To Calculate Directions With Sun Shots and Star Shots
Sun shots calculate a direction using solar observations by the hour angle method and use a multiple foresight method. Star Shots calculate a direction from Polaris or a star observation by the hour angle method and use a single foresight method.
Click
Analyze tabGround Data panelSurvey drop-downAstronomic DirectionFind.
In the
Calculation Type list, select either
Sun Shot Calculation, or
Star Shot Calculation.
Under
Observation Station Data, specify the following:
Note: Enter zero (0) if you are sighting either the center or both the trailing and leading edges of the sun. The left edge is always the leading edge at latitudes greater than 23.5 degrees north and greater than 23.5 degrees south. If only the left edge is being sighted (left when facing the sun), then the semi- diameter is positive; likewise, the semi-diameter is negative when only the right edge is sighted.
Click
to create an observation set. Enter
Direct and
Reverse observations for the
Backsight Observation,
Sun Observation or
Star Observation and the
Stop Time.
The observations determine the true astronomic direction from the first setup to the backsight. When you enter the stop time for an observation, the observed and average directions are calculated automatically.