The Stellarium Gornergrat: Astrophysics with your own Data

Remote-controlled telescopes in education provide the opportunity to obtain high quality astronomy images for a broad variety of users. The Stellarium Gornergrat is such a telescope. In addition to pure observation, it offers a user-friendly interface and teaching modules so that astronomical and astrophysical projects can be integrated into everyday school life without any special prior knowledge and without requiring a lot of time. This contribution presents the Stellarium project and a provides an overview of several teaching activities.


Introduction
Observations are the most important method of data collection in astronomy and astrophysics.Unlike in other fields of physics, experiments are generally not possible, as one cannot manipulate the distant objects under investigation.At the same time, the general public has demonstrated particular interest in astronomy and astrophysics.Nevertheless, people are becoming more and more alienated from the nightsky; observations are becoming increasingly difficult in the ever-brighter environment.Astronomical observation requires a dark environment, yet in cities at night, even with a clear sky, only the brightest stars can be seen.
Thanks to modern technology it is now possible to control powerful telescopes in dark places via the internet.Such remote-controlled telescopes hold particular promise for educational purposes.Remote control allows observations that correspond to current research, and learners can use remote controlled telescopes to both mirror current research and conduct their own investigations.In classrooms, learners can explore current issues in physics using methods that align with modern research.Modern astrophysical research is thus brought into the school without great cost or effort, providing students and teachers with advanced tools to support student engagement in the scientific process, potentially even paving the way for students to make their own discoveries.
The first remote-controlled telescope in Switzerland used only for education and citizen science is the Stellarium Gornergrat, located at the Gornergrat close to the Matterhorn in the Alps.While this telescope and others like it cannot and should not replace learners gazing up at the stars with their own eyes or or through a visual telescope, the Stellarium Gornergrat provides learners with access to a whole new way to wonder about and investigate the universe around them, regardless of location.
This article describes the technical basics and the learning environment of the Stellarium Gornergrat.Empirical investigations in the field of astronomy education have not yet taken place due to the pandemic, but are in planning.

Astronomy and Astrophysics: A special Topic?
Astronomy and astrophysics are very interesting for learners [1], especially in wealthy countries [2.However, both topics receive relatively little coverage in the various curricula of the school systems of the world (an overview can be found in [3]).If astronomy and astrophysics is covered at all in the curriculum, it is usually integrated into physics or geography classes (though notable exceptions can be found in former Eastern Bloc countries).In most countries, astronomy and astrophysics are prioritised behind other subjects in the competition for available classroom time.Given that astronomy and astrophysics are unlikely to be offered as separate subjects in the majority of countries, we must ask "what are the advantages of integrating astronomy and astrophysics into other areas of physics?" Astronomy and astrophysics contexts are particularly well-suited for motivating a need-to-know about canonical topics in school mathematics and physics.For example, many observations are mainly based on geometric concepts common in school mathematics courses.Such observations require spatial thinking [4], but do not demand an advanced mathematical apparatus like quantum mechanics.At the same time, many real astronomical data are freely available on the Internet.Often, these are also organised in ways that are accessible for school students (see for example [5,6]).This gives the opportunity to solve real astronomical problems in class, serving as a potentially valuable context for in project-based learning environments.In such environments, learners collaborate on meaningful problems through posing questions, designing and conducting investigations, and publicly sharing their conclusions and receiving peer and teacher feedback (for details, see for example [7]).Research in the U.S. and Finland, in particular, has shown that students who have worked on project-based Learning projects outperform traditionally-taught students [8,9,10].
There is also a robust body of research on the effects of astronomy education.Apart from the effects on motivation and interest in science, this research base focuses on involving learners in scientific inquiry and supporting science literacy.This research has been conducted in formal school settings [10,11] as well as universities [12].These studies show significant effects of astronomy education on the understanding of science.Overall, existing research suggests the astronomy and astrophysics hold significant promise for supporting student interest/motivation and understanding of science.

