1 Introduction

This dissertation describes the motivation, design, development, and app evaluation in astronomy education based on AR functions. In this project, the entire project’s production process and evaluation are described in detail as a case study with the star life cycle, and the results are analysed.

1.1 Motivation

Basic education accounts for the full educational career of a large part of the students. During this stage, the students will be exposed to basic knowledge in different fields. Whether the education of different disciplines stimulates the interest of students will largely determine which subjects they will choose when entering higher education, basic education, therefore, plays an important role in the future development of students (Bretones, 2019). Knowledge in basic education is divided into figurative knowledge and abstract knowledge. They are all abstract knowledge, similar to physics and astronomy. Students have difficulty mastering this kind of knowledge efficiently, and most students have difficulty relying on formulas for pictures and text. Now, AR technology is known for its visualisation characteristics, three-dimensional vividness and low investment. Some scholars have combined AR with the teaching of physics and found that AR can help students better understand abstract content compared to general teaching (Metaxa, 2019). Taking astronomy as an example, most knowledge of astronomy can not be fully understood merely through words and single pictures. Just like stellar evolution, students can not compare different stages intuitively, and the pictures in the books are too general (Pellas, Fotaris, Kazanidis and Wells, 2018). Students can not grasp Stellar’s real development in depth. Hence, the project explores how AR technology will be used in basic astronomy education, and whether it can improve the understanding of astronomy knowledge among students.

1.2 Structure of the Dissertation

Figure 1.1 below shows the structure of the dissertation; there are six parts of this thesis. Chapter 1 provides the motivation and structure of the dissertation.  Chapter 2 presents a review of the literature, including astronomy education history; astronomy education in schools; and an overview of AR and AR in education. The materials and methods used in the project are provided in Chapter 3. Chapter 4 shows the results of the development of an app and a picture book. Chapter 5 shows the evaluation process and the outcome. Chapter 6 shows the project’s findings, the future work of the project.

2 Literature Review

2.1 History of astronomy education

Astronomy is an old subject. Astronomy seems distant from life, but the time and date that surrounds us is the most basic astronomy. Nowadays, according to research methods, astronomy is divided into astrometry, Celestial mechanics and astrophysics. It is often classified as basic physics in basic education; in basic education, it is arranged in basic astronomy learning, similar to knowledge of celestial bodies (Frey and Accomazzi, 2018). The purpose of astronomy teaching in basic education is not only to grasp the knowledge, but also to enable students to generate a sense of thinking and a way of thinking in science, and to subtly provide students with a way to look at the question, lay the foundation for them to be exposed to deeper astronomical knowledge in the future, which is why astronomical education is introduced in basic education. Take as an example the NGSS issued by the United States in 2010 which specifies the core knowledge that students at different levels need to master, these core knowledge are connected to different fields in higher education (NGSS Hub, 2020).

On the other hand, looking at astronomy education, with the development of various educational platforms and educational resources, astronomy education is no longer limited to schools, and the audience is no longer limited to students. The Science Museum is an important educational place for popularising astronomical knowledge. NASA launched a series of actions on “Inspiring the Next Generation of Explorers,” including cooperation with the Planetarium, aimed at enhancing the participation of citizens in science. Citizens’ knowledge of astronomy has been improved after regular tests and assessments (Rosendhal, Sakimoto, Pertzborn and Cooper, 2004). Next is the “science training club” Common clubs such as the Astronomical Observation Club, Gary Leonard Cameron, in his research, pointed out that observation instruments became popular with the development of the economy and industrial production, and a small number of observation clubs were also created. The amateur astronomers are born when enthusiasts gather to learn from one another. In a way, this also promotes astronomy research (Cameron, n.d.). At the same time, the astronomy club in the school is also constantly attracting the attention of students. In their research Powers and Lynn Louise found that such extracurricular activities greatly enhance student participation and enthusiasm (Louise, 2004). From this point of view, basic astronomy education appears in all aspects of life, and it covers all classes, from policy formulation to private research, astronomy education has always been a necessary aspect for improving citizens’ quality.

