Panchanga- Tantra - Department of Mathematics - National

30
Panchanga- Tantra: The Magic of the Indian Calendar System / 1 Foreword to the Second Edition The fable of Apara Ganita and the Mystical Garden of Enchanted Numbers is obviously fictional. The inspiration is Leelavati Ganitam, a chapter in the ancient mathematical treatise, the Siddhanta Siromani, written by Bhaskaracharya in 1150CE. The Leelavati Ganitam is fascinating not only for its treatment of indeterminate analysis and a method to solve Pell’s Equation, but also, as a Canadian university’s website on mathematical history puts it, for its poetic conversation between the narrator and a narratee named Leelavati 1 . The similarity between this poetic construct and the conversation between Apara Ganita and the dwara palika is probably noticeable. Frame stories are not common for scientific research papers, but they certainly have a historical precedent. 1 “Bhaskaracharya”, History of Mathematics, Simon Fraser University, <http://www.math.sfu.ca/histmath/India/12thCenturyAD/Bhaskara.html > (21st September, 2002.)

Transcript of Panchanga- Tantra - Department of Mathematics - National

Page 1: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

Fore

wor

d to

the

Seco

nd E

ditio

n Th

e fa

ble

of A

para

Gan

ita a

nd t

he M

ystic

al G

arde

n of

Enc

hant

ed N

umbe

rs i

s

obvi

ousl

y fic

tiona

l. Th

e in

spira

tion

is L

eela

vati

Gan

itam

, a

chap

ter

in t

he a

ncie

nt

mat

hem

atic

al t

reat

ise,

the

Sidd

hant

a Si

rom

ani,

writ

ten

by B

hask

arac

hary

a in

115

0CE.

The

Leel

avat

i Gan

itam

is fa

scin

atin

g no

t onl

y fo

r its

trea

tmen

t of i

ndet

erm

inat

e an

alys

is

and

a m

etho

d to

sol

ve P

ell’s

Equ

atio

n, b

ut a

lso, a

s a

Can

adia

n un

iver

sity’

s w

ebsit

e on

mat

hem

atic

al h

istor

y pu

ts i

t, fo

r its

poe

tic c

onve

rsat

ion

betw

een

the

narr

ator

and

a

narr

atee

na

med

Le

elav

ati1 .

The

sim

ilarit

y be

twee

n th

is po

etic

co

nstru

ct

and

the

conv

ersa

tion

betw

een

Apa

ra G

anita

and

the

dwar

a pa

lika

is pr

obab

ly n

otic

eabl

e.

Fr

ame

stor

ies

are

not

com

mon

for

sci

entif

ic r

esea

rch

pape

rs,

but

they

cer

tain

ly

have

a h

istor

ical

pre

cede

nt.

1 “B

hask

arac

hary

a”,

His

tory

of

M

athe

mat

ics,

Sim

on

Fras

er

Uni

vers

ity,

<http

://w

ww

.mat

h.sf

u.ca

/hist

mat

h/In

dia/

12th

Cen

tury

AD

/Bha

skar

a.ht

ml>

(21s

t Sep

tem

ber,

2002

.)

Page 2: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 2

Prol

ogue

The

Mys

tical

Gar

den

of E

ncha

nted

Num

bers

O

nce

upon

a t

ime,

in

the

mag

ical

mys

tical

city

of

Suva

rnap

uri2 ,

ther

e liv

ed a

stud

ent c

alle

d Ap

ara

Gan

ita3 . A

para

Gan

ita w

as v

irtu

ous

and

devo

ted

to h

is s

cien

ces.

Hav

ing

spen

t con

side

rabl

e am

ount

of t

ime

lear

ning

the

shas

tras

from

his

gur

u, h

e wa

s

surp

rise

d wh

en o

ne d

ay h

is g

uru

calle

d hi

m u

p.

“You

hav

e pe

rfor

med

wel

l, O

sis

hya4 m

ine”

, the

gur

u sa

id, “

but t

he ti

me

has

now

com

e fo

r you

to ta

ke le

ave”

.

Apar

a G

anita

was

at

once

sad

, fo

r he

had

lea

rned

a l

ot u

nder

him

. Bu

t he

rem

aine

d qu

iet a

nd c

ontin

ued

liste

ning

to h

is g

uru.

“Lis

ten,

Apa

ra G

anita

, I sh

all n

ow te

ll yo

u so

met

hing

that

my

guru

told

me

when

I

finis

hed

my

stud

ies.

For,

a st

udy

in G

anita

Sas

tra

(mat

hem

atic

s) is

not

com

plet

e, u

nles

s

one

visi

ts th

e M

ystic

al G

arde

n of

Enc

hant

ed N

umbe

rs”

“You

mus

t go

and

find

this

pla

ce fo

r you

r edu

catio

n to

be

trul

y co

mpl

ete”

.

And

so A

para

Gan

ita w

ent

abou

t se

arch

ing

for

this

pla

ce.

Inde

ed,

afte

r m

uch

trav

ellin

g an

d se

arch

ing,

he

was

final

ly s

hown

the

way

to

the

Mys

tical

Gar

den

of

Ench

ante

d N

umbe

rs.

And

lo, w

hat

a be

autif

ul s

ight

it w

as!

For

it wa

s si

tuat

ed i

n th

e m

idst

of

a lu

sh

gree

n va

lley,

sad

dled

by

mou

ntai

ns o

n ei

ther

sid

e. D

own

ther

e, A

para

Gan

ita c

ould

see

fam

ous

mat

hem

atic

ians

exp

ositi

ng t

heir

the

orie

s an

d sk

ills,

like

hawk

ers

on a

baz

aar

stre

et. T

here

was

Euc

lid s

tand

ing

on a

rec

tang

le, e

xpla

inin

g th

e be

auty

of

the

Gol

den

Ratio

in c

lass

ic G

reco

Cal

dean

arc

hite

ctur

e. P

ytha

gora

s wa

s st

andi

ng n

ext t

o hi

m a

s a

2 Suv

rnap

uri =

City

of G

old

3 A

para

Gan

ita =

som

eone

with

a lo

t of m

athe

mat

ical

tale

nt.

4 Sish

ya =

stud

ent

Page 3: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 3

part

of

the

Gre

ek e

xhib

it, e

xpla

inin

g th

e vi

rtue

s of

a r

ight

-ang

led

tria

ngle

to a

cur

ious

crow

d. F

rom

the

far

end

of th

e O

rato

r’s

Cor

ner,

Zha

o Ju

n Q

ing

look

ed a

t Pyt

hago

ras

and

smile

d. H

e wa

s hi

mse

lf ho

ldin

g a

righ

t-ang

led

tria

ngle

and

was

exp

lain

ing

his

proo

f

for

the

Pyth

agor

as’

Theo

rem

. M

ande

lbro

t wa

s de

cora

ting

the

Gar

den

with

flo

wers

of

frac

talla

te b

eaut

y. J

ohn

Nas

h wa

s cl

ose

by;

he w

as p

oint

ing

at a

gro

up o

f wo

men

,

prob

ably

exp

lain

ing

gam

e th

eory

to

onlo

oker

s ar

ound

him

. In

ano

ther

cor

ner

of t

he

gard

en,

(Sec

tor

1729

), Sr

iniv

asa

Ram

anuj

an w

as v

ocife

rous

ly a

rgui

ng a

poi

nt w

ith

Thom

as H

ardy

.

