Ederlinda Viñuales Gavín
Grupo de Mecánica Espacial, Universidad de Zaragoza (España)
This workshop can be performed during both sunrises and sunset, but it is more convenient to work with sunsets because the time table.
One of the purposes of this practice consists of observing the shape and colour of the solar disc changes depending on time at which the Sun is close to the horizon. In particular, we study the refraction phenomenon of the sunbeams since because of them the Sun diameter is reduced in vertical with respect to the horizontal size that does not change. We will work on a set of photographs.
Another aim of this practice is to consider the inclination of the solar path with respect to the horizon and its relation with the local latitude by means of a set of photographs taken along a sunset. It is possible to check that this inclination agrees with the stars' tracks and changes with the latitude of the observation place.
Summing up, working on a set of photographs, our goals are:
1 - To observe deformation of the solar disc during either the sunrises or sunsets.
2 - To check that the Sun diameter along the vertical decreases or increases depending on the Sun altitude over the horizon.
3 - To check that the horizontal diameter does not change.
4 - To study the existing relation between the solar path respect to the horizon and the local latitude.
5 - To check that this inclination agrees with the stars tracks and it changes with the place latitude.
6 - To observe that the Sun disappears each day through a different point on the horizon.