NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
LOP's
From: Barry Hudson
Date: 1999 Jun 23, 18:13 EDT
From: Barry Hudson
Date: 1999 Jun 23, 18:13 EDT
>Date: Wed, 23 Jun 1999 09:12:43 -0700 >To: Navnet >From: bhudson <bhudson@XXX.XXX> >Subject: LOP's > >Hi, >All LOP's of a celestial nature need an arrow at each end. This is >perhaps not so important with say a single sun observation but when >it comes down to a multi star/planet set of observations (as many as >six or maybe more) you need to distinguish the azimuth lines from >the Position lines by placing the arrows.What a clutter we have if we >dont do this. Electronically of course only the PL's appear on the LCD so >it does'nt matter about the arrows. Someone already mentioned that >the celestial PL is an arc of a circle and harking back to coastal nav >when taking a sextant or radar distance off it is part of a circle of >position so we put an arrow at each end of that arc of the circle we >are most likely to be on. In coastal navigation we also have other >arrow symbols to identify lines on the chart and prevent confusion e.g. >is it a course line, bearing, tide or current drift,and so on. It is >also important to bear in mind how many people are involved in the >navigation of the vessel.For instance take a large commercial vessel >with many users of the same chart one has to be particular with symbols >used they must be readily understandable to all. In the case of a >single navigator then he can do what he wants as long as the PL's make >sense to him. >Myself if I did'nt use arrows to distinguish between azimuth and PL >confusion would rain supreme. >This is a most stimulating network. >Barrie Hudson >