fix: use the real column names rather than the IDs that astropy generates

CHANGES.rst

@@ -163,6 +163,9 @@ vizier
 
 - Fixed search by UCD -- they were ignored. [#3147]
 
+- Fixed column names -- some characters were replaced by ``_`` instead of keeping
+  the original name [#3153]
+
 vsa
 ^^^
 

astroquery/vizier/core.py

@@ -844,7 +844,7 @@ def _parse_vizier_votable(data, *, verbose=False, invalid='warn',
                     name = t.name
                 if name not in table_dict.keys():
                     table_dict[name] = []
-                table_dict[name] += [t.to_table()]
+                table_dict[name] += [t.to_table(use_names_over_ids=True)]
         for name in table_dict.keys():
             if len(table_dict[name]) > 1:
                 table_dict[name] = tbl.vstack(table_dict[name])

astroquery/vizier/tests/test_vizier_remote.py

@@ -72,6 +72,13 @@ def test_vizier_column_restriction(self):
         for table in result:
             assert 'Bmag' not in table.columns
 
+    def test_vizier_column_exotic_characters(self):
+        # column names can contain any ascii characters. This checks that they are not
+        # replaced by underscores, see issue #3124
+        result = Vizier(columns=["r'mag"],
+                        row_limit=1).get_catalogs(catalog="II/336/apass9")[0]
+        assert "r'mag" in result.colnames
+
     @pytest.mark.parametrize('all', ('all', '*'))
     def test_alls_withaddition(self, all):
         # Check that all the expected columns are there plus the _r

docs/vizier/vizier.rst

@@ -14,6 +14,13 @@ radius. Similar to the VizieR web interface, the queries may be further
 constrained by specifying a choice of catalogs, keywords as well as filters on
 individual columns before retrieving the results.
 
+.. note::
+    In earlier versions of astroquery (<0.4.8), columns with special characters like 
+    ``r'mag`` were renamed into ``r_mag`` and columns starting with a number like
+    ``2MASS`` were prepended with an underscore ``_2MASS``.
+    In astroquery >=0.4.8, the column names are the same in VizieR's webpages and in
+    the tables received (for the two examples: you'll see ``r'mag`` and ``2MASS``).
+
 Table Discover
 --------------
 
@@ -182,7 +189,7 @@ To access an individual table from the `~astroquery.utils.TableList` object:
 
     >>> interesting_table = result['IX/8/catalog']
     >>> print(interesting_table)
-      _2XRS     RAB1950      DEB1950    Xname ... Int   _RA.icrs     _DE.icrs  
+       2XRS     RAB1950      DEB1950    Xname ... Int   _RA.icrs     _DE.icrs   
                                               ... uJy                          
     --------- ------------ ------------ ----- ... --- ------------ ------------
     06429-166 06 42 54.000 -16 39 00.00       ...  -- 06 45 08.088 -16 42 11.29
@@ -347,7 +354,7 @@ the ``"+"`` in front of ``"_r"``.
     >>> vizier = Vizier(columns=["*", "+_r"], catalog="II/246")
     >>> result = vizier.query_region("HD 226868", radius="20s")
     >>> print(result[0])
-      _r    RAJ2000    DEJ2000        _2MASS       Jmag  ... Bflg Cflg Xflg Aflg
+      _r    RAJ2000    DEJ2000        2MASS        Jmag  ... Bflg Cflg Xflg Aflg
               deg        deg                       mag   ...                    
     ------ ---------- ---------- ---------------- ------ ... ---- ---- ---- ----
      0.134 299.590280  35.201599 19582166+3512057  6.872 ...  111  000    0    0
@@ -395,8 +402,8 @@ index to the ``agn`` table (not the 0-based python convention).
 
     >>> guide = Vizier(catalog="II/246", column_filters={"Kmag":"<9.0"}).query_region(agn, radius="30s", inner_radius="2s")[0]
     >>> guide.pprint()
-     _q  RAJ2000    DEJ2000        _2MASS       Jmag  ... Rflg Bflg Cflg Xflg Aflg
-           deg        deg                       mag   ...
+     _q  RAJ2000    DEJ2000        2MASS        Jmag  ... Rflg Bflg Cflg Xflg Aflg
+           deg        deg                       mag   ...                         
     --- ---------- ---------- ---------------- ------ ... ---- ---- ---- ---- ----
       1  10.686015  41.269630 00424464+4116106  9.399 ...   20   20  0c0    2    0
       1  10.685657  41.269550 00424455+4116103 10.773 ...  200  200  c00    2    0