the A0 standards. The spectra were wavelength-calibrated using observations of an Argon reference lamp. The wavelength values used for lines greater than 1.1  are from Rao et al. (1966); for lines less than 1.1 , the wavelengths were taken from Wiese, Smith, & Miles (1969) and corrected to vacuum wavelengths. The average 1$\sigma$ uncertainty in the measured wavelengths of the lines is about 5 Å.

Infrared photometric standard stars were observed in the same way as the PNe and used to flux calibrate the spectra. Absolute calibration is difficult with these spectra because not all of the flux from the star enters the narrow slit during a single integration, and the amount differs for each integration depending on how well the star is centered on the slit (the seeing at 2  during typical observations was 05 – 10). The amount of light lost was estimated by the following method: the full width at half maximum (FWHM) brightness of the standard star was measured along the spatial direction of the slit, in the spectrum with maximum flux for that star. It was then assumed that the point spread function (PSF) is well represented by a two-dimensional Gaussian distribution with the measured 