Spectra Precision Survey Pro v4.5 Ranger Reference Manual - Manual (Page 166)

Survey Pro Reference Manual
R-158
Center
.
Note: Typically Left Edge of Center is selected when performing a sun
shot in the northern hemisphere and Center is selected for star shots.
Corrections : displays which corrections are
currently selected with an N for no, or a Y for
yes. When tapped, the Corrections dialog box
opens where the following corrections are
configured.
• ; Non-linear Declination Correction:
applies a correction for the linear
interpolation of the declination of the
sun for the time that an observation is
taken. This error is usually negligible,
but is removed when this is checked.
(This should only be checked when performing sun shots.)
• ; Correct to State Grid: when selected, the computed
azimuth is referenced from the local State Plane grid rather
than true north.
• ; Center Meridian / Zone Constant: these values are used
to adjust the computed azimuth to the local State Plane grid.
Appendix A lists these values for the United States.
GHA0: is the Greenwich Hour Angle of the sun at zero hour Universal
Time, Greenwich, on the current date.
Decl0: is the declination of the sun at zero hour on the current date.
GHA24: is the Greenwich Hour Angle of the sun at zero hour
Universal Time, Greenwich, on the following day (24-hours later).
Decl24: is the declination of the sun at zero hour on the following
day.
Solar Semi-Diameter: is the semi-diameter of the sun, expressed in
minutes and seconds.