Other astronomy activities

An electronic Lesson and Exercise "The Life of Stars and their Spectra"

"SpectrJ" is the exercise provided by Greece. It is developed by:

Dr. Margarita Metaxa,
Dr. Ioannis Bellas-Velidis,
Dr. Anastasios Dapergolas,
Dr. Aglaia Bobetsi.

It is an electronic pedagogical tool for secondary schools that aims to provide a ready-to-use resource, inspired by real observations and research activities applying modern processing techniques. This tool presents to you an e-Lesson and a corresponding e-Exercise focused on the stellar spectra and their importance in astrophysics. Travelling through the pages of the lesson you will get basic information on light and its spectra, on the stellar spectra and their classification into spectral types, and how they provide us with knowledge about the stars and their life. This lesson will be the theoretical base to understand the exercise. On the other hand, by doing the exercise you will follow, in a simplified manner, the steps taken in a real research project. You will find the age of stellar systems in the neighboring galaxy SMC by classifying and analysing the spectra of their stars.

Languages supported:

EN - English

GR - Greek

SV - Swedish (new)

Introduction

About

Readme

Languages

DOWNLOAD FILE	REMARKS
SpectrJ_setup.exe [~40.8 MB] SpectrJ_plugin.exe [~21.2 MB] SpectrJ.tar.zip [~36.0 MB]	Setup file contains SpectrJ 1.0 (EN/GR/SV) for MS Windows. It includes the ImageJ 1.36b (with Java RTE 1.5.0_06). This setup installs SpectrJ and ImageJ ready to run. The installed package size is about 130MB. Setup file contains SpectrJ 1.0 plugin (EN/GR/SV) for MS Windows. You should have already installed the ImageJ (1.34 or above). The plugin increases the ImageJ size by about 50MB. Zipped tar file contains SpectrJ 1.0 plugin (EN/GR/SV) for Linux/UNIX. You should have already installed the ImageJ (1.34 or above). The plugin increases the ImageJ size by about 50MB. Select the appropriate setup file for you. If you already have installed an older version of SpectrJ, remove it before installing the new one. For information on the ImageJ see: Home site http://rsb.info.nih.gov/ij
SpectrJ_Manual_EN.pdf[5.5 MB] SpectrJ_Manual_GR.pdf[5.9 MB] SpectrJ_Manual_SV.pdf[5.9 MB]	The Manual contains simply screen-copy of both, the e-Lesson and the e-Exercise Help. There are EN, GR and SV language versions. (The interactive e-Lesson and the e-Exercise Help are part of the setup files above, in html form, and are accessible online from the SpectrJ)

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Introduction to

"The Life of Stars and Their Spectra"

INTRODUCTION

What is SpectrJ ?

SpectrJ is an electronic pedagogical tool for secondary schools that aimes to provide a ready-to-use resource, inspired by real observations and research activities applying modern image processing techniques. This tool presents to you an e-Lesson and a corresponding e-Exercise focused on the stellar spectra and their importance in astrophysics.

Travelling through the pages of the lesson you will get basic information on light and its spectra, on the stellar spectra and their classification into spectral types, and how they provide us with knowledge about the stars and their life. This lesson will be the theoretical base to understand the exercise.

On the other hand, by doing the exercise you will follow, in a simplified manner, the steps taken in a real research project. You will find the age of stellar systems in the neighboring galaxy SMC by classifying and analyzing the spectra of their stars.

Why SpectrJ ?

Spectra is the key to understanding the Universe

On a clear night face south and you will see the constellation of Orion. Immediately your eye catches two stars that shine the brightest, Betelgeuse, which looks reddish, and Rigel, blazing bluish white. To the south and east of Orion lies Canis Major, the Great Dog, Orion's hunting companion. You will easily notice Sirius the jewel of Canis Major, as the brightest star in the sky. The differences in these stars typify the astronomers' dilemma: what can we know about these distant stars, how do these stars compare with our sun, are they more luminous, and many other questions about their physical properties.

The techniques used to understand light derive from investigations begun by Newton in the mid-1600s. Newton used a prism to break up a beam of white light into a band of colors called a spectrum. He also showed that the colors could not be broken down further, and that they could be recombined to give white light. The existence of radiation beyond the two ends of the visible spectrum was unheard of at that time.

