sun_position: rename Ecliptic to Diurnal

The name "Ecliptic" for the Sun trajectory visualization was wrong. I
renamed it to "Diurnal" because it actually visualizes the apparent
trajectory of the Sun in one single day.

sun_position/properties.py

@@ -157,17 +157,17 @@ class SunPosProperties(PropertyGroup):
 
     object_collection: PointerProperty(
         type=bpy.types.Collection,
-        description="Collection of objects used for analemma",
+        description="Collection of objects used to visualize sun motion",
         update=sun_update)
 
     object_collection_type: EnumProperty(
         name="Display type",
-        description="Show object group on ecliptic or as analemma",
+        description="Show object group as sun motion",
         items=(
-            ('ECLIPTIC', "On the Ecliptic", ""),
-            ('ANALEMMA', "As Analemma", ""),
+            ('ANALEMMA', "Analemma", ""),
+            ('DIURNAL', "Diurnal", ""),
         ),
-        default='ECLIPTIC',
+        default='ANALEMMA',
         update=sun_update)
 
     use_sky_texture: BoolProperty(
@@ -214,7 +214,7 @@ class SunPosProperties(PropertyGroup):
 
     time_spread: FloatProperty(
         name="Time Spread",
-        description="Time period in which to spread object group",
+        description="Time period in which to spread object collection",
         precision=4,
         soft_min=1.0, soft_max=24.0, step=1.0, default=23.0,
         update=sun_update)

sun_position/sun_calc.py

@@ -178,8 +178,8 @@ def move_sun(context):
             and sun_props.object_collection):
         sun_objects = sun_props.object_collection.objects
         object_count = len(sun_objects)
-        if sun_props.object_collection_type == 'ECLIPTIC':
-            # Ecliptic
+        if sun_props.object_collection_type == 'DIURNAL':
+            # Diurnal motion
             if object_count > 1:
                 time_increment = sun_props.time_spread / (object_count - 1)
                 local_time = local_time + time_increment * (object_count - 1)

sun_position/ui_sun.py

@@ -185,7 +185,7 @@ class SUNPOS_PT_Panel(bpy.types.Panel):
                 col.prop(sp, "object_collection", text="")
                 if sp.object_collection:
                     col.prop(sp, "object_collection_type")
-                    if sp.object_collection_type == 'ECLIPTIC':
+                    if sp.object_collection_type == 'DIURNAL':
                         col.prop(sp, "time_spread")
                 col.separator()