It wa

s suc

h an

env

iron

men

t tha

t Apa

ra G

anita

wan

ted

to e

nter

.

How

ever

, as

he w

as a

bout

to e

nter

thro

ugh

the

grea

t doo

rs g

uard

ing

the

gard

en,

he h

eard

a so

noro

us v

oice

cal

ling

out h

is n

ame.

He

stop

ped

and

turn

ed a

roun

d to

see

who

was

cal

ling

him

onl

y to

saw

a y

oung

wom

an c

omin

g to

ward

s hi

m. W

ith e

yes

burn

ing

with

cur

iosi

ty a

nd a

voi

ce s

weet

er th

an

a ni

ghtin

gale

, she

said

: -

O S

tude

nt E

rudi

te,

Wha

t is

it th

at y

ou st

udy

toni

ght?

Just

wha

t I

need

ed,

a m

ystic

al d

war

a pa

lika

(fem

ale

door

kee

per)

, he

sai

d to

him

self.

Sha

king

his

hea

d in

wry

am

usem

ent,

he lo

oks

at th

e bo

oks

in h

is h

and

and

take

s

a de

ep b

reat

h to

beg

in h

is d

isse

rtat

ion.

...

Page 4: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 4

Con

tent

s

Fore

word

1

Prol

ogue

– T

he M

ystic

al Ga

rden

of E

ncha

nted

Num

bers

2

Cont

ents

4

Stha

ana P

raka

rana

– H

ow th

e cale

ndar

is d

iffer

ent i

n di

ffere

nt re

gion

s Err

or! B

ookm

ark

not

defin

ed.

The S

outhe

rn A

maan

ta Ca

lenda

r E

rror

! Boo

kmar

k no

t def

ined

. W

ester

n Ama

anta

Calen

dar

Err

or! B

ookm

ark

not d

efin

ed.

Purn

imaa

nta C

alend

ar

Err

or! B

ookm

ark

not d

efin

ed.

The M

alaya

li Cale

ndar

E

rror

! Boo

kmar

k no

t def

ined

. Ta

mil C

alend

ar

Err

or! B

ookm

ark

not d

efin

ed.

Beng

ali C

alend

ar

Err

or! B

ookm

ark

not d

efin

ed.

Oriya

Cale

ndar

E

rror

! Boo

kmar

k no

t def

ined

. Th

e Nan

aksh

ahi C

alend

ar

Err

or! B

ookm

ark

not d

efin

ed.

Natio

nal C

alend

ar of

1957

E

rror

! Boo

kmar

k no

t def

ined

.

Maas

a Naa

mak

aran

a - H

ow th

e Mon

ths g

ot th

eir N

ames

. Er

ror!

Boo

kmar

k no

t def

ined

. 1)

Mo

nths n

amed

after

Nak

shat

ras

Err

or! B

ookm

ark

not d

efin

ed.

2)

Month

s nam

ed af

ter ra

asis

Err

or! B

ookm

ark

not d

efin

ed.

Parv

a Din

a Nirn

aya –

How

the d

ays o

f fes

tivals

are d

ecid

ed.

Erro

r! B

ookm

ark

not d

efin

ed.

Sam

vad

Sand

esha

– Ho

w Er

as co

me i

nto

play

Er

ror!

Boo

kmar

k no

t def

ined

.

Ksha

ya S

utra

– H

ow ce

rtain

mon

ths a

re d

ropp

ed.

Erro

r! B

ookm

ark

not d

efin

ed.

Epilo

gue –

The

Beg

inni

ng

25

Bibl

iogr

aphy

26

Ackn

owled

gem

ents

27

Appe

ndix-

The

Stru

ctur

e of t

he In

dian

Cale

ndar

Sys

tem

28

Appe

ndix

– Ksh

aya U

ntan

gled

. 29

Appe

ndix

– Why

Ksh

aya d

idn’

t occ

ur b

etwe

en 18

41 an

d 19

64CE

. 30

Page 5: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 5

Sth

aana

Pra

kara

na –

H

ow th

e ca

lend

ar is

diff

eren

t in

diffe

rent

regi

ons

In a

sono

rous

voi

ce, t

he d

wara

pal

ika

said

, “I

n or

der t

o as

certa

in y

our d

isse

rtatio

n’s v

erac

ity,

can

I hea

r you

talk

abo

ut th

e ca

lend

ar’s

regi

onal

com

plex

ity?”

To

whi

ch A

para

Gan

ita li

stene

d to

the

mul

titud

es o

f voi

ces i

n th

e G

arde

n, a

nd re

plie

d th

us:-

Prob

ably

the

easi

est w

ay to

cla

ssify

Ind

ian

cale

ndar

s is

by th

e re

gion

of u

sage

. It

mus

t be

reite

rate

d th

ough

, tha

t suc

h an

exe

rcise

mig

ht b

e m

isle

adin

g. T

he c

lass

ifica

tion

is

inde

ed n

ot w

ater

tight

; al

l ca

lend

ars

are

intr

insi

cally

int

er-li

nked

with

one

ano

ther

. A

flow

char

t of

the

var

ious

Ind

ian

cale

ndar

s an

d th

e lin

ks b

etw

een

them

is

give

n in

the

App

endi

x.

W

ith t

his

cave

at,

we’

ll no

w t

rave

rse

Indi

a on

a c

alen

dric

al v

ehic

le o

f so

rts. I

n

parti

cula

r, w

e try

to

asce

rtain

the

fol

low

ing

elem

ents

in

each

reg

ion’

s ca

lend

rical

prac

tices

: -

B

asis

of th

e C

alen

dar

Lo

cal V

aria

tion.

W

hen

does

the

year

beg

in?

Er

a Fo

llow

ed

We’

ll fin

d th

e fo

llow

ing

cale

ndar

s def

ined

with

thes

e m

etric

s: -

The

Sout

hern

Am

aant

a C

alen

dar

Th

e So

uthe

rn A

maa

nta

Luni

sola

r C

alen

dar

is p

redo

min

antly

fol

low

ed in

the

Sout

h an

d So

uth-

Wes

t Ind

ian

stat

es o

f And

hra

Prad

esh,

Kar

nata

ka a

nd M

ahar

asht

ra.

