I didn't even think of that at all.
Very good points, gentlemen

On Wed, Mar 8, 2017 at 12:33 PM, C. Berry <xxxxxx@gmail.com> wrote:
> You can get a more precise latitude (in the sense we use the term)
> measurement by measuring the angle of the ecliptic with the horizon. Shoot
> any two other bodies in the system that happen to be reasonably close to the
> horizon; with 8 to choose from, that shouldn't be hard (and assuming they're
> all pretty much coplanar, which I believe is the case). Your latitude is the
> angle between that line and a vertical line.
>
> If the coplanarity constraint isn't met, you need an ephemeris to pull off
> the trick, but it still works.
>
> Combine that with "solar latitude" as Leonard describes and you can get a
> very precise position fix. Actually, you'll get a couple of solutions, one
> on each side of the noon meridian, but (a) you'll usually have a rough idea
> where you are so you'll know which one to pick, and (b) failing that, you
> can disambiguate using a compass.
>
> On Wed, Mar 8, 2017 at 6:00 AM, (via tml list) <xxxxxx@simplelists.com>
> wrote:
>>
>> On 5 Mar 2017 at 9:02, Jeffrey Schwartz wrote:
>>
>> > There is very, very limited ocean travel - Sailing ships on the trade
>> > winds that are pretty regular, but navigation is a bit freaky with no
>> > good clocks and no noon-sun shoot.
>>
>> Actually, shooting the sun will tell you how far from the "noon pole"
>> you are. That places you on a circle. Call it solar latitude.
>>
>> Since the planet *has* to have a magnetic field to be habitable
>> (don't ask how it maintains it) because of flares from the star (red
>> dwarves are prone to flares), comparing the direction of the sun with
>> north, places you at one point on the circle.
>>
>> It won't be nearly as accurate as what we are used to, but it'd
>> likely place you within a few dozen miles. Not great for avoiding
>> reefs or the like, but usable for a rough idea of where you are.
>>
>> The solar latitude will be a lot more accurate than the "magnetic
>> longitude". So you won't have a circle of uncertainty in your
>> position. More of an ellispe with the long axis running along the
>> line of solar latitude.
>>
>> --
>> Leonard Erickson (aka shadow)
>> shadow at shadowgard dot com
>>
>>
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>
>
>
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