NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Slide Rule Azimuth
From: Greg Rudzinski
Date: 2009 May 29, 12:44 -0700
From: Greg Rudzinski
Date: 2009 May 29, 12:44 -0700
An interesting azimuth formula presented by H.H. Shufeldt in his book SLIDE RULE FOR THE MARINER (pg. 77) Azimuth = INV SIN of COS declination Sin meridian angle divided by COS altitude ( Ho or Hc ) Shufeldt states that Ho or Hc altitudes can be used. The INV SIN result is added or subtracted from 360 or 180 degrees depending on orientation. An alternate arrangement for the formula: Azimuth = INV SIN of SEC altitude COS declination SIN meridian angle I like the expediency of this formula but it does suffer from inadequate slide rule scale resolution for azimuths approaching 270 or 90 degrees. A trick to by-pass this problem for a sun observation would be to directly observe a corrected bearing of the sun (which should be low in the sky) for use as an altitude intercept azimuth. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