The well known physicist Auguste Compte wrote in 1835: "we understand the possibility of determining their (celestial bodies) shapes, their distances, their sizes and motions, whereas never, by any means, will we be able to study their chemical composition" and this is a classic example of the risk inherent in trying to set a priori limits to human knowledge. Though Compte could conceive of no method that could span the vast distances between the stars and determine their composition, a century later astronomers would carry out such analyses routinely.

During the nineteenth century, laboratory experiments by physicists showed that the spectra of light emitted from various luminous substances differed greatly from each other. Finally in the twentieth century, is become possible to obtain detailed information about the stars by studying their spectra. It is not exaggeration to say that the overwhelming majority of modern astrophysical knowledge comes from a study of the spectra of celestial bodies.

Indeed

Spectra is the key to understanding the Universe.

Learning objectives

e-Lesson
To learn the optical spectrum, its parts, and the different types of optical spectra. To learn the basis for classification of stars by spectral types and to be able to describe their basic types. To understand the information we can get from the spectra about the evolution of stars and how we can estimate the age of a stellar system using the spectral classification of its stars.

e-Exercise
To execute a research task example using an image processing based application. To understand the correspondance of a stellar image with its spectrum image and graph. To learn a simple method of spectral classification by comparison with standard spectra. To understand how a simple numerical distribution of stars by spectral types in a stellar system can be used to obtain the age of the system.

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SpectrJ v1.0 READ ME

1. INSTALLATION

1.1 MS-Windows standard installation: SpectrJ_setup.exe

This setup includes ImageJ 1.36, Java JRE 1.5.0_06. There is an executable setup file SpectrJ_setup.exe (about 40MB). Running it, the SpectrJ is installed automatically and a shortcut SpectrJ will be created on your desktop to run it. This setup includes the ImageJ ver. 1.36b, a public domain Java image processing program by Wayne Rasband at the National Institute of Mental Health (see http://rsb.info.nih.gov/ij), bundled with Java (JRE 1.5.0_06). Uninstalling SpectrJ will uninstall also the ImageJ.

1.2 MS-Windows plugin installation: SpectrJplugin_setup.exe
Only SpectrJ plugin and windows launcher SpectrJ.exe are included. There is an executable setup file SpectrJplugin_setup.exe (~20MB). If you already have the ImageJ (version 1.34 or above) installed, this will install only the plugin subdirectory SpectrJ and SpectrJ.exe launcher. You can create a shortcut to the launcher on your desktop. Uninstalling SpectrJ will not uninstall your ImageJ.

1.3 LINUX/UNIX plugin installation: SpectrJ.tar.gz

This setup contains only the SpectrJ plugin. You should have ImageJ (version 1.34 or above) for your system already successfully installed (see http://rsb.info.nih.gov/ij). Unzip and untar the SpectrJ.tar.gz under the ImageJ's plugin directory. This will create a SpectrJ subdirectory with the plugin. You can then run SpectrJ as plugin from the ImageJ Plugins menu.

2. RUNNING

2.1 MS-Windows SpectrJ executable run

You can start the SpectrJ double-clicking on its icon created on your desktop after successful installation. Temporary appears the ImageJ toolbar that is then replaced by the SpectrJ main window. Here you have the controls to access the different functions of the SpectrJ (Introduction, e-Lesson, Help, e-Exercise, About, Language, and QUIT). Quitting the SpectrJ, closes its Main Menu, temporary reappears the ImageJ and exits automatically (you have no access to ImageJ itself). This executable-type run is available independently of the installation method on MS-Windows.

2.2 MS-Windows ImageJ/SpectrJ plugin run

You can also run the SpectrJ from the ImageJ. Start the ImageJ program double-clicking on its icon. Click on the Plugins on the ImageJ menu, this opens a list of items, point to the SpectrJ and then click on the SpectrJ tab that appears on the right of the list. The ImageJ toolbar disapears and as above appears the SpectrJ Main Menu. Here, quiting the SpectrJ only closes its menu and reapears the ImageJ available for use. The plugin-type run is available independently of the installation method on MS-Windows.

2.3 Linux/UNIX ImageJ/SpectrJ plugin run

In this case, you proceed exactly as in the MS-Windows plugin run. An executable-type run is not available in this installation method.

2.4 SpectrJ rerunning

In either case, if you have already executed (partially or totally) particular task of the eExercise and then exited, rerunning this task will automatically show the already executed steps. This is true if you are reentering with the same working code as before (see Section 4 below).

