NavList:

   

Reply

> > and then compare this pattern with the (in this case)
> > horizontal slope?
>
> Eh? Wouldn't a graph of the sights still follow the familiar parabolic curve
> leading up to and then following local noon? I wasn't aware that the
> declination being almost zero would have any affect on that (of course, the
> slope of the LOP *is* horizontal at meridian passage, but that's the case
> any time of the year as far as I know...).

Over a few minutes spanning LAN there is very little change in the
body's altitude - they used to say the sun tends to "hang in the sky"
at this time.

So differences in recorded altitude over those few minutes are mostly
caused by random errors in observation. By comparing a graph of them
with your horizontal line it may be possible to derive a better
altitude to adopt for calculation of your latitude than any of the
recorded sights (see: "An example of a slope", 10 March 07) .

You could also (if you had a reason to) calculate the standard
deviation of those sights, which could be useful in terms of analysis
of the resulting position line (see recent thread on "Cocked Hats").

Since you have the sights recorded it might be informative to go back
to them and try it out. This particular case lends itself easily to
the technique, since you don't even need to calculate a slope - it is
effectively a horizontal line over five minutes of time spanning LAN.

Let us know the results ...

--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---

   

Reply