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9

With some trig and simple approximations, for the case where the sun is rising directly to the east, and is rising in the direction perpendicular to the horizon, the result is T = (24 hours)(1/2π)√(2h/R), where h is your height above the spherical surface of the earth, R is the earth's radius, and T is the amount of time, in units of hours, by which sunrise ...

4

The question asks for first light but let's assume the time difference will be the same as for dawn. And also that the terrain is flat, apart from an observer in a tower 1 mile high, and the radius of the Earth is 3959 miles. Here is an exaggerated geometry sketch showing a horizontal line in the direction of the sun for an observer at ground level, and a ...

2

Down slippers weigh very little and store very small. Always pack them and use them along side high altitude down overmitts. Dont find out the hard way.I used them on the Cairngorms overnight minus 22 with the wind, in a bivvy shelter partially covered in snow. Of course the best way to retain heat is out of the wind and off the ground so always have a 3/4 ...

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