Louis Kahn said that all spaces need natural light.When natural light into a building,normally through skylights ,it is known as zenithal light .When the skylight is circle and at the highest of a building it is called an oculus. This opening way can absorb more light than normal window during whole day,because of this has a good position (Verges,2007). Zenith light has dramatic effect and easy to use,so it is often use in churches and temples such as pantheon in Rome.The light of pantheon is classic in the world, and the light of the Pantheon inspired Le Corbusier.
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Why zenith light often use in Religious buildings,like temples and churches?
Because the zenithal light expression of spiritual light of God.
Interior of Pantheon is a single space, but it is very complete and full of harmony.Accordance to the prevailing concept ,the dome symbolizes Sky and Contact symbolizes God's world and the human world(Plumer,2009).The natural light from the east to illuminate the interior space, in this way,the light give people a quiet atmosphere and ambiance.
Hagia Sophia is anther example about zenith light.
Because Hagia Sophia has diverse entries of light into the domes,the interior space has richness light .Interior space is rich and varied which under the dome, between the pillars, connecting the every space around .The bottom of the dome has 40 windows, when light into the space through the windows in the dome.The interior dome looks like floating in the air.
References:
PLUMMER,H,.2009.The architecture of natural
light.London:Thames and Hudson Ltd.
VERGES,M,.2007.Light in architecture. UE: Tectum Publishers .