Each sort of ray is used in Art Deco.
When using angles as your basis, divide then add the remainder to the center angle. That provides a mild (or major) emphasis to the middle, which looks rather snazzy.
This is a sunray made of the standard architectural angles: 0, 15, 30, 45, 60, 75, 90.
Most of the time, you won't see this because other designs actually work better. You may see partial implementations of the angles, but jiggered in some way to look better.
Return to: Art Deco 101
Douglas Milewski is a fantasy writer who liked drafting class too much. In his recent artistic struggles to produce art deco for his own covers, he found no internet sites dedicated to the technical underpinnings of the art. Seeing a niche that needed filling, he has documented his hard learned experiences. He doesn't claim that he's right, and would very much appreciate it if someone more competent would save him from his own folly.