Optical variability of the supersoft source RX~J0019.8+2156

We present a 100 yr optical lightcurve of the recently discovered supersoft X-ray source RX~J0019.8+2156 as deduced from photographic plates of Harvard and Sonneberg Observatory. Apart from the periodic orbital variations two different timescales of optical variability are discovered. The timescales and amplitudes of this variability are discussed in the framework of the steady nuclear burning model.