Catch a Transit

Title:   Study and observation of Venus transit from school

Participants:        Albert Capell   (teacher),
Albert Castelltort
(14 years),
LLorenç Samsó
(13 y
ears)  and
Ricardo González (14 years) .

School:               Institució Pere Vergés
Av. de les Palmeres núm. 5
Urbanització del Mas Ram
08916 Badalona

Lat. N.      41º 45' 00''
Long. E.   02º 25' 00''




Fotografía del grupo (1600X1200 - 515KB)  





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Física+Matemáticas en Acción


The survey parts:

I. I nformation about the phenomenon and the reason why it takes place and preceding observations : We visited some webs where information about the transit was provided. We also had the help of the CD -Rom VT 2004 ”, which was very useful to understand the phenomenon correctly and to find out the practical applications of the calculation of distances.

In this part we must also highlight the previous preparation work, that is, the procedures: telescopes, photographic camera, special glasses, etc, necessary to carry out the observation and to register sequences of the transit.

II. Observation and registering of the transit : We went to the school earlier than ever. Although it was cloudy at the beginning, we could watch the transit well and also take images with enough quality. Another important aspect was the parade of the students in the school, from the youngest to the eldest, so that they could watch it. They could do so by means of the telescope (reflector with filter) and also directly by the glasses we had. In addition, they could see the images from the telescope at the computer screen. It was exciting, and they will probably never forget the experience.

III. Making of the web page : This part was the hardest, especially when doing the web page with the animations, organizing the pictures and choosing them, selecting some of the many tasks done by the young, writing down everything and registering at this contest.

IV. We have profited from the photographs we took to make and original Christmas card, in order to give a sample to all the members of the school-teachers and students-, as well as to make use of it. Such card could be turned into a filoscope.

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                A Study on Venus Transit

A transit is the apparent movement of a planet in front of the Sun. From the Earth we can observe the transits of Mercury (13 each century) and Venus (13 every millennium). This only happens when each orbit is in exactly the same plane - in the lower conjunction (when the planet is moving between the Earth and the Sun) - and Venus orbit cuts the Earth’s orbit. Then they are almost lined up  ,which causes that it can be seen from the Earth as a black spot moving slowly in front of the bright surface of the sun.


 Computer graphics made at the ICT classroom using Flash 5

The following are data of the planet Venus compared to the Earth.


Venus is the second planet closer to the Sun, so we could expect it to be colder than Mercury, but that is not so. In fact it is extremely hot with temperatures of 470ºC at day and night. This is due to the fact that Venus atmosphere is the densest of the rocky planets, and because 98 per cent of its gases are carbon dioxide , which causes a greenhouse effect and therefore a very high temperature; besides, it has sulphuric acid, which makes it the most hostile planet for space probes. 


Heliocentric distance

10800000 km = 0.722 au

Equatorial diameter

121034 km

Reciprocal mass, Earth

  1: 0.82

Orbital period

224.7 earth days

Rotation period

243  earth days

Average orbit speed

35 km / sec.



The Earth is the third planet as regards distance from the Sun. It is the biggest  of the rocky planets and the most geologically active planet in the solar system. It is a world in which water can be found in gaseous, solid and liquid state. In liquid state it takes 71 % of the whole Earth surface. The atmosphere is also dense and it is made up of mainly nitrogen (78 %) , oxygen(21 % ) and water vapour (1 % )  and  carbon dioxide, all of which is enough to cause a moderate greenhouse effect that helps to keep the heat  and to balance the changes in night and day temperatures. The distance from the Sun makes that it is neither very hot, nor very cold  and what is more  it has a big satellite, the Moon , the diameter of which is 3476 Km.

The biodiversity of the Earth is huge. There are all kinds of animals: from microscopic beings  -as bacteria-  to gigantic animals  -as whales and elephants.


Helio centric distance

149608700 km = 1 au

Equatorial diameter

12753 Km



Orbital period

365,26 days

Rotation period

23 h. 56 m. 4 s

Average orbit speed

29,8 km / sec.




