Why does my family say Kartik and my friend's say Ashvin?
मेरे घर में कार्तिक और दोस्त के घर आश्विन क्यों कहते हैं?
The short answer
You're probably both right, and talking about the same two weeks. North India usually ends each lunar month at the full moon, while much of the west and south ends it at the new moon. So the bright half of the month has the same name for both of you, but the dark half has names one month apart.
Same sky, two places to cut the month
A lunar month has a bright half (shukla paksha, moon growing) and a dark half (krishna paksha, moon shrinking). The purnimanta system, “ending at the full moon”, starts each month with the dark half. The amanta system, “ending at the new moon”, starts each month with the bright half.
Think of it as a string of beads, dark and bright alternating. Both systems agree on which bead is which. They just bracket them differently. So a bright half is always named the same in both, but the dark half before it belongs, in the north, to the month that's about to come and, in the west and south, to the month that's finishing.
Who uses which
As a broad pattern, purnimanta is used in much of north and central India: Uttar Pradesh, Bihar, Rajasthan, Madhya Pradesh, Punjab, Himachal. Amanta is used in Maharashtra, Gujarat, Karnataka, Andhra Pradesh and Telangana. Tamil, Malayali, Bengali and Odia calendars add a further twist because their month names follow the Sun's sign, which gives a third answer when you compare notes.
Your family's system usually depends on where your family came from, not on where you live, so you could be in Bengaluru and still say Kartik the way your grandmother in Lucknow did.
Why two systems exist at all
Both are old, and neither is a mistake or a corruption of the other. Scholars have debated which came first without a result we could treat as settled, so we're not going to pick one. India's National Calendar, adopted after the Calendar Reform Committee reported in 1955, was an attempt at a single civil calendar, and it runs alongside these traditions and hasn't replaced them for religious use.
“Then Diwali must be in a different month for different Indians, and Janmashtami too.”
- Diwali, north
- Kartika Amavasya
- Diwali, west and south
- Ashvin Amavasya
- Karva Chauth, north
- Kartika Krishna Chaturthi
- Karva Chauth, west and south
- Ashvin Krishna Chaturthi
- Janmashtami, north
- Bhadrapada Krishna Ashtami
- Janmashtami, west and south
- Shravana Krishna Ashtami
- Rama Navami, both
- Chaitra Shukla Navami. It's in the bright half, so the name is the same
Only the name differs, not the night. Any festival in the dark fortnight will have a month name that differs by one between the two systems, while the actual moon is the same one over both your houses.
Ask your elders
“Ask your grandparents what month they call the fortnight before Diwali, and whether a relative who married in from another region ever called it something else. Ask if it ever caused a mix-up over a fast or a ceremony.”
Sources
- Report of the Calendar Reform Committee (Government of India, 1955)
- Robert Sewell and Sankara Balkrishna Dikshit, The Indian Calendar (1896)
- Encyclopaedia Britannica, “Hindu calendar”
- Spasht calendar engine: month naming in both reckonings
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