The general tradition with Hindus is that all the temples would remain closed during any eclipse. However as an exception to this,the Sri Kalahasti Temple located in Andhra Pradesh near Tirupati remains open during grahan also. In the year 2012, the chandra grahan occurs on the 28th of November.
Srikalahasti Temple is one of the most famous Shiva temples in south India and it is the place where Kannappa was ready to offer his eyes to cover the blood flowing from Shiva linga before Shiva stopped his act and granted him moksha. It is famous for the Vayu linga and is one of the Panchabhoota stalams representing wind.
Apart from this, the temple is also famous as a Rahu Ketu Kshetra and thousands of devotees come to the temple to perform the worship of Rahu and Ketu and sarpa dosha. Rahu and Ketu are the navagrahas which are responsible for the Surya and Chandra grahan in Hindu tradition. Hence the worship of Rahu and Ketu is considered very auspicious during grahana. So devotees come in thousands to the temple to worship and get the blessings of the Lord. This is the reason this temple remains open even during a grahana.