It is

esse

ntia

lly a

lun

isola

r on

e; i

.e.,

its d

ays

and

mon

ths

are

calc

ulat

ed b

ased

on

the

mot

ions

of t

he m

oon.

Lik

e th

e C

hine

se c

alen

dar,

the

mon

th is

cal

cula

ted

from

new

moo

n

to n

ew m

oon.

It

how

ever

, di

ffers

fro

m t

he C

hine

se c

alen

dar

in t

hat

the

luna

r da

y

(“th

ithi”

) of t

he n

ew m

oon

is c

onsi

dere

d th

e la

st d

ay o

f the

pre

viou

s m

onth

. Aga

in, a

s in

Page 6: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

1

(Cha

itrad

i) la

st

full

moo

n be

fore

M

esha

Sa

nkra

nti

Tam

il N

adu

Sola

r K

ali,

Jovi

an

cycl

e (S

outh

ern

Scho

ol)

Mes

ha S

ankr

anti

Tri

pura

So

lar

Kal

i, B

enga

li Sa

n So

lar

Day

af

ter

Mes

ha S

ankr

anti

Ben

gali

rule

s fo

r be

ginn

ing

of

mon

th

Utt

aran

chal

Pu

rnim

aant

a V

ikra

ma

Era

(Cha

itrad

i) O

ne d

ay a

fter

the

last

fu

ll m

oon

befo

re

Mes

ha

Sank

rant

i

Utt

ar P

rade

sh

Purn

imaa

nta

Vik

ram

a Er

a (C

haitr

adi)

One

day

afte

r th

e la

st

full

moo

n be

fore

M

esha

Sa

nkra

nti

Wes

t Ben

gal

Sola

r K

ali,

Ben

gali

San

Sola

r D

ay

afte

r M

esha

San

kran

ti B

enga

li ru

les

for

begi

nnin

g of

m

onth

Ta

ble

1: -

Cal

endr

ical

pra

ctic

es in

diff

eren

t Ind

ian

stat

es

Not

e:

1)

The

tabl

e is

exh

aust

ive

neith

er i

n te

rms

of c

alen

dars

nor

in

term

s of

sta

tes.

Aru

nach

al P

rade

sh, M

anip

ur, M

egha

laya

, Miz

oram

, Nag

alan

d an

d Si

kkim

wer

e

left

out.

2)

Cha

tterje

e m

entio

ns th

at th

e O

rissa

Sch

ool f

or d

ecid

ing

the

begi

nnin

g of

the

sola

r

mon

th i

s al

so u

sed

in P

unja

b an

d H

arya

na “

whe

re t

he s

olar

cal

enda

r is

also

used

”.19

19 C

hatte

rjee,

SK

p. 1

4

Page 7: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

2

Maa

sa N

aam

akar

ana

- H

ow th

e M

onth

s go

t the

ir N

ames

. Li

sten

ing

to th

is, s

he sa

id,

“Sin

ce w

e ar

e de

ep in

this

gam

e,

Mig

ht I

ask

how

eac

h m

onth

got

its n

ame?

” To

whi

ch A

para

Gan

ita st

ared

at a

gul

moh

ar fl

ower

with

twen

ty-s

even

bud

s and

repl

ied

thus

:-

Th

e co

mpl

exity

of

the

Indi

an c

alen

dar

syst

em i

s no

t ju

st i

n th

e pl

etho

ra o

f

cale

ndar

s av

aila

ble,

but

also

in

the

man

ner

in w

hich

the

y lin

k up

with

one

ano

ther

. A

prin

cipa

l poi

nt o

f lin

kage

of m

ost I

ndia

n ca

lend

ars

is in

thei

r nam

es o

f the

mon

ths;

as

we

shal

l se

e, t

he s

imila

r se

ts o

f m

onth

nam

es a

re u

sed

in m

ore

than

one

cal

enda

r. In

thi

s

sect

ion,

we

aim

to fo

rmul

ate

rule

s det

erm

inin

g th

e na

min

g of

the

mon

ths.

Our

mot

ivat

ion

is no

t jus

t tax

onom

ic; m

onth

nam

es, w

e sh

all s

ee, a

re c

ritic

al to

und

erst

andi

ng th

e In

dian

cale

ndar

sys

tem

.

W

e pr

opos

e th

at th

ere

are

two

type

s of m

onth

nam

es: -

1) M

onth

s na

med

afte

r Nak

shat

ras

Th

e se

t of

mon

th n

ames

nam

ed a

fter

naks

hatr

as i

s us

ed b

y bo

th s

olar

and

luni

sola

r cal

enda

rs, a

ddin

g to

see

min

g co

mpl

exity

of t

he In

dian

cal

enda

r sys

tem

. Ind

eed,

as w

e sh

all

see,

thi

s ty

pe s

houl

d ac

tual

ly c

alle

d as

‘M

onth

s in

itial

ly n

amed

afte

r

Nak

shat

ras’

; th

ere

has

been

an

in

fusio

n of

so

lar

rule

s in

to

an

esse

ntia

lly

luna

r

conv

entio

n.

Le

t us

then

, firs

t con

side

r the

orig

inal

rule

. Sah

a an

d La

hiri

men

tion

that

pak

shas

or fo

rtnig

hts

wer

e di

ffer

entia

ted

base

d on

the

naks

hatr

a “w

here

the

moo

n is

full”

.20 T

hat

is to

say

, if

a pa

rticu

lar

full

moo

n oc

curs

nea

r, sa

y, th

e lu

nar

aste

rism

, Vis

akha

, the

full

moo

n w

ould

be

calle

d as

Vai

sakh

a Pu

rnim

aasi

, and

the

mon

th w

ould

be

Vais

akha

. The

earli

est

luni

sola

r m

onth

s, th

en,

wer

e pu

rnim

aant

a, t

hat

is, t

he n

ame

of t

he f

ull

moo

n

20 S

aha

et a

l. p.

221

Page 8: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

3

corr

espo

nded

to th

e na

me

of th

e m

onth

. Of c

ours

e, th

e fu

ll m

oon

occu

rs a

t all

naks

hatr

as.

Fifte

en w

ere

take

n in

to a

ccou

nt fo

r nam

ing

of th

e m

onth

, spa

ced

mor

e or

less

equ

ally

.

