NavList:

Another puzzle...

The date is 5 July 2023. You are sailing in the North Sea... gliding along on a due South course at 3 knots. Height of eye 25 feet. Sextant index correction is zero. The sky is mostly clouded over, but you can see bright stars low in the north and west. Venus is near the horizon in the west. You've planned ahead to shoot Capella "below the pole". At 21:50 Capella appears to be near due North but it's altitude is still decreasing. Have to wait a little longer. In this latitude twilight lasts all night near the summer solstice so you have time...

You turn to shoot Venus. It's very low, but still quite bright. Your raw sextant observation:
   Venus: 1°27' at 21:51:05 UT.
That's very low in the sky, and you should probably make corrections for atmospheric density (temperature and pressure) but you decide "meh. close enough."

Back to Capella. This one goes to 11... Starting at 22:08 UT the altitude of Capella is unchanging at 11°11' for ten full minutes. It is on the meridian "below the pole". Raw sextant Hs:
   Capella: 11°11' at 22:11 UT.
What was your latitude at 22:11 UT? Now combine that with your Venus sight. What is your position? You can work this either for a 2151 fix or a 2211 (conveniently separated by 20 minutes... why convenient?).

Reminder: for sights below the pole, Latitude = Corrected Altitude + Polar Distance.

Frank Reed
Clockwork Mapping / ReedNavigation.com
Conanicut Island USA