2001A&A...374..584B

We present new, high signal-to-noise spectroscopy of the Crab Pulsar in the range λλ5000-7000Å. The observations were carried out with the 6-meter telescope of the SAO with the spectrograph SP-124 with a resolution of 2 Å. After reduction of the Crab Nebula emission, the dereddened pulsar spectrum can be fitted by a power law with α=-0.15±0.15. There are no lines (emission and absorption) with a relative intensity (depth) of more than 2% (with a confidential probability of 99%). At this level we did not find absorption at λ6000Å, possibly of ion-cyclotron origin, as detected by Nasuti et al. (1996A&A...314..849N). This detail can be variable as a consequence of the variability of the ion ejection from the neutron star (NS) surface. We suggest a possible relationship between ejection intensity and inhomogeneity of the NS surface connected with pulsar glitches.