The SWAN25B comet appears suddenly: now we can also observe it in Italy

Friday 12 September 2025, thanks to the instrument Swan of the space telescope Soinastronomers have identified one new comet never observed before. The object, at the moment called Swan25bhe pointed out why, after having passed very close to the sun, he showed a truly spectacular light tail.

This comet is about 10 kilometers large and is currently located a 78 million kilometers from the earth. For scientists, it is a typical “spatial ice ball” composed of dust and gas which, approaching the sun, heat and form the characteristics Code also visible from the ground. In the case of Swan25b, one is observed Intense green hair and one blue ions tailperfectly aligned with that formed by dust. In practice, a real show for those who love heaven.

Visible first in the southern hemisphere, now it also arrives above Italy

For days, Swan25b remained hidden behind the sunand that’s why it had never been noticed before. Only after passing the perihelion (the closest point in his orbit), has become visible, appearing prospectively close to Marsin the constellation of the Virgin.

The comet was immediately photographed by fans and astrophotographers, especially in the southern hemisphere, where the night sky is more favorable in this period. South America, Africa and Australia These are the places from which the first breathtaking images arrived. Among these, also the one published by the Australian Astrophotographer Michael Mattiazzowho captured the comet with one Tail about 3 degrees in the sky – that is to say Six times the diameter of the full moon.

According to the portal data Theskylivehis magnitude is between 7 and 8which means that, but it can be easily observed with a binoculars or one camera with 200 mm lens. And if you are curious to try too, here’s what to know.

How to observe Swan25b from the Italian sky

Based on the simulations conducted with the virtual planetarium Stellariumthe comet will be low on the western horizon Immediately after sunset, in the days between the 15 and 16 September. Will pass Between Mars and the star Spicain the constellation of the Virginvisible just after the 19:20 (hour of Rome). The fundamental condition to see it? Have a clearing horizon to the westwithout buildings or mountains that hinder the view.

Although it cannot be observed to the naked eye, a binoculars are enough To follow it, and for those who love photography, one long exposure With a telephoto lens it can offer excellent results.

But be careful: It is fundamental. Pointing optical tools to the sun, even accidentally, can cause Permanent damage to sight. The ideal is to wait for sunlight to completely disappear before starting to observe.

A comet that could become even brighter

At the moment, The SWAN25B trajectory is still under observationtherefore it is not yet possible to predict with certainty if the comet it will become visible to the naked eye also from Italy. According to the astrophysicist Tony PhillipsSwan25b could approach up to 0.25 Astronomical units from the earth (about 38 million kilometers) in the month of October. If the brightness increases, it could become a real astronomical event not to be missed.

In the meantime, those who want to try to see it must rely on optical tools and keep an eye on the weather conditions, in addition to the position of the comet that moves from day to day. The next few days will be crucial to understand If it will give us an even more intense show or if it will be an opportunity reserved only for the most equipped observers.