Previous D day preparation


1. Understanding the transit :

  •  Forming the team of students that is going to study the transit

  •  Teacher informs us -students- of the project, the kind of assignment, the rules to      b e taken  into account, etc. We -students- agree formally to carry the project     forward.

  • Research of more information in web pages.

  • Reading of the magazine “Tribuna de Astronomia”, May 2004.

  • Analysing the CD-Rom VT-2004 about the transit.

  • Organizing the team work: work distribution.

2. Preparing the classroom notice boards:


  • We make and place around the school a notice about the transit to increase the pupils and teachers curiosity.

  • We set around the school drawings, texts and data of Venus , the Earth and the Sun .

  • We go to the classrooms to invite the boys and girls  to come to see it. We also invite their parents.


3. Preparing the observation:


  • Visual: reflector telescope whit a filter, computer monitor and with special glasses.

  • Photographic: refractor telescope whit a filter ( a refractor one whit a photographic duplicator, resulting focus 1400 cm) placed  parallelly to the main telescope and digital EOS 300D Canon camera.


4. The day before, Monday:


  • We put everything in its right place, a place from where  we can always see the Sun, considering how long  the transit lasts and the Sun position.

  • We assemble the telescope and put  it in the station  whit the help of a compass for  the RA   and a graduated circle for the declination. We fit the camera, filters, computer, as if it where  the D day. We look at the Sun  and focus everything, and check that  the motorized tracking is good  enough so that we don’t have to make important corrections.

  • We cover  the box inside walls with black cardboard so that the screen (where the images  we make will be seen) can be seen properly.

  • We realise how  difficult looking through the telescope is, depending  on its position and that is why we look for a scale to avoid this problem.

  • Once we check that everything is all right, we get it ready  for the next  day and remember  we will have to get  up early and this phenomenon will not be able to be seen in 122 years, so we have  to take advantage of this opportunity to observe and study it more carefully.


Tuesday 8 th: the D day Preparant l'observació (1600x1200 - 392KB)


The observation day has come. We were about to live a phenomenon that could  not be seen in 122 years  time.

One  of us, Ricardo, was there from the very first moment and explained  to the others, Lloren ç and Albert, how the had seen it from the beginning and that because  of the cirr u stratus that were there  at that  time the first contact could not be seen. However, that did not prevent us from seeing the rest of the astronomic phenomenon, which lasted for s i x hours.

During this time, we watched out for the Venus movement. All the morning was very exciting, specially the time when a ll of school students and their parents came for the observatio n. M ore than 200 counting the youngest and oldest ones, a part from many of the their parents .

First, they used the special glasses that we lent them, after that they looked through the telescope and finally on the computer  screens, where the y could see the picture just taken whit a digital camera fitted to the telescope.


Sequenc e o f the phenomena :


  • 07:10   We are ready for the beginning of the transit  to Venus.

  • Visual and photographic observation of the transit to Venus.

  • 09:00  The school classes come to look at the transit.

  • Some clouds.

  •   More and more pupils still come .

  • 13:10    The end is getting closer and we are very attentive to what is happening.
    As the end is getting closer, our nerves increase and we take a lot of      photographs to get good pictures of the third and fourth contact

  • 13:25  The transit is over.

  • We go and have lunch: we eat hungrily and talk about the transit.

  • I n the afternoon we start working on the web, writing compositions, preparing moving pictures,... In class the students draw pictures and write summaries in which they explain a experience they will never forget.


Trànsit Venus (450x450 - 328KB)

Speed: Very  fast - Fast - Average

(450x450 - 328KB)


Moving picture made with
MS-GIF Animator
with pictures taken on the observation day

Making our webpage


To make the web page we went to the computer science classroom.

After deciding our work structure, we chose the programs that were more suitable in each case. To make our web page we used FrontPage as a basic editor, but to include the moving pictures made with Flash we used Dreamweaver as well. The choose the pictures and create one about the contacts we used the XNView program.

