NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Distance by Vertical Angle Adaptation
From: Greg Rudzinski
Date: 2009 Jul 26, 22:04 -0700
From: Greg Rudzinski
Date: 2009 Jul 26, 22:04 -0700
Example of vertical distance short of horizon for: Height of eye 6ft. Height of Object 250ft. M.O.A. by sextant 60' .567(250)/60 = 2.36 NM Example of vertical distance beyond horizon for: Height of eye 9ft. Height of object 250ft. M.O.A. by sextant 18' Approximate distance 8 NM (8/1.144 - 3)Sq = 15.9ft. (height correction to be subtracted from object height) .567(234.1)/18 = 7.37 NM Run calculations again using 7.37 NM as approximate distance (7.37/1.144 - 3)Sq = 11.8ft. .567(238.2)/18 = 7.5 NM (more accurate distance) note - Nav.Mark is replaced by Object in original post. On Jul 26, 4:00�pm, Greg Rudzinskiwrote: > An interesting adaptation of the distance by vertical angle short of the horizon formula: > > Dist.(NM)=(.567 x Height of Nav.Mark in ft.)/Observed Minutes of Arc > > To get distance by vertical angle beyond the horizon - correct the height of the navigation mark (subtract ft.) using formula: > > ((Approx.Dist.Nav.Mark/1.144)-Root Height of Eye)Squared > > Now try this out using a slide rule. > > Greg --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---