Cain, Payton David
--- a/geomagio/residual/Calculation.py

+ 3

− 1
+++ b/geomagio/residual/Calculation.py

+ 3

− 1
 @@ -154,6 +154,8 @@ def calculate_D_absolute(
 @@ -154,6 +154,8 @@ def calculate_D_absolute(
    # for diagnostics
    if average_mark > 180:
        average_mark -= 90
+    if meridian > 180:
+        meridian -= 90
    return (
        Absolute(
 @@ -167,7 +169,7 @@ def calculate_D_absolute(
 @@ -167,7 +169,7 @@ def calculate_D_absolute(
        average_mark,
        south_meridian,
        mark_azimuth,
-        (meridian - average_mark),
+        (average_mark - meridian),
    )