Complex sentence: Occurrences of novae occur most often in the sky along the path of the Milky Way, but usually, concentrate near the observed galactic centre in Sagittarius, however, it is also quite possible for them to appear anywhere in the sky.
Split into simpler sentences: Occurrences of novae mostly occur in the sky along the path of the Milky Way, but usually concentrate near the observed galactic centre in Sagittarius. However, it is also quite possible for them to appear anywhere in the sky.