3. PARAMETERS (optional, influencing the eExercise only)

There are four optional parameters for modifying the eExercise execution. They are provided as a way to speed up the interactive execution of the exercise if this is necessary. The parameters are in the SpectrJ.properties file in the plugins\SpectrJ subdirectory (an editable text file). There are comment-lines (line starts with #) and parameter-lines (name = value). Do not change spjTitle and spjVersion parameters. The other four parameters are for running the e-Exercise and affect only the way the COMPLETE button is available for an automated completion of the particular task (Detection, Extraction and Classification, see the ExerciseHelp). This COMPLETE button switches on an automated execution of the particular task up to the task's end without user interaction, only displaying the tasks steps.

minTasks = 4
After completing (100%) of this number of tasks of a given type, the COMPLETE is always available for this type tasks (say, after full finishing the Detection for the AF, AS, BF, BS, the COMPLETE is always available for the Detection task of the remaining CF and CS field/frame), no matter the parameters below

minDetect = 5
After detecting of this number of objects the COMPLETE button is enabled for the particular DETECT task

minExtract = 3
After extracting of this number of spectra the COMPLETE button is enabled for the particular EXTRACT task

minClassify = 6
After classification of this number of spectra the COMPLETE button is enabled for the particular CLASSIFY task

4. USER WORKING SUBDIRECTORY

Running the eExercise creates a working subdirectory under the user's home directory (e.g. under C:\Documents and Settings\username on MS Windows XP Pro). The name of the working subdirectory is fixed in the beginning of the eExercise run by specifying a "Work Name" on the start dialog request. This subdirectory is never deleted by the SpectrJ. It contains the current state of the execution of the eExercise by the user and is used to restore the already executed task(s) in a case of temporary exiting and rerunning SpectrJ again. But, you can simply delete the working directory after the user has finished the exercise. So well, different users if they are working under the same user name on the particular computer should use different work names (see the eExercise Help).

5. EXERCISE RESULT

The final result of this exercise, after all the tasks completing is always the same. This is due to the fact, that the user is not allowed to misidentify or to skip spectra during the detection and to classify exactly their spectral type, so the final statistics, wherefrom the result is obtained, is always the same.

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Languages (internationalization of SpectrJ)

LANGUAGES By default the base installation is provided for English and Greek languages only. There are three types of objects where the "translation" has to be applied if you wish to implement the SpectrJ in your preferred language. These objects are: A. java programs, B. html pages, C. images with text. Following the instructions bellow, will assure automatic recognition and use of the new language by the SpectrJ. If you followed the standard installation, the base directory mentioned below is C:\Program Files\ImageJ\plugins\SpectrJ
A.	eExercise (java program)
	The internationalization here is based on the JAVA-language standards. There is a subdirectory "Locales", under the base directory, where the different language files should exist. By default there should be the following three files: spjBundle.properties - the base file that should not be changed spjBundle_el.properties - the greek language file spjBundle_en.properties - the english language file (base file copy) These are text files with comment lines (starting with #) and parameters lines. Each parameter line starts with the parameter name, follows three characters (space, =, and space), and then is the parameter value to the end of the line. The value is in UNICODE representation, see below, except for the base and the english language files. The steps you should follow are:
	a.	Make a copy of the spjBundle.properties file and name it spjBundle_??.txt where "??" should be the two-letter ISO-code for your language. For example el - greek en - english es - spanish fr - french it - italish pl - polish pt - portuguese sv - swedish
	b.	Open the txt-file with simple text editor (say Notepad) and replace the text in the value part of the parameters with your translation. Do not change the names. It is not necessary to translate the comments. Please, remember that each parameter (name = value) should be on one line (there is a "\n" command in the text for breaking line if this is necessary), no matter how long it is.
	c.	Optionally, and only if your language is none of the above listed, you should update in your text-file the parameter allLanguages. Currently it is allLanguages = enelesfritplptsv and it should be allLanguages = enelesfritplptsv?? where ?? is your language ISO-code. Then, you should add a new parameter ??_Language = ??????? after the last Language parameter with ??????? being the name of your language (this will appear on particular button on the SpectrJ menu).
	d.	Convert the spjBundle_??.txt file to UNICODE naming it spjBundle_??.properties. To convert to UNICODE you can use the JAVA's native2ascii program native2ascii inputfile outputfile This program is included in the Java Development Kit that can be downloaded for free (as of June 2006, Java 2 Platform Standard Edition JDK 5.0 Update 6) from http://java.sun.com/j2se/1.5.0/download.jsp Under MS Windows the JDK is installed by default under the C:\Program Files, so in this case open the Command Prompt window, change to the Locales subdirectory, and run "c:\Program Files\Java\jdk1.5.0_06\bin\native2ascii" spjBundle_??.txt spjBundle_??.properties (all in one line). It is not recommended to remove the txt-file (it is good to save it somewhere out of the SpectrJ for the case you would like to correct your translation).
	The english language spjBundle_en.properties file can also be updated, say to correct our english. This can be done directly on the properties file without transforming it to UNICODE. But, please do not change the base spjBundle.properties file.