We created a contact sheet

We have centred and cut the pictures.

For the moving pictures we used two different programs: MS-GIF Animator and Flash.

First of all we had to centre and cut the photos we had chosen for the moving pictures, which we made by means of Corel Draw. Once they were ready we put them in order by using GIF Animator. As we didn’t come to and agreement about the reproduction speed, we decided to the reproduce them in three different speed levels so that they could be seen in mosaic on the Windows screen.


We centred and cut the pictures one of the things we discussed  more as how to design the moving pictures with Flash: at the beginning we didn’t know how to represent the movement of the planets and show its visual effect on the Sun disc at the same time. We had to modify them many times until we were satisfied with the result. It was worth doing that because our school mates told us they could understand them much better than only with the explanation of the text.



We made plan of the moving pictures of the transit with Flash 5



We also used CorelDraw to make the plan of the eclipses. To make it we scanned a picture  from a book and we drew on it.
It was tough work, but we are very satisfied with its result.


Reproduction of an eclipse plan made with CorelDraw.


Construction of filoscope


During the first term of the current school year, 2004-2005, after a long holiday, we have revised all the work about the transit of Venus that  we did last June, and we have started to translate it into English in order to take part in “Catch Venus”

We have profited from the photographs we took to make and original Christmas card, in order to give a sample to all the members of the school -teachers and students-, as well as to make use of it. Such card could be turned into a filoscope.


First page: Contact sheet

Reverse: assembling instructions


Eclipse del 5 de maig de 2004 (600x600 - 140KB)

5th May, 2004 eclipse

(600x600 - 140KB)

Picture taken by the school astronomy team


Other similar phenomena.

During the school curse 2003-04 we saw two total eclipses of the Moon (9 th November 2003 and 5 th May 2004). The weather and astronomy school teams collected information about these eclipses and published it in the school magazine. Now we are going to reproduce some paragraphs of this article that we can use to compare it with this transit of Venus. During the eclipse evolution we can observe a great variety of tones and colours, as the density of the Earth shadow isn’t homogeneous on the eclipsed lunar disc.

And eclipse of the Moon takes place when it is lined with the Sun and passes behind the Earth shadow. Theoretically, there should be an eclipse every time there was a full Moon, but it isn’t like this because the lunar orbit  is inclined in relation to the plane of the elliptical orbit of the Earth and this is why, in each full Moon, our satellite is usually a bit above or below the plan of the land orbit. This fact explains that there is only one or two eclipses every year. For similar reasons the transit of Venus can only be seen thirteen times every thousand years.


We have made a  diagram of a total Moon eclipse (left)  and Sun (right)



Neither the three of us and our teacher, nor all the boys and girls , kids , teachers and parents that came to our school to observe the transit will never be able to forget this experience. All the effort that we made ,despite the fact that we were taking final exams has been largely rewarded by  the  gratitude shown  by all our school mates, who have been able to fully satisfy the expectations we had aroused.

The subsequent work (task) in the classroom can be seen at the Picture Gallery , where a sample of some of the tasks, which shows the interest  raised (aroused ) and the things that we have learnt ,  can be seen. An interest in Astronomy and astronomic observation has been encouraged.  For us –the team- it has been an unforgettable experience and we have been able to use what we learnt in other subjects to carry on this task and we have brought ourselves to future Astronomy observation.

We have not been able to state (set down) all we have done due to the ten page limit , but we expect you will be understanding.

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Picture Gallery

Pictures taken by the school astronomy team

First selection of 78 best pictures of transit...

And the final selection of the best pictures (Click on them for make it bigger)

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Nosaltres treballant (1600x1066 - 377KB)

Efecte gota negra (266x427 - 19KB) 

Observant (1200x900 - 297KB)

Observant (1200x900 - 369KB)

  Anunci (1024x1446 - 240KB) Noticiari final (1200x800 - 151KB)

Observant (1200x900 - 267KB)

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