DIY History | Transcribe | Scholarship at Iowa | Eccentricity of the Sextant by Frederic Furbish, 1893 | Eccentricity of the Sextant by Frederic Furbish, 1893, Page 121

Transcribe
Translate

Eccentricity of the Sextant by Frederic Furbish, 1893

Eccentricity of the Sextant by Frederic Furbish, 1893, Page 121

y = (1/3)y' and z = z'. Fulfilling the conditions we have x = 0.72474, y= - 0.00095 and z = + 0.00393.
   Now as a test of the value of the results we know that (x) reduced to gradual measure should very nearly equal the latitude of the observer. As (x) is expressed in circular measure we multiply it by 206264.8".
   By the original formulae tan theta = y/[z or 2?] and p/[i?] = (square root of (y[superscript][z or 2?][/superscript])) + (z[superscript][z or 2?][/superscript]) . By substituting the values found for y and z the unknown terms may easily be found.

[underlined]Formation of a correction table.[/underlined]
Knowing (y) and (z) a correction table can be formed giving the corrections to be applied to any angle measured with the sextant.
   In the development of this scheme for the determination of eccentricity this formula was deduced 
ε = 2(1 - cos(1/2)α')y + 2sin(1/2)α'z .

Saving...

y = (1/3)y' and z = z'. Fulfilling the conditions we have x = 0.72474, y= - 0.00095 and z = + 0.00393. Now as a test of the value of the results we know that (x) reduced to gradual measure should very nearly equal the latitude of the observer. As (x) is expressed in circular measure we multiply it by 206264.8". By the original formulae tan theta = y/[z or 2?] and p/[i?] = (square root of (y[superscript][z or 2?][/superscript])) + (z[superscript][z or 2?][/superscript]) . By substituting the values found for y and z the unknown terms may easily be found. [underlined]Formation of a correction table.[/underlined] Knowing (y) and (z) a correction table can be formed giving the corrections to be applied to any angle measured with the sextant. In the development of this scheme for the determination of eccentricity this formula was deduced ε = 2(1 - cos(1/2)α')y + 2sin(1/2)α'z .