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## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: Latitude by two stars observed simultaneously
From: Brad Morris
Date: 2017 Dec 22, 12:30 -0500
Hello David

Bowditch, from the 1800's, provides many formulaic examples of solving just this problem.

Almost any online Bowditch from that time frame will provide you with the method(s ).   My printed copy from 1849 has several.

I've refrained from pointing this out as I didn't want to spoil the fun.

Brad

On Dec 22, 2017 11:05 AM, "David Pike" <NoReply_DavidPike@fer3.com> wrote:

I’m afraid I know where this is, because I stumbled upon the original snap while looking for Milky Way illustrations on the net.  All I have to do now is prove it from the information given.

My first problem is that I’m pretty sure which constellation we’re looking at, but I can’t positively identify all the stars from pictures on the web.  When I try to download ‘Stellarium’, my best laptop gives me all sorts of dire warnings and recommends not doing so.  Therefore, should I download it anyway, or should I download it onto the less important net-book I use when travelling?  Also, should I download the 64bit or 32bit version?
I’m running a version of Windows 7, and I'm a digital dinosaur.

My second problem is that I’m sure I’ve seen a method of finding latitude from two simultaneous altitudes and no timing information somewhere, but I’ve looked at all my books and I can’t find it. The net wasn’t much help either.  The thing is, am I looking for a simple 2D solution like Mer-Pass, or am I supposed to get into spherical geometry equating two or more spherical triangle with known sides, namely co-alt and co-dec, and a known angle between, namely diff in SHA, to find a common unknown side, co-lat?  More hints please. DaveP

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