How to Take Part
|Register & Log In||Choose a Plate||Pick a Star||Classify Your Star||Using the Tools||View Your Stars|
To get started, Login or Register for an account. Once logged in, Choose a Plate , select a star from the plate and classify the star! Your previous star classifications are recorded and can be viewed through your account under My Stars.
The classifier window will now load and you are ready to start the classification process!
Once you find a standard star type from the 7 major classes that you think is a close match to your unknown star, you have the option of using the Zoom and Shift tools to verify your suspicions (see Using the Tools below).
If you are happy with your selection, click on "View Next Level" (circled button, top image). You now see all of the subclasses for the major class you selected.
When you are happy with you classification, click on "Save the Classification" at the top of the page (circled button, bottom image). You will be shown your classification and given the opportunity to make a comment. Your comment may be about features that didn't match, trouble you had deciding between two different subclasses, or any suggestions for SCOPE's improvement, for example. Click on "Record" and your classification will be saved in the database.
You may notice that the comparison tool from SCOPE 2.1 is no longer being used. It was removed because, unfortunately,
For fun, try your hand at classifying a star!
This can provide you some experience classifying stars or serve as a refresher course for those who may have forgotten the process.
Shown below are the 7 major star classes. Notice the differences in the images, specifically the number and placement of the spectral lines.
In the B and A stars, the dark lines are due mostly to hydrogen. In the later stars, the hydrogen lines don't dominate quite as much. Instead, we see other sets of more complicated patterns of lines. When you classify a star, your objective is to match as closely as possible the unknown star spectrum (patterns of lines) to one of the known stars like those shown below.
Below is a spectrum of a star. Look at the pattern of lines. Match the pattern to the one above that fits the best. Then, put your mouse cursor over the spectrum below to see if you guessed the correct star spectral classification.
Great! Now let's go one step further. Each of the star types you just classified is subdivided to match finer details in a star's spectrum. For example, the B type stars have subclasses B1, B2, B3, B4, B5, B6, B7, and B8
Below is a B type star.
Here's another example. This time, you are shown the subclasses of M type stars.
Here's an M type star.
Have you noticed the letter "III" in the classification you just did for the M3III star? You will often see other designations like "I" or "III" or "V" in the list of comparison star spectra. The "I" means the star is a Supergiant, "III" means the star is a Giant star, and "V" means the star is a Main Sequence Star. See The Science section of this website for more details about these designations.
Because the spectral classifications include the Main Sequence, Supergiant, and Giant types, the list of comparison star spectra will be longer than shown for the B type stars above. This will make classification a bit more challenging. But, this is why we are asking you to contribute. Classifying hundreds of thousands of stars by one person is a daunting task, but with your help, we can more deeply explore our neighborhood of the Milky Way Galaxy!