Remote Telescopes in Education
In addition to asking questions and conducting research, collecting data is also an important part of science and thus of understanding it.As noted previously, astronomical data is almost exclusively observational, and while it is possible to do basic observations without any equipment, advanced observations need a powerful telescope, a high-resolution camera, and a location with minimal light pollution -locations that are generally far away from the cities and schools.
There have been projects since the early 1990s that involved students remotely controlling professional telescopes [13].Initially, however, these were not telescopes used exclusively in education, but scientific facilities that provided observation time.Accordingly, the available time was extremely limited and school students were often restricted to pure observation.But only in the last decade did the number of available telescopes increase, so that remote-controlled telescopes became a realistic option for schools [14].Meanwhile, there are also several projects that are used only for educational purposes and citizen science, with little or no astrophysical research taking place.
Two types of remotely-operated telescopes have emerged: telescopes that are controlled directly by the users with the help of an interface and those that operate completely autonomously.Here, images are commissioned by the user and then processed independently by the telescope [13].Both have advantages and disadvantages.While direct control is a more intense experience, it requires much more time, since each group must first go through and orientation process and learn the controls.An autonomous observation is much more efficient; here observation time includes only the time required to move the telescope to the correct position and to expose the image.From a pedagogical perspective, autonomously operating telescopes provides potentially impactful experiences connected to engaging in the scientific process.Though remote-controlled telescopes offer significant benefits for learners, we believe that the first contact with astronomy and telescopes should be analogue.Otherwise, it may be very difficult for younger children to make the connection between the observation, the telescope, and the image [15].
But there is more to a remote telescope in education than just providing the hardware.In most cases, the users are not professional astronomers or astrophysicists, but students and teachers who often want to use the projects without prior knowledge.Nevertheless, the user group is typically diverse, including astronomy courses with experience or even (semi-)professional users requesting observation time.In order to address all target groups, an interface that is as simple as possible is necessary, but still allows manual adjustments as necessary [16].For school users, additional supporting materials for teachers important of what a remote-controlled telescope facility should offer, as teachers generally do not have the time or the specific expertise to plan lessons around the captured images.To enable appropriate use, materials adapted to each curriculum and written in the native language are important.Materials in other languages (i.e., generally in English) present an additional hurdle for students to understand, making use of the materials difficult or impossible, depending on the age of the students and their competency with the language(s) in which the materials are offered [16].Whether the materials are provided as an interactive website or more traditionally with elaborated worksheets depends largely on available school resources and teacher preferences.Finally, teacher trainings and workshops are also an important part of the suite of resources remote-controlled telescope institutions should offer.
Overall, the impact of remote telescope in education is likely a combination of three main factors: the hardware (in particular the telescopes), the software (including the interface), and the educational resources (including teaching materials and teacher trainings) (see figure 1).

Goals of the Project "Stellarium Gornergrat"
The central goal of the Stellarium Gornergrat is to promote astronomical education in German and French-speaking Switzerland and several associated institutions abroad.This is done by providing the necessary hardware, learning materials and user interface.This central goal is divided into several subgoals: 1. Promote astronomical education in the school curriculum from the end of elementary school to the end of high school.2. Promote astronomy education in special astronomy projects or courses, especially (but not only) in high school and university.3. Encourage individual (typically high-performing) students with their own science projects that go beyond the curriculum.4. Involving the public in citizen science projects.

The Stellarium Gornergrat
The Stellarium Gornergrat was the first remote-controlled telescope in Switzerland used only for education and citizen science (see figure 2 and [17]) and is one of the few targeting native German and French speakers.Moreover, the observatory not only offers professional telescopes for various purposes, but is also located at a place with conditions that enable excellent astronomical observations.The Stellarium Gornergrat is designed for a wide target group of leaners, i.e., from elementary school to university students.In robotic mode (which is most common), the telescopes are not controlled directly, but images are booked and then processed independently, just as in professional scientific operation.The images are then available for download the next day, provided that the observations were successful.The entire booking process takes place via a user-friendly website (https://stellariumgornergrat.ch/), which allows both preset settings for the observations and custom settings for more advanced users.However, no astronomical expertise is required.
The services offered by the Stellarium Gornergrat are not limited to the observation process.There are also fully elaborated learning materials available, including worksheets with solutions for teachers and extra materials, but also back-up images in case observations fail due to bad weather or technical problems (see section 4 for details).
A total of four remote-controlled telescopes are available, plus one for on-site visual observations (see figure 2).Each telescope has its specific strengths, so each is suitable for different types of observations.With the exception of an AllSky camera (see Section 3.4), all telescopes are attached to a single mount, so they all look in the same direction -independent, simultaneous observation with the different telescopes is therefore not possible.

