Hinduism...Why temples in South India are closed during Solar Eclipse?

There must be some reason. Can you guys tell me why?
Is it a belief that Deities in such temples are also affected by Rahu during solar eclipse? What is the real reason?

K

i think there is no any practical reason. this is the belief that people are following since past. is is believed that the rays are harmful during eclipse, that's why, pregnant women are also restricted from going out. also people take food in advance to prevent intake of food which is affected by those rays. we are also protecting our eyes from the rays of eclipse, because of harm. so, the doors of temples may be kept because there should not be any harm to the eyes of the GOD.
in the past it was also believed that the eclipse are due to some seen or some black magic, that may be also one of the reason i.e. to prevent our GOD from such black magic or such seen.
i think there is another one reason that there may be harm to the statue of GOD by the rays, so to prevent that, older people have started to keep doors closed during the period of eclipse.

Give them money, they will open at any time,

Quite unfortunate incidents happening in India. This is a super superstition. There is NO reason for doing such things. Even in Vedas and Upanishads it was not mentioned. Some people however come up with some stupid reasons in the name of science. They say ultraviolet rays affect the temple environment so on so forth. However they are damn baseless.

if people are not ready to change then it is meaning less to blow a conch shell before deaf.

It is done as per Veda Astra's.

Vaastu Shastra and ancient Agamas gives great emphasis on the role of energies and their manifestation, with sun being the primary source of energy. So it is a widespread belief that when the sun is eclipsed, the energies are low and ill in characteristics. It is also a fact that millions of living organisms and microbes which are harmful to mankind die only while there is radiant sunlight. This phenomenon affects man and animals alike, depending on the severity of the eclipse. A sanctum in the temple is to be maintained with the most positive of energies and when a phenomenon of eclipse occurs the energy levels fall down within the sanctum too. But there are exceptions to this practice too.

The Tiruvarppu Krishna Temple in Kerala does not close during eclipse. This is because of a strange occurrence in the temple during ancient times. The temple is supposed have the presiding deity of a young Krishna who is very hungry after killing Kamsa. So closing the temple during eclipse meant no food for the deity for a long period. You can read the article about this temple here
http://stotraratna.awardspace.com/sruthi/Temples%20of%20Kerala/kt57.pdf