W

e th

us h

ave

the

follo

win

g se

t of n

ames

alo

ng w

ith th

eir r

espe

ctiv

e na

ksha

tras

21:

-

Nak

shat

ra o

n Pu

rnim

a M

onth

Nam

e C

hitra

C

haitr

a V

isakh

a V

aisa

kha

Jyes

tha

Jyai

stha

(P

urva

& U

ttara

) Aas

haad

ha

Aas

haad

ha

Srav

ana

Sraa

vana

(U

ttara

& P

urva

) Bha

adra

pada

B

haad

rapa

da

Asv

ini

Asv

ayuj

a (A

asvi

na)

Krit

tika

Kaa

rthik

a M

ruga

sira

Maa

rgha

sira

Pu

shya

mi

Paus

a (P

ushy

am)

Mag

haa

Maa

gha

(Utta

ra a

nd P

urva

) Pha

lgun

i Ph

algu

na

It m

ay b

e no

ted

that

the

mon

ths

of A

asha

adha

, Bha

drap

ada

and

Phal

guna

are

linke

d to

tw

o na

ksha

tras

res

pect

ivel

y. C

hatte

rjee

and

Cha

krav

arth

y gi

ve t

he f

ollo

win

g

crite

ria fo

r cho

osin

g na

ksha

tras

for m

onth

nam

es22

: -

1)

The

yoga

taar

as o

r th

e id

entif

ying

sta

rs o

f th

e na

ksha

tras

are

pro

min

ent o

r ha

ve

tradi

tiona

l sig

nific

ance

.

2)

The

y ar

e sp

aced

mor

e or

less

equ

idist

ant f

rom

one

ano

ther

.

It m

ust b

e m

entio

ned

that

this

rule

is n

ow a

n ap

prox

imat

ion

larg

ely

due

to E

arth

’s

prec

essio

n; fo

r in

stan

ce, t

his

year

’s C

hitr

a Pu

rnim

aasi

had

Swa

ti as

its

naks

hatr

a. A

lso,

poss

ibly

for

hist

oric

al r

easo

ns, a

nd a

llow

ing

for

regi

onal

var

iatio

n in

pro

nunc

iatio

n, th

e

Oriy

a, B

enga

li, A

ssam

ese,

Pun

jabi

and

Tam

il so

lar

cale

ndar

s al

so u

se t

he s

ame

set

of

mon

th n

ames

. To

reco

ncile

all

this,

we

mig

ht fr

ame

a ne

w r

ule;

that

, the

am

aant

a lu

nar

21Sa

ha e

t al.

p. 2

21

22 C

hakr

avar

thy

et a

l, p.

281

Page 9: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

4

mon

th ta

kes

its n

umbe

r fro

m th

e so

lar

mon

th th

at s

tarts

in it

, but

its

nam

e fro

m th

e so

lar

mon

th in

whi

ch it

sta

rts, w

hile

follo

win

g th

e pu

rnim

aant

a m

onth

s in

chr

onol

ogic

al o

rder

.

That

is to

say

, sin

ce C

hitr

a oc

curr

ed d

urin

g th

e pu

rnim

a of

this

yea

r’s

first

pur

nim

aant

a

mon

th,

we

call

this

mon

th a

s ‘C

haitr

a’.

Con

sequ

ently

, th

e fir

st a

maa

nta

mon

th w

ould

also

be

‘Cha

itra’

, w

hich

also

wou

ld b

e th

e na

me

of t

he s

olar

mon

th d

urin

g w

hich

the

amaa

nta

‘Cha

itra’

sta

rted.

How

ever

, the

‘nu

mbe

r’ o

f the

sol

ar m

onth

(‘1

’ in

the

case

of

amaa

nta

and

purn

imaa

nta

Cha

itra)

is n

ot q

uite

the

sam

e; th

e so

lar C

haitr

a is

the

last

(i.e

.,

12th)

mon

th o

f the

yea

r. Th

e lu

niso

lar

Cha

itra’

s nu

mbe

r is

take

n by

the

sola

r m

onth

that

begi

ns in

it, n

amel

y th

e so

lar

Vai

sakh

a. A

ll th

is ca

n be

see

n in

the

gra

phic

in t

he n

ext

page

.

The

rela

tions

hips

for a

ll th

e m

onth

s m

ay b

e m

appe

d ac

cord

ing

to th

e fo

llow

ing

tabl

e23: -

Raa

si

App

roxi

mat

e na

ksha

tra

on

Purn

ima

Lun

ar

Mon

th

Nam

e

Sola

r M

onth

N

ame

Ass

ames

e V

ersi

on

Tam

il V

ersi

on

Punj

abi

Ver

sion

24

Mes

ha

Chi

tra

Cha

itra

Vai

sakh

a B

ahag

C

hitta

rai

Vai

sakh

V

rsha

va

Visa

kha

Vai

sakh

a Jy

aist

ha

Jeth

V

aika

si

Jeth

M

ithun

a Jy

esth

a Ja

isht

a A

asha

adha

A

har

Aan

i H

arh

Kar

kata

(P

urva

&

Utta

ra)

Aas

haad

ha

Aas

haad

ha

Sraa

vana

Sa

on

Aad

i Sa

wan

Sim

ha

Srav

ana

Sraa

vana

B

haad

rapa

daB

had

Aav

ani

Bha

don

Kan

ya

(Pur

va &

U

ttara

) B

haad

rapa

da

Bha

adra

pada

Asv

ayuj

a (A

asvi

na)

Ahi

n Pu

ratta

asi

Asu

Tula

A

svin

i A

svay

uja

(Aas

vina

) K

aarth

ika

Kat

i A

rppi

si

Kat

ik

Vris

chik

a K

rittik

a K

aarth

ika

Maa

rgha

sira

A

ghon

K

arth

igai

M

agha

r D

hanu

s M

ruga

sira

Maa

rgha

sira

Pa

usa

(Pus

hyam

) Pu

ha

Maa

rgal

i Po

h

Mak

ara

Push

yam

i Pa

usa

(Pus

hyam

) M

aagh

a M

agh

Thaa

i M

agh

Kum

bha

Maa

gha

Maa

gha

Phal

guna

Ph

agun

M

aasi

Ph

agun

M

ina

(Utta

ra a

nd

Purv

a)

Phal

guna

C

haitr

a C

hait

Pang

uni

Che

t

23 C

hakr

avar

thy,

et a

l. p.

280

24

Pal

Sin

gh P

urew

al, N

anak

shah

i Sam

at. <

http

://w

ww

.sikh

.net

/sik

hism

/Nan

aksh

ahi.h

tm >

Page 10: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

5

Phal

guni

The

Ass

ames

e, P

unja

bi a

nd T

amil

vers

ions

hav

e be

en p

rovi

ded

to g

ive

an id

ea o

f

the

lingu

istic

var

iatio

n. I

t is

also

int

eres

ting

to o

bser

ve t

hat

the

Nat

iona

l C

alen

dar

sugg

este

d by

Sah

a an

d La

hiri

also

use

s th

e sa

me

set

of m

onth

nam

es,

incr

easi

ng t

he

pote

ntia

l con

fusio

n. A

s is

pro

babl

y ob

viou

s by

now

, the

rul

e do

es n

ot c

orre

spon

d to

the

Tam

il, N

atio

nal a

nd N

anak

shah

i cal

enda

rs.

