European Southern Observatory (ESO)European Association for Astronomy Education (EAAE) Observatoire de ParisInstitut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE)Astronomical Institute of the Academy of Sciences of the Czech Republic The Venus Transit 2004 European Science & Technology Week 2004Visit the websites of the VT-2004 organisers

The Venus Transit 2004

... Educational Sheet 2

Appendix 1

Building a quadrant

Materials: a protractor, a drinking straw, scotch tape, some thread and a fisherman's lead weight.


  1. Fix the straw to the straight part of the protractor by scotch tape as shown in the drawing.
  2. Attach one end of the thread to the centre point of the protractor
  3. Finally fix the lead weight to the other end of the thread.

Two students can use the quadrant to measure vertical angles. One holds the instrument and views the object through the straw. The other one reads the angle defined by the thread on the protractor scale.

It is possible to build more accurate quadrants (like the wooden one in the photo), but the previous one is sufficient to carry out the following experiment.

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