In introductory astronomy courses one spends a lot of time learning about the many different types of stars in the universe. A quick look at the HR diagram below illustrates some of the main types. Teachers spend a lot of time going through all this but, to the inquisitive student, there is one BIG problem, and that is.... QUESTION: The HR classification diagram says that most stars are blue or red or yellow... but when I look at the stars myself, they all appear white, what's wrong?  These are the photographs each group of students took of the Constellation Orion on Feb. 27, 2014.
Photograph of the constellation Orion. This is a 25 second exposure made with a Canon T4i DLSR camera. Many stars appear blue, a result of their high surface temperatures. Betelgeuse is the coldest star and it appears yellow/orange. To the naked eye, which is not very sensitive to color when the light source is very dim, all stars appear essentially white. But a digital camera is much more sensitive to dim lights and the true star colors quickly come out. |
ASTR116 Spring 2014 >