2) M

onth

s na

med

afte

r raa

sis

Onl

y so

lar

mon

ths

shar

e th

eir

nam

es w

ith r

aasi

s. SK

Cha

tterje

e an

d A

purb

a K

umar

Cha

krav

arth

y gi

ve th

e fo

llow

ing

nam

es a

long

with

the

asso

ciat

ed ra

asis

25.

Raa

si

Sans

kriti

sed

Ver

sion

M

alay

alam

Ver

sion

M

esha

M

esha

M

edam

V

rsha

va

Vrs

hava

Ed

avam

M

ithun

a M

ithun

a M

idhu

nam

K

arka

ta

Kar

kata

K

arita

ka

Sim

ha

Sim

ha

Chi

ngam

K

anya

K

anya

K

anni

Tu

la

Tula

Th

ulam

V

risch

ika

Vris

chik

a V

risch

ikam

D

hanu

s D

hanu

s D

hanu

M

akar

a M

akar

a M

akar

am

Kum

bha

Kum

bha

Kum

bham

M

ina

Min

a M

inam

Th

at is

to s

ay, t

he m

onth

sha

res

its n

ame

with

that

of i

ts c

orre

spon

ding

San

kran

ti.

For

inst

ance

, if

Mes

ha S

ankr

anti

occu

rs o

n a

certa

in d

ay, t

hen

the

perio

d un

til th

e ne

xt

Sank

rant

i wou

ld b

e M

esha

maa

sa (M

edha

m m

aasa

m).

This

nam

ing

rule

is f

ollo

wed

prim

arily

in t

he M

alay

alam

cal

enda

r. In

cide

ntal

ly,

Abh

ayan

kar s

ays t

hat t

he O

riya

cale

ndar

also

follo

ws t

his r

ule.

26

25 C

hakr

avar

ty, e

t al.

p. 2

80

26 A

bhay

anka

r, p.

55

Page 11: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

6

Parv

a D

ina

Nirn

aya

How

the

days

of f

estiv

als

are

deci

ded.

H

eari

ng h

im sp

eak,

she

aske

d,

“The

cul

tura

l com

plex

ity is

inte

rest

ing,

bu

t per

haps

you

hav

e a

fest

ival

s lis

ting?

To

whi

ch A

para

Gan

ita lo

oked

at b

irds

chi

rpin

g an

d re

plie

d th

us:-

We

prov

ide

a lis

t of

Ind

ian

fest

ival

s, al

ong

with

the

ir (I

ndic

) da

tes

and

the

cale

ndar

use

d to

rec

kon

the

parti

cula

r fe

stiv

al.

The

list

of f

estiv

als

is by

no

mea

ns

exha

ustiv

e; th

e en

tries

are

mos

tly p

ublic

hol

iday

s in

Indi

a.

Fest

ival

27

Indi

c D

ate

Add

ition

al R

ules

C

alen

dar

Use

d

Mak

ara

Sank

rant

i/

Pong

al

Mak

ara

Sank

rant

i N

one

Sola

r

Mah

a Si

va R

aatr

i M

agha

K 1

4 M

ust c

over

a n

isita

Lu

niso

lar

Hol

i Ph

algu

na P

urni

ma

Hol

ika

Dah

ana

is

obse

rved

on

the

nigh

t

of t

he P

urni

ma;

Hol

i

is ob

serv

ed

on

the

sola

r da

y af

ter

Hol

ika

Dah

ana

Luni

sola

r

Uga

di /

Gud

i Pad

wa

Cha

itra

S 1

Non

e Lu

niso

lar

Ram

a N

avam

i C

haitr

a S

9 M

ust c

over

Mad

yahn

a

Tam

il N

ew

Yea

r,

Vish

u,

Ben

gali

New

Yea

r

Mes

ha S

ankr

anti

R

espe

ctiv

e Sa

nkra

nti

rule

s

Sola

r

Gan

esh

Cha

turti

B

hadr

apad

a S

4 M

ust c

over

Mad

yahn

a Lu

niso

lar

Bud

dha

Purn

ima

Vai

sakh

i Pur

nim

a

Luni

sola

r

Rak

sha

Ban

dan

Sr

avan

a Pu

rnim

a

Luni

sola

r

Janm

asht

ami

Srav

ana

K 8

Luni

sola

r

27 C

hatte

rjee,

p. 6

0-68

Page 12: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

7

Ona

m

Moo

n is

in S

rava

na

naks

hatra

in

So

lar

Bha

drap

ada

Lu

niso

lar

and

Sola

r

Mah

anav

ami

Asv

ayuj

a S

9 (M

ahan

avam

i is

reck

oned

be

fore

th

e

othe

r 8

days

of

Dus

sehr

a28)

Luni

sola

r

Vija

yada

sam

i (T

he

thith

i af

ter

Mah

anav

ami)

Mus

t cov

er a

Nis

ita

Luni

sola

r

Dee

pava

li A

svay

uja

Am

avas

ya

Mus

t cov

er p

rado

sha

Luni

sola

r

A

bit

of e

xpla

natio

n is

nece

ssar

y. F

irst,

the

term

s. “N

isita

” is

defin

ed to

be

a tim

e-

perio

d m

easu

red

by t

wo

ghat

ikas

(1/

60th o

f a

sola

r da

y; a

ppro

xim

atel

y 20

min

utes

)

stre

tchi

ng o

n ei

ther

sid

e of

mid

nigh

t. “P

rado

sha”

is

the

time-

perio

d st

retc

hing

for

tw

o

muh

urta

s (1

/15th

of

the

time

betw

een

sunr

ise a

nd s

unse

t; ap

prox

imat

ely

1 ho

ur 3

6

min

utes

) af

ter

suns

et. “

Mad

hyah

na”

is on

e-th

ird o

f the

tim

e-pe

riod

betw

een

sunr

ise a

nd

suns

et. T

his

fract

ion

cove

rs m

id-d

ay.

Seco

nd,

thes

e da

tes

are

valid

onl

y on

non

-inte

rcal

ary

thith

is f

or a

ll lu

niso

lar

fest

ival

s. B

oth

leap

day

s an

d no

n-le

ap d

ays

in le

ap m

onth

s ar

e de

emed

unf

it fo

r fes

tival

s.

(Ksh

aya

maa

sas

are

not

an i

ssue

her

e be

caus

e a)

jug

ma

mon

ths

are

deem

ed f

it fo

r

relig

ious

obs

erva

nce

and

b) in

the

East

ern

and

Nor

thw

este

rn sc

hool

s, th

e ex

tra in

terc

alar

y

mon

th is

dee

med

to b

e no

rmal

).

