NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: iPhone as artificial horizon
From: Paul Saffo
Date: 2008 Sep 10, 10:36 -0700
From: Paul Saffo
Date: 2008 Sep 10, 10:36 -0700
F- "iKamal"... I love it! -p On Sep 10, 3:49�am, frankr...@HistoricalAtlas.net wrote: > > A simple app that could be written would measure the angular tilt of the > device and record it when the screen is tapped. One could then aim the > device at the Sun by minimizing its shadow, and then immediately read out > the altitude. As you say, these altitudes are only accurate to 30 minutes of > arc or maybe somewhat better, but you might still be able to extract some > useful navigational information out of it (and this would work even if the > device has no access to network information/cell phone capability). It might > make a very good digital compass... > > There are off-the-shelf digital levels available that measure angles to > about +/-10 minutes of arc reliably (at 6' nominal precision). You could > stick a simple sighting tube on top of one and you have a digital "sextant" > in no time. But a device like this is not that useful for manual > observations. It abandons the most important trait of the sextant: > double-reflection. Without double-reflection, we're right back to the days > of the backstaff or the kamal, and shaky hands are the limiting factor in > taking sights. So I guess in the end, I would call a device like this a > "digital kamal" rather than a digital sextant. > > �-FER --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---