Live streaming the Sun from the Dwingeloo Telescope

© CC-BY-4.0 Tammo Jan Dijkema

Sunday July 5th was the second Dutch edition of Zonnekijkdag (Solar observing day), a public event dedicated to the Sun. Typically, public observatories put out their solar telescopes - obviously with the right filters and strong warnings never to look directly into the Sun - and let people observe the Sun. This year was a special edition where most activities were organized in the form of livestreams due to corona restrictions. Zonnekijkdag is organized by KNVWS, the Royal Netherlands Association for Meteorology and Astronomy.

This was the first time where the Dwingeloo Telescope participated. We organized a livestream, which was quite broadly announced by RTV Drenthe and RTL Nieuws. The KNVWS announced Zonnekijkdag also on displays in trains and railway stations.

This explains the large amount of viewers of the livestream: more than 700. This is almost equal to the total number of physical visitors of the radio telescope over a normal summer.

Together with Ard Hartsuijker I demonstrated how the radio telescope observes the radio emission from the Sun by slewing over the Sun and plotting the power in the radio signal, showing the live telescope position in Stellarium. After this, we did the same with Cassiopeia A, showing that the Sun is more resolved, and that Cas A is surprisingly bright.

Code for the demonstration is here, the observed data is available here and here.

Due to the cloudy weather, the radio experiment was a welcome addition to the Zonnekijkdag 2020 programme. The live stream can be viewed back from camras.nl. RTV Drenthe also made an item about the livestream.