We report some new spectroscopic data on high-lying excited autoionizing levels and Rydberg progressions of atomic uranium. Accurate determinations of the first (f3s2 4I9/2) and the second (f3ds6L11/2) ionization limits, I1 and I2, have been achieved; the values are 49958.4 ± 0.5 and 50247.3 ± 0.5 cm−1, respectively. We have been able to observe the series f3s2np and f3s2nf for n values between 38 and 70, as well as the autoionizing series f3dsnp, f3dsns, and f3dsnd located between these two ionization limits.
