NavList:

Yes Peter,

If you have sufficient data storage space like Frank and if your Computer can process (zillions of operations)**(3/2) per second, using (huge) precomputed tabular values and performing super fast first (or even higher) order interpolations is the right way to do. That is certainly the solution of future for us all and Frank is leading the way here. Thanks to his superior and far seeing approach we are all able to benefit from a number of his recent innovations in which computations are almost finished before they are ever started.

If you only have limited storage, or if your environment constraints require you to fit ALL your software into a small hand-held calculator without losing ANY accuracy - at the sole expense of a much increased computation time, while still achieving a sufficient speed compatible with sailing or even real time Jet Aircraft operations - then using the generally VERY MUCH SMALLER "footprint" given by the fitting formulae or equivalent is the way to go.

That is exactly the same for the Planetary computations - where precomputed tabular values are definitely a "must" with the JPL and BdL numerical integrations - or the Moon apparent contour shape computations for super-fine Moon Occultations predictions. Frank seems to have a huge storage space compared to what some others have and this is the ideal situation for his own aims. And I have found extremely instructive to guess what various constraints and philosophies can be.

What is the most wonderful is that, even if we mathematically tackle the same phenomena through different approaches - including some mathematical approaches entirely from scratch - we consistently keep getting exactly the very same end results, which is the most important point of all.

In other words, your own choice given our own constraints is the best one for your own needs. This does not and should not prevent you from admiring and commending what other "Navigation Fellows" have rightly and proudly performed.

Your turn now on .... :-)) !!!!

Happy Easter and

Best Regards

Antoine M. "Kermit"
Couëtte
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