to the list!

There is one thing which does bother me.  Bayly is obviously a skilled navigator, on a scientific expedition with other skilled navigators.

His numbers and reductions are obviously peer reviewed, at the time, by Capt Cook et al.  Therefore, in the discussion of these numbers,

some will be highly variable (like time) and others not so variable (like latitude).  They would not have accepted a latitude with a 29 minute swing, even if it

was 18 hours after the previous latitude determination, with a published declination.  In a previous communication, you provided values with

a 29 arc minute variability in latitude.

I do not believe we will find many arithmetic errors, due to the peer review by so many aboard.  Hence using the published ephemeris only permits

us to understand what values (and their meaning) are used.  For example, by using a modern calculated sun’s declination instead of the 1773 published declination,

the latitude will be altered as a function of declination and altitude.  As the time will then be altered, the longitude derived will be altered.  With so

many altered values, how are we to define the inputs such as altitude (the current debate)? 

Therefore, I believe that we must somehow reduce to the given position, using period published inputs (like the sun’s declination) and altering those

values to a degree which makes sense as a function of the variable type.  Of course, since I believe in reasoned debate and discourse, I would be

happy to hear other viewpoints.

Best Regards

Brad