
Sextant Observation
Having taken your sight, in the Observation screen you enter the time of the sight and the measured altitude. For sights on the sun or moon, also select whether you have taken the sight on the upper or the lower limb. You also enter your height of eye and the sextant's index error - these values are saved between sights.
The values of the corrections to the sight - dip, parallax and refraction - are shown. These are used in converting the observed altitude to the actual altitude of the body. Now click on Show Position Line to do the sight reduction calculations and obtain your Line of Position.

Sextant Observation
Having taken your sight, in the Observation screen you enter the time of the sight and the measured altitude. For sights on the sun or moon, also select whether you have taken the sight on the upper or the lower limb. You also enter your height of eye and the sextant's index error - these values are saved between sights.
The values of the corrections to the sight - dip, parallax and refraction - are shown. These are used in converting the observed altitude to the actual altitude of the body. Now click on Show Position Line to do the sight reduction calculations and obtain your Line of Position.