Pentax 13.5 Atmospheric refraction and earth curvature correction

73
C°
Unit:mm
[Error table:With mmHg (15°C,760mmHg as standard)]
900 800 760 700 600 500 400
45 2.0 -1.3 -2.6 -4.6 -8.0 -11.3 -14.6
35 3.0 -0.4 -1.8 -3.9 -7.3 -10.8 -14.2
25 4.0 0.5 -0.9 -3.1 -6.6 -10.2 -13.7
15 5.2 1.5 0.0 -2.2 -5.9 -9.6 -13.3
5 6.3 2.5 1.0 -1.3 -5.1 -8.9 -12.7
-5 7.6 3.7 2.1 -0.3 -4.2 -8.2 -12.2
-15 9.0 4.9 3.2 0.8 -3.3 -7.4 -11.5
13.5 Atmospheric refraction and earth curvature correction
• Atmospheric refraction and earth curvature correction refers to correcting both the
bending of the light beam caused by atmospheric refraction and the effect on the
height differential and horizontal distance caused by the earth curvature.
• Correction called “atmospheric refraction and earth curvature correction”is initiated to
correct error when the slope distance and vertical angle are caused to determine the
horizontal distance and the height differential,with this instrument, the following
formula is used to correct these factors.