EDP Sciences
Free access
Volume 409, Number 2, October II 2003
Page(s) 793 - 797
Section Physical and chemical processes
DOI http://dx.doi.org/10.1051/0004-6361:20031077

A&A 409, 793-797 (2003)
DOI: 10.1051/0004-6361:20031077

High spatial resolution capabilities of Doppler measurements with the Pic du Midi MSDP spectrograph

Th. Roudier1, J. M. Malherbe2, P. Mein2, R. Muller1, C. Coutard2, M. Lafon1 and F. Grimaud1

1  Laboratoire d'Astrophysique de Toulouse, Observatoire Midi-Pyrénées, 14 avenue É. Belin, 31400 Toulouse, France
2  LESIA, Observatoire de Paris, Section de Meudon, 92195 Meudon, France

(Received 7 April 2003 / Accepted 3 July 2003)

We analyse observations in the NaD1 line ( $\lambda$ 5896 Å) obtained with the MSDP spectrograph of the Turret Dome of the Pic du Midi Observatory. Individual images reveal high spatial resolution and the data reduction shows the high capabilities of the spectrograph to get doppler measurements up to the limit of the resolution of the refractor (0 $\farcs$3). Dopplershifts are obtained in the middle and high photosphere. The smallest granules 0 $\farcs$4 show upward motions in the middle photosphere.

Key words: Sun: photosphere -- Sun: granulation

Offprint request: Th. Roudier, roudier@bigorre.bagn.obs-mip.fr

© ESO 2003