Researching Active Solar Longitudes
Choosing Images
The ImageJ Toolbar | Choosing Images | Using the Macros | Finessing the Image | Submitting Data

Your students will be able to open and work with images quickly using ImageJ. There are two ways for your students to view a series of image files to determine where they would like to begin their research. The first way is to view the magnetogram movie that is part of the RASL program. This movie is a quicktime file containing 23 years worth of magnetogram images of the sun. The second way is to load an image sequence from your target year. The steps for each of these techniques follows.

Place the "Solar Magnetic Cycle" disk in your disk drive and double click the "My Computer" icon on your desktop.

A window similar to this one will open on a PC.

One of the drive icons will show that the "Solar Cycle" CD is in the computer.

Double click the icon for that drive.

The "Solar Cycle" disk contains six folders as shown here. These folders include:
Data Table Sample
Magnetogram Movie
PNG Magnetograms
READ ME
Software Macintosh
Software Windows

Double click the Magnetogram Movie folder to open it and double click the file in that folder to start the movie.

A window will open on your desktop and the movie is ready for you to play.

Notice the control buttons at the bottom of the window. They are similar to the control buttons on a typical VCR. From left to right they will:
Return to the beginning
Rewind
Stop/Start
Fast forward
Go to the end

Browse through the images until you notice a particularly active period in the solar cycles. There is a date stamp in the lower left corner of the image.

When you find an active time, stop the movie and arrow forwards and backwards through the image slides keeping track of the calendar dates.

Here's a hint: take a look at the dates around August 1990. The examples in the following pages will be taken from those dates.
Reminder: you will want to follow an active region as it progresses from left to right across the solar disk. Find a range of dates for which an active region can be easily seen to do this.

The second way for you and your students to find a sequence of images to use is to build an image sequence.

To do this go to File and choose Import from the drop down menu and Image Sequence from the side menu.

You may need to navigate to your Active Solar Longitudes disk and choose the folder titled PNG Magnetograms.

If you have downloaded the PNG Magnetograms folder and have saved it to another area, navigate to that folder.

Choose a year folder in which you are interested and open that folder.

In this example, the folder for 1990 has been chosen.

Double click the folder of the year of your choice.

The folder will contain files with the names similar to the following:

yymmddma
900101ma
This translates to January 1, 1990 magnetogram image.

Double clicking on a date of your choice will open the Sequence Options dialog box.

The image to the left shows the dialog box for data from the year 1990, and indicates the following information:
Number of Images: (there are 268 magnetogram images for calendar year 1990)
Starting Image: (you can enter the number of any image for the calendar year)
Increment: (an increment of "1" will add images from successive days; larger numbers will skip intervening images)
File Name Contains: (allows you to choose specific months or days, in this example only days from August were selected because it was particularly active.)

You can also choose to:
Convert to 8-bit Grayscale
Open 1/2 Size (this will decrease the amount of available memory needed to construct the stack.)

The stack of images created from the above parameters resulted in a collection of 25 magnetograms from August 1990.

A student can now easily view this month for its activity and determine the start and stop dates for particular sunspots on the solar disk. This type of image preview can also be constructed for an entire year.

Once you and your students have found target dates for your study you can move on to using the macros.

The ImageJ Toolbar | Choosing Images | Using the Macros | Finessing the Image | Submitting Data

RASL is a project supported by funds from National Solar Observatory Research Experience for Teachers, NASA, and in part by the Office of Naval Research. The NSO is operated by AURA under cooperative agreement with the National Science Foundation.