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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Index arm angle for Artificial Horizon sights
From: David Pike
Date: 2023 Apr 19, 14:23 -0700
From: David Pike
Date: 2023 Apr 19, 14:23 -0700
Frank
Forgive me. I'm coming to this late. Been busy working on the tiny 17' Doranne. A British A Level Science student could have answered this easily in the 1960s. Q. Prove that the angle measured by a sextant is twice the angle between the mirrors. At 79, this is a good way of oiling the brain every couple of months. If using an AH, the angle measured is twice the Sun's altitude, so the angle between the mirrors is the Sun's altitude. Using an AH, as the Sun rises the horizon mirror has to go down by an angle equal to the Sun's altitude, so the index mirror doesn't need to move. Therefore, the index arm maintains the same position with respect to the vertical. This is just what the others have said but in fewer words. DaveP
