Positions of the PSP and Solar Orbiter spacecraft around the studied line-up. Panel a shows the positions of PSP (blue) and Solar Orbiter (orange) on April 29, 2021 (dots) and the trajectories (lines) within the ecliptic plane between April 24, 2021 and May 4, 2021 as seen in an inertial reference frame centered on the Sun. The radial line from the Sun that passes through PSP and Solar Orbiter for the spacecraft coalignment time t₀ is indicated by the dashed black line. Panels b and c show the longitude ϕ, and latitude θ of PSP (blue) and Solar Orbiter (orange), respectively, as functions of time for the same interval as in panel a. We indicate the spacecraft coalignment time t₀ = 00 : 45 UT on April 29, 2021 as a vertical dashed black line in both panels.