ROSAT PSPC field in the Alpha Per cluster containing its eponymous member, α Per. The left panel illustrates inner 1° of the image; α Per is source 1, 19′ off-axis. Gray contours represent the exposure map: higher sensitivity in the center; but diminished in the outskirts due to vignetting and shadows of the window support ribs blurred by "dithering." The right-hand panels depict coincidences between USNO-A2 optical objects (large red X) and X-ray sources (small blue X marks centroid of pattern). The derived astrometry of the PSPC frame is excellent (1σ accuracy better than 1''), given the numerous A2 matches. Note, however, that the optical position of α Per is slightly offset from the X-ray centroid. Mismatch might indicate a coincidental source near the bright star.