(12-16-2015, 05:34 PM)Fred_B Wrote: Pub. No. 229 is way too cumbersome to lug around so I solve for Hc and Zn using the respective formulae for them.
These are handy to carry- http://thenauticalalmanac.com/Formulas.html
and a lot lighter than books.
Messing around with the various formulae to determine Z led me to the one on the Formulas page. Most of the others require too many conditions ("if, then") to arrive at a solution.
Would like to hear what others use or maybe a quicker method.
Fb
Fred,
Here's the one I use (you mentioned earlier);
Cos-1((Sin(Declination) – Sin(AP Latitude) x Sin(Hc)) / (Cos(AP Latitude) x Cos(Hc)
Pretty easy to enter except you must calculate Hc using this formula first;
Sin-1(Sin(Latitude) x Sin(Declination) + Cos(Latitude) x Cos(Declination) x Cos(LHA)
Much easier than hoisting Pub. No. 229.
How fast are you at getting both answers?
Roland D.