In [1]: from astropy.table import Column
In [2]: from astropy.time import Time
In [3]: x = Column([1])
In [4]: Time(x, format='jd')
---------------------------------------------------------------------------
UnitsError                                Traceback (most recent call last)
<ipython-input-4-2acb9071d863> in <module>()
----> 1 Time(x, format='jd')

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/time/core.pyc in __init__(self, val, val2, format, scale, precision, in_subfmt, out_subfmt, location, copy)
    196                 self._set_scale(scale)
    197         else:
--> 198             self._init_from_vals(val, val2, format, scale, copy)
    199 
    200         if self.location:

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/time/core.pyc in _init_from_vals(self, val, val2, format, scale, copy)
    238 
    239         # Parse / convert input values into internal jd1, jd2 based on format
--> 240         self._time = self._get_time_fmt(val, val2, format, scale)
    241         self._format = self._time.name
    242 

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/time/core.pyc in _get_time_fmt(self, val, val2, format, scale)
    272             try:
    273                 return FormatClass(val, val2, scale, self.precision,
--> 274                                    self.in_subfmt, self.out_subfmt)
    275             except (ValueError, TypeError):
    276                 pass

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/time/core.pyc in __init__(self, val1, val2, scale, precision, in_subfmt, out_subfmt, from_jd)
   1296             self.jd2 = val2
   1297         else:
-> 1298             val1, val2 = self._check_val_type(val1, val2)
   1299             self.set_jds(val1, val2)
   1300 

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/time/core.pyc in _check_val_type(self, val1, val2)
   1323             # set possibly scaled unit any quantities should be converted to
   1324             _unit = u.CompositeUnit(getattr(self, 'unit', 1.), [u.day], [1])
-> 1325             val1 = val1.to(_unit).value
   1326             if val2 is not None:
   1327                 val2 = val2.to(_unit).value

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/table/column.pyc in to(self, unit, equivalencies, **kwargs)
    686             ``unit``.
    687         """
--> 688         return self.quantity.to(unit, equivalencies)
    689 
    690     def _copy_attrs(self, obj):

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/units/quantity.pyc in to(self, unit, equivalencies)
    603         unit = Unit(unit)
    604         new_val = np.asarray(
--> 605             self.unit.to(unit, self.value, equivalencies=equivalencies))
    606         return self._new_view(new_val, unit)
    607 

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/units/core.pyc in to(self, other, value, equivalencies)
    943             If units are inconsistent
    944         """
--> 945         return self._get_converter(other, equivalencies=equivalencies)(value)
    946 
    947     def in_units(self, other, value=1.0, equivalencies=[]):

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/units/core.pyc in _get_converter(self, other, equivalencies)
    847         except UnitsError:
    848             return self._apply_equivalences(
--> 849                 self, other, self._normalize_equivalencies(equivalencies))
    850         return lambda val: scale * _condition_arg(val)
    851 

/Users/aldcroft/anaconda/lib/python2.7/site-packages/astropy/units/core.pyc in _apply_equivalences(self, unit, other, equivalencies)
    838         raise UnitsError(
    839             "{0} and {1} are not convertible".format(
--> 840                 unit_str, other_str))
    841 
    842     def _get_converter(self, other, equivalencies=[]):

UnitsError: '' (dimensionless) and 'd' (time) are not convertible