And

fin

ally

, if

the

give

n th

ithi d

oesn

’t co

ver

the

give

n tim

e, o

r co

vers

the

give

n

time

on tw

o so

lar d

ays,

then

the

seco

nd so

lar d

ay is

reck

oned

to b

e th

e re

spec

tive

fest

ival

.

28 S

ivas

ri Sa

rma,

Mad

ugul

a. In

terv

iew

by

auth

or. H

yder

abad

, Ind

ia. 4

th Ja

nuar

y, 2

002.

Page 13: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

8

Sam

vad

Sand

esha

How

Era

s co

me

into

pla

y Pe

rcei

ving

the

resp

onse

, she

que

stio

ned,

“I

don

’t kn

ow if

this

is a

n im

porta

nt p

art,

but f

rom

whe

n do

all

cale

ndar

s sta

rt?”

To w

hich

Apa

ra G

anita

look

ed a

t a fo

unda

tion

stone

and

repl

ied

thus

:-

Th

e In

dian

cal

enda

r sy

stem

fol

low

s a

wid

e ra

nge

of e

ras,

som

e of

hist

oric

al

inte

rest

. A

lso,

we

do n

ot a

ttem

pt t

o lin

k in

divi

dual

cal

enda

rs t

o er

as,

for

the

sam

e

cale

ndar

may

be

reck

oned

with

two

diffe

rent

era

s in

two

diffe

rent

pla

ces.

Her

e’s t

he li

stin

g29: -

Era

Z

ero

Yea

r B

egin

ning

of

Era

with

res

pect

to

indi

vidu

al y

ear

Saka

78

CE

Mes

ha S

ankr

anti,

Cha

itra

S 1

Vik

ram

a 57

CE

Mes

ha

Sank

rant

i, C

haitr

a S

1,

Kar

tika

S 1,

Ash

adha

S 1

Kal

i 31

01 B

CE

Mes

ha S

ankr

anti,

Cha

itra

S 1

Kol

lam

82

4 C

E K

anya

San

kran

ti, S

imha

San

kran

ti

Ben

gali

San

963

+ so

lar y

ears

sin

ce 1

556

CE

Mes

ha S

ankr

anti

In a

dditi

on, s

ome

regi

ons

also

nam

e th

eir

year

s ac

cord

ing

to th

e na

mes

of t

he J

ovia

n

year

s. Sa

ha a

nd L

ahiri

poi

nt o

ut th

at th

ere

are

two

scho

ols

for

this

; the

Sou

ther

n sc

hool

nam

es i

ts y

ears

in

cont

inuo

us s

ucce

ssio

n, w

hile

the

Nor

ther

n sc

hool

nam

es i

ts y

ears

corr

espo

ndin

g to

the

pres

ent J

ovia

n ye

ar30

.

29 S

aha

et a

l. p.

252

– 2

58.

30 Ib

id. p

272

Page 14: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 1

9

Ksh

aya

Sutr

a –

H

ow c

erta

in m

onth

s ar

e dr

oppe

d.

Obs

ervi

ng th

e re

actio

n, sh

e en

quir

ed,

To c

alen

dars

you

seem

to b

e an

act

ive

saak

shya

31,

But h

ave

you

stud

ied

the

ephe

mer

ally

con

foun

ding

ksh

aya?

To

whi

ch, A

para

Gan

ita lo

oked

at s

ome

falle

n le

aves

and

repl

ied

thus

:-

O

ne o

f the

mos

t int

eres

ting

aspe

cts

of th

e In

dian

luni

sola

r ca

lend

ar is

its

ksha

ya

maa

sas,

liter

ally

“de

caye

d m

onth

s”. O

ccas

iona

lly, c

erta

in m

onth

s ar

e dr

oppe

d fro

m th

e

luni

sola

r cal

enda

r. W

e no

w tr

y to

und

erst

and

the

mod

aliti

es b

ehin

d th

is o

mis

sion;

we

try

to a

nsw

er h

ow, w

hy, w

hen

and

whe

re it

hap

pens

.

Fi

rst,

let’s

try

to

defin

e a

ksha

ya m

onth

. C

hatte

rjee,

in

his

wor

k on

Ind

ian

cale

ndar

s, sa

ys th

at a

cer

tain

luna

r mon

th “

may

com

plet

ely

over

lap

any

of th

e sh

ort t

hree

nira

yana

sola

r mon

ths o

f Mar

gasi

ra, P

aush

a an

d M

agha

”, w

ith th

e re

sult

that

ther

e w

ill b

e

no n

ew m

oon

in th

e re

spec

tive

sola

r m

onth

. Con

sequ

ently

, the

re w

ill b

e no

luna

r m

onth

nam

ed “

afte

r …

this

sola

r m

onth

”.32

A g

raph

ic d

escr

ibin

g th

is in

tera

ctio

n is

give

n in

App

endi

x C

.

We

lear

n th

e fo

llow

ing

from

thi

s st

atem

ent:

- a)

tha

t th

e so

lar

mon

ths

of

Mar

gasir

a, P

ausa

and

Mag

ha a

re s

mal

l, b)

that

at a

cer

tain

tim

e, th

ere

mig

ht b

e no

new

moo

n in

the

se m

onth

s, an

d c)

the

cor

resp

ondi

ng l

unar

mon

th i

s dr

oppe

d fro

m t

he

cale

ndar

. Not

e th

at C

hatte

rjee

is si

lent

on

whe

ther

the

drop

ped

luna

r mon

th is

am

aant

a or

purn

imaa

nta;

a n

aïve

ass

umpt

ion

wou

ld b

e th

at s

ince

he

talk

s ab

out

new

moo

ns,

the

mon

th w

ould

be

amaa

nta.

But

, a

stud

y of

the

(C

haitr

adi)

amaa

nta

and

purn

imaa

nta

cale

ndar

s fo

r th

e pr

esen

t ye

ar r

evea

ls th

at th

e di

ffer

ence

bet

wee

n th

ese

two

cale

ndar

s is

still

two

wee

ks. T

here

fore

, it’s

saf

e to

con

clud

e th

at k

shay

a m

onth

s w

ere

drop

ped

from

the

purn

imaa

nta

cale

ndar

as w

ell.

31 sa

aksh

ya =

witn

ess (

in S

ansk

rit)

32 C

hatte

rjee,

p. 3

4

Page 15: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 2

0

Mor

eove

r, th

e st

atem

ent

abou

t “c

orre

spon

ding

lun

ar m

onth

” is

unc

lear

; ar

e w

e

talk

ing

abou

t th

e lu

nar

mon

th w

ith t

he s

ame

num

ber

as t

he n

ew-m

oon-

lack

ing

sola

r

mon

th?

Or a

re w

e ta

lkin

g ab

out t

he lu

nar m

onth

with

the

sam

e na

me

of th

e so

lar m

onth

?

