The ATNF Logo Revisited White, Graeme L.
Publications of the Astronomical Society of Australia,
1990, Letnik:
8, Številka:
4
Journal Article
Recenzirano
The Logo of the Australia Telescope National Facility (ATNF) depicts a linear array of six antennas in the Southern Hemisphere. Precision measurement of this image implies that the Compact Array is ...located at latitude 37° south and azimuth 176°; this corresponds (surprisingly) to an approximately north-south array. Furthermore, the ATNF Logo was apparently prepared at LST 04h 00m.
Astrometric CCD observations have been made of wide (~3 to 80 arcsec) southern binary pairs using the 0·6 m telescope at MSSSO. Separations ρ and position angles (PA) have been calibrated against ...known astrometrie pairs, and have rms uncertainties of 0·16 arcsec and 7·8/ρ degrees (ρ in arcsec) respectively. These stars have not been well studied; typically they have not been measured since approximately 1930, and 52% of them have been observed only once prior to our observations. A comparison has been made with values published in the Washington Double Star (WDS) catalogue. Of the 304 pairs measured in the declination range −60° to −70°, 82% show no evidence of motion since the last observation.
We present moderate-resolution (<5A) long-slit optical spectra of 51 nebular objects in the nearby Sculptor Group galaxy NGC 300 obtained with the 2.3 meter Advanced Technology Telescope at Siding ...Spring Observatory, Australia. Adopting the criterion of SII/Ha>=0.4 to confirm supernova remnants (SNRs) from optical spectra, we find that of 28 objects previously proposed as SNRs from optical observations, 22 meet this criterion with six showing SII/Ha of less than 0.4. Of 27 objects suggested as SNRs from radio data, four are associated with the 28 previously proposed SNRs. Of these four, three (included in the 22 above) meet the criterion. In all, 22 of the 51 nebular objects meet the SII/Ha criterion as SNRs while the nature of the remaining 29 objects remains undetermined by these observations.
The Windsor amateur astronomer, John Tebbutt, had a ceased observing in 1907. However, in 1909, at the age of 75, he came out of retirement to observe Halley’s comet and his astrometric positions ...were published in the Monthly Notices of the Royal Astronomical Society. These data were used, together with most published observations from the 1835 and 1910 apparitions, for the computation of Halley’s orbit for ESA’s Halley intercept spacecraft, Giotto. A detailed analysis of the observations have shown minor imperfections that, when corrected, gave rms errors of 3''.5 arc in right ascension and 2''.8 in declination. His systematic errors are negligible at the 0''.2 level.
Accurate radio positions with a precision of about 0.01 arcsec are reported for eight compact extragalactic radio sources south of -45-deg declination. The radio positions were determined using VLBI ...at 8.4 GHz on the 9589 km Tidbinbilla (Australia) to Hartebeesthoek (South Africa) baseline. The sources were selected from the Parkes Catalogue to be strong, flat-spectrum radio sources with bright optical QSO counterparts. Optical positions of the QSOs were also measured from the ESO B Sky Survey plates with respect to stars from the Perth 70 Catalogue, to an accuracy of about 0.19 arcsec rms. These radio and optical positions are as precise as any presently available in the far southern sky. A comparison of the radio and optical positions confirms the estimated optical position errors and shows that there is overall agreement at the 0.1-arcsec level between the radio and Perth 70 optical reference frames in the far south.
Speckle interferometry of Hipparcos link stars – III White, Graeme L.; Jauncey, David L.; Reynolds, John E. ...
Monthly notices of the Royal Astronomical Society,
02/1991, Letnik:
248, Številka:
3
Journal Article
Recenzirano
We present here a third list of stars is presented which have been tested by speckle interferometry for use in the Hubble Space Telescope link between the Hipparcos astrometric reference frame and ...the extragalactic VLBI reference frame. Structural information on angular scales of 0.15–1.2 arcsec for 34 Southern Hemisphere stars is reported from observations made with the Imperial College Speckle Interferometer mounted on the Mount Stromlo 1.9-m telescope. Twenty-four percent of the stars (8 out of the 34) show evidence of multiplicity, in agreement with previous observations in this program.
Radio emission from the source 0427–53 surrounds the 13.9-mag galaxy IC 2082, a giant cD with a double nucleus in a cluster of more than 80 members. Radio images at 843 MHz (Molonglo; 43 arcsec beam) ...and 1415 MHz (Fleurs; 20 arcsec) show a double head and complex tail structure. We identify the radio emission with the fainter optical nucleus which is probably a second galaxy in a transient encounter with the cD galaxy. The radio tail to the west is closely confined in a ridge that bends sharply south 5 arcmin (160 kpc) from the head. We suggest that in the dark cluster medium which surrounds IC 2082 there is tangential drag from ordered flow.
The Lands Department Building in Sydney is situated on the block bounded by Bridge Street, Gresham Street, Bent Street and Loftus Street. The northern (Bridge Street) end is surmounted by a small ...copper dome.
Presented here are optical identifications for southern radio sources using new arcsecond positions determined with the six-dish array of the Fleurs Synthesis Telescope. These sources were drawn from ...the Parkes 2700-MHz Catalogue and are all flat radio-spectrum sources stronger than 0.25 Jy at 2700 MHz. All lie between right ascension $\text{(RA)}\,\text{(B1950.0)}{18}^\text{h}{00}^\text{m} \,\text{and} \,\text{06}^\text{h}{00}^\text{m}$ declination (Dec.) -80° and $-{50}^{\circ}(\text{B}1950.0)$. The radio positions have standard deviations of about 1.0 arcsec in both RA and Dec. The optical positions are with respect to the FK4 reference system as approximated by the Perth catalogs and have position uncertainties of 0.5 arcsec. Magnitude estimates are on the IIIa-J scale and are accurate to 0.4 mag for QSOs and 0.5 mag for galaxies. The sample is complete to the 22.5-mag limit of the SERC IIIa-J sky survey. There are 198 sources in the complete sample (here and Paper I). Thirty-one sources (16 percent) show some radio structure with the 20-arcsec beam. For the 175 unresolved sources, there are 124 QSOs (71 percent), 26 galaxies (15 percent), and 25 empty fields (14 percent) suggested.
Radio observations of a sample of EA eclipsing binaries, including early-type main-sequence pairs as well as classical Algol-type eclipsing binaries, indicate the presence of a moderately strong ...coronal magnetic field, B of about 100 G, between the component stars. This translates to a surface magnetic field of about 1000-10,000 G on one or both stars. This is the first compelling evidence for magnetic fields on early-type stars, apart from the Ap and Bp magnetic stars first detected in 1947. 47 refs.
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