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Geometry of the Hubble Space Telescope Wide Field/Planetary Camera Field
Gould, Andrew; Yanny, Brian
We present a solution for the relative positions and orientations of the four CCD chips on the Hubble Space Telescope (HST) Planetary Camera (PC). An accurate solution is required when matching HST images with ground-based images or with one another. The solution is accurate to about 2/3 PC pixel or about 0.03", a 10-fold improvement over the best…
MG II Chromospheric-Emission Dating of HR 1614 Moving-Group Stars
Smith, Graeme H.; Hufnagel, Beth
A 2800 A Mg II line index (Mg II) that is sensitive to chromospheric activity has been measured from International Ultraviolet Explorer spectra of a sample of eight HR 1614 moving-group dwarfs. All of these dwarfs have values of I(Mg II) indicative of ages >= 3 Gyr. The relatively old ages of these dwarfs, togther with their similar and peculia…
HL Canis Majoris in Preoutburst and SS Cygni -- The Interoutburst Disk Instability
Garnavich, P. M.; Kaitchuck, R. H.; Dinshaw, N. +2 more
SS Cygni and HL Canis Majoris were observed by IUE for three consecutive nights in November of 1992. During the first two nights, simultaneous photometric ground-based observations of SS Cyg were made at the Ball State University Observatory. Observations of SS Cyg and HL CMa were also obtained simultaneously with the 90-inch telescope at the Stew…
The Effect of Double Stars on the Guiding System of the Hubble Space Telescope
Hershey, John L.; Bely, Pierre Y.
The interferometric system used for guidance of HST is sensitive to close binaries. Before the launch of HST it was believed that up to 25% of all guide star pairs would lead to guidance failure due to duplicity. After more than 3 years of operation the actual failure rate ascribable to duplicity is estimated to be just below 1%. A computer simula…
Optical and Ultraviolet Spectroscopy of VW Hydri
Saygac, A. Talat
Spectra of the SU UMa type dwarf nova VW Hydri obtained in the visual (lambda-lambda 3400-7200A) and ultraviolet (lambda-lambda 1150-3200A) spectral regions are presented. During the quiescent phase, visual spectra of VW Hydri present strong double-peaked Balmer emission lines. In addition, He I lambda 5876, Fe II lambda-lambda 4233, 5196 He I lam…
The UV Polarization of X-Ray Binary Systems Observed with the Hubble Space Telescope
Wolinski, Karen
The High-Speed Photometer (HSP) was one of the four axial instruments on the Hubble Space Telescope (HST) from April, 1990 to December, 1993. We used this instrument to observe the X-ray binary systems HD 153919, Vela XR-1 and Cyg XR-1 both photometrically and polarimetrically in the UV. The photometric and polarimetric light curves of each target…