Today, astrophysicists use highly sensitive instruments and register every year thousands of supernovae, dozens of gamma-ray bursts, and even sources of gravitational waves. Due to the enormous distances, these objects are usually very faint, so large aperture telescopes are needed to observe them. But, you don’t have to worry about having new constellations, the vast majority of these “new” objects are invisible to the naked eye. However, an exception confirming the rule occurred at the beginning of May, when the brightness of the nova in the constellation Cassiopeia with the designation Nova Cas 2021 rose to 5 mag and it was observable even without a telescope for several nights.
More information about this object (including spectrum obtained with Perek 2m Telescope in Ondřejov) you can find in this Astronomers telegram.
And also on official pages of the Astronomical Institute (in Czech): ASU Press Release.