Why Do Scientists Use Filters?

filtered images

When astronomers observe astronomical objects in the sky they often use different filters to enhance the aspects they are most interested in. At the same time, this mutes other features that might be distracting.

The blue filter on your color wheel for instance is a good choice if you are interested in studying the hot, central portion of the Crab nebula. The red filter is a better choice for enhancing the outer gaseous regions. The yellow filter enhances the filament structure in the center of the nebula.

Filters are a very useful tool for scientists. When taking data from an image one must always be careful and remember that things look different if the image has been filtered. The Crab nebula looks very hot and small through the blue filter and very large and cool through the red. Niether of these views alone give an accurate representation, but by combining the information gained with the different views, we can create an accurate discription of the object.

This method of observing through different filters and then collecting the information into a complete picture is used all time when we look at our nearest star, the Sun. Let's investigate how solar scientists use filters to view the Sun.

Red Filtered Crab Filters Lesson Our Star the Sun