Karwa Chauth is a traditional Hindu festival for married women, and is celebrated in some parts of India.
Married women fast one whole day without food or water for the long life of their husbands. The ritual signifies extreme love and devotion to the husband, as evidenced by the wife's willingness to suffer for his well being.
It is celebrated on the chaturthi tithi after the full Moon in the month of kartik in the Hindu calendar. According to the religious scriptures like Dharma sindhu, Nirnay sindhu and other shastra that governs rules of when to observe festival says, "Karwa Chauth to be observed at moonrise (chandrodaya vyapini) and poorvaviddha, best if its tritiya viddha. If visible during both days take the first one, if not visible on both days then take the second one".
There is a misconception that Indian tithis are connected to English dates as given in Indian panchanga. The Indian panchangam is computed for the IST and the area they represent. Since India has little variation in terms of sunrise/sunset/moonrise, a panchanga computed for one area of the country is generally usable as-is throughout India. This is not true when the a festival is computed for a different location on earth, say the Americas, the Europe, the Australias, the Middle-East, etc. Please do not use one published in indian calendars for your location. If you are not living in india and using the date published in indian calendar for karwa chauth outside indian then you could be either celebrating karawa pancham or karwa tritiya which is not a valid festival, for example if you are in usa you could be observing karwa chauth on panchmi, if you are in australia you could be observing karwa chauth on Tritiya day which is not the right festival due to time differences with Indian Standard time and respective time zones. To find out when is karwa chauth if you are living out of india do the following:
The tithis ends at the same instance all over the world. So, we need to subract the time difference (IST to your place) from India's Tithi end timings to arrive at tithi ending timings to your location. Now find out moonrise at your location and check if Chaturthi is visible during the moonrise karwa chauth at that place is on that day. 1) Note down india's tithi ending times for Ashwin Krishna Paksha Tritiya (Amavasyant) or Kartik Krishna Paksha Tritiya (Purnimant)
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