dear muthuraji and dave08, nice to know you want to light a lamp for lord damodar, he is very merciful during this month, and will bless you alot. damodar month is the last month of chaturmasya, i'm not sure of the name according to the tamil calender. but this year it starts from 18th oct to 17th nov. light a ghee diya, and offer to a picture of lord damodar by the normal method of circling it round the picture 7 times. it should be done everyday for a month. get a picture of lord damodar from any iskcon temple if you don't have one. like i said the picture depicts krishna being tied to a rope by mother yashoda. it is the most important month for vaishnavs,it is the month when there is maximum darkness and offering a ghee lamp during this month, gives million times punya. if you gave any other doubts, you can ask me whenever.
Dear Dave Thank you very much. I think I have wrongly mentioned it as Aippasi. It should be Purattasi only.
Dear thegirlygirl Thank you for clarifying the doubts. Will do this year onwards. I will get a picture of what you have mentioned (as I have only a normal Krishna picture) from Iskcon temple.