PVO-V-OMAG-4--SCCOORDS-24SEC-V1.0 PVO VENUS MAG RESAMPLED SC COORDS 24SEC AVGS V1.0" This dataset contains vectors collected by the Pioneer Venus Orbiter (previously Pioneer 12) Magnetometer which have been averaged over two spin periods (approximately 24 seconds). The averaging intervals are overlapped and data are output on single spin period centers, the time stamp corresponding to the center of the averaging window. This results in an unevenly sampled dataset as the spin period varies. The amplitude of the ''flutter'' in the averaging window size is generally less than 0.004 seconds in the 12 second period of an orbit. Orbits that have spin period adjustment thruster firings will have larger variations in the output time steps, but such adjustments are seldom, if ever, done in the hour surrounding periapsis. The data are provided in spacecraft coordinates whose system has it Z axis antiparallel to the spacecraft spin axis during orbit. This choice maintained the Z axis along roughly the Earth's ecliptic north pole. Late in the mission when it was believed that the shadowing of the solar panels by the booms was causing a problem, the spin axis was moved to the pole of the Venus orbital plane. The X-axis of the spacecraft coordinate system is toward the sun along the projection of the Venus Sun line on the spacecraft equatorial (X-Y) plane. The Y axis is chosen to form a right handed orthogonal triad if the axis are selected in alphabetical order. Hence, the Y direction points roughly opposite to the direction of Venus motion about the sun. Software is provided which allows users to convert the magnetic field data from S/C coordinates to geophysical coordinates. The program PVROT will rotate the data into Venus Solar orbital (VSO) coordinates using the magnetic field data and the ephemeris data. Other datasets on the CD-ROM are the Ephemeris which contains spacecraft position in Venus Solar Orbital coordinates, spacecraft altitude, solar zenith angle, Venus centered longitude and latitude, spacecraft spin axis components, celestial longitude and latitude of the spacecraft, celestial longitude of the earth, and the Sun-spacecraft range. Other ancillary datasets are the: 1) phase and offset which contains the phase amplitude of sun synchronous modulation of the 4 signals (E100, E730, E5.4 and E30K), and offsets of the G sensor. 2) The engineering dataset which contains temperatures, magnetometer modes, magnetometer sample format, magnetometer spin average select, telemetry data format, telemetry bit rate, spacecraft spin period, pulse time, the difference between the Sun pulse time and the Rip pulse time, and the pulse time flag. 3) The instrument status dataset which contains amplitudes of spin ripple, differences between amplitudes, ratio of the amplitudes, phase differences between pseudosensors, average field seen by the pseudosensors, cosine amplitude, and sine amplitude." CONFIDENCE_LEVEL_NOTE = " These data have been reprocessed several times during the course of the mission. Each successive reprocessing has eliminated some of the problems found in earlier version of the data. Please bring to the attention of the original investigator any suspicious section of data. No zero level correction has been applied to the data because of the small size of the determined zero level. " Russell, C.T., R.C. Snare, J.D. Means and R.C. Elphic, 'Pioneer Venus Orbiter Fluxgate Magnetometer', Ieee Trans. Geo. Elec., vol. GE 18, no. 1 p. 32, 1980." /* Elphic R.C., C.T. Russell, J.A. Slavin, L.H. Brace, and A.F. Nagy, 'The location of the dayside ionopause of Venus: Pioneer Venus Orbiter Magnetometer observations', Geophys. Res. Lett., vol. 7, no. 8, p. 561, 1980." /* Elphic R.C., C.T. Russell, J.A. Slavin, and L.H. Brace, 'Observations of the dayside ionopause and ionosphere of Venus', J. Geophys. Res., vol. 85, no. A13, p. 7679, 1980." /* Luhmann J.G., R.C. Elphic, C.T. Russell, and J.A. Slavin, 'Observations of large scale steady magnetic fields in the nightside Venus ionosphere and near wake', Geophys. Res. Lett., vol. 8, no. 5, p. 517, 1981." /* Russell C.T, J.G. Luhmann, and R.C. Elphic, 'The distant bow shock and magnetotail of Venus: Magnetic field and plasma wave observations', Geophys. Res. Lett., vol. 8, no. 7, p. 843, 1981." /* Elphic, R.C., C.T. Russell, and J.G. Luhmann, 'The Venus ionopause current sheet: Thickness length scale and controlling factors', J. of Geophys., vol. 86, no. A13, p. 11,430, 1981." /* Luhmann J.G., C.T. Russell, L.H. Brace, H.A. Taylor, W.C. Knudsen, F.L. Scarf, D.S. Colburn and A. Barnes, 'Pioneer Venus observations of plasma and field structure in the near wake of Venus', J. Geophys. Res., vol. 87, no. A11, p. 9205, 1982." /* Russell, C.T., J.G. Luhmann, and J.L. Phillips, 'The location of the subsolar bow shock of Venus: Implications for the obstacle shape', Geophys. Res. Lett., vol. 12, no. 10, p.627, 1985." /* Phillips,J.L., J.G. Luhmann, and C.T. Russell, 'Magnetic configuration of the Venus magnetosheath', J. Geophys. Res., vol. 91, no. A7 p. 7931, 1986." /* Saunders, M.A., and C.T. Russell, 'Average dimension and magnetic structure of the distant Venus magnetotail', J Geophys. Res., vol.91, no.A5 p.5589, 1986." /* McComas,D.J., H.E. Spence, C.T. Russell, and M.A. Saunders, 'The average magnetic field draping and consistent plasma properties of the Venus magnetotail' J. Geophys. Res., vol 91, no. A7, p. 7939, 1986." /* Phillips, J.L., and C.T. Russell, 'Upper limit on the intrinsic magnetic field of Venus', J. of Geophys. Res, vol. 93, no. A3, p. 2253, 1987." /* Russell, C.T., E. Chou, J.G. Luhmann, P. Gazis, L.H. Brace and W.R. Hoegy, 'Solar and interplanetary control of the location of the Venus bow shock', J. of Geophys. Res, vol. 93, no. A6, p. 5461, 1988." /* Russell,C.T., 'Magnetic flux ropes in the ionosphere of Venus', Geophysical Monograph, vol. 58, p. 413" /* Orlowski D.S., and C.T. Russell, 'ULF waves upstream of the Venus Bow Shock: Properties of one-hertz waves ', J. Geophys. Res., vol. 96, no. A7, p. 11271, 1991."