The absorption spectrum of N2O was photographed at a resolution limit of 0.0008 nm, from 134 nm to the ionization potential, at 96 nm. Ab initio calculations of the electronic energies and transition moments were carried out including spin-orbit interaction in the frozen core approximation. Rydberg states considered are those corresponding to l=0-5 and principal effective quantum number n* up to 5.5 (6s and 6p, 5d, 5f, and 5g terms), and three ionic cores (X) over tilde (2)Pi, (A) over tilde (2)Sigma (+), and (B) over tilde (2)Pi. It is shown that in N2O, like in CO2 or CS2, np pi terms are at lower energy than np sigma. The strongest band of the low-resolution absorption spectrum, at about 77 900 cm-1 is too broad and diffuse to be observed here. It is assigned to the origin of the ...2 pi (3)3p pi (1)Sigma (+)-(X) over tilde (1)Sigma (+) transition. The most prominent bands in the 84 000-104 000 cm(-1) interval are the electronic origins of the ...2 pi (3)np sigma transitions, observed from n=3 to n=19. Previous low-resolution absorption and resonance enhanced multiphoton ionization spectra are reviewed in the light of the present results.