City Skyline Day and Night – Single Timelapsed Photography

Mixing day and night images with the technique in astrophotography known as ‘star trails’ it is possible to capture a single image detailing both day and night activity. In the photograph below to the left is the moon streaking across the scene and the lights of aircraft at night, to the right is the sun with traffic captured below. Depending on your location the technique can create some interesting timelapse single views photographs, below we detail how to create your own.

You will need:

1 x Timelapse System, you can use a simple webcam as per our previous Tutorial: Torch + Webcam = HD Timelapse System a DSLR such as the Canon G9 with CHDK , a iPhone with the free Gorrilacam app or any camera that can take photos at regular intervals. We used a Go Pro HD camera in timelapse mode, taking a picture every 5 seconds.

1 x Copy of Photoshop, you can download a 30 day trial.
1 x Photoshop Stacking Action (thanks to Deep Space Astrophotography

Time Taken, 4 to 12 hours to capture, 2 to 6 hours to process.

The concept is simple, set up your camera, webcam or iphone at a suitable location, and capture an image at regular intervals, for our example we captured an image every 5 seconds pointing at the skyline of London. Capturing an image at least every 5 seconds is vital for star/aircraft trails as it allows for closer spacing between the lights in the final image.

We left the camera running for approximately 12 hours capturing 8000+ images, saved into a folder on our computer. Ours captured covered both day and night time, resulting in the following timelapse:

The next step is to open up photoshop, chose the images you want to use, and start stacking.

Image Stacking in Photoshop


The images will be stacked onto of an intially blank image via a simple automated action:

1) Create a new blank black image the same size are your captured photographs.
2) Load the action into the action windows in Photoshop and load the action Startrails.atn.


3) In Photoshop click ‘File’, ‘Automate’ and ‘Batch’. Select the action you have just loaded and choose your directory with the images as source and make sure you select ‘None’ for the output directory.
Click ‘Ok’ and leave it running, our Mac laptop took around an 2 hours to stack the images – resulting in the Star/Aircraft Trail’ below:
The line across the centre is a star and the bright line on the left is the moon coming into shot. The rest of the lights are aircraft in the sky above London. If you use a complete day/night sequence then you can create images of stars/activity in a blue sky, as in our first photograph.
You can view higher resolution versions via our Flickr Photostream.

A Sociable Physics Animation

The animation below details the real-time behaviour of hire bikes in London on October 4th 2010, the day of a major tube strike, and the busiest day for the scheme to date.

Departure times and journey durations are real; routing is calculated from OSM data; average speed from journey duration and route length.

London Hire Bikes animation from Sociable Physics on Vimeo.

In the visualisation, the fixed circles represent stands – when a stand flashes red, it means that one or more bikes have left it – and a yellow flash means a bike has arrived. The bikes themselves are represented by the Boris Barclays Blue Tadpoles whizzing around – leaving at the right time, travelling at their correct average speed, and taking a (generally) realistic route.

The movie was created by Martin Austwick of Sociable Physics, here in CASA with the help of Ollie O’Brien (again CASA) for collection and routing.

We are a bit biased on such work, here at digital urban, but its great….

CASA Bike Route Map in Wired

Ollie O’Brien’s work of the now widely featured Boris bikes visualisations gain a double page spread in this months Wired magazine.

Image courtesy of Adrian Short

Embedded below is a view of Ollie’s work as a timelapse to illustrate the distinctive weekday commuting patterns of the London cycle hire scheme:

You can run the animation direct via the Cycle Hire Dock Visualisation Map, and find out more about Ollie’s work at CASA and beyond via his Suprageography blog.