"Jeff" wrote in message ...
Capt. JG wrote:
"Jeff" wrote in message ...
Capt. JG wrote:
...
The disadvantage is that each position depends upon the previous one,
so that small errors may build up to be large ones.
No, you can go a number of days referencing the last fix.

Don't understand... yes, you can go a number of days, but after that it
seems to me it would start to get way off.

If you start with a fix, you don't accumulate error each day, only when
you change stars. In other words, as long as you can use the same set of
stars, you only have one sight's worth of error. In theory, if you have a
large number of stars, you can go quite a while, since three good LOPs
would count as a new fix.


Yes, absolutely. My point was that 1) you're going to have to use multiple
sets and 2) if you're inaccurate in your observation, this will translate
into larger and larger errors later.... well, unless you only make one
error.

--
"j" ganz @@
www.sailnow.com