The Blue Filtered Crab Nebula

Yellow Filter
Blue Filter
Red Filter
No Filter

When you look at the Crab Nebula through the blue window on your filter wheel it is easy to see that most of the blue light passes through the blue cellophane. The red and other colored light is mostly absorbed. This is why the cellophane looks blue to us. It is absorbing all colors except blue. What do you expect the Crab nebula to look like through the red cellphane?

When you have viewed all the filtered images let's discuss why filters are useful.

Yellow Filtered Crab Filters Lesson Red Filtered Crab