Astrometry and Photometry with Coronagraphs

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dc.creatorSivaramakrishnan, Anand
dc.creatorOppenheimer, Ben R.
dc.date2006-06-07
dc.date.accessioned2026-07-07T10:39:13Z
dc.date.available2026-07-07T10:39:13Z
dc.descriptionWe propose a solution to the problem of astrometric and photometric calibration of coronagraphic images with a simple optical device which, in theory, is easy to use. Our design uses the Fraunhofer approximation of Fourier optics. Placing a periodic grid of wires (we use a square grid) with known width and spacing in a pupil plane in front of the occulting coronagraphic focal plane mask produces fiducial images of the obscured star at known locations relative to the star. We also derive the intensity of these fiducial images in the coronagraphic image. These calibrator images can be used for precise relative astrometry, to establish companionship of other objects in the field of view through measurement of common proper motion or common parallax, to determine orbits, and to observe disk structure around the star quantitatively. The calibrator spots also have known brightness, selectable by the coronagraph designer, permitting accurate relative photometry in the coronagraphic image. This technique, which enables precision exoplanetary science, is relevant to future coronagraphic instruments, and is particularly useful for `extreme' adaptive optics and space-based coronagraphy.
dc.descriptionTo appear in ApJ August 2006, 27 preprint style pages 4 figures
dc.identifierhttps://arxiv.org/abs/astro-ph/0606136
dc.identifierhttp://arxiv.org/abs/astro-ph/0606136
dc.identifierAstrophys.J.647:620-629,2006
dc.identifierdoi:10.1086/505192
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/180953
dc.subjectAstrophysics
dc.titleAstrometry and Photometry with Coronagraphs
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