NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Fwd: Re: Sextant accuracy with short distance to horizon
From: Dale Tilson
Date: 2001 Jun 26, 1:50 PM
From: Dale Tilson
Date: 2001 Jun 26, 1:50 PM
Re: the Aussie using his fence for a horizon, several people wrote: > >> That's interesting. But surely one must make an allowance for the fact > >> that the fence is not at the same altitude as the horizon. > > > >I can't remember that much about the post, but I THINK he had some kind > of HE > >correction for his eye above the fence line. > > >He would need extremely accurate survey data if there was >any meaning to be had. He would have to know the relative >height of the fence and his eye, as well as the distance to >the fence. OK, guys, I'm new at this so somebody help me out. I thought the "dip" correction was necessary because the horizon isn't level with your height of eye. Aren't we actually trying to measure altitude above a line horizontal with the line-of-sight? If so, our Aussie friend would only need to find a perch so that his eye was level with the fenceline. If not, somebody straighten me out quick, because I was gonna set up an observation post in the back yard based on that premise. Thanks, Dale