This simulator is part of the StarBlink project and reproduces the occultation of Betelgeuse by the asteroid Leona that will take place on December 12, 2023 and that will be visible, among other places, in the north of Andalusia (Spain). It draws an approximation of the star and the asteroid, as well as the light curve that would be produced and a simulation of the variation of the brightness of Betelgeuse over a starry sky.

The following controls can be used to perform the simulation:

• Time: This slider allows you to set the time between 12 seconds before and after the maximum of the occultation.
• Betelgeuse size: Apparent size of the star in milli-arcseconds (mas).
• Leona size (d1, d2, ang): The asteroid is approached by an ellipse with axes d1 and d2 and with a rotation of ang degrees.
• Limb darkening (u): Optical effect by which stars and planets appear brighter in the central part of their disk. Its effect can be simulated with the u parameter.
• Observer displacement: Distance from the observer to the center chord of the occultation.
• Zoom: Magnification factor.

The Animate button allows to automatically move the time controller to simulate the occultation "in real time".

The Reset Graph button allows you to delete the points added to the graph.

For any kind of comment or suggestion you can send us an email. In fact, if you use it for any kind of didactic or divulgation initiative, we would love to hear about it - don't hesitate to contact us!

Disclaimer: This simulator is intended for educational purposes and may not represent the phenomenon in a very accurately way.