2.2 Development and opportunity of astronomy education in schools

The significance of astronomy education to the whole society was mentioned in the previous article. Astronomy education in school education has been continually improving in recent decades. The first factor affecting education in astronomy is the emergence of new technologies. As a huge institution, the number of teaching instruments required is also huge. After the 20th century, the widespread use of astronomical telescopes provided more convenient educational equipment; the development of IT resources also allows various rich and poor schools to share lesser-cost teaching resources. These technological advances have supported teachers and students to invest more experience in astronomy (Fitzgerald et al., 2014).

The second point concerns the improvement of the teaching model. L. Danaia mentioned in his research that the educational model of the school puzzles students in the learning process. In his project, he improves the research part of learning to enable students to increase their interest in learning. M. T. Fitzgerald also mentioned in his research that students use tools to explore knowledge through the development of practical projects independently. Later, most students have shown that their knowledge is more profound, and knowledge is not limited to theory (Danaia, McKinnon and Fitzgerald, 2017). Also, it can be seen that an increasing number of practical projects have played a role in promoting astronomy education. Finally, the teacher’s role often plays a significant part in learning. Julia D. Plummer added the learning progression (LP) framework for her project.  This structure increases the ability of the students to think spatially, and the ability to think spatially encourages abstract knowledge similar to astronomy. The subsequent project feedback also proved this positively (Plummer, 2014).

As stated above, astronomy is an abstract subject. It is, therefore, very useful to visualise abstract knowledge in the teaching process. Some of the teaching methods mentioned above are also aimed at supporting abstract knowledge. New media have also constantly interfered with teaching in the development of education in recent years. New media can be reused at any time, anywhere, for astronomy education, and the highly communicative features make it a better practice in astronomy education (Gay, 2020). At the same time, Voelzke and Marcos Rincon also found in their research that interactive textbooks can better assist and meet educational needs and that this is also a future direction for the development of astronomy education (Marcos Rincon and Josue, 2016).

It could be found that with the assistance of the computer technology, the visual presentation effect in astronomy education is more realistic than before, which also promotes the students’ understanding of knowledge, such as Blender, an open-source modelling software. 3D software engineers can perform data visualisation based on the data provided by astronomy. This kind of 3D data visualisation can help scientists analyse from different angles. Compared with 2D data visualisation, 3D can be performed with more comprehensive multi-dimensional comparison and analysis. Brian R. Kent used the M81 Nebula data as a reference in his project to create an astronomical data visualisation workflow. Blender’s series of rendering and material setting functions have been proven to help scientists perform better analysis. At the same time, it is also useful in other fields such as Medicine, Biology and Blender Visualization, all of which are successful. The team also used this workflow to simulate the dwarf planet’s 3D model. Although the parameters of this workflow still need to be continuously adjusted, it can be seen that Blender has a role in promoting the expansion and popularisation of astronomy knowledge (Kent, 2013).

On the other hand, Zeynep Isik-Ercan also explained in his case study the role of teaching tools developed by 3D software for young students to understand the knowledge of the Earth, the Sun and the Moon. Since traditional education can not express the relative positions of the sun, the earth, and the moon, teachers can only use clumsy, non-realistic 3D models to make presentations that are not conducive to the growth of student interest. The team used computer graphics to create more realistic images, combined with specially designed glasses to help students better understand the depth of the models. Computer aids provide flexibility for students’ thinking, which can help them improve their geometric thinking skills. 3D visualisation teaching is also gaining more and more attention in astronomy education. Although this technology has higher requirements for teachers’ actual operations and requires more financial support, the Government is also actively promoting this operation. Moreover, this teaching mode is currently very useful for younger students. However, whether it also affects students in the upper grades, it still requires more project experiments (Isik-Ercan, Zeynep Inan, Nowak and Kim, 2012).

