Showing papers by "Dominion Astrophysical Observatory published in 1983"
33 citations
TL;DR: In this paper, the International Ultraviolet Explorer (IUE) observations of the symbiotic binary AR Pav through its 1982 eclipse show that the hot star is associated with an extended region of continuum emission which is partially eclipsed.
Abstract: Observations with the International Ultraviolet Explorer (IUE) of the symbiotic binary AR Pav through its 1982 eclipse show that the hot star is not eclipsed. The hot star is associated with an extended region of continuum emission which is partially eclipsed. The eclipsed radiation is hotter near to its center, with a maximum temperature of about 9000 K. The uneclipsed flux is hotter than this. UV emission lines are not measurably eclipsed and presumably arise in a much larger region than the continuum. These data provide new constraints on models of the system but also are apparently in contradiction to those based on ground-based data.
13 citations
TL;DR: In this paper, photometriques uvbyβ dans une region d'environ 20° autour du pole galactique sud were used to identify plusieurs objets evolues and de population II
Abstract: Observations photometriques uvbyβ dans une region d'environ 20° autour du pole galactique sud. On identifie plusieurs objets evolues et de population II
9 citations
University of Washington1, University of Toronto2, Australian Astronomical Observatory3, University of Chicago4, University of North Carolina at Chapel Hill5, Dominion Astrophysical Observatory6, University of Arizona7, University of Paris8, University of Texas at Austin9, Carnegie Institution for Science10, University of Basel11
TL;DR: It is not easy to measure distance to galaxies as mentioned in this paper. But we do try, and we feel that we must try, because so many of our grandest questions and most basic problems about the universe depend on our knowledge of its size and scale.
Abstract: It is not easy to measure distance to galaxies. That we even try is as musch a measure of our audacity as it is an indication of our ingenuity. But we do try, and we feel that we must try, because so many of our grandest questions and most basic problems about the universe depend on our knowledge of its size and scale.
2 citations
01 Jan 1983
TL;DR: In the last few years radio and x-ray astronomers have produced high-resolution imagery of the remnant of Cas A using the 5-m Hale telescope as discussed by the authors, which is shown in Fig. 1.
Abstract: During the last few years radio and x-ray astronomers have produced high-resolution imagery of the remnant of Cas A. Since the most recent published optical photographs of Cas A date back to 1975 (Kamper and van den Bergh 1976 a, b) it seemed worthwhile to present new optical results based on plates obtained with the 5-m Hale telescope in 1976, 1977 and 1980. A photograph taken in 1980 is shown in Fig. 1.
1 citations
TL;DR: The contribution of UV spectroscopy to the understanding of massive X-ray binaries is reviewed in this article, where the authors show that the IUE results have enabled a greater understanding of the effects of accretion disks and Xray heating in the systems, and provide absolute fluxes and luminosities.
1 citations
08 Nov 1983
TL;DR: In this article, the authors proposed a corrector lens design which will provide a 0.5 degree field of good definition from 134nm to 280nm at the Ritchey-Chretien focus of the F/2-F/15 Starlab 1-metre telescope.
Abstract: Parameters are given for a corrector lens design which will provide a 0.5 degree field of good definition from 134nm to 280nm at the Ritchey-Chretien focus of the F/2-F/15 Starlab 1-metre telescope. The optimization includes the window of the detector which is aspherized on the outside but not on the inside where the photocathode is deposited. The 130 mm diameter detector is preceded by two lenses, the first of which is convex-plano. Because this element has a flat surface it can be interchanged with other elements to either compensate for the chromatic aberration of filters (by making the lens thinner), and/or to provide dispersion for multi-object slitless spectroscopy. In the latter case, the interchanged element is wedged and has a course transmission grating deposited on the flat side. This combination of grating and lens is referred to as a grens.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
1 citations
01 Jan 1983
TL;DR: Conditions in the astronomer's violent universe manage to render large volumes of phase space available to the atoms which occupy it and there is urgent needed in some domain of astronomy.
Abstract: The astronomer’s requirments for atomic data are so massive that it is not easy to approach this subject in a way that sound responsible to someone who is not thoroughly familiar with the situation. the simple truth is that there is urgent needed in some domain of astronomy. This comes about partly becuase of the high temperatures and very long path legths in astronomical objects which can make tham extremely powerful light sources. More generally, we can say conditions in the astronomer’s violent universe manage to render large volumes of phase space available to the atoms which occupy it.