NavList:

RE : http://www.fer3.com/arc/m2.aspx?i=115413
[NavList] lat/long from meridian passage
From: goold---edu
Date: 22 Jan 2011 20:43

Dear Patrick,

From your own data, summarized as follows :

22 Jan 2011 (TT-UT=67.2 s) SUN Local Apparent Noon
Fixed Position T=-4�C, P=1013.25 mb/Hpa = 29.92", Height of Eye = 0 ft
All Heights "H" herebelow are "as would be observed in the Sextant and corrected for only instrument error",

1 - UT=17h00m00.0s H=33�08'0
2 - UT=17h15m00.0S H=33�18'0
3 - UT=17h17m00.0s H=33�17'8
4 - UT=17h19m23.0s H=33�18'0
5 - UT=17h34m20.0s H=33�08'0

Without knowing your position I derive the following results :

SUN transit, i.e. "crossing" the Observer's Meridian happened at Time UT = 17h17m00.3s

Observer's Position : N36�49'3 W076�21'9
Standard deviation of your 5 data set : 0.7 NM
Uncertainty in Longitude (1 Sigma) = 2'6

EXCELLENT LUCK for your first Local Apparent Noon Observation. Your CelNav Observed Position falls quite close (0.7 NM !!!) from your actual GPS position recorded as N36�50'0 W076�21'7

Also - and as just recently noted too by Jeremy - Latitude determination is generally (very) much better than Longitude determination when performing LAN's Observations, a fact which has long been recognized. See in particular "Calculator Navigator" by M. Mortimer Rogoff.

Best Regards

Antoine

Antoine M. "Kermit" Cou�tte

----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
----------------------------------------------------------------