d'Avila, V. and Reis Neto, E. and Coletti, A. and Oliveira, L. C. and Matias, V. and Andrei, A. H. and Penna, J. L. and Calderari Boscardin, S. and Sigismondi, C. (2013) A new approach for the heliometric optics. Il nuovo cimento C, 36 (Sup. 1). pp. 237-242. ISSN 1826-9885
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Abstract
The heliometer of Fraunhofer in Koenigsberg (1824) is a refractor in which the lens is split into two halves to which is applied a linear displacement along the cut. Later in 1890s a variation of the heliometer has been realized in Goettingen using a beam splitting wedge: these methods were both subjected to chromatic and refractive aberrations; the second configuration being much less affected by thermal fluctuations. The reflector version of the heliometer conceived at the Observatorio Nacional of Rio de Janeiro overcome these problems: the two halves of the vitrified ceramic mirror split at a fixed heliometric angle produce the two images of the Sun exempt of chromatisms and distortions. The heliometer of Rio is a telescope which can rotate around its axis, to measure the solar diameter at all heliolatitudes. A further development of that heliometer, now under construction, is the annular heliometer, in which the mirrors are concentric, with symmetrical Point Spread Functions. Moreover the location of the Observatory of Rio de Janeiro allows zenithal observations, with no atmospheric refraction at all heliolatitudes, in December and January.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Optical system design ; Solar instruments ; Solar physics ; Diameter, rotation, and mass |
| Subjects: | 500 Scienze naturali e Matematica > 530 Fisica |
| Depositing User: | Marina Spanti |
| Date Deposited: | 07 May 2020 17:21 |
| Last Modified: | 07 May 2020 17:21 |
| URI: | http://eprints.bice.rm.cnr.it/id/eprint/18444 |
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