This table contains compiled data on Galactic planetary nebulae based on absolute optical spectroscopy. It is primarily derived from spectroscopic observations, supplemented by selected values from other sources. Based on these data, physical characteristics of the nebulae were calculated, including sizes, densities, temperatures, and parameters of the central stars.

For each object, the table includes its identifiers, excitation class, and interstellar extinction at H_beta. Morphological and distance-related properties are given through angular diameters (Diam_arcsec), physical sizes (Diam_pc), and distances (D_kpc). Electron densities are derived from [SII] 6717/6731 ratios.

Effective temperatures of central stars were estimated using both Zanstra method (T_HI) and empirical calibrations based on [OIII] lines (T0_[OIII], T1_[OIII]), corresponding to the beginning and end of the observational interval. These values are expressed in 10**4 K units.

The columns delta_t_obs_year and delta_t_model_year provide the duration of available observations and the time span over which the photoionization model reproduces observed changes. Model number and progenitor mass were taken from M. Bertolami (2016, A&A 588, A25; doi:10.1051/0004-6361/201526577). The age of the nebula is estimated from the same model set.

Absolute fluxes of emission lines are provided for H_beta HeII 4685, [OIII] 5007, H_alpha, [NII] 6583, HeI 6678, [SII] 6717/6731, HeI 7065, [ArIII] 7136, and [OI] 7324. Each flux entry includes a measurement uncertainty; all fluxes are in erg cm**-2 s**-1. A separate column indicates the power-of-ten exponent to be applied where applicable.

The final column lists reference codes for the sources of spectroscopic data, primarily indicating the source of absolute flux calibration for H_beta and associated lines.

The table is provided in a machine-readable format. For each quantity, values are organized into separate columns: value, uncertainty, and, where applicable, a power-of-ten exponent (e.g., value * 10**power). This structure ensures precise numerical handling and interoperability with Virtual Observatory tools and pipelines.

• Emission nebulae
• Planetary nebulae
• Spectroscopy
• Optical observation