ARCturus

The stars are not evenly distributed in the sky. When surveying the night sky people have observed or imagined stars as a part of various figures or groups. These shapes have inspired their imagination to create mystified stories and even living creatures. The reality is different as the stars belonging to the same constellation can physically be very far from each other. The only reason we see them create a constellation is the direction they are observed from. Seen from other parts of the universe the relation between the same stars would be totally different. This is also the case with the Big Dipper in the picture below (picture IH, Finland).

 

Aim: To learn to recognize the most common constellations and their brightest stars.

 

Explorations: For the people living north of the equator, it is easy to see and recognize the constellations around the North Pole, and therefrom down to the equator and even to a little south of it.  The people on the southern hemisphere see the sky on the other side of the globe, i.e. the constellations around the South Pole. Learning to recognize all constellations seen from the globe is a task too large for the students. It is enough to study the sky under which we live and its constellations. Every student has a star map. In the beginning the students are taught how to make use of it. The map is held above the observer’s head and the orientations on the map should point to the natural orientations.

1) A good point to start in getting acquainted with the constellations is to observe them in nature, either with the help of a star map or under the guidance of a teacher. Nearly everybody knows the figure of the Big Dipper: seven stars in the constellation Ursa Major. Find it first. Discuss the names of its stars and the meanings the figure has in various languages. In English the constellation is called the Big Dipper and in Swedish Karlavagnen (’vagnen’ in English means ’carts’; maybe the shape has a vague resemblance to a cart!) With the help of the Big Dipper, it is easy to find the North Star, i.e. Stella Polaris, along with the constellations nearby, such as Cassiopeia and Perseus, resembling the letters ‘w’ and ‘t’, and Corona Borealis, i.e. the Northern Crown, resembling a bowl.

Using a star map, find all constellations which are circumpolar, i.e. near the North Star, and always above the horizon. In many constellations only a small part of the stars can be recognized. For instance, the ‘ladle’ of the Big Dipper with its seven stars is only is a small end, ‘a tail’, of the constellation Ursa Major. Discuss the distribution of the stars and the positions of the constellations in relation to each other in the sky. This is a good opportunity to emphasize the meaning of the Zodiac, the belt of the constellations, i.e. the ecliptic.

2)  By observing in nature, get to know some very bright stars and discuss, using source material, their substance, temperature, phase of development and the question: How far are they? Stars worth knowing, for instance, are Vega in the constellation Lyra, Sirius in the constellation Canis Major, and Capella in the constellation Auriga. These stars can even be seen in the twilight, while the sky is still light. When the darkness falls, there are more luminous stars in various constellations to be seen. Orientation is a good means of recognizing them. For example, the following stars are easily observed: Regulus in the constellation Leo, Procyon in the constellation Canis Minor, Arcturus in the constellation Bootes, as well as the stars Betelgeuze and Rigel in the constellation Orion.

3)  * For systematic studying of the constellations in the northern hemisphere, there is source material available. Its educational meaning is based on the so called ‘snow ball –effect’, i.e. dot maps. It means that the teaching starts from a small and familiar topic (usually the Big Dipper) and it then proceeds to the neighbouring constellations one by one. That is how the star map in the student’s hands gets completed, step by step, always adding new material on the basis of the facts already familiar. This is to ensure the chain; recalling the facts taught earlier helps the student in making the new information his own.

4)  * Write the name of its brightest star in each constellation. If there is enough interest, the background of the map can be sketched with a mythological figure. In literature, there are myriad versions of these legends. The students can get acquainted with various interpretations and, if they want to, they can also sketch figures of their own. Discuss with the students the history and necessity of the figures.

5) * Explore the star map of the southern hemisphere. Discuss the names of the constellations and their historical background. Find the names of the brightest stars. Compare the star maps of the northern and southern sky with each other.

Methods: Observation in nature, learning to know constellations with the help of a computer and literature. Using dot maps to drawing constellations. Getting acquainted with the historical facts with the help of the Internet and literature.

Materials: Star maps, drawing tools, colours, films, planisphere.

Pondering: Why was there a need for mythology? How was the essence of the figures formed? One part of the constellations resemble the figure in their name, but not the majority of it. Could the shape and essence of the figures be changed in our time? What does the modern man think of mythology? What would the future night sky be like?

Evaluation of results: It is important to emphasize to the students that mythology is not astronomy but entertainment produced by human imagination. What would the world view of the antiquity be like if it could be revised to reflect the way of thinking of the modern man? What would be the similarities? Could it bring new ideas for the modern man to use?

Hints: The use of dot maps in teaching needs a lot of time. Only then is it possible to take all benefit of the effect the recalling has on learning. Bringing something new on the basis of old always needs digestion. It is not a mere technical achievement. Dot maps.

Keywords: Constellation, Zodiac, ecliptic, star map, planisphere, mythology.

 

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