Will observing Betelgeuse through a telescope during its supernova be hazardous?

Betelgeuse, a red supergiant star, is approaching the end of its lifespan and is expected to undergo a supernova explosion within the next 1,000 years.

The topic of when Betelgeuse will go supernova frequently emerges in mainstream discussions, particularly when the star, which forms the left shoulder of the Orion constellation, appears to brighten in the night sky.

Between December 2019 and February 2020, Betelgeuse experienced a dimming event, but it appeared to brighten by up to 50% in May and June 2023.

Concerns have been raised regarding the potential danger of a Betelgeuse supernova to Earth. Additionally, people wonder if observing the supernova through a telescope would be harmful due to its brightness.

At a distance of 640 light-years, Betelgeuse is far enough away that it does not directly pose a threat to life on Earth. However, during the weeks of the supernova event, it would burn intensely in the sky, shining as brightly as the full Moon and easily visible even during the day.

The brightness would be concentrated in a point source, rather than spread across the entire disc of the Moon. Therefore, observing the supernova at its peak brightness through a telescope could indeed be dangerous.

Nevertheless, when Betelgeuse goes supernova, it is not expected to be as bright as the Geminga supernova, which occurred approximately 300,000 years ago and was located just 550 light-years away from Earth.

red supergiant is an enormous star, larger than our Sun, that is approaching the end of its fuel supply. The existence of a star relies on a delicate balance between fusion energy and gravity. As long as fusion reactions continue, there is enough heat generated to counteract the force of gravity. When a star has a mass less than the Chandrasekhar limit, approximately 1.44 times the mass of the Sun, it eventually collapses and becomes a white dwarf star.