Total Eclipse on August 12, 2026: observations in Spain and prediction with COCONUT

Because of the lack of white light coronagraph observations in the low solar corona (1-1.5 solar radius), total solar eclipses are a standard way of assessing coronal structures and testing coronal models. Total solar eclipses constrain the validation period of coronal modelling, as they occur rarely. However, currently, it is the only way to distinguish features in the low corona near the solar surface. Soon, the PROBA 3 mission will provide continuous observations of the low corona. Total solar eclipses provide a single snapshot of the solar corona, whereas time-dependent simulations require continuous white-light observations.

COCONUT was utilised to predict the previous total solar eclipse in April 2024 (Baratashvili et al. 2025, A&A, in press). In the setup demonstrated in the manuscript, a low-resolution, simplified approach is used. However, multiple developments in the COCONUT model since the previous total solar eclipse allow the continuous time-dependent and high resolution simulations (Wang et al, 2025, in press) for the predictions on the upcoming total solar eclipse on August 12, 2026, at 18:27 UT.  Additionally, we plan a network of observations in Spain with multiple sites  (Santiago Compostela, Teruel, Villadolid, Riga)  to obtain the best coverage of the total solar eclipse and obtain high-quality images to use them for validating the predictions performed by the COCONUT model. Synthetic white-light images will be generated from the COCONUT simulations to compare to the observed images directly.

This way we can use the total solar eclipse on August 12, 2026, to validate the COCONUT model, and identify its strengths and weaknesses.