NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2015 Feb 6, 14:44 -0800
Stan, you wrote:
"In 'real life' this is pretty unimportant, since the HP never varies by more than 0.1' from one hour to the next"
Exactly! COMPLETELY unimportant. The choice is not tough: do you want to give students instructions that are more accurate by at most a tenth of a minute of arc (which translates to even less than that for average altitudes), or give them instructions that are less prone to error and do not introduce a pointless extra step. If you're actually writing "practical" instructions, the first choice, going for a trivial improvement in accuracy, would be foolish, wouldn't it? If you are working on the last line at the bottom of a page, would you really want navigators turning to the next page to get that HP from the next line??
Use the easy one line data lookup.
Frank Reed
Conanicut Island USA