Prague -- Czech astronomers have discovered a star outburst in the Perseus constellation, three quarters of a year earlier than expected, the Astronomical Institute of the Czech Academy of Sciences said on Friday.

The astronomers found that the brightness of the star fluctuates in intervals of minutes to hours, Petr Sobotka from the institute said.

The star designated as GK Per outbursts once in three years, but the exact moment cannot be predicted, Sobotka noted.

Astronomers observed the first distinct brightening up of the star 105 years ago. The star was then visible easily even without a binocular.

The outburst of the star this year was first discovered by an amateur astronomer Lubos Brat a few days ago.

As the process continued next night as well, Brat informed his colleagues from the Astronomical Institute, which confirmed his discovery.