2.3 Augmented Reality

2.3.1 Definition and technology of Augmented Reality

Augmented reality is a technology developed based on virtual reality. Augmented reality allows users to see virtual images generated by computers on top of real scenes, in real-time. What the user sees is not a complete virtual image, but an image interacting with a real scene, which is completely different from virtual reality. This technology highlights the feature of “augmented” (Figure 2.1). The first AR device was developed by Ivan Sutherland in 1966 and was named Sword of Damocles. Due to the limitations of computer technology at that time, Sword of Damocles could only display some simple 3D wireframe images through the camera. The first generation of AR helmets is very bulky and only popular with some science fiction fans and academics. For ordinary people, this is still a distant technology. It was not until 1997 that Ronald Azuma published a report on AR. The report proposed that AR includes three features, the combination of virtual and reality, real-time interaction, and the addition of positioning virtual objects in three-dimensional space. Until then, the definition of AR was adopted (Carmigniani et al., 2010).

（Figure 2.1: Milgram’s Reality-Virtuality Continuum）

In 1999, the Nara Institute of Science and Technology developed the first AR open-source tool ARToolKit, so that normal programmers can also operate AR technology. It can be said that after this AR technology has gradually moved to the general public. Technology is also seen as a technological revolution in augmented reality (Mark, 2004). As far as ARtoolkit is concerned, the simple way is for the camera to transmit the real-world video to the computer. The computer captures the square in each frame and calculates the relative position of the square using mathematical methods. After confirming the position, the computer model is drawn at the position, and the final output is shown in the display. However, this technology also has limitations, similar to when the detection object moves, which will affect the reality of the virtual object, and the direction of the camera will also affect the computer’s detection of the relative position. Outside, the reflectance of the material also affects tags (Figure 2.2) (Abdullah and Martinez, 2002). With the need for code technology and industry, the successor to ARToolKit has also been developed—-Studierstube Tracker. Although the concept of Studierstube Tracker is very similar to ARtoolkit, it is not an open-source software and cannot be downloaded directly. Compared with ARtoolkit, the memory occupied by Studierstube Tracker is very small, and the cutting processing speed is very fast. With the continuous advancement of computer algorithms, more and more trackers are being developed, such as Vivepaper, developers add gesture tracking to the device (Zheng et al., 2017).

(Figure2.2: ARToolKitwork flow)

With the continuous development of related technologies, the field of AR applications is also expanding. EZ Barsom mentioned the role of Augmented Reality applications (ARA) in the training of medical staff in his research. For example, ProMIS, which is a simulator training laparoscopic procedures, has an excellent tactile feedback system and path tracking system, can check the stability of the operation process, and give some data feedback. After surveying 55 highly-qualified users, it is generally regarded as a good training tool. The addition of AR operation can better simulate the operation in some dangerous situations, providing medical staff with sufficient experience. Another AR-based operation tool mentioned in the study is called “The Perk Station”, which can use AR to superimpose images; trainers can learn operations based on the superimposed images. This operating system provides newcomers with better learning opportunities. Researchers believe that ARAs help to provide a more realistic operating environment, which has certain potential value in the field of medical education. However, ARAs are often based on a rigorous and complete structure. Thus, cost and technology are also a problem. Therefore, not all educated people can accept this learning method. This is also a part of AR technology that needs to be improved in the future (Barsom, Graafland and Schijven, 2016).

Except cooperation with the medical education industry, AR technology has also expanded to include wearable devices. Google Glass is a well-known wearable haptic device, the problem is that these haptic stimuli are limited to vibration, so researchers turned their attention to more complex haptic interfaces. Maurizio Maisto et al. evaluated 3-PRS Fingertip Cutaneous Device in their research, combining the device with the AR scene, simulating the tactile experience of writing with chalk on a wooden board. It turns out that the combination of the wearable device and the AR scene does not cause damage to users. On the contrary, it may also improve the illusion problem that exists in the AR environment. The project put forward a positive view of the combination of AR and hand-worn devices, which also heralds the possibility of AR devices in wearable games (Maisto et al., 2017).

