NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sextant Accuracy and anomalous dip.
From: Gary Harkins
Date: 2003 Mar 17, 20:37 EST
From: Gary Harkins
Date: 2003 Mar 17, 20:37 EST
In a message dated 3/17/2003 8:09:43 PM Eastern Standard Time, ffive@TPG.COM.AU writes:
No.
Imagine yourself on top of a mountain taking a sight. Imagine that the sight measures 45 degrees using a bubble horizon or artificial horizon. At sea level and the same geographic location (if that were possible) the sight would measure higher. If you measured the same 45 degrees at sea level you would have to be further away from the sun's GP. I hope that's clear, it's easier to show using a sketch.
Gary Harkins C400 #140 "Cygnus"
Website http://www.hometown.aol.com/htycgary/myhomepage/index.html
Harbour Towne Marina, Muskegon, Michigan Slip C-28
Harbour Towne Yacht Club, Life Member
C400 National Association
United States Power Squadrons-JN
NRA Life Member
MCRGO (Michigan Coalition for Responsible Gun Owners)
JPFO (Jews for the Preservation of Firearms Ownership)
Is your house at sea level? If not you will have error caused by your
>elevation.
Is this identical to the dip factor caused by height of eye?
> Usually these can be ignored at moderate elevations, but in your
>case, attempting to get ultimate accuracy, they may be a factor. The
>error will be greater when the sight is a smaller Hs.
Why?
No.
Imagine yourself on top of a mountain taking a sight. Imagine that the sight measures 45 degrees using a bubble horizon or artificial horizon. At sea level and the same geographic location (if that were possible) the sight would measure higher. If you measured the same 45 degrees at sea level you would have to be further away from the sun's GP. I hope that's clear, it's easier to show using a sketch.
Gary Harkins C400 #140 "Cygnus"
Website http://www.hometown.aol.com/htycgary/myhomepage/index.html
Harbour Towne Marina, Muskegon, Michigan Slip C-28
Harbour Towne Yacht Club, Life Member
C400 National Association
United States Power Squadrons-JN
NRA Life Member
MCRGO (Michigan Coalition for Responsible Gun Owners)
JPFO (Jews for the Preservation of Firearms Ownership)
