NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Navigation exercise
From: George Huxtable
Date: 2008 May 30, 14:45 +0100
From: George Huxtable
Date: 2008 May 30, 14:45 +0100
Mike Burkes wrote- "speaking of early Mixter I have a 15th printing circa Oct, 1943 and my question is regarding the dip table on the inside cover, part of Table A . If you have reference to it I noticed with much confusion that most of the correction is positive. I tried to find the explanation but I seem to be missing something." Yes, Mike is missing something. Table A is not a dip table. Table C is the dip table, given for different heights of eye, and it is always negative. Table A is the correction for other-than-dip, that is, for refraction (which is why it's tabulated for different altitudes) and for semidiameter (which is why there are different columns for Sun and for stars). Taking any parallax to be negligible, all you have to do is to add A and C. And B, which reflects seasonal changes in Sun diameter, if you're being particularly fussy. It's all explained on page 223 (para. 1907) in my 1943 edition. George. contact George Huxtable at george@huxtable.u-net.com or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