Although AR can be used in gaming, manufacturing and other industries, it already has good performance and potential, but AR technology has just begun in the tourism sector. First of all, AR’s travel plan can certainly provide tourists with photos and background-aware travel experience that is very important in the tourism industry, especially for traditional tourist attractions. The use of AR technology has a long history and has had a positive effect. Moreover, the AR technology marker capture system is now very mature, and there are still many developmental locations for certain fixed attractions (Jung, Chung and Leue, 2015). There are, however, few successful, related AR programs in the tourism industry. In his study, Dai-In Han collected data from 49 participants in 5 groups. The data shows that AR applications have great potential. The surrounding environment provided by the AR program is interesting for users, but there is little interest in the attraction itself. The AR application of the tourism industry should, therefore, develop multiple spaces around the attraction, not just the tour itself. The good point is that when the AR application is combined with GPS, the application requirements of the program will be increased, and the AR navigation program can break language restrictions, people can browse through interactive maps. Therefore, the development of mobile AR travel products is still necessary, and the general public has a certain demand for AR navigation. If the offline mode is added, the potential for development of AR technology in the tourism industry will be greater (Han, tom Dieck and Jung, 2017).

2.3.2 Development and application of Augmented Reality in education

Teachers often use some new tools in the field of education to enhance the enthusiasm of students. Among them, AR is a tool that is commonly used. First of all, AR can better support online education, combine formal classroom education with informal, autonomous learning, and provide a better interactive element. This kind of interaction directly increases the emotional investment of learners in the “Explore the Starry Sky” AR textbook test, the tester found that by monitoring brain wave data of selected learners, learning emotions increased with increased attention when using the AR teaching tool but, This is only a test for a small number of learners, and it is necessary to introduce data from scholars of different learning levels to be more objective (Xiao et al., 2016). Next, AR technology is very suitable for combination with a laboratory, such as electrical current or microorganisms, these things are tiny, difficult to observe with the naked eye, and the IoT-Lens project at the University of Essex has always used AR technology to allow students to explore. Augmented Reality technology is suitable for amplifying and exposing hidden knowledge. Researchers at the University of Essex use loT-Lens to monitor the internal data transmission process when the robot moves. This application makes AR an interpreter between teaching and sharing information (Wang et al., 2017). In K-12 education, AR directly helps learners improve their academic performance, enhance their understanding and interest in learning, and reduce the cost of materials for some abstract concepts of education (Clemens, Purcell and Slykhuis, 2016). AR education is a field with potential. AR has become a unique teaching medium, and AR applications can enable students of different levels to obtain more suitable knowledge for themselves. Still, there are also reasons for restricting the popularity of AR education. Normative technical standards, high 3D cost of production, etc., these limitations are also the future direction of AR education.

As mentioned earlier, AR as a training tool has guided doctors’ training and provided them with experience. Similarly, in the training and education of patients, AR technology has also played a promoting role. Andrés-Marcelo Calle-Bustos proposed an augmented reality game in his study, whose purpose is to teach diabetic patients how to control their condition. The game simulates common foods in life and marks them with carbohydrate content. This AR game is aimed at children and adolescent patients. Some studies have shown that pathological education and intervention in childhood and adolescence of diabetes have a greater impact than education in the adult period. The researchers have designed these AR games to stimulate their interest in mastering the knowledge of carbohydrate content in food. In addition to understanding carbohydrate content, users can carefully observe the structure of food and finish game tasks for users to match their food combinations. The task is to detect whether the user has mastered the required knowledge. Through investigation and data analysis, it is concluded that patients using AR tools have a higher degree of mastery of the required knowledge, and user satisfaction is also relatively good. Thus, AR tools provide greater learning achievements (Calle-Bustos, Juan, García-García and Abad, 2017).

In addition to achieving educational purposes through AR games, with the diversification of publications, AR applications have also been added to the combination with pop-up 3D books. In a study based on an innovation education, the researchers used year3 of students as research questions, developed AR pop-up 3D books on English education for them. The combination of AR and pop-up books makes the monotonous content on the books more malleable. This new type of learning model increases the enthusiasm of students. About teaching, with the support of augmented reality, students can learn through continuous animation and game modes. Through observation, students are excited about this kind of learning mood. Still, this research is only for younger students, perhaps for high-level students, AR may not necessarily stimulate students to a sufficient level of excitement (Vate-U-Lan, 2012).

