It has been later noticed that some Seyfert nuclei show intermediate properties, resulting in their being further subclassified into types 1.2, 1.5, 1.8 and 1.9 (see Classification).
Posteriormente sóubose que algúns núcleos Seyfert mostran propiedades intermedias, que serven para subclasificalas nos subtipos 1.2, 1.5, 1.8 e 1.9 (ver Clasificación).