  We have observed the Crab Pulsar in the optical with S-Cam, an instrument
based on Superconducting Tunneling Junctions (STJs) with $\mu$s time
resolution. Our aim was to study the delay between the radio and optical pulse.
The Crab Pulsar was observed three times over a time span of almost 7 years, on
two different locations, using three different versions of the instrument, and
using two different GPS units. We consistently find that the optical peak leads
the radio peak by 49$\pm$90, 254$\pm$170, and 291$\pm$100 $\mu$s. On assumption
of a constant optical lead, the weighted-average value is $\sim$170 $\mu$s, or
when rejecting (based on a perhaps questionable radio ephemeris) the first
measurement, 273$\pm$100 $\mu$s.
