We obtained at the same time G-band images at the Dutch Open Telescope (DOT) on La Palma and spectropolarimetric data in the near infrared at the German Vacuum Tower Telescope (VTT) on Tenerife. The spectropolarimetric data show interesting correlations. Bright filaments have a smaller magnetic field s trength, and higher Evershed velocities occur

We report the results of a multisite observing campaign of observations of OJ287 in the visible, near infrared and submillimetric in Winter 1989-90. Simultaneous UBVRIK and white light data were obtained with three telescopes in Tenerife and La Palma on three nights in December-January, supported by follow-up observations in January and March 1990

The two main perturbative schemes for the non-linear evolution of large-scale structures are the Lagrangian and the Eulerian ones. The former has been set as a much more powerful technique, due to its property of yielding the exact solution in the plane-symmetric case. We have applied the Eulerian scheme to this plane symmetric case and have

Phase and gain relations between low-degree acoustic modes measured as intensity and velocity fluctuations have been carried out using various instruments and techniques. The helioseismic instrument aboard the Solar and Heliospheric Observatory (SOHO) satellite provides an opportunity to observe solar oscillations in intensity and velocity under

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