The Back Azimuth measures the absolute (compass) angle to the previous station. It is common to measure this angle in decimal degrees (0-360). However, it is also possible to enter this angle in other formats such as degrees, minutes and seconds. See Edit - Traverse Entry Options for more information on angle formats.
Note: this angle is measured in the same sense as the Foreshot e.g. if the Foreshot was 0 the Backshot should be approximately 180. See also Foreshot/Backshot dialog.
The Fore Azimuth and Back Azimuth are averaged to calculate the coordinate of the next station.
It is also possible to change absolute angles to turning angles to minimize the influence of local magnetic attractors. See Magnetic Anomalies for more information.