Celestial Navigation, Day 1
Notes from Celestial Navigation, Day 1
Well, we tried! And we will get better.
Celestial navigation is pretty complicated, yet pretty simple. You can navigate with any object in the sky - we are using the sun. By measuring the angle of the sun at mid-day using a sextant, we can calculate how far north or south we are from the equator. The first picture is of Jace, Isabel and Autumn measuring the angle of the sun. Our average angle was 61.5 degrees. Because the earth's axis is tilted, we have to account for that. Right now, the sun is in the southern hemisphere (it is winter up here in the northern hemisphere) and the tilt of the earth causes a 8.75 degree declination of the sun. We add that to the 61.5 we measured and subtract it all from a perfect 90 right angle. The result is 19.75 degrees North. We were actually at 19.25 degrees North, or about 80 nautical miles off. That's pretty bad, but actually not too bad for our first time.
Calculating longitude is also pretty complicated but pretty simple. Today's local noon, when the sun is at its highest point, was at about 12:45pm or so. That's 10 hours and 45 minutes behind noon in Greenwich England, where the prime meridian is. So the math is simple: 10.75 of 24 hours is equal to 0.448. A circle, like the earth is divided into 360 degrees. So, we were 0.448ths of the way around the world from Grenwich. 0.448ths of 360 degrees is 161 degrees West. We were actually at 159.5 degrees West, or about 100 nautical miles away. Again, not great but not too bad for our first time.
The map up top shows our actual location as a blue pin, and our celestial navigation location as a yellow pin. And guess what? Seas are calm and we are happily heading from Hawaii toward the equator.
Tomorrow, and the day after, we will try again. We will be improving our technique and reporting back with how our celestial navigation is improving. Stay tuned.
