A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2014 Dec 20, 13:37 -0800
Marty Lyons, you wrote:
"I could make an Excel sheet, look up LHA once and then increment it on the sheet by 15' per minute of time."
And that would take you, what, ten minutes? Maybe an hour if you're really rusty? And then you would have it available forever with the open option of future customization and extension as your time permits. Formatting sexagesimal time and angular measure is always a huge pain in the neck whether on paper or computer, and as David Pike suggested, you would need to find some "kid" (=enthusiastic amateur coder) to figure out how to do it exactly and perfectly right, but this is a problem best fixed at the source. Just decimalize. For your astro compass experiments, you would surely never need the LHA of the Sun more precise than a tenth of a degree (and even that is one step beyond what you need, but most people do prefer to have that extra digit). And then just add 0.25° per minute. Furthermore, for everyone following (not Marty specifically), rather than seeing the creation of a small spreadsheet as a chore, shouldn't we see it as an opportunity to learn something useful?? If you can make this spreadsheet, then you can make others.
Got more tech? If you have a smartphone or tablet, there's probably an app for this. Sean and I were recently discussing the simple little "Sidereal Clock" app for Android. It can be set up to display local apparent time as a "live" clock display. It doesn't show LHA but you can either do that in your head or maybe there's another app for that. And of course, you could install Stellarium on your laptop computer. It displays LHA in time units (a simple "time to arc" table might be part of a solution here).
Conanicut Island USA