From the perspective of an observer on Earth, the Norma Arm of the Milky Way passes through the constellation Norma, and it’s from the constellation that the arm’s name is derived.- Norma is a small constellation in the Southern Celestial Hemisphere between Ara and Lupus, one of twelve drawn up in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. Its name is Latin for normal, referring to a right angle, and is variously considered to represent a rule, a carpenter’s square, a set square or a level. It remains one of the 88 modern constellations.