<Home>  <400 Navigational Equipment>

Added 03/07/2004

I'm trying to learn celestial navigation, and the more I read, the more

confused I get.  I read and worked the problems in the book that came with the sextant and got nowhere.  I read and worked the problems in 'One Day Celestial Navigation' by Brown and got within 50 miles on a noon sight.  Now I'm lost in 'A Star to Steer Her By' by Bergin that needs pub 229 from 1984!  I have pub 249 vol 2 and this years nautical almanac.  I took sights on 2 stars or planets tonight (I don't know which) and I'm just totally confused and ready to throw the whole lot overboard, except I've got too much money and time involved.  The question is has anyone taken a class lately from somewhere local or Starpath or something and how was it and how much etc. or found a book that works.  Question 2.  Is there anyone out there that's any good at this and willing to tutor me for a small fee on Sundays in Long Beach? 

Chris

First question: do you have a clear horizon to take your sights ? or  an artificial horizon ? Second try and locate the North Star (that is what Columbus and Co navigated by...) and take its height (will give you a latitude). Then try to locate the Orion constellation (quite visible relatively low on the horizon) and identify its various stars (some of them like Rigel are quite bright). Orion could be compared to a T-shirt cinched at the waist by a belt. Once you have found the North Star and Orion, you can progress by "triangulation" from these two to other Stars and constellations

john

pampero iv

I am a certified celestial navigator as well and good old chris probably used

the sun more.

 Allan

No, he didn´t and for a very simple reason: they didn´t have filtering glasses on their instruments, so he would have been blinded by the sun... That´s why they used the "backstaff" when they had to shoot the sun. Practically all there "accurate" positions were taken ashore when they had discovered new land and they mostly relied on DR for their positions (especially in longitude) but they used the North Star for navigation at sea (and had a very good idea of its actual declination) using th astrolabe.

john

Here is a Navy ROTC nav course online.  Chapter 16-19 are celestial nav.

http://www.vpul.upenn.edu/nrotc/ns301/index2.htm

Johnny Revel, C26 MkII #1090, Lady Revel, Solomons, MD

I maintain what I said, that they could only establish their longitude by DR because they didn’t have a way to establish their longitude by observation. At the time when Harrison came out with his chronometer, there was as big a discussion about that unreliable gizmo as there was a few yearsd back about the GPS... because the astronomers were about to have accurate enough sextants to make lunar observations which would allow them to establish the longitude. Joshua Slocum was an expert "lunarian" so he didn’t need anything but his clock with the missing minutes hand....

john

You are right, the US Power and Sail Squadron offers celestial navigation,

The only problem with the squadron is that you have to do a lot of other

Courses before you can take celestial navigation. I completed all the previous courses but never took celestial.

Alex Bustamante

"Orion" C26 MKII

Berkeley, CA

   John is correct in that longitude requires a chronometer set to Greenwich

time. Latitude is easy, just shoot the North Star. There is one rare exception. If you luck out and can observe an eclipse, you can figure your longitude at that moment. That is why all the various explores took the time to observe any eclipses. They could get an exact fix and reset their chronometer. (Eclipses were predictable and there were charts that foretold that exact time of the eclipse in Greenwich time).

 Bruce K

Bruce, you don’t  need an eclipse to establish time. If you take the changing angle between the moon and a star, you’ll be able to find the time. That was the argument made by the Astronomer Royal and his supporters against Harrison’s chronometer,  that "newfangled device that could fail at any time"

john