The Red Filtered Crab Nebula
As you might have predicted, when viewed through the red window on your
filter wheel the Crab Nebula looks much different than through the blue
cellophane. Here we can see all of the cooler, red gas on the outer edges
of the nebula which was mostly invisible in the image before.
When you have viewed all the filtered images let's discuss why filters are useful.
Blue Filtered Crab
Why Use Filters?