# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

**Re: Mathematical Advancement of a celestial COP**

**From:**Russell Sher

**Date:**1998 Oct 26, 01:13 EST

I have some formulas as well from Navigation by Pocket Computer - in which the author (Mike Harris) discusses advancing LOPs by formula to solve for the position - (You mention COP; should that be LOP?) I'll bring the formulas in - just give me a few days...will be away. Russell > -----Original Message----- > From: John Brenneise [SMTP:jbrennei@XXX.XXX] > Sent: Friday, October 23, 1998 11:39 PM > To: 'navigation@XXX.XXX' > Subject: [Nml] Mathematical Advancement of a celestial COP > > I have some code that takes the place of H.O. 229 or H.O. 249 by > numerically solving the following: > > sin(h1) = cos(phi)cos(beta1)cos(theta-alpha1) + sin(phi)sin(beta1) > sin(h2) = cos(phi)cos(beta2)cos(theta-alpha2) + sin(phi)sin(beta2) > > where h1 is the corrected angle of elevation for a circle centered > at latitude beta1, GHA alpha1 and h2 is the corrected angle of > elevation for a circle centered at latitude beta2, GHA alpha2. > > > The question concerns running fixes. > > The COP from the earlier of the two observations must be advanced > along the DR course. In terms of the center of the circle, I propose > that (beta1,alpha1) must be moved along the loxodrome defined by > the course angle for a distance to be scaled by a factor related to the > difference between the course angle and the azimuth angle to the > celestial object. > > > So, what I need is a good reference and or insight on Spherical > Trigonometry to test my assumption. > > Any ideas? > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-= > =-= TO UNSUBSCRIBE, send this message to majordomo@XXX.XXX: > =-= > =-= unsubscribe navigation > =-= > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-= =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-= =-= TO UNSUBSCRIBE, send this message to majordomo@XXX.XXX: =-= =-= unsubscribe navigation =-= =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=