NavList:

Hello, David C in NZ,

Yes, I sure can get into that one. It's a story with a fascinating history and a connection to a fine article written by NavList member Roger Sinnott back in 1984 in the pages of Sky & Telescope. Unfortunately, some computation "experts" are still referencing this article as if it applies today. It does not. Here's Roger's essay from 1984:

There's an internet meme that says "friends don't tell friends that 1980 was forty years ago". Most of us in this community feel that pain. But let's remember how different the world of computing was in 1984. Back then you were genuinely lucky if you could write Basic programs on an Apple II, and you were lucky and wealthy if you could buy an IBM PC or lay hands on an Apple Macintosh. Those computers had kilobytes of memory. Modern smartphones have gigabytes of memory. Those 36 years between 1984 and today really aren't all that much more than a third of an entire century, but just to put a big fact number on it, the difference between kB and GB is a factor a million. It's a mega-difference. 

In NavList messages, I try hard to avoid saying, "I wrote about this before and here it is" because that's a conversation-killer, but I'm going to start with that cheat, and I will get back to you with something fresh on it tomorrow! I will nail my fingers to the keyboard by saying I promise to get back with you with something new on the topic tomorrow. For now, here's what I wrote about the topic in 2019: Calculators-cosines-floating-point-computation-FrankReed-jun-2019.

Frank Reed
Clockwork Mapping / ReedNavigation.com 
Island of Misfit Toys