CAOSP abstracts, Volume: 28, No.: 3, year: 1999
- Author(s): GABRYL, J.-R.; CUGNON, P.; CLETTE, F.
- Journal: Contributions of the Astronomical Observatory Skalnate Pleso,
vol. 28, no. 3, p. 216-223.
- Date: 03/1999
- Title: Polarization observations and results of the 1998 February 26th solar corona
- Keyword(s): ECLIPSES, WHITELIGHT CORONA, ELECTRON DENSITY
- Pages: 216 -- 223
In the frame of the long-term study program of the solar corona, we have
organized an expedition in Curacao (Dutch Antillas) to observe the total solar
eclipse of February 26th, 1998. As the totality duration was quite short, we
had to improve again the CCD experiment layout in order to record a sample of
images as wide as possible in both polarization and brightness ranges. This was
made possible by the acquisition of a new PC with fast hard disc and data
transfer port. We managed then to record 7 series of different exposures, each
containing polarization measurements of 24 images (thus 8 times oversampled).
The data processing led to accurate brightness and polarization maps as well
as electron density models. The shape of the corona is highly flattened with
large polar holes filled by numerous wide plumes. Large streamers are also
observed and are essentially aligned along the solar equatorial plane.
Moreover, the polarization indicates that these structures are located in the
vicinity of the plane of the sky. Unfortunately, the unusually high sky
brightness hid the faintest coronal structures and limited the visibility up
to 3 solar radii implying a similar limitation in our modelling. We present
here these results and give a brief comparison with our previous eclipse
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