05-05-2017, 02:01 AM
No, you're not making any mistakes.
Pub. No. 249 Vol 1. (7 varied navigational stars) provides stars that are brightest and best for producing an LOP with sharp angles between them. The magnitude (brightness) of Polaris is such, I suspect, that it's not a good choice. Pub. No. 249 Volumes 2 & 3, of course, do not cover declinations over 29° so Polaris can't be used.
If using a calculator Hc can be determined in about 10 seconds. Zn is a little more time consuming- maybe 30 seconds.
The formulas for Z have been updated in the 2017 Nautical Almanacs and here-
https://thenauticalalmanac.com/Formulas....etermine_Z
The "rules" to determine Zn had been omitted as I assumed, incorrectly, that most people knew the rules.
Pub. No. 249 Vol 1. (7 varied navigational stars) provides stars that are brightest and best for producing an LOP with sharp angles between them. The magnitude (brightness) of Polaris is such, I suspect, that it's not a good choice. Pub. No. 249 Volumes 2 & 3, of course, do not cover declinations over 29° so Polaris can't be used.
If using a calculator Hc can be determined in about 10 seconds. Zn is a little more time consuming- maybe 30 seconds.
The formulas for Z have been updated in the 2017 Nautical Almanacs and here-
https://thenauticalalmanac.com/Formulas....etermine_Z
The "rules" to determine Zn had been omitted as I assumed, incorrectly, that most people knew the rules.