Sailing navigation with sextant

Posted on September 18, 2023  •  1 minutes  • 170 words

Description

Experience of celestial navigation during the sailing back from acores to the scilly islands before to come back to cherbourg.

Here is the sun positions computed with sight reduction methods. This is using the gps position as the estimation position, so it’s show the error mesurement with the sextant. We can see that they are always less than 10 NM and that we often underestimate the celestial body altitude.

A triangle position in red is estimate for a specific date. Two mesurements are propagated using exact route estimate (difference between two gps positions). This gives a triangle position and an estimate position (minimum from the 3 lines) that is around 10 NM from the true gps postion. The weather conditions was not easy this day with waves and clouds.

On the sailing weather routing page, the weather conditions can be seen in a simulation.

The full moon was the 1st of september 2023, so we could also make sextant mesurements with the moon. This is coming soon.