Sextant application
Does a sextant work on both a planar earth model and globular? Does anyone have any expertise or knowhow with sextants?
4 Replies
a sextant uses a flat baseline for it's angles. A ball earth does not have a flat baseline.
The whole methodology require a flat Earth, with a marine sextant you measure an angle between the line of sight to the celestial body and the line to the visible horizon, it's the sextant sight(Hs) as showed in the first image. To find your angle of elevation you need to correct for height of eye above sea level. Once you removed your height of eye using the dip correction, the angle is firmly put on the Earth's surface and as you can see, it require an horizontal baseline, something that the globe does not have.
On a ball they assume a tangent to the curve as a reference frame... Soooooo...
