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The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
| Spectropolarimetry of SN 1987A - Observations up to 1987 July 8
Spectropolarimetric observations of SN 1987A in the LMC are presented.These are the first such observations of a supernova with asignal-to-noise ratio sufficient to show polarization variations acrossthe spectral lines. Observations have been made at several epochs andcover a number of spectral regions; in most cases these include theregion around H-alpha. In general, the polarization through the lines isdouble peaked above a continuum value. The interstellar component isdiscussed in some detail in order to investigate its effect on thepolarization profile. The presence of polarization shows that thesupernova explosion was asymmetric. The axis and degree of asymmetry isdependent on wavelength. The observations are interpreted in terms ofexisting models, but more detailed modelling will be needed to obtainfull agreement with the observed polarization spectrum. It is alsoinvestigated whether the position angle of the polarization may berelated to the position of the companion source observed using speckleinterferometry. The principal symmetry axis of the supernova envelopeappears to be aligned with the angle to the speckle companion. Themodifications made to the existing spectropolarimetry on theAnglo-Australian Telescope in order to obtain the high signal-to-noiseratios required for the observations are also described.
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