A website at this link has posted the below information regarding Live Streaming of the 2012 Karthigai Arunachala Mahadeepam:-
"Thiruvannamalai Maha Deepam 2012 Live Streaming and Live Telecast:
The Thiruvannamalai Maha Deepam 2012 will be aired live on following TV Channels – Jaya TV, Raj TV, Vasanth TV, Podhigai TV, Zee Tamil, SVBC TTD TV, Sri Sankara TV, etc.
Live Streaming of Thiruvannamalai Maha Deepam 2012 will also be available on Ustream.com and Justin.tv"
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Last year Vasanth TV as well as having a live TV Telecast also had a wonderful live online streaming of Bharani Deepam from 3 am or 3.30 am in the morning and a live telecast of Maha Deepam from 4.00 pm in the evening
The photograph is of last year’s live feed from the inside of the
Arunachaleswarar Temple Compound. It is expected that Vasanth TV will
also have a live stream this year 2012 at this link, (I hope to
confirm that early tomorrow morning).
For Ramana Maharshi devotees, the Ramana Maharshi ashram will be running
a live feed on their website of a Deepam function to be held at their
Ashram, which will include film of Arunachala from a distance with
the deepam on top.