Fixed Star Photographs

• 1). Fully charge the camera battery. Long exposures mean that the shutter will be held open for a long time, which uses a lot of battery power.
  
  
• 2). Switch the lens to manual focus and rotate the focus ring to infinity. This allows the camera to focus on distant objects so that stars and other celestial bodies will look sharp when the picture is taken.
  
  
• 3). Choose an aperture between f/5.6 and f/8. For modern lenses, this is the sweet spot for producing the sharpest images. A suitable ISO--or light sensitivity--setting is 400 to 800, which strikes a balance between making the dimmer stars more visible and reducing image noise.
  
  
• 4). Select an exposure time of a few seconds. The best exposure time depends on the lens being used: The wider the lens, the longer the image can be exposed, because the movement of the stars is less apparent. As a guide, a 15 millimeter lens can expose for around half a minute, and this exposure time decreases as focal length increases.
  
  
• 5). Fix the camera to the tripod and ensure it is steady. Using the shutter release to operate the camera without touching it, shoot several test shots to determine the best exposure time.
  
  

Photographs with Star Trails

• 1
  Example of star trails caused by the Earth's rotation.Star Trails image by Joseph Chiapputo from Fotolia.com
  
  Set up the camera, tripod and shutter release as described in the instructions for fixed-star photos. To get the star trail effect, the aperture and exposure time are changed.
  
  
• 2). Choose an aperture between f/5.6 and f/11 and an ISO of 400 to 800. Because the exposure is going to be much longer, the smaller apertures can be used to reduce the effects of light pollution.
  
  
• 3). Experiment with the exposure time, but it should be at least a few minutes to give the Earth time to rotate enough to capture the star trails.