NavList:

Hi Alan

When I first became interested in polar exploration, I marveled at the fortitude of the explorers.  I was puzzled by the eternal daylight.  How could the sun be out all day, so high in the sky? 

After a bit of thought experiment, I found myself figuratively on the south pole, looking over the expanse of the solar system, and realized that I was looking at the edge of the system, with the orbital paths all around me.  The sun just skimmed around the horizon at the poles, it never went high in the sky.  While to most of the audience here, it rates a "well duh!", but to me it was a marvelous epiphany.  I have since seen videos of this effect (most recently in the US on the show "Ice Road Truckers"), and it never ceases to have that same sense of 'wow' for me.

One of the first things I did with my Bygrave Slide Rule was to calculate the altitude of the sun, as if I was standing near the Antarctic Circle.  Because the Bygrave is so very fast to a solution, I went from upper meridian crossing to lower meridian crossing and back full circle, in steps of 30 degrees if memory serves me correctly.  Sure enough, it was never "high in the sky".   The azimuth changed rapidly, the altitude gradually.

I share this with you to encourage the thought experiments that Frank suggests.  Those thought experiments will yield a deeper understanding.

Don't get discouraged.  Its within your grasp!

Best Regards
Brad Morris