The two-dimensional temperature distribution in a highly structured sunspot and in two small umbrae is determined from a three-colour photometry in narrow spectral continua. Disturbing influences from the earth’s atmosphere are removed by speckle masking techniques, yielding a spatial resolution limited by the telescope’s aperture. The corresponding colour temperatures are consistent over a ran...

this paper presents a simplifiedlagrangian multiplier based algorithm to solve the fixed head hydrothermalscheduling problem. in fixed head hydrothermal scheduling problem, waterdischarge rate is modeled as quadratic function of hydropower generation andfuel cost is modeled as quadratic function of thermal power generation. thepower output of each hydro unit varies with the rate of water discha...

In order to study umbral oscillations, running penumbral waves and the relationship between them, we analyzed CCD, high resolution, sunspot observations obtained at center and the wings of the Hα line and the Fe I 5576 Å line. The UBF filter was used in order to produce high cadence sequences of filtergrams. Images were processed to remove the sharp intensity gradient between the umbra and the ...

Context. Upflows in the corona are of importance, as they may contribute to solar wind. There has been considerable interest upflows from active regions (ARs). The coronal that seen at edges have elemental composition and can slow sources challenging determine because be multiple, spatial resolution previous observations is not yet high enough. Aims. In this article, we analyse AR 12960 unusual...