Run

ning

the

cal

endr

ica

code

pro

vide

d by

Der

show

itz a

nd R

eing

old

with

the

ir bo

ok

Cal

endr

ical

Cal

cula

tions

– T

he M

illen

ium

Edi

tion

(see

tabl

e fo

r val

ues)

, we

see

that

it’s

the

luna

r mon

th w

ith th

e sa

me

nam

e th

at g

ets d

ropp

ed.

To

acc

ount

for a

pur

nim

aant

a ks

haya

, and

to fu

rther

cla

rify

whi

ch m

onth

to d

rop,

we

re-p

hras

e th

e de

finiti

on o

f a

ksha

ya m

onth

to b

e th

us: -

“in

any

giv

en lu

nar

year

, if

two

cons

ecut

ive

Sank

rant

is oc

cur

betw

een

two

cons

ecut

ive

new

moo

ns, t

hen

the

luna

r

mon

th, w

heth

er a

maa

nta

or p

urni

maa

nta,

with

the

sam

e na

me

as th

e so

lar m

onth

in w

hich

this

occu

rs, i

s dr

oppe

d.”

As

we

shal

l see

, suc

h a

re-p

hras

ing

is us

eful

for

com

puta

tiona

l

purp

oses

.

In

deed

, as

w

e m

entio

ned

earli

er,

we

ran

the

Der

show

itz

and

Rei

ngol

d’s

cale

ndri

ca p

acka

ge to

get

val

ues

for

the

occu

rren

ce o

f a k

shay

a m

onth

. Sin

ce s

earc

hing

for

a ks

haya

mon

th is

com

puta

tiona

lly v

ery

heav

y33, w

e us

ed a

tab

le p

repa

red

by S

aha

and

Lahi

ri (ta

ble

22 in

the

book

)34 a

s a

star

ting

poin

t. W

e al

so ta

bula

ted

resu

lts fo

r no

n-

ksha

ya m

onth

s, sp

ecifi

cally

yea

rs w

ith g

aps

of 1

9, 4

6, 6

5, 7

6, 1

22 a

nd 1

41 y

ears

resp

ectiv

ely.

The

resu

lts a

nd th

e gr

aphs

from

thes

e re

sults

are

tabu

late

d in

the

appe

ndix

.

It

mus

t be

note

d th

at a

ll ca

ses t

abul

ated

pre

viou

sly

have

bee

n ca

lcul

ated

acc

ordi

ng

to S

urya

Sid

dhan

tic r

ules

and

tha

t w

e m

ay g

et a

diff

eren

t se

t of

res

ults

if

calc

ulat

ed

acco

rdin

g to

eph

emer

is ca

lcul

atio

ns. I

ndee

d, a

s C

hatte

rjee

has

poin

ted

out,

ther

e w

as a

diffe

renc

e in

196

4 C

E; e

phem

eris

calc

ulat

ions

sho

wed

Mar

gasir

a to

be

ksha

ya (

and

33 D

ersh

owitz

, Nac

hum

and

Rei

ngol

d. C

alen

dar T

abul

atio

ns –

190

0 to

220

0. (2

002:

Cam

brid

ge) C

ambr

idge

U

nive

rsity

Pre

ss. p

. 24

34 S

aha

et a

l. p.

250

Page 16: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 2

1

Kar

thik

a, C

haitr

a to

be

adhi

ka),

whi

le a

s w

e’ve

see

n, S

urya

Sid

dhan

tic c

ompu

tatio

n

show

ed P

ausa

to b

e ks

haya

(and

Asv

ina

and

Cha

itra

to b

e ad

hika

).35 C

hatte

rjee,

how

ever

,

seem

s to

be

in a

gree

men

t w

ith D

ersh

owitz

and

Rei

ngol

d in

say

ing

that

the

re w

as a

ksha

ya in

Mag

ha in

198

3 C

E36, d

espi

te h

is us

e of

eph

emer

is ca

lcul

atio

ns.

Wha

t do

we

get f

rom

all

this

? W

e se

e th

at a

ksh

aya

mon

th c

an o

ccur

eve

ry 1

9, 4

6,

65,

76,

122

or 1

41 y

ears

. In

deed

, Sa

ha a

nd L

ahiri

’s t

abul

atio

n pr

ovid

e us

with

the

follo

win

g fre

quen

cies

of o

ccur

renc

es fo

r gap

s bet

wee

n ks

haya

mon

ths:

-

Inte

rval

Num

ber o

f tim

es o

ccur

ing

1911

463

651

761

122

114

16

Ta

ble

– N

umbe

r of t

imes

a p

artic

ular

inte

rval

gap

occ

urre

d

We

ther

efor

e se

e th

at b

etw

een

525

CE

and

1985

CE,

ksh

aya

occu

rred

11

times

with

a g

ap o

f 19

year

s, th

rice

with

a g

ap o

f 46

year

s, si

x tim

es w

ith a

gap

of 1

41 y

ears

,

and

once

eac

h w

ith g

aps o

f 65,

76

and

122

year

s. Th

e ob

viou

s qu

estio

n on

e w

ould

like

to

ask

wou

ld b

e w

hy. W

hy d

oes k

shay

a oc

cur o

nly

in th

ese

gaps

?

To a

nsw

er t

his

bette

r, w

e re

-iter

ate

wha

t ca

uses

ksh

aya

in t

he f

irst

plac

e. W

e

alre

ady

said

that

a k

shay

a w

ould

occ

ur w

hen

two

cons

ecut

ive

Sank

rant

is oc

cur b

etwe

en

two

Am

avas

yas.

That

is

to s

ay,

whe

n a

sola

r m

onth

is

shor

ter

in l

engt

h th

an,

and

is

com

plet

ely

encl

osed

by,

a (

an A

maa

nta)

luna

r m

onth

. Sah

a an

d La

hiri

go o

n to

say

that

the

“max

imum

dur

atio

n of

a lu

nar m

onth

exc

eeds

the

leng

ths

of th

e so

lar m

onth

s on

ly in

35 C

hatte

rjee,

SK

. p. 3

8 36

Der

show

itz,

Nac

hum

and

Edw

ard

M.

Rein

gold

. Ca

lend

rical

Cal

cula

tions

– T

he M

illen

nium

Edi

tion.

(2

001:

Cam

brid

ge) C

ambr

idge

Uni

vers

ity P

ress

. p. 2

69

Page 17: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 2

2

the

case

of M

arga

sira,

Pau

sa a

nd M

agha

”37 a

nd th

at, t

here

fore

, ksh

aya

is p

ossi

ble

only

in

thes

e m

onth

s.