The Deep-Sky-Telescope (RiFast)
The largest and most powerful telescope of the Stellarium Gornergrat is the deep sky telescope, also called RiFast (Riccardi Fast Astrograph), manufactured by Officina Stellare.It is a reflecting telescope with a diameter of 60 centimeters and a focal length of 2280 millimeters.Together with a CCD camera and a filter wheel, impressive images of nebulae and galaxies in the universe are possible (figure 4), but images of the entire moon can also be taken.Between 80 and 90 percent of the bookings at the Stellarium Gornergrat are for this telescope.

The Planet Hunter
For higher magnifications, for example when observing planets, the Planet Hunter is used -a reflecting telescope with an aperture of 250 millimeters and a focal length of 3000 millimeters.Compared to the deep-sky telescope, the Planet Hunter collects significantly less light and is therefore less suitable for faint objects.The higher magnification, however, makes it possible to observe individual craters on the moon or the planets in more detail, which appear relatively bright anyway.The telescope is equipped with a CCD camera that can take color images.

The Constellation Cam
The ConstellationCam is a standard Canon 60Da with a Canon lens.It is protected by a housing built at the University of Bern, and the zoom can also be adjusted remotely.The camera can be used to capture very large structures in the night sky, such as constellations.

The AllSky Camera
The AllSky Camera is the only instrument mounted outside the protective dome.With this camera, images of the entire sky can be taken 24 hours a day -whether to check the position of the sun, see what the weather is like, or clearly show the movement of the stars over the course of a night.Thanks to a heating system, the camera is also ready for use in cold weather, although snow and lightning in particular pose problems that sometimes lead to downtime.

The Look Through Telescope
In addition to the remote-controlled telescopes presented, there is also a telescope for visual observations during guided tours, a refracting telescope with 150 millimetres aperture and 1100 millimetres focal length.Thanks to different eyepieces, the telescope can be used so versatile as a real all-rounder.

Learning Activities
In addition to the excellent observing opportunities, educational activities are a key component of the Stellarium Gornergrat.These cover different astronomical topics at various levels -from elementary school to university.Each activity consists of several components: • Teacher document.This is the most comprehensive and central part.Here, the learning objectives and methods are described as well as additional notes and connecting points for other school subjects.In addition, all exercise sheets for the students including the solutions as well as the observation assignments are included.• Student document.Here are the exercise sheets and observation assignments without solutions.
• Images from the exercise sheets.The images from the exercise sheets are saved again in enlarged form in an extra document so that they can be used for alternative forms of presentation (such as PowerPoint).• Back-Up Images.If an observation was not successful, for example due to bad weather or technical problems, the Back-Up images can be used.This way, the entire lesson does not have to be rescheduled if an observation fails.• Other documents.Depending on the activity, there are other documents, such as games (for example, Memories).So far, learning activities are available in German and French.In order to cover the whole of Switzerland, implementation in Italian is also planned, and English documents are also envisaged in the longer-term.
The activities are divided into four levels of difficulty: A.
Basic activities that have no prerequisites.

B.
Advanced activities that require elementary math and basic physics concepts (at the high school level).

C.
More complex activities that require more advanced mathematics (such as differential calculus) and more advanced physics (at the high school level).

D.
Difficult activities at (or near) university level, aimed at special courses or undergraduates.
Table 1.Educational modules of the Stellarium Gornergrat.In the following, the newly developed activity "Exoplanets" is presented in more detail.The search for exoplanets is an exciting topic for a Stellarium Gornergrat activity for several reasons.First, exoplanets are one of the central current topics in astrophysics.The first detection of an exoplanet orbiting a main sequence star such as the Sun was less than 30 years ago, and only in recent years has a larger number of exoplanets been detected.Few other topics in physics interest the public more, likely because the quest for evidence of life on other planets is closely linked to the search for exoplanets.

