How to Take Part
Here are details about registration, log in, and classification procedures:
We encourage you to Register and Login to help classify stars that may have never been
classified by anyone else ever before! It's easy and it's fun! Click on one of the menu items for details.
Briefly, To Proceed - go to the CLASSIFY menu item shown at the top of this page
and login. If you have not already registered you will be asked to do so. Once logged in,
choose a plate, choose a star from the plate and classify the star! Star classifications are recorded
and as new stars are officially classified you will be notified of these new discoveries through your account under MY SCOPE.
Register
Click on the
CLASSIFY menu item shown at the top of this page. You will see the words "Not a registered user? Click here to register."
in the Login box shown on the Classify page. Click to register and get your Login name and password. You will only need to
do this once.
Log In
Click on the
CLASSIFY menu item shown at the top of this page. You will see the Login box on the Classify page.
Log in using your Login name and password. The adventure begins!
Choose a Plate
Choose a plate (or a collection of stars) from the list by clicking on the plate name that you see on the Classify page after you have logged in. The
plate will be displayed in a separate window, and it could take a few seconds for it to load. We are using JAVA control software,
so make sure you have the most recent version JAVA.
The SCOPE control software requires JAVA version 1.6 or greater. If you need to update your JAVA version you
can download directly from the Sun JAVA Web site. Just click on the link below and follow the instructions.
Pick a Star
After choosing a plate, an image of the plate will be displayed. You can use the scroll bars to move the image around and
see different parts of the plate and the stars that are on it. Stars that are available for selection are outlined with blue borders on the plate image.
Select a star by clicking once on it. Clicking on a star will bring up a dialog box that tells you the name and location of the star. Once you find a star you wish to classify, click on the "Classify a Star" button at the top of the page to classify the star you
currently have selected.
After a few moments, the classifier window will open and now you are ready to start the classification process!
Classify Your Star
A new window pops up after you choose and click on "Classify a Star". The window shows on the left the image of the
star you chose. On the right are selections of the 7 major spectral types. Drag the best matching of the 7 major classes
to the empty box above your chosen star. You may also double-click a star type on the right to select it, instead of dragging it.
Once you find a standard star type from the 7 major classes that you think is the closest match to the unknown star you chose to classify,
you have the options of using the Expand and Compare tools to verify your suspicions (see
Using the Tools below).
If you are happy with your selection, click on "View Next Level". You now see all of the subclasses for the major class you
selected. Go ahead and double-click or drag the best matching subclass to the left. You have the options of using the Expand and Compare tools here as well.
When you are happy with you classification, click on "Save the Classification" at the top of the page. You will be shown your classification, and given the opportunity to make
a comment. Your comment may be about features that didn't match, or if you had trouble deciding between two different subclasses,
for example. When you're done commenting, click on "Record" and your classification will be recorded in the database.
You will be given the option to do another classification either from the same plate or a different one. Have fun!
Using the Tools
The Expand Tool allows you to shift and zoom the two spectra in order to ensure that all of their spectral
lines match. You can use the two large green arrows to shift the top spectrum left and right, respectively.
The magnifying glasses allow you to zoom in, reset the ratio, and zoom out the two spectra, respectively. A
comparison image also shows below the two spectra at all times to show how well your classification matches the unknown.
The Compare Tool shows you a comparison of how well your standard star selection matches the unknown star by matching the lines in the two images.
The resulting comparison image is displayed directly on the main classifier window. The green areas of the comparison are areas of both spectra that match.
The red areas of the comparison are areas that do NOT match on both spectra. The text that overlays the comparison is on a scale of 1 to 10.
View Your Stars
Once you have classified a few stars, feel free to view your classified stars at any time by clicking on the
MY STARS menu item shown under the
MY SCOPE tab at the top of this page.
Here you can see all of the stars that you have classified in the past, along with how many others have classified each star you have, and the official star type (if it has been determined). Your comments may be viewed here as well.
The number of times that a star has been classified is shown in parentheses next to the stars name. To view the official star type, click on the star type of the star you'd like to view. If no official star type has been determined for
a particular star, then a question mark [?] will be shown next to the star type in the table, along with a popup message to that affect.
To print your previously classified stars, click on one of the two print buttons at the top of the
MY STARS page.
Get Some Classification Experience
For fun, try your hand at classifying a star!
This can provide you some experience with classifying stars before you get started for real or it can serve as a refresher course for those who may have forgotten how it's done.
Shown below are the 7 major star classes. Notice the differences in the images.
The biggest differences are the number and placement of the lines in each image. In the B and A stars, the dark lines are
due mostly to hydrogen.
Looking further down the set of images, 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.
Another star is shown below. Look at the pattern of lines again. Notice how the pattern is somewhat similar to the
star you just looked at, but there are not quite as many lines. Go ahead and classify the star by comparing it to
one of the comparison stars above. Run your mouse cursor over the image to see how you did.
Here's another star. Look at the pattern of lines again. Notice how the pattern is different than the previous two
stars you just looked at. The pattern is more compicated. Go ahead and classify the star - which one does it match
best? Run your mouse cursor over the image to see how you did.
Here are several more to practice on:
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
Here's a B type star.
Which one of the B subclasses does it look closest to? Put your cursor over the image to
check your classification.
Here's another example. This time, you are shown the subclasses of M type stars.
| M0V |
 |
| M1V |
 |
| M1I |
 |
| M2I |
 |
| M3III |
 |
| M4III |
 |
| M5V |
 |
| M5III |
 |
Here's an M type star.
Which one of the M subclasses does it look closest to? Put your cursor over the image to
check your classification.
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!
You are now ready to classify stars.
