Date時間からRobertson時間への変換
20:48:30
-7
13:48:30
+2
+2
+0
+0
+0
+0
+0
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-2
-2
-2
-3
-3
-3
-3
-4
-4
-5
-6
-6
-6
-6
-6
-6
-6
-7
-7
-7
-7
-8
-8
-8
-8
-8
-8
-8
-9
-9
-12
-12
-12
-12