Time series of observations at Solar Orbiter I. The top four panels show EPT foil observations from different telescopes, as indicated in the upper-right corner of each panel. Pitch angle is also shown as a dot-dashed line; its scale is shown on the right-hand axis. The next four panels from the top show observations in the EPT magnet channel by telescope, as indicated in the upper-left corner of each panel, as well as pitch angle, as in the previous panels. The slanted dotted and dashed curves show the earliest ion onsets as seen by the Sun and north telescopes and as determined in Sect. 3. It is obvious that the north telescope sees the highest flux, which in itself is a clear indication of an anisotropic flow. The two bottom panels show counts of helium isotopes as measured by SIS between 0.5 and 2.0 MeV nuc⁻¹, with the central pitch angles shown as a dash-dotted gray line. The vertical dotted lines and annotations (a)–(f) are discussed in Sect. 4, as are the thick vertical dashed lines. They mark the onset and end of a time period with very low Alfvénic Mach number in which this event is embedded.