By Katherine Duke '05
Photos by Samuel Masinter '04
Think of the proverbial “billions and billions” of stars in the universe, and the hundreds or thousands we can see from Earth. Now consider that, for centuries before the advent of computers or GPS navigation, experienced sailors used 57 of those stars, plus the sun and moon, to determine their own locations in the vastness of the sea. That’s what 12 students began learning to do in Henry Parker Hirschel’s course, “Celestial Navigation.”
Ben Lin '12 (left) and Elizabeth Carbone '12 use sextants at Avery Point, Conn.
Ryan Milov '10 shoots the sun on Avery Point.
Students in the Celestial Navigation course draw lines on a Mercator plotting sheet.
The next task, a “p.m. sun sight,” was even trickier: The students tookmultiple sextant readings as the sun made its way across the sky, used these readings to draw precise lines on a Mercator plotting sheet, and finally determined our location based on where the lines intersected. I could only vaguely grasp how they were doing this. And to think of how many generations of sailors and mathematicians, how many flashes of genius and rounds of trial-and-error, it must have taken for the human race to invent the sextant and to develop the Nautical Almanac—it was like pondering the size of the ocean or the sky itself.
Captain Henry was pleased with the accuracy of the students’ reckoning of our longitude and latitude—they weren’t far off from what he rather intimidatingly called “Truth.” “I think you’re all to academy standards, as far as I can see,” he said. The next day, as the culmination of the course, the class would go out on an actual boat, to Block Island, R.I. But, the captain reminded them, they were all just at the “neophyte” stage. To get enough real practice at celestial navigation takes nothing short of days and days at sea.