NavList:

Sam,

Good luck on documenting and retracing the Powell Expedition of 1869.

http://en.wikipedia.org/wiki/Powell_Geographic_Expedition_of_1869

A worthy project ! Keep us here on NavList informed on your progress.

Greg Rudzinski

Horizontal Sextant Angles and False Horizons etc.
From: Sam Willis
Date: 2013 Jun 6, 08:44 -0700
Hello everyone. HELP!

I am involved in a project that will involve the use of sextants in the Grand Canyon.

1. We will need to use a false horizon because we are in the middle of the desert. Am I right in thinking that a) using a false horizon makes it very difficult to shoot the stars? and that b) because of our lattitude (36) and the declination in August, I will not be able to do a Mer Pass on a 120 degree sextant because the sun will be too high to use a false horizon [and double the angle]?

2. It would be great to do some exercises with horizontal sextant angles. Can someone advise me on this because I am unfamiliar with it. Do I need a special plotting tool?

many thanks
Sam Willis

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