def dmsStrFieldsPrec(dmsStr):
    """Return the following information about a sexagesimal string:
    - the number of colon-separated fields
    - the precision of the right-most field
    """
    if dmsStr == "":
        return (0, 0)

    precArry = dmsStr.split(".")
    if len(precArry) > 1:
        precision = len(precArry[1])
    else:
        precision = 0
    nFields = dmsStr.count(":") + 1
    return (nFields, precision)