In summary, it seems that AR can be used to stimulate education interests. It can also enable learners to gain more knowledge than was originally expected. AR technology has already started in the field of education, the problems that are waiting to be solved are how to standardise the development of AR education programs and how to teach teachers to use AR teaching aids as auxiliary education tools (Baker and Reborn, 2019).

2.3.3 Development and application of Augmented Reality for abstract knowledge education

Abstract knowledge corresponds to specific knowledge in education classification. It can not be achieved through direct observation in learning, but it must be achieved through a defined method. In general subjects, such as mathematics, it is an abstract subject. On the contrary, concrete knowledge is what we can feel in our lives. The human brain does not like abstract things, so learners often need to visualise abstract things to learn. As a visualisation tool, AR technology can easily visualise things in specific things that can be felt in life. This is also a feature of visualisation technology. As a result, AR technology provides good auxiliary teaching (Bujak et al., 2013). In the study, Stéphanie Fleck et al. compared the degree of student mastery of day and night and the change in the moon phase in the teaching situation of the AR model and the ordinary 3D model. The study points out that teaching in a virtual environment not only enhances students’ senses, but also demonstrates astronomical phenomena in different situations, and allows students to modify the model screen as they learn to achieve the purpose of exploration. The normal 3D model has relatively large limitations. This shows that the AR environment is suitable for teaching astronomy (Fleck and Simon, 2013). In terms of the interaction of AR teaching, Billinghurt et al. proposed an interactive method called Tangible Augmented Reality (TAR), which is a more advanced interaction mode based on the Tangible User Interface (TUI). The user can directly pass Operate the existing solid model to interact with the virtual model (collaboration with tangible augmented reality interfaces). Aw Kien Sin et al. mentioned the AR teaching tool of Live Solar System (LSS), which uses the TAR interactive method to let students learn the internal structure of the sun. Compared with the results, this new learning method is more fascinating and more interactive AR teaching tools are beneficial for mastering abstract knowledge.

2.4 Conclusion

Augmented reality has entered the education sector as a new type of support for education. It can be seen that this new technology with visual expansion has an impact on the education sector. For teachers, although augmented reality improves students’ knowledge acceptance to a certain extent, it also means that teachers must change the previous teaching mode and mechanism, which is also a challenge for some older teachers. For students, augmented reality enhances their curiosity about knowledge, and research by many researchers shows that knowledge mastery has indeed increased, but too much information in augmented reality education can also interfere with learning objectives. This status quo is also applicable to the basic education of astronomy, but only to the basic education of astronomy, the focus should be on how to concretise the abstract knowledge in astronomy. The aim of basic astronomy education is to make students interested in astronomy knowledge and to stimulate students ‘ interest in continuing to learn deeper knowledge. The next section focuses on how to use augmented reality to materialise knowledge since it helps students master basic astronomical knowledge.

3 Materials and Methods

3.1 Materials

This chapter provides the software, hardware and third-party assets used in app development.

3.1.1 Software

Table1 lists the software used in the development of astronomy learning application.

3.1.2 Hardware

Table 2 lists the hardware used for development and testing.

3.1.3 Third-party Assets

The description text about the star life cycle at astronomy learning application are all from NASA and Rebekah Derdoski.

3.2 Method

The following graph shows the workflow for the application development process ( Figure 3.1). First, determine the theme and then read the relevant literature to determine the specific content of the application, followed by the production and testing of APPs.

Figure.3.1: The workflow of the development of the game.

3.2.1 Concept

The purpose of the application is to provide students or learners with learning assistance for the astronomical knowledge Star life cycle.

The application provides different 3D planet models that can interact with each other and learn the definition of the target planet through the information on the screen.

In contrast to 2D image teaching, users can observe the shape and colour of the three-dimensional Star by rotating the angle of the screen or interacting with the screen directly with their hands, hoping to visually deepen the memory of what stars look like in different processes of star evolution.

