I started off by bringing in a Jpeg of color bars. I used color bars for their luminance values. I then created a noise map and set its values to my liking. (Download a sample image and project file from the green bar above.)
The next order of business was to duplicate that noise map, you will see why very soon. On the mac splat-D duplicates a track, sorry I dont use a PC so I dont have the shortcut. I made a few changes to the noise map before using it. I changed the flow speed and the morph rate slightly so as to offset the movements of the noise map.
My next step was to create a new 3d plane that I used just for its parameters. I dropped the noise map onto the face of that track. I then applied a linear luma key to this track and added some softness to the key.
I then dropped this layer onto mask track of the color bar layer. So far so good. The second noise map was used as a displacement map on the color bar layer. I adjusted the displacement map filter, as I wanted quite a big displacement.
The next step was to add some blur to this thing. I used basic blur and set it to 100. I wanted to blur a lot, because I have always found that northern lights are not all that easy to see and one color seems to blend into another. The blur did this trick for me. I then applied a tint-tritone filter and mapped the mid-point color to a bright green (You'll see why later).
Your track should look something like this.
Click image to view larger image.
Your composite window should look something like this (minus the stars, I added those at the end)
Now instead of redoing all of this work, I simply duplicated the color bar track with all of its filters and effects. I changed the color of the tint-tritone effect to Red, and adjusted the morph rate and flow speed of both of the noise maps (the one in the displacement map and the one in the mask track) as to offset them from the other ones used.
So now you have two tracks, slightly different, but both doing the same type of thing. Well next, I selected the uppermost of the two tracks, and in the composite tab, I set the apply mode to add. On both tracks, I then set the opacity to 48.78 percent (Use 50, it's quicker to type)
Finally, I selected both tracks and dropped them into a 3d container, just to group them together. I then dropped that container onto the face of a new 3d layer that I created, and closed the media eye on that track. I did this because I wanted the opacity properties of the 3d layer to adjust the transparency of the 2 tracks together. I also set the scale to 164.63
again you can use 165
I created a star field by just using the defaults that came with the star filter. You should probably play around with this filter to get the look you want. So your timeline should look something like this.
Click image to view larger image.
This of course can be modified to your hearts content. Try adding more than two colors by simply duping the color bar layer more times and changing the tint color. Don't forget to play with other add modes, and change the morph rate and flow speed on all layers to offset things. You can also play with direction of the flow map and scale to offset your maps. You can also get some fantastic results by changing the basic blurs for directional blurs. Just set the blur direction upwards.
I hope you enjoyed this rather short tutorial, it is my first, so please be kind
.. Just kidding, naturally.