Brian, I've got it, I think. What threw me was the sequence of events, as written. I thought that the Cessna being South of the DC-10 was determined on the magnetric headings only, which isn't possible. (Is it
) If the events are reversed, sun elevation first, then heading, it's obvious - sort of.
Like I said, I knew I'd regret asking. Brilliant bit of work though - bl**dy genius.
Captain Vette, a qualified navigator, contacted Prochnow and asked him to head toward the Sun and to report his magnetic heading. Prochnow pointed the Cessna to magnetic heading 274 degrees as Vette steered his DC-10 toward the Sun and read his magnetic heading as 270 degrees. Next Vette instructed Prochnow to determine the elevation angle of the Sun above the horizon using his partially outstretched arm and fingers as a sextant. Prochnow established the elevation of the Sun as four fingers as Vette measured the elevation of the Sun as two fingers.