Camera: Nikon FM-2
Lens: Nikkor 50mm f1.4 AIS
Film: Fuji Velvia 50
The skies in Australias outback are INCREDIBLE. Being so remote there is virtually no atmospheric pollution so they are crystal clear. This is the South Celestial Pole - by using the Southern Cross and Alpha/Beta Centauri its position in the sky is easily determined. By drawing a line to the horizon from that point you have due south.
The green colour in the sky is due to Reciprocity failure which requires exposure compensation (usually adding a stop or 2 to the metered EV value) and also causes this colour shift (green in this example) Most films are designed to be exposed between 1 second and 1/10000th sec. Anything outside these parameters causes this effect.
By using faster speed films you can decrease the exposure time but of course you then get smaller arcs as the stars arent travelling as far across the frame. I really dont know of any way to limit the green colour cast effect in Velvia other than using a magenta colour correction filter or colour correcting in post.
Tungsten balanced film will have a different colour shift. Provia 100F requires no correction at all for exposures shorter than 128 seconds wheras Velvia exhibits colour shift after 4 seconds.