Example spectra of PNe, cHII, SNR, and an emission line star in units of erg cm⁻² s⁻¹ per 1.25 Å spectral bin in the Hβ-[O III] and Hα regions, plotted against wavelength in Å. The spectra are offset by some arbitrary bias to better show the noise level. Panels a–d: PNe over the full range from the brightest to the faintest objects. The very faint object a03 with m₅₀₀₇ = 28.88 is an uncertain PN candidate, given that the [SII] line ratio, although critically dependent on diffuse nebular background subtraction, could also be indicative of a cHII, or even a SNR. Panels e, f: a bright and a faint cHII, and panels g, h: a bright and a faint SNR. Panel i: an emission line star is shown, presenting an Hα emission line width of 6.6 Å.