Left: derived map for τ(3889) using the He I λ7065 and λ6678 emission lines and a ratio of expansion velocity to thermal velocity for the nebula of 3. Centre: map for singly ionised helium as determined using the extinction corrected flux map for the singlet line at λ6678 and the N_e and T_e simultaneously derived with the [S II] and [N II] lines. Right: map for doubly ionised helium as determined using the extinction corrected flux map for the line at λ5411, the median N_e as determined from the [Cl III] doublet, and the median T_e as determined from the [S III] lines.