Abstracts submitted by Guy ARTZNER

Solar chromospheric and coronal stereoscopy

Guy Artzner

Institut d'Astrophysique Spatiale, Orsay

We use the MEDICIS correlation program in order, firstly to validate the geometrical parameters given in the headers of the STEREO-Secchi-Euvi A (ahead) and B (behind) images, and secondly to present comfortable stereo pairs.
The relative centering between A and B is obtained within half a pixel by integer X and Y shifts. The relative magnification between A and B is determined within 0.0002, i. e. 0 .14 pixel at the solar limb. At any time, up to mid June, 2007, the relative roll angle between A and B is adjusted within .01°, i. e. 0.12 pixel at the solar limb. On May 1st, 2007, at a six degrees separation between A and B, the epipolar angle is determined within .05°.
Static stereo pairs prepared according to the above prescription are viewed from computer screens by different methods. On small (800x1200, or 1200x1600) screens, anaglyphs have the advantage of displaying a large field of view. On high quality (IBM 2400x3840) screens, left/right or up/down stereo pairs viewed with the adequate convenient left/right or up/down Viewmagic TM devices allow simultaneously for a high quality and a large field of view. The amount of disparities, such as cosmic ray impacts, between the A and B images, is very small.
As a results of the MEDICIS correlation program, we obtain the apparent altitude of solar chromospheric or coronal structures above the solar hemisphere. We also obtain some quality index for the local correlation between A and B views of the same structures. We determine how this quality index grows worse from low to high compression data, and from static to dynamic structures. We also investigate the time evolution of the altitudes of solar structures.