Photo Courtesy of Steve MacKay


Excerpt from Steve MacKay's Blog:  http://www.stevemackayphotography.com/section363141.html 


While learning tips on night photography and star trails on the internet I stumbled upon an application 

called  "startrails.exe", this software allows a photographer to take multiple exposures (several hundred if 

necessary) and  blend/stack them together, the image on the top is made up of approx 40 different 1min 

exposures blended together  in startrails.exe.



Each individual shot (out of the 40) shows the stars as the human eye sees them (small round dots), but 

after the 40 minutes the earth has rotated so much around it's axis that the stars are in slightly different 

positions in all the shots,  the software purely joins up all the stars to create the star trails effect.


Of course you could take a single 40 minute exposure to get the same result....the problem is that (in my

  
part of the world at least) you will have a lot of light pollution which can ruin the shot, or you will have to 

select a lower iso and or narrow aperture that will render the star trails much fainter.


Below I will give some tips on how to take the shots and use the software, plus some pro's and con's (of 

which there  are both). also some alternative techniques to create the same effect.  To read the entire 

article click on this link: http://www.stevemackayphotography.com/section363141.html   and then go to the Star 

Trails article.     I hope you will  find this article as fascinating as I did, and that you will be able  to attempt 

your own shots!