  We summarize JWST's measured telescope performance across science Cycle 1.
The stability of segments alignments is typically better than 10 nanometers RMS
between measurements every two days, leading to highly stable point spread
functions. The frequency of segment "tilt events" decreased significantly, and
larger tilt events ceased entirely, as structures gradually equilibrated after
cooldown. Mirror corrections every 1-2 months now maintain the telescope below
70 nm RMS wavefront error. Observed micrometeoroid impacts during cycle 1 had
negligible effect on science performance, consistent with preflight
predictions. As JWST begins Cycle 2, its optical performance and stability are
equal to, and in some ways better than, the performance reported at the end of
commissioning.
