observations revealed a complex profile, not obviously related to the pulse profiles previously recorded at radio, optical, and gamma-ray wavelengths. The observed pulsed fraction of $4.4 \pm
1.1\%$ was diluted by the inability of the PSPC to resolve the pulsar from the surrounding nebula; using the approximate model described above, the authors estimated a soft X-ray pulsed fraction of 11%. Seward et al. (2000) constructed a higher signal-to-noise profile by combining six ROSAT HRC observations; they estimated a pulsed fraction of 12% divided between a broad component (8%) and two narrow peaks (4%). Strickman et al. (1999) and Gurkan et al. (2000) have recently derived 2-30 keV profiles based on RXTE observations of Vela. Strickman et al. illustrate a trend in which the component separation of the main pulse increases with energy.

We have determined the X-ray pulse period for our two observations and compared them to the radio ephemeris (Don Backer, personal communication). We began by constructing a periodigram around a narrow range of periods centered on the expected period $\pm 0.1$ ms, sampled in increments of $0.05 \times P^2/T$, where $T$ is the observation duration, and $P$ is the test period. For each trial period, we folded photons 