NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Timed Noon sights for position
From: Bill Noyce
Date: 2004 Jan 23, 08:30 -0500
From: Bill Noyce
Date: 2004 Jan 23, 08:30 -0500
> Bill,I don't understand what you're try to convey.
> If you took the noon sight while the DR was 30 m to
> the east the resulting GHA of the Sun would reflect
> that.The 120414zt time is only valid for the one EP.
No, I wanted to take the noon sight when the EP was the
same, but the *true* position was far from the EP, to
see whether the sight would reveal that my EP was bad.
I tried to work through what the observation would be
in that case, and what the calculated latitude and
longitude would be. Latitude came out within about a
mile of right, but longitude simply parroted the EP's
longitude. But perhaps I didn't understand.
- Do you take just one sight, aiming for the time
that you calculated for LAN?
- Or do you track the sun's rise and try to record the
time at which it reaches a maximum?
- What values provide the inputs for your longitude
calculation? From your worksheet, it looks as if
the major input is the pre-calculated time of LAN
at the EP. Is that a correct interpretation of
your procedure?
-- Bill
