A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2019 May 15, 13:26 -0700
I have been asked by Jean Villemagne and Hewitt Schlereth to post Jean's new "abridgement" of HO 229. The attached documents explain the purpose and other details.
Please note: I have no connection to this project. I have not reviewed the files. Please direct questions (in reply to this message) to Jean Villemagne. I understand he will be following along.
From the Introduction:
This HO 229 abridgment with its two Complement Booklets and Polar Latitudes extensions is an attempt to drastically reduce HO 229's massive classic edition to a suitable size for small boat navigation life. These four new booklets are a single set designed to be easily handled and stored on an ocean-voyaging sailboat.
Hewitt Schlereth was the first who presented such an attempt in his 1983 work "Sight Reduction Tables for Small Boat Navigation." Although limited in declination range, its premise of limiting LHAs and Latitudes to even numbers was the inspiration for this project and should receive full credit for such an innovative solution. The abridged HO 229 table found here is a digital version of the public domain HO 229 tables used in his 1983 work.
Like his, my HO 229 Abridgment Booklet contains solutions for latitudes from 0 to 58 degrees, which covers the huge band of the earth that starts just south of Greenland and goes below Cape Horn. This booklet also covers only those celestial bodies with declination equal to or less than 29 degrees. This limits the use of navigational stars to 30 rather than all of the traditional 57, but includes the sun, the moon, Mars, Venus, Jupiter and Saturn.
[see files below for more...]