The left panels are our measurements at 0, right panel at 90, and date increases from top to bottom. Figure 3 is H-alpha. Figure 4 is H-beta. Figure 7 is He I 4471 and He II 4542. Figure 8 is He II 4686.
Several results are immediately obvious.
Though sometimes the peaks are of equal strength, in most lines one peak is stronger. The dominant peak changes in different lines, at different position angles, and with time. We now investigate these changes in more detail. Again, the values were consistent from observation to observation. The velocity of expansion did not vary, nor did the velocity width of the shell change.