An annular eclipse of the Sun took place on the 10th of June 2021. Not only was it visible from Sweden, but also from the Canary Islands where the Swedish Solar Telescope, SST, is situated. We are interested in observing solar eclipses for calibration purposes. The sharp edges of the lunar disk allow us to test our modelling of instrumental and atmospheric disturbances on our images.

The image below shows a snapshot of the SST observation of the partial eclipse. In the image, the Sun is covered up by the Moon. The wavy black line is the silhouette of the Moon, showing some of its mountains. The mountains in this image have a height of approximately 5 km above the lunar surface. This observation was made the 10th of June 2021 at 09:09 UT by Alexander Pietrow, Flavio Calvo, Carlos José Días Baso, Peter Sütterlin and Oleksii Andriienko.

The Moon covering the Solar disk. Some lunar mountains are visible against the Sun.

The Sun covered up by the Moon. The wavy black line is a silhouette of the moon, showing some of its mountains. Behind the Moon the solar granulation pattern is visible. Image: Institute for Solar Physics, Stockholm University.