The application uses a 5-page picture book (including cover). The design of the Picture Book is based on the 2D illustration style, which is distinguished from the 3D style presented by AR, and the visual differences will also deepen the learner ‘s impression of the target learning content. In the choice of text content, there is less text information in the picture book, but the essential names of the different stages and more specific content needs to be studied in depth through AR. Even if the AR trigger in picture books has lost its function, learners can still perform essential learning through a picture book.

Star Life Cycle teaching can be simple but complex in choosing the degree of difficulty of learning. The choice of more basic knowledge is appropriate for students who have never learned relevant knowledge before. Combined with the AR technology mentioned in the previous literature review, because it can show more three-dimensional, concrete knowledge, it is suitable for science education, so it also tends to show the picture in the design of the App, so it is not more detailed. Similar to the introduction of chemical reactions in the evolution process. After a complete round of study, the learner can clearly understand the general knowledge of the star life cycle.

3.2.2 Storyboard

The storyboard for the application to help learners interact with the content.

“Stellar Nebular” Scene

The first pattern scanned by the user when using the App is Stellar Neublar.

This scene was designed to present the first stage of stellar evolution, which is also the beginning of all stellar life and uses this scene as the beginning of the entire App. In the interface, the first interface adds two buttons, “Click white text to continue scanning” button, without any real interaction, but as the prompt appears all the time at the top of the screen, reminding the user that they can perform other interactions by clicking a button similar to this button, which appears as the main button in each scene. Right at the bottom of the screen is another “Next Stage” button that guides the user to the next stage of learning.

Because only the stellar nebular is introduced in this scene, the interface button setting is also elementary (Figure 3.2).

The model and particle effects of Stellar Nebular will appear in the middle of the screen when the user scans the target image. Users can rotate the model by clicking and moving the screen, taking a closer look at the model. Click on the model, and there will be instructions on the stellar nebular on the lower side of the screen, which users can learn. After learning, click the “Next Stage” button to proceed to the next stage of the study.

“Average star and Massive star”Scene

As Stellar Nebular continues to evolve, it will be divided into the average star and the massive star. Therefore, this site’s primary function is to help users distinguish between the two different quality stars formed after the Stellar Nebular phase. Scanning the aim picture book will show the 3D model of Average and Massive star on the left and right sides of the screen. Users can also use the screen rotation to watch the details, click on the model, the introduction will appear below.

About the design of the interface. There are three buttons on this scene. In addition to the “Click white text to continue exploring” button, which each scene will have, there will be a button under the average star and massive star model, and the user can enter the life cycle learning of the corresponding star by pressing the corresponding button (Figure 3.3).

Average star life cycle” Scene

This scene shows the life cycle of an average star. Including four stages: Average Star, Red Giant, Planetary Nebula and White Dwarf. There are four buttons on the left of the scene, Users can sequentially press the buttons to observe the shape of the star at different stages. The description of each stage star appears at the bottom of the screen, and the user can also use his fingers to drag the screen to rotate to observe the 3D model. Besides, there are two buttons on the right side, “Back to Nebula” and “Back to main sequence”. The “Back to Nebula” button can bring the picture back to the beginning of the scene; the user can start learning, the “Back to main sequence” button can let the scene back to the “Average and Mass Star” scene, the user can re-choose which branch of knowledge you need to learn (Figure 3.4).

“Massive star life cycle” Scene

This scene shows the life cycle of a massive star. Including five different status: Massive Star, Red Supergiant, Supernova, Neutron Star and Black Hole. Other layouts and operations are the same as the “Average Life Cycle Star” scene. This scene is the end of the entire life cycle of the star teaching process (Figure 3.5).

3.2.3 Interface Design

The interface of this application is simply because almost all of the interfaces are made with the canvas provided by Unity. Button’s UI is designed with a 50 per cent transparent # BF3BB8 colour, and the font is white because the colour of the picture book is dark, so using a white font can attract the user’s attention (Figure 3.6).

3.2.4 3D Modeling

There are10 3D models in this application, they all made by Unity.

Stellar Nebular

Stellar nebular consists of four particle systems, two of which are flat shapes, using blue-purple tones as the brighter nebular in the universe, and dark green and red particles to simulate the thicker nebular in the universe. The remaining two particles are used to simulate nebular asteroids, choose a set of warm colours and a set of cool colours to coordinate with each other. Particles have a dynamic effect of movement that simulates the effect of free movement of matter in the universe. Also added five spheres as fixed star (Figure 3.6).