This

wou

ld e

xpla

in t

he s

olar

mon

th p

art,

but

wha

t of

luna

r? H

ow c

an t

he lu

nar

mon

th b

e bi

gger

than

the

sola

r m

onth

? A

la’a

Juw

ad h

as s

ome

answ

ers;

in h

is ar

ticle

, he

sugg

ests

tha

t th

e ca

noni

cal

syno

dic

mon

th,

a lu

nar

mon

th b

etw

een

two

cons

ecut

ive

phas

es o

f the

moo

n, is

not

con

stan

t in

leng

th. I

ndee

d, h

e go

es o

n to

say

that

bet

wee

n 16

00

and

2400

CE,

the

syno

dic

mon

th e

xten

ds in

leng

th fr

om 2

9 da

ys 6

hou

rs a

nd 3

1 m

inut

es

to 2

9 da

ys 1

9 ho

urs

and

59 m

inut

es.38

Mor

eove

r, he

say

s th

at th

e “l

onge

st lu

nar

mon

ths

… o

ccur

whe

n th

e da

te o

f the

new

Moo

n co

inci

des

with

apo

gee”

.39 A

bru

te-fo

rce

sear

ch

for t

he lo

nges

t syn

odic

mon

th d

efin

itely

won

’t gi

ve u

s a

ksha

ya; f

or k

shay

a to

occ

ur, t

he

luna

r m

onth

nee

ds t

o be

onl

y bi

gger

tha

n its

sol

ar c

ount

erpa

rt an

d m

ore

impo

rtant

ly,

com

plet

ely

enco

mpa

ss it

. Ind

eed,

Jaw

ad s

ays

that

the

long

est s

ynod

ic m

onth

occ

urre

d in

1610

CE,

a y

ear w

hich

occ

urs w

ithin

the

141

year

long

ksh

aya

hiat

us b

etw

een

1540

-154

1

CE

and

1680

– 8

1 CE

.

We

ther

efor

e se

arch

for o

ther

clu

es to

uns

cram

ble

ksha

ya. O

n a

pure

ly a

rithm

etic

pers

pect

ive,

we

obse

rve

the

follo

win

g: -

19

= 19

* 1

46

=

19 *

2 +

8

65

= 19

* 3

+ 8

76

=

19 *

4

122

= 19

* 6

+ 8

14

1 =

19 *

7 +

8

That

is to

say,

the

year

-gap

s are

in th

e fo

rm 0

, 8 m

od 1

9.

37 S

aha

et a

l. p.

250

38

Jaw

ad, A

la’a

. “H

ow L

ong

Is a

Lun

ar M

onth

?” in

Sky

& T

eles

cope

, Nov

embe

r 199

3. p

. 76

39 Ib

id.

Page 18: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 2

3

Is it

pos

sibl

e th

en, t

hat t

he k

shay

a m

onth

has

som

ethi

ng to

do

with

the

Met

onic

cycl

e? T

he M

eton

ic C

ycle

is a

fairl

y w

ell d

ocum

ente

d ph

enom

enon

; firs

t obs

erve

d by

the

Gre

ek a

stro

nom

er M

etos

, eve

ry 1

9 ye

ars,

the

luna

r da

tes

over

lap

with

the

tropi

cal o

nes.

The

unde

rlyin

g m

athe

mat

ical

reas

on is

sim

ple:

- 19

sid

erea

l yea

rs c

onta

in 1

9*36

5.24

2189

= 69

39.6

sola

r day

s, w

hile

235

syn

odic

mon

ths (

with

a m

ean

of 2

9.53

sola

r day

s) c

onta

in

235*

29.5

3058

8853

= 6

939.

68 s

olar

day

s. Th

e le

ngth

s ov

erla

p. B

ut t

his

obvi

ousl

y is

neith

er n

eces

sary

nor

suf

ficie

nt; i

t mig

ht b

e us

eful

for t

he d

ates

to re

peat

, but

it d

efin

itely

does

n’t f

ulfil

the

requ

irem

ent f

or k

shay

a.

One

sug

gest

ion

ther

efor

e, m

ight

be

that

the

ksh

aya

occu

rs w

hen

the

num

ber

of

sola

r day

s of

a s

ider

eal y

ear i

s eq

ual t

o th

at o

f a s

ynod

ic m

onth

, whi

ch in

turn

is e

qual

to

that

from

an

anom

alist

ic m

onth

. An

anom

alist

ic m

onth

is d

efin

ed to

be

the

time

– pe

riod

betw

een

two

cons

ecut

ive

perig

ee p

assa

ges

and

has

a m

ean

valu

e of

27.

5545

5 da

ys.

Taki

ng t

hese

ave

rage

val

ues,

we

calc

ulat

e th

e av

erag

e va

lues

of

sola

r da

ys i

n w

hole

num

bers

of

sy

nodi

c an

d an

omal

istic

m

onth

s (c

anon

ical

ks

haya

ye

ars

shad

ed

for

refe

renc

e): -

Inte

rval

Occ

urre

nce

Mod

ulo

Sola

r Yea

rSy

nodi

c M

onth

sAn

omal

istic

Mon

ths

1911

1*19

6939

.601

591

6939

.688

3869

43.7

466

270

1*19

+898

61.5

3910

398

63.2

1667

798

64.5

289

380

2*19

1387

9.20

318

1387

9.37

676

1388

7.49

3246

32*

19+8

1680

1.14

069

1680

2.90

506

1680

8.27

5557

03*

1920

818.

8047

720

819.

0651

420

831.

2398

651

3*19

+823

740.

7422

923

742.

5934

423

752.

0221

761

4*19

2775

8.40

636

2775

8.75

352

2777

4.98

6484

04*

19+8

3068

0.34

388

3068

2.28

182

3069

5.76

8795

05*

1934

698.

0079

634

698.

4419

3471

8.73

310

30

5*19

+837

619.

9454

737

621.

9702

3763

9.51

5311

40

6*19

4163

7.60

955

4163

8.13

028

4163

4.92

505

122

16*

19+8

4455

9.54

706

4456

1.65

858

4455

5.70

735

133

07*

1948

577.

2111

448

577.

8186

648

578.

6716

514

16

7*19

+851

499.

1486

551

501.

3469

651

499.

4539

5

B

road

ly s

peak

ing,

we

mig

ht s

umm

ariz

e th

e ab

ove

tabl

e as

thu

s: -

for

the

mos

t

part,

the

num

ber

of s

olar

day

s in

sol

ar y

ears

, syn

odic

and

ano

mal

istic

mon

ths

over

lap

in

Page 19: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 2

4

ksha

ya y

ears

. H

owev

er,

this

over

lap

does

n’t

occu

r on

ly i

n ks

haya

yea

rs;

as t

he t

able

show

s, th

ere’

s an

ove

rlap

for

133

year

s as

wel

l. D

oes

this,

the

n, e

xpla

in t

he k

shay

a

phