NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Latitude AND Longitude by Noon Sun
From: Stacy Hanna
Date: 2004 Jan 25, 18:47 -0500
From: Stacy Hanna
Date: 2004 Jan 25, 18:47 -0500
Jim, My best answer to that is that LAN is the easiest sun LOP to compute. Since you have less steps, there are less chances of making an error that will carry over to your final answer. Many people equate the fact that LAN gives you a line of latitude with that making t more valuable. In actual practice it is better to shoot several sunlines and advance them to a common time to give you Lat and Long. Latitude alone is only extremely valuable if you plan to finish your voyage by latitude sailing rather than sailing a more direct course to your destination. I mean no disrespect to the current author of Dutton's (CDR Thomas Cutler) or any other Naval Officer, but I feel that while Dutton's is a great resource there are many more knowledgeable celestial navigators available outside the officer ranks of the US Navy including many of the members of this list. -----Original Message----- From: Navigation Mailing List [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM] On Behalf Of Jim Thompson Sent: Sunday, January 25, 2004 18:31 To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM Subject: Re: Latitude AND Longitude by Noon Sun -----Original Message----- From: Navigation Mailing List [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM]On Behalf Of Stacy Hanna Jim, I'm not entirely sure what you are asking. I'm not sure if you are questioning why LAN should be observed or why the Navy is doing celestial at all. (snipped) Stacy: thank you for your very illuminating message on the current day's work at sea instruction in the US Navy, however it does not answer my poorly-framed question. I was just pointing out the current Dutton's emphasis on LAN observations, within the context of all the discussion we have been seeing about the risk of error in deriving certain information from a noon sun sight. This thread is splitting into two themes: (1) current CN practice at sea, and (2) discussion about the fine points of noon sights, particularly error due to difficulty in determining the precise point of LAN. Recall that I am still finishing up my CN course, not an experienced celestial navigator. I made that quote because of the phrase, "it (noon sun sight) can usually be relied upon to yield the most dependable celestial LOP of the day". Given the concerns expressed about errors in determining LAN, I am still not sure that I understand why Dutton's uses the term, "dependable"? -----Original Message----- From: Navigation Mailing List [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM] On Behalf Of Jim Thompson From Dutton's, 15th edition (new this month): "...the LAN observation is extremely important in navigation, chiefly because it can usually be relied upon to yield the most dependable celestial LOP of the day. The Sun should be observed at LAN as a matter of routine aboard every vessel.". Why do they make that statement in 2004? Especially naval authors writing for beginners in the modern digital navy. Jim Thompson jim2@jimthompson.net www.jimthompson.net Outgoing mail scanned by Norton Antivirus -----------------------------------------