About observational astronomy

Astronomers can gain an understanding of objects in the universe by using a telescope. A CCD imaging system is a type of digital camera that is very sensitive to the dim light from distant objects. The CCD camera is attached to a telescope and the images are stored on a computer where they can later be analyzed. In this learning activity a computer program will be used to view and study images taken with telescopes to learn basic concepts in astronomy.

Activity

Astronomical images are stored in a computer file format called FITS. These images can be opened and viewed by using computer software that understands this file format. We will start by using a program called the Aladin Sky Atlas to retrieve images taken with a telescope and study them.

• Open another window in your web browser by clicking on this link to the Aladin previewer program.
• In the text box type the name of the object that we are interested in studying. Try typing M101 and then click the Default image button.

This image of a galaxy was taken as part of the Palomar Sky Survey. The common name for this object is the Pinwheel Galaxy.

Readings

• Wikipedia article: w:Observational astronomy
• Wikipedia article: w:Telescope