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From: Henry Halboth
Date: 2015 Sep 14, 00:14 -0400
Jacques,
Although used prior thereto, the intercept method became really popular in the USA during WWI and immediately thereafter with the introduction of a number of short tabular methods. Amongs the tabular methods then introduced were “Simultaneous Altitudes & Azimuths of Celestial Bodies”(HO 201), “Sumner Line of Position of Celestial Bodies” (HO 203 & 204), and “Altitude & AzimuthTables” by Radler de Aquino of the Brazilian Navy (published as HO 200) – all of which can beownloaded from the internet for free.
Please note that HO 203 & 204 were also basically intercept methods in that based on entry with whole degrees of assumed Latitude and Altitude, plus an interpolation for Decination only, a Longitude & Azimuth are obtained – thereafter a LOP is plotted at right angles to the Azimuth at a distance equal to the difference between th\e observed and assumed altitudes from the position described by the assumed Latitude and the calculated Longitude, away or towards as the case may be.
Henry
Hello,
I would like to get an information about the use of "intercept method" (or St Hilaire method) in USA.
It seems to me that this method had been used in France before 1900 (it is logical, because St Hilaire was french !). But when this method is become usual in USA ?
The reason of my question is the fact that the HO 203 tables was published in 1923, and these tables was use only for the calculation of hour angle and azimuth ... for Sumner's method ! But I know that tables as HO 208 or HO 211 was already used for intercept method.
Thank you in advance.
Best Regards
Jacques
