NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: gyroscopic compasses
From: Geoffrey Kolbe
Date: 2007 Jun 24, 10:36 +0100
From: Geoffrey Kolbe
Date: 2007 Jun 24, 10:36 +0100
Thanks to all those who replied to my question. I was inspired by a comment by George on the ability to get your latitude and longitude from a single sighting of a celestial object using a theodolite, where the altitude and azimuth could be obtained at the same time and from which the latitude and longitude of the observer could be deduced. Not a new idea, of course, but it got me thinking. I sat down and derived some formulae from Napiers rules to get the latitude and LHA of the observer's position, given the altitude, azimuth and declination of the observed body as inputs. But, to get the azimuth, you need to know where true North is. Finding true North at night is not a problem, if you can see Polaris. But I was thinking more of a day-time sighting where only one celestial body is usually available, and where you might not want to hang around waiting for the sun to move appreciably to get a second sighting and use the LOP method to get your position. Theodolites are available with gyro-compass attachments which will give true North to within a minute or so, but they are hideously expensive. I wondered if there was something out there that would get me true North at a more reasonable cost. Thanks, Geoffrey Kolbe --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "NavList" group. To post to this group, send email to NavList@fer3.com To from this group, send email to NavList-@fer3.com For more options, visit this group at http://groups.google.com/group/NavList?hl=en -~----------~----~----~----~------~----~------~--~---