Average Star

The average star is made up of a sphere with colour #F5B61E and colours RGB (190, 122, 0) as the core, and the particle of sphere shape with color#C32100 is added as the outer flame produced by material combustion (Figure 3.7).

Massive Star

The size of the model Massive star is twice large than the average star.

His kernel is a sphere with colour #0AA6FF, which is emitted by colour code RGB (0,75,255). The outer flame’s material is a sphere shape particle with the colour #5190D1 (Figure 3.7).

Red Giant

The size of the model Red Giant is about quadruple than Average star.

The core is a sphere, outer flame with colour #FF4407, emission RGB (217, 15, 0). The material of the outer flame is a sphere shape particle with colour #E22506 (Figure 3.8).

Planetary Nebula

The model of Planetary Nebula is similar to Stellar Nebular, which only changes the bright colour part of nebular to colour #34AD82 and colour #B25EA1 based on Stellar Nebular. The dark part was changed to colour #59474D and colour #3B4B49. Increase the number of particles of asteroids to represent planetary (Figure 3.9).

White Dwarf

The size of the model White Dwarf is the eleventh of the Average star, consisting of a luminous white ball and a pure white particle (Figure 3.10).

Red Supergiant

The size of the model Red Supergiant is much bigger than the Massive Star. The colour of the core is #FF6D00, emission colour is RGB (255,28,0) sphere. The material of the outer flame colour is #E23206 and #FF7D46 sphere shape particle (Figure 3.11).

Supernova

Supernova is similar to a planetary nebula, except that size is twice as small, and the primary particle colour has been changed to colour #1A55B4 and #D17B4B. Also, joined the White emission sphere (Figure 3.12).

Neutron Star

The size of the Neutron Star is similar to White Dwarf, the colour of the core is #EE79D3 black sphere plus same colour particle with box shape made up (Figure 3.13).

Black Hole

Black Hole’s model is not easy to deal with, so we choose the earliest black hole images to show it, adding colour #FF990C to emission sphere with a kernel of black. The particle of Black Hole is composed of the outer nucleus (Figure 3.14).

3.2.5 Picture Book Design

A four-page picture book is used to present the basic knowledge of the life cycle of the star, to divide knowledge into four parts, each of which represents one part of the content. The picture simplifies text and focuses on pictures to ensure that too much text does not interfere with the use of AR by the user. The simple text also ensures that the user can learn the most basic knowledge in the event of AR failure.

To distinguish pictures from the 3D model in AR, the design of the picture book chooses the style of graphic illustration, simplifying each object into a shaped colour block, so that users can clearly distinguish what the content of the picture book is and what it is (Figure 3.15). All objects are made in the illustration, and information about the stars using the pan and gradation tool generates different stars from the NASA website.

3.2.6 Application Development

The whole App has a total of 4 scenes. Each scene has an interactive function, and Figure 3.16 shows the scene layout.

3.2.6.1 Interactive Components

The table shows the interactions in the App are written by C # scripts, table list all C# scripts used in the App.

3.2.6.2 Integration of AR

The whole App is the built-in Android environment, and need to use Android Studio SDK and JDK to build, download, and then set the corresponding paths in Unity’s player setting.  Also, the scanning of AR is carried out with the support of Vuforia, so need to download Vuforia’s AR package for Unity on the official website.

Using Vuforia needs a license, and add Target to license. Upload AR trigger markers, Vuforia in target manager, and add the trigger automatically. Download the trigger package, import it to Unity, and then use it after adding the AR camera object. The following table lists AR trigger markers and their corresponding trigger in Vuforia.

Each AR trigger marker corresponds to a single scene, and the position of the model corresponds to the position of the marker. The following figure shows the effect of combining the AR trigger marker with the Model after adding to the Unit (Figure 3.17).

3.2.6.3 Build

The App was build to be tested on a Samsung Tab2 running on an Android 9.0 operating system.