TMSS-528: When observing beamforming is done on the intersection of all...

TMSS-528: When observing beamforming is done on the intersection of all stations in this list and the used stations in the observation. So, specifyng all possible stations here means that all observation-stations are used. Specifying a small subset here means that only the observing-stations in this small list are used

SAS/TMSS/backend/src/tmss/tmssapp/schemas/task_template-beamforming_observation-1.json

@@ -237,10 +237,10 @@
               "enabled"]
           },
           "stations": {
-            "description": "Stations to beam form. Empty list = beam form all stations in the observation.",
-            "allOf": [{"$ref": "http://tmss.lofar.org/api/schemas/commonschematemplate/stations/1/#/definitions/station_list"}],
-            "default": [],
-            "minItems": 0
+            "description": "When observing beamforming is done on the intersection of all stations in this list and the used stations in the observation. So, specifyng all possible stations here means that all observation-stations are used. Specifying a small subset here means that only the observing-stations in this small list are used.",
+            "$ref": "http://tmss.lofar.org/api/schemas/commonschematemplate/stations/1/#/definitions/station_list",
+            "default": ["CS001", "CS002", "CS003", "CS004", "CS005", "CS006", "CS007", "CS011", "CS013", "CS017", "CS021", "CS024", "CS026", "CS028", "CS030", "CS031", "CS032", "CS301", "CS302", "CS401", "CS501", "RS106", "RS205", "RS208", "RS210", "RS305", "RS306", "RS307", "RS310", "RS406", "RS407", "RS409", "RS503", "RS508", "RS509", "DE601", "DE602", "DE603", "DE604", "DE605", "DE609", "FR606", "SE607", "UK608", "PL610", "PL611", "PL612", "IE613", "LV614"],
+            "minItems": 1
           }
         },
         "required": [