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Abstract. Many studies recently have been performed to determine the velocity vector of the Sun, mainly using the latest data on proper motions and parallaxes given by the Hipparcos satellite. We wished to carry out a similar study using totally independent data: the numerous radial velocities (RV ) obtained with the Fehrenbach Objective Prisms (PO). This method allows the determination of the RV s of all the stars contained in the same field. These RV s are relative to each other but are linked to the IAU standard system by means of at least two calibration stars of known RV belonging to that field. These data are very homogeneous. We discuss the precision of the results, and deduce that this material is relevant for the computation of the movement of the Sun towards its Apex. We have performed several studies: 1) With 6965 stars of magnitudes ranging from 7 to 10, measured with the small PO of 15 cm diameter (PPO), with the whole sample and with the same sample split into blue and red stars. 2) With 11 978 stars of magnitudes ranging from 7 to 11, by adding to the previous sample the stars measured with the 60 cm diameter PO associated with the Schmidt telescope of Observatoire de Haute Provence (SPO). The results of both studies are consistent. 3) We have estimated the distance D of all stars studied and determined U , V , W and S for four groups of stars selected according to their distances: D < 100, 100 < D < 300, 300 < D < 500, D > 500 parsecs. We have determined the variation of U , V , W and S with respect to the distance of the stars. The variation of U , V and S is linear up to 500 parsecs. We can consider that W is constant.

Abstract. We publish 1879 radial velocities of stars distributed in 105 fields of 4• × 4• . We continue the PPO series (Fehrenbach et al. 1987;Duflot et al. 1990Duflot et al. , 1992Duflot et al. and 1995, using the Fehrenbach objective prism method.

Binding energies of high-L Rydberg levels of Th 3+ were measured using the resonant excitation Stark ionization spectroscopy technique. Analysis of the data with the long-range polarization model leads to determination of dipole and quadrupole polarizabilities of the free Th 4+ ion, α d = 7.61(6) a.u., α Q = 47(11) a.u.

The binding energies of high-L Rydberg levels of Pb + with n = 19 or 20 and 6 L 10 were measured with resonant excitation Stark ionization spectroscopy (RESIS). When combined with previous measurements of members of the nh Rydberg series in Pb + , and analyzed with the long-range polarization model, these determined the polarizability of the 5d 10 6s 2 ground state of Pb 2+ to be α d = 13.62(8) a.u. This value is substantially larger than the estimate published recently based on the measured lifetime of the 6s6p 1 P 1 resonance level of Pb 2+ , 7.9(6) a.u. The difference is mostly due to the polarizability of Pb 4+ , the 5d 10 core of the Pb 2+ ion. This was established by observation of resolved fine structure in the excitation of n = 39, high-L Rydberg levels of Pb 3+ , using the same RESIS technique. Analysis of this spectra determined the polarizability of Pb 4+ to be α d = 3.61(4) a.u. Reanalysis of optical spectra of nh and ng levels in Pb + and Pb 3+ in view of the polarizabilities determined in the RESIS studies indicates revised ionization energies of both ions, E I (Pb + ) = 121245.28(6) cm −1 and E I (Pb 3+ ) = 341 435.1(8) cm −1 .