def correct_time_dilation(df):
    """Short summary.

    Parameters
    ----------
    df  : Pandas DataFrame
        The dataframe containing the photometry of all events.

    Returns
    -------
    Pandas DataFrame
        The same dataframe with undilated times.

    """

    for idx, row in df.iterrows():
        row['T'] = row['T'] / (1.+row.ZCMB)
    return df