true anomaly - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: General Forum (/forum-4.html) +--- Thread: true anomaly (/thread-8127.html) true anomaly - nsg - 04-06-2017 11:59 PM There is a formula that converts eccentric anomaly to true anomaly and vice versa: $\tan(\nu/2)=\sqrt{\frac{1+e}{1-e}}\tan(E/2)$ I just noticed that $\sqrt{\frac{1+e}{1-e}}=\exp(\tanh^{-1}(e))$ which could save some keystrokes (or precious program steps) on a calculator which has atanh function. Also this is a rare opportunity to use that built in function that almost nobody ever uses. RE: true anomaly - Geoff Quickfall - 04-07-2017 12:31 AM Nice shortcut, But I thought marriage did that! RE: true anomaly - d b - 04-07-2017 03:25 AM (04-07-2017 12:31 AM)Geoff Quickfall Wrote:  But I thought marriage did that! Geoff; She probably always qualified, but I think that marriage granted your wife sainthood.