Obituary: Sergio Cortesi

Sergio Cortesi left us. Doyen of professional and amateur astronomy in Ticino, former director of the Specola Solare Ticinese, with 64 years of activity in the Sunspot observations, among the founders and then long-time president of the Società Astronomica Ticinese, Sergio Cortesi is no longer with us. We will miss him very much.

 

EST Newsletter June 2021

The European Solar Telescope (EST) will be the largest solar telescope ever built in Europe, pursuing unique observations of the magnetic processes taking place on the Sun. IRSOL is part of the SOLARNET project, which, amongst other aspects of the telescope operation and scientific goals, deals with new and cutting-edge instrumentation. The current issue of the EST Newsletter focusses on parts of the technology planned to contribute to EST. IRSOL contributes to this newsletter by presenting the first results obtained in the SOLARNET H2020 project “High-precision absolute spectropolarimetry“.

1st- and 2nd-light CALLISTO solar radio spectrometer at IRSOL

It took exactly two years after instrument commissioning to finally get 1st- and 2nd-light at the very same day with Callisto at IRSOL.
Obviously, the Sun started to get active in terms of radio radiation at decametre wavelength (here 45-70 MHz).
Following the NOAA, Space Weather Prediction Center classification, the instrument observed twice a small group of type III bursts.
Type III radio bursts are a group of fast drifting radio emissions associated with solar flares. These radio emissions are believed to be excited at the fundamental and second harmonic of the electron plasma frequency.
Solar type III radio bursts are an important diagnostic tool in the understanding of solar accelerated electron beams.
They are a signature of propagating beams of non-thermal electrons in the solar atmosphere and the solar system.
Consequently, they provide information on electron acceleration and transport, and the conditions of the background ambient plasma they travel through.

Christian Monstein

1st light Callisto observation at IRSOL
2nd light Callisto observation at IRSOL