The constellation Triangulum lies close to overhead in northern skies on December evenings. It contains the Triangulum galaxy, a gorgeous pinwheeling spiral.
In Northern Hemisphere autumn (Southern Hemisphere spring), you can see some constellations representing a "celestial ocean in the sky" to early stargazers.
Microscopium the Microscope is a constellation with very dim stars. It holds a star, AU Microscopii, that has a disk of dust that is probably forming planets.
Equuleus the Little Horse is a diminutive constellation that lies south of the Summer Triangle. September nights are a great time to view the Little Horse.