Mountains on the
Moreover, research has shown that the question of life beyond Earth is of particular interest to young people.Finally, the mathematical requirements of the method used -the transit method -are not particularly high, since the evaluation is based purely on geometric principles.
Thus this activity allows students to do astrophysics on a cutting-edge topic with their own observations.In special projects, (known) exoplanets have already been observed by high school students; via an activity currently under development, this possibility will soon be available to a larger groups of learners.The software necessary for the analysis is freely available.
The transit method can be used to detect planets orbiting the star in the same plane as their central star and the Earth.As soon as the planet moves between the Earth and the star, it covers part of the star and its apparent brightness (measured on Earth) decreases.The central element of the transit method is therefore photometry, in which the brightness of a star is measured over time.A photometric evaluation is possible with the help of software, for example, "AstroImageJ" (https://www.astro.louisville.edu/software/astroimagej/).
For the evaluation, besides the observed star, a few stars in the apparent environment are needed.Since the atmosphere influences the observation, the apparent brightness of the star can change even without the planet.This can be calibrated and calculated with the help of stars in the vicinity, whose brightness changes only due to the atmosphere.Finally, a light curve can be generated using the software (figure 5).Here one can clearly see the decrease in brightness during the transit as well as the constant brightness of the other stars.The planet shown in the example was discovered in 2019, in 2020 it was already observed by a student and analysed in a school project.By recording two transits, one can easily determine the length of a year and above that the distance between planet and star.The temperature on the planet depends on the distance between planet and star and the brightness of the star.Therefore, if the brightness is known (e.g., by spectroscopy), it is possible to estimate the average temperature on the planet.In addition, the size of the planet can be estimated on the basis of geometrical considerations, provided that the size of the star is known.This allows learners to produce a claim regarding whether the planet is likely a rocky or a gas planet.Finally, learners can construct and defend an evidence-based claim regarding whether life could be possible on the planet under investigation.
Overall, this learning activity enables students to explore a highly topical subject in physics that represents a crucial step in the search for extra-terrestrial life.The detailed structure of activity and additional documents differs depending on the topic and level.In Table 2, the just presented activity Exoplanets is combined with an activity for beginners: The Phases of the Moon.This one does not require any prior mathematical or astronomical knowledge and has a more playful structure.

Conclusion
Remote-controlled telescopes have great potential for education.High-quality images can be taken from anywhere, and the procedure is similar to that used by professional scientists.School-aged students can also do their own science, such as searching for previously unknown exoplanets.
Using remote-controlled telescopes, modern astrophysics can be done in school by the students, leveraging the documented interest in these subjects among learners of all ages.This may also lead to a better understanding of the nature of science and scientific inquiry, but this remains to be directly investigated.Furthermore, remotely-controlled telescopes provide learners with opportunities to obtain high-quality images from any location.This is a great advantage especially in the cities, where light pollution makes high-quality astronomical observations difficult or even impossible.
The high utilization of the Stellarium Gornergrat (e.g., more than 4000 requests with a success rate of about 50% and seven individual projects of pupils in 2021) show the demand for a project that offers not only hardware, but also teaching materials that are designed to support teachers in schools.The utilisation of the Stellarium Gornergrat shows its promise as an effective multiplier for the promotion of astronomical education for a wide range of learners, from elementary school to students conducting their own scientific work.Therefore, we encourage others to consider similar projects in other countries and languages that complement the famous remote telescopes in education.
The Stellarium Gornergrat is constantly being expanded both in terms of technology and available activities (both in terms of number and supported languages), and we welcome the possibility of further international collaborations and the exchange of ideas and experiences.Furthermore, the Stellarium Gornergrat offers a great potential for research in astronomy education.Appropriate research is planned, in addition to the development of new activities and translation into Italian and English, but could not be carried out so far due to the pandemic.

Figure 1 .
Figure 1.The main aspects from a remote telescope in education, taken from [16, p. 260] (CC BY 4.0).

Figure 2 .
Figure 2. The Stellarium Gornergrat in the left dome with the Matterhorn in the background.

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World Conference on Physics Education Journal of Physics: Conference Series 2727 (2024) 012011

Figure 4 .
Figure 4.The first light of the DeepSky Telescope.

Figure 5 .
Figure 5.The transit of Kelt-23 A from July 2020, taken from the school project of A. Graf [19].

Table 2 .
Comparison between an activity for beginners and an activity for advanced students.