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Дата изменения: Mon Oct 26 13:43:26 2015 Дата индексирования: Sun Apr 10 00:29:43 2016 Кодировка: Поисковые слова: messenger |
Christian Hummel
European Southern Observatory Karl-Schwarzschildstr. 2 D-85748 Garching GERMANY Phone: +49 89 3200 6151 Email: chummel@eso.org |
Interferometers measure amplitude and phase of the complex visibility, which, by definition, are unity and zero, respectively, for an ideal instrument in the absence of the atmosphere observing an unresolved star through a monochromatic filter. In reality, the measured amplitude is always smaller due to atmospheric turbulence and instrumental degradation, thus the amplitude measured on a science target has to be normalized by the amplitude measured on a calibrator.
Calibrators are rarely unresolved, and if bright ones are needed, they tend to be big enough to require good estimates of their angular diameter. These are extracted from their photometry, assuming they are described by a single photosphere of a non-rotating star.
Thus, we have two issues in this business: first, to define suitable selection rules based on astrophysical insight, and second, to share data on calibrators especially if they turn out to be unsuitable for any reason.
ResourcesHere we compile a list of resources to aid in the selection of calibrators. Clicking a link will open the resource in a new window. |
PublicationsPapers related to the topic |
ProjectsOngoing projects to improve the data bases |
DiscussionAreas of concern, comments, issues... |
Last updated: 9 July 2015 by Christian A. Hummel