NavList:

Resistance if futile. You will be assimiliated.

Interesting examples which I just took time to rework.

Lunars report 3 angles : Lunar distance, and "corrected" heights of 2 Bodies corrected for only dip and refraction.

With modern computation power, it is possible to directly transform these 3 angles into UT, Lat and Lon at the time of the Lunar and compare with Navigators' published results.

1st Example , On Aug 25th, 1830 (TT-UT = +7.4s), Lunar distance 80°42.45' with SUNL = 36°14' and MOONL =  44°49'

 Retro-engineered uncorrected hights (hoe = 0 m with "standard" P & T) SUNL = 36°15.3' MOONL = 44°50'

OWN RESULTS

Lunar taken at 17h58m20s UT1 from position N24°34.4' W034°27.9' with a cleared distance 80°48.2'

To be compared with:

NAVIGATOR's results : DR Latitude N24°51' (some 2h10 m earlier) and Lunar Longitude W034°11'15".

Discussion: Unfortunate uncertainty (but that's the way they navigated then) about the Latitude which was probably [much] closer to N24°34.4' since Themis was most probably sailing south.

Actual NAVIGATOR's Longitude error close to 15' . Reasonable blue water fix.

2nd Example : On Aug 28th, 1830 (TT-UT = +7.4s) ,  Lunar distance 114°42.9'  with SUNL = 27°25' and MOONL = 28°52'

 Retro-engineered uncorrected heights (hoe = 0 m with "standard" P & T) SUNL = 27°26.8' MOONL = 28°53.8'

OWN RESULTS

Lunar taken at 18h19m59.7s UT1 from position N17°32.3' W030°50.7' with a cleared distance 114°35.4'

To be compared with:

NAVIGATOR's results DR Latitude N18°20' (some 2h earlier) and Lunar Longitude W030°39.5'.

Discussion: Unfortunate uncertainty (but that's the way they navigated then) about the Latitude which was probably [much] closer to N17°32.3' since Themis probably kept sailing south.

Actual NAVIGATOR's Longitude error close to 11' . Looking good, and certainly well within uncertainties safely permitted in the open sea.

Am I resisting OK ? :-)

Kermit