a two-step optical excitation, starting from a metastable level, has been used to populate rydberg levels in a krypton atomic beam. the metastable level is populated in the beam 'oven' by means of a hf discharge and the rydberg atoms are detected by the field ionisation method. using two n/sub 2/-pumped pulsed dye lasers, the rydberg spectra have been obtained with a resolution better than 0.1 cm/sup -1/. the fine structure of the (4p/sup 5/)/sup 2/p/sub 3/2/ nd sub-configuration has been resolved and the wavenumber of the corresponding transition has been measured with an absolute accuracy of 0.03 cm/sup -1/. the energies of 187 levels (n 24) belonging to seven different series, 4p/sup 5/nd and 4p/sup 5/ns, have been determined: 153 of these levels (j=2 and j=3) had never been observed before. the value of the first ionisation limit has been redetermined to be i=(112914.47 +or- 0.03) cm/sup -1/. the critical ionisation fields and the lifetimes of some of the rydberg levels have also been measured. significant deviations from the hydrogenic model laws been found in both cases