B.	ExerciseHelp (html and images with overlying text)
	In order to have also the ExerciseHelp available in your native language you should prepare your language version of the Help. Else, the english version will be used. The Help is a set of HTML-files and the "translation" task here is quite different.
	a.	Go to the directory ExerciseHelp and copy all the EN subdirectory (english version) to a new one named ?? where ?? is the two-letter ISO-code for your language (see above) in capital-letter case.
	b.	Go to the new subdirectory and edit one by one the HTML-files with your preferred html-editor (you can use also the Notepad under MS Windows). Translate, whenever it is necessary the english text (not the html commands) to your language. Please, be careful not to change the overall shape of the html-page as it has predefined size that can not be changed nor the content can be scrolled. So, it is preferable to use WYSIWYG-type html-editor.
	c.	Under the ??\images subdirectory there are some images used by the html-pages that have english-version text. Most of them are simply screen copies from running the SpectrJ. You can replace them with the corresponding taken while running SpectrJ in your language after the step A. above (do not change the image file names). Under MS Windows, use Alt-PrintScreen key combination on your keyboard to copy the active window, then paste it (usually with Ctrl-V keys) to your image-editor, get the necessary part of the image resize it to the "english"-version image's size and replace the original image file with the new. This should be done for the images: Intro1.jpg Intro2.jpg Tasks.jpg Detect.jpg Extract.jpg Classify.jpg Analyze.jpg Result.jpg The text on two more images should be changed directly using your image editor. These are SpectrJ_title.jpg spectr_extract.jpg Please, be careful with the jpg-compression (high values could make unclear the resized image)!
C.	The "translation" of the eLesson is similar. There are html-pages and lot of images with text on them. If there is no your language version of the lesson, the english version will be used.
	a.	Go to the directory eLesson and copy all the EN subdirectory to a new one named ?? where ?? is the two-letter upper-case ISO-code for your language (see above).
	b.	Go to the new subdirectory and edit one by one the HTML-files with your preferred html-editor (you can use also the Notepad under MS Windows). Translate, whenever it is necessary the english text (not the html commands) to your language. Please, be careful not to change the overall shape of the html-page as it has predefined size that can not be changed nor the content can be scrolled. So, it is preferable to use WYSIWYG-type html-editor.
	c.	Finally, there are about sixty images that should be edited directly with your preferred image-editor. Most of them are under the subdirectory eLesson\??\images SpectrJ_title.jpg (the same as in ExerciseHelp) wavelengths.jpg Image1_1d.jpg Image1_2a.jpg spic-sun-ant.jpg SunCenter.jpg Image4_1b.jpg Image4_3.jpg m45_m11_m3.jpg the other are buttons and images for interactive displaying, that are under particular subdirectories: eLesson\??\images\drop-rainbow\ button_all.gif button_next.gif raindrop?.jpg (? is 1,2,3,4) eLesson\??\images\spectra_em_ab\ spectraEmAbs_button?.gif (? is 0,1,2,3) spectraEmAbs?.jpg (? is 0,1,2,3) eLesson\??\images\planck_graphs\ planck_button5.gif planck?.jpg (? is 1,2,3,4,5) eLesson\??\images\elements_spectra\ Element_base_ab.gif Element_base_em.gif Element_ab99.gif Element_em99.gif eLesson\??\images\hipparcos_h-r\ button?.jpg (? is 1,2,3) hip_hr?.jpg (? is 1,2,3) eLesson\??\images\evolution\ ev_base?.jpg (? is 1,2) ev_?4.jpg (? is dwarf,normal,giant,super) eLesson\??\images\cluster_evo\ button_?.jpg(? is 0,all) evolution_?.jpg(? is 0,8,256,3000,8000,all) eLesson\??\images/smc_ages\ smc_age?.jpg (? is 0,1,2,3,4,5,6,7,8)

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