A nano-stabilization technique is developed for the observation of Ramsey fringes in low repetition rate Rydberg electron wavepacket experiments. The stabilization system consists of a CCD array monitoring optical interference fringes of a reference CW laser beam passing through a Michelson interferometer, a PID feedback circuit generating an error voltage, and a piezo responding to the error voltage to compensate for geometric fluctuations in the interferometer of nm with a response time ms. The proficiency of the stabilized interferometer is demonstrated in an experiment to observe Ramsey fringes in autoionizing Rydberg states of Xe.