Pentax R-315(N) - Manual (Page 82)

13-2 Atmospheric Correction
The speed at which light travels through the air varies depending on the
temperature and atmospheric pressure. The R-100 series is designed to measure
distances at the speed of light in order to measure accurately, Atmospheric
Correction needs to be used. The instrument is designed to correct for weather
conditions automatically if the temperature and pressure are input. Correction is
then carried out based on the following formula.
Calculation formula
K=(276.26713 –
78.565271· P
)
×
10 - 6
273.14941 + t
K: Atmospheric Correction Constant
P: Atmospheric pressure (hPa)
t: Temperature(°C)
Distance after Atmospheric Correction D = Ds (1+K)
Ds: Measured distance when no Atmospheric Correction is used.
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13 APPENDIX
PENTAX R-300 (p65-88) 10/30/02 11:11 AM Page 80