Hi Jens,
You can certainly use whatever color you like.
The further up one goes, I would expect the color of city lights to become more color-distorted because of the atmosphere.
But before you make your final decision, please do like I did, and spend several hours searching the Internet for "night lights" along with whatever other keywords you would like. Then, when you find photos, read
what the photo was taken with and
how the picture was taken (ie. snapshot camera, single exposure, multiple exposure, timed exposure, film, CCD, etc., etc.).
Most, if not all, of the orangish light photos I found were taken by astronauts from the space stations or shuttle. These were taken with hand-held, single exposure, snapshot cameras -- some film and some CCD. There are no multiple exposure photos, because the shuttle and/or space station move too fast -- the pictures would not overlap correctly.
On the other hand,
all of the white light photos I found were taken with a satellite. If you read about
how these pictures were taken, you will find that most are multiple exposures over many days, weeks and even months. Then, the individual pictures are combined in a special process which brings out the light. The same thing can be done with snapshot cameras, but the camera and subject must both be stationary.
I'm sure Fridger could explain this in more detail since he is an optics and telescope making amateur. It's all about gathering light to the highest possible extent, which satellites and multiple exposure scene shots do quite nicely. Single shot, snapshot cameras do not do a good job at this.
-Don G.
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