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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Home made artificial horizon
From: Gary LaPook
Date: 2011 Oct 1, 17:30 -0700
From: Gary LaPook
Date: 2011 Oct 1, 17:30 -0700
The difficulty with using tables such as H.O. 229 when working out practice sight is that they are not convenient to work from your known position which you want to do so that you can compare your sextant observations with what should have been measured at your known position. You can, of course, plot the LOPs from the AP and then measure the distance from the LOP to your known position, the distance representing the error in your sextant work. Older tables such as H.O. 214 provided a way to interpolate for your exact longitude and latitude and I have uploaded these tables which can also be used with H.O. 229, see: http://fer3.com/arc/m2.aspx?i=105707 http://fer3.com/arc/m2.aspx?i=105708&y=200807 http://www.fer3.com/arc/m2.aspx?i=115531 Or, you can use a slide rule that also allows you to work from your known position and the instructions for making it are available here: https://sites.google.com/site/fredienoonan/other-flight-navigation-information/modern-bygrave-slide-rule It's really quite easy, your merely print out two scales and move them against each other. Or you can use the rule of cosines on a calculator. I posted a step by step key stroke list here: http://fer3.com/arc/m2.aspx?y=200806&i=105525 It solves the cosine formula this way: ((Cos LHA X Cos Dec X Cos Lat )+ ( Sin Lat X Sin Dec)) Arc sin = Hc (1/Cos Hc X Sin LHA X Cos Dec)Arc sin = Z gl --- On Thu, 9/29/11, Randall.F.Morrow@kp.org <Randall.F.Morrow@kp.org> wrote:
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