def get_pmin(survey):
    """
   A function to get the pmin value for the aplpy chart, as a function of the instrument.
   
   Args:
      fc_params: the parameters of the finding charts (a dictionary)
   Returns:
      pmin (float): the pmin value
   """
    if survey in ['2MASS-J', '2MASS-H', '2MASS-K']:
        return 30.0
    else:
        return 10.0
