They'll never look exactly like the long exposure, ultra vibrant photos. However, when they are really strong you can see both greens and purples very distinctly with the naked eye.
One experience you can get in person when they're really strong is how fast they can dance around above you as well. I've found the dancing lights to the naked eye are much more astounding than in timelapses or videos, 1) because that's when they're most vibrant in person, and 2) because you can see just how fast and jittery and energetic they are, unlike in a video which is usually captured at much less than 30fps for low light and denoised and frames mashed together to create those soupy smooth videos and timelapses. Nice in their own way, but nowhere near the same experience.
And when they're very low energy they will just look like green grey clouds to the naked eye.
One experience you can get in person when they're really strong is how fast they can dance around above you as well. I've found the dancing lights to the naked eye are much more astounding than in timelapses or videos, 1) because that's when they're most vibrant in person, and 2) because you can see just how fast and jittery and energetic they are, unlike in a video which is usually captured at much less than 30fps for low light and denoised and frames mashed together to create those soupy smooth videos and timelapses. Nice in their own way, but nowhere near the same experience.
And when they're very low energy they will just look like green grey clouds to the naked eye.
Source: live in the arctic