Using our recent tutorial on image stacking it is possible to stack images from both day and night to create a single image of the city skyline over time. The photograph below consists of 8400 images taken using a Go Pro HD with one image every 5 seconds. The streak of light to the left is the moon during the night time sequence, while the right hand light is the daytime sun. The small lights are aircraft during the evening:
You can view a higher resolution version on our Flickr Stream, we will have more on the Go Pro HD next week, including a tutorial to create 24 hour+ timelapses.