Yes, its just that simple. You understand perfectly. There's only one problem.
Here's what Bowditch has to say, from the 2002 edition (LAN is Local Apparent
Noon):

Determining the time of meridian passage presents a
problem because the Sun appears to hang for a finite time
at its local maximum altitude. Therefore, noting the time
of maximum sextant altitude is not sufficient for
determining the precise time of LAN. Two methods are
available to obtain LAN with a precision sufficient for
determining longitude: (1) the graphical method and (2)
the calculation method. The graphical method is
discussed first below.
See Figure 2011. For about 30 minutes before the
estimated time of LAN, measure and record several sextant
altitudes and their corresponding times. Continue taking
sights for about 30 minutes after the Sun has descended
from the maximum recorded altitude. Increase the sighting
frequency near the meridian passage. One sight every 20-30
seconds should yield good results near meridian passage;
less frequent sights are required before and after.

Bowditch goes on to describe the process of plotting the curve and estimating
the time. The other approach is similar, except they give a more mathematical
method for averaging all the sights. Either way relies on taking a number of
sights before and after the Meridian Passage.

The exercise of plotting a Noon Sight is one of the first things a novice
learns. Neal's lack of understanding shows he has never actually done this.

Reference section 2011
http://pollux.nss.nima.mil/NAV_PUBS/APN/Chapt-20.pdf


"Wally" wrote in message
...
Jeff Morris wrote:

One sight at local noon yields your latitude and longitude.

Clearly not true - for starters, you can't take "one sight at local
noon" unless you already know your longitude. If Neal had actually
ever taken a Noon Sight, he would know this!

I am but a sweet, innocent, fresh-faced n00b, and wonder if my reasoning is
correct...

I have a sextant and an accurate chronometer set to GMT. I am somewhere on
the surface of the earth, but know not where. I awaken from my slumbers one
morning and find myself wondering what my longitude is, so I watch the sun's
upward climb across the sky. As it approaches zenith - local noon - I note
the time on my chronometer and then crunch time into degrees to determine my
longitude.


--
Wally
www.art-gallery.myby.co.uk
Latest work: The Langlois Bridge (after Van Gogh)