Revert "Only grab server/API URL during initialization."

This reverts commit da856a5.

Author: mkelley

astroquery/jplhorizons/core.py

@@ -104,8 +104,6 @@ def __init__(self, id=None, location=None, epochs=None,
         self.id = id
         self.location = location
 
-        self.server_url = conf.horizons_server
-
         # check for epochs to be dict or list-like; else: make it a list
         if epochs is not None:
             if isinstance(epochs, (list, tuple, ndarray)):
@@ -513,6 +511,8 @@ def ephemerides_async(self, airmass_lessthan=99,
 
         """
 
+        URL = conf.horizons_server
+
         # check for required information
         if self.id is None:
             raise ValueError("'id' parameter not set. Query aborted.")
@@ -611,7 +611,7 @@ def ephemerides_async(self, airmass_lessthan=99,
             return request_payload
 
         # query and parse
-        response = self._request('GET', self.server_url, params=request_payload,
+        response = self._request('GET', URL, params=request_payload,
                                  timeout=self.TIMEOUT, cache=cache)
         self.uri = response.url
 
@@ -743,6 +743,8 @@ def elements_async(self, get_query_payload=False,
 
         """
 
+        URL = conf.horizons_server
+
         # check for required information
         if self.id is None:
             raise ValueError("'id' parameter not set. Query aborted.")
@@ -819,7 +821,7 @@ def elements_async(self, get_query_payload=False,
             return request_payload
 
         # query and parse
-        response = self._request('GET', self.server_url, params=request_payload,
+        response = self._request('GET', URL, params=request_payload,
                                  timeout=self.TIMEOUT, cache=cache)
         self.uri = response.url
 
@@ -973,6 +975,8 @@ def vectors_async(self, get_query_payload=False,
 
         """
 
+        URL = conf.horizons_server
+
         # check for required information
         if self.id is None:
             raise ValueError("'id' parameter not set. Query aborted.")
@@ -1055,7 +1059,7 @@ def vectors_async(self, get_query_payload=False,
             return request_payload
 
         # query and parse
-        response = self._request('GET', self.server_url, params=request_payload,
+        response = self._request('GET', URL, params=request_payload,
                                  timeout=self.TIMEOUT, cache=cache)
         self.uri = response.url