ARTOA4-UserManual/Offsets.md

@@ -42,7 +42,7 @@ taken from "-empric_offset" in soso file. Gives Empric Offset entered manually b
 
 This window gives an overview of known offsets and drifts of the assigned sound sources, based on either physical measurements at sea (Start and End Offsets and Drift), user experience (Empirical (Start-)Offset and Empirical Drift), or Matrix Inversion (Optimum Offset and Drift).
 
-Any of these values can be assigned to "Applied", which will be used in calculating float positions.  Unknonw Values (NaNs) default to 0, or can be populated with Optimal Values (from Matrix Inversion)
+Any of these values can be assigned to "Applied", which will be used in calculating float positions. Unknonw Values (NaNs) default to 0, or can be populated with Optimal Values (from Matrix Inversion)
 
 **column Emprical Drift (non editable)**
 
@@ -60,6 +60,8 @@ calculated by ARTOA "Calculate offsets" by inverting the eqation:
 
 value is set by either copying "Measured", "Emprical" or " Optimum" to "Applied" (see window "Offset controls", lower right) or by manually typing into this field.
 
+**_!_** _column Applied Offsets must be populated to be able to execute "Calculate Offsets".  The value is used to calculate the Satellite-Fix to Sound Source hypothetical travel time from the respective distance **!**_
+
 **column Applied Drift (editable !)**
 
 value is set by either copying "Measured", "Emprical" or " Optimum" to "Applied" (see window "Offset controls", lower right) or by manually typing into this field.
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