def seconds_to_timestamp(seconds):
    """
    timestamp hh:mm:ss derived from seconds since midnight
    """
    h = int(seconds / 60 ** 2)
    seconds = seconds - 60 ** 2 * h
    m = int(seconds / 60)
    seconds = seconds - 60 * m
    s = int(seconds)
    timestamp = '{0:2d}:{1:2d}:{2:2d}'.format(h, m, s)
    timestamp = timestamp.replace(' ', '0')
    return timestamp
