Double Stars

A number of the stars that are visible in the night sky are not in fact single stars, but rather what is known as double stars. When these stars are viewed through a telescope or even a pair of binoculars, a second companion star is found to be right next to it. Some cases resolve three stars in the grouping. Most stars are part of a system of stars of some sort. Binarys are stars that are very close to one another.

Binary stars have unique evolutionary properties. When one dies, the other is typically close behind. The remanat of the first will often feed off of the other shortening its lifespan. In the case of the star Sirius, it has a dark companion, often known as the pup, which is a remnant of a former partner.


  1. Devise a Plan of Attack. Consult with the observatory manager and choose the objects you wish to try to view through the telescope. For this project, there are several recommended stars: 
     - Alcor and Mizar.
  2. Locate each star in the telescope at Davis Hall. Ideally, you should now be able to separate the light from the two stars and see them both.
  3. With the manager's assistance attach either a camera or the CCD to the scope.
  4. Capture at least one image, or more if you choose. Try several different images in different scopes and powers of magnification.
  5. With use of photography, or with the CCD images, the pictures may be enlarged so that they may be more visible. For the stars, it is enough to observe their color differences and brightnesses and to resolve their companions.

Data Intepretation

For the most part, this should be self explanatory. A write up should include discussion of the evolution of binary systems and of the different types of binaries.

Observatory Manager

Sarah Choate


Davis Hall Room 703
Normal and Locust Roads
DeKalb, IL 60115
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