This app could also be used to check a compass, as long as you know the local Variation, and can get a good bearing on the Sun, the Moon, or the Big Dipper.Īll of which is a long winded way to say that there are some amazingly neat little apps out there, and I hope you all will share your favorites here.
It also shows why we’re early risers in Maine (we’re way over on East side of the Eastern Time Zone) and how pathetically low the Sun is even at true noon at this time of year. The $.99 cent app above would have been a lot easier, but at least it shows that my efforts worked I took that screen shot when the shadows lay straight back from all my south facing windows, and it confirms that this house is a giant sun dial. When I built my home in 1978, I recall using two techniques to assure its True South orientation - a compass which I corrected to the local Magnetic Variation taken off a chart, and the shadows at the time of Local Apparent Noon as calculated with my Longitude and the wondrous Equation of Time for that day. Admittedly ‘compass’ may be a confusing name, but this app uses spherical trigonometry and an ephemeris to calculate the bearings (azimuths) of three celestial bodies at your location so you can line one of them up with the screen and thus orient yourself to True North, E, S, W, etc…
The Celestial Compass above, for instance, has seventy 1 or 2 star “this app doesn’t work/sucks” type reviews versus just fifteen positive ratings, even though it does exactly what it purports to do, and that’s not trivial. It’s hard to keep up with marine related iPhone apps, and the reviews at Apple’s iTunes Store often don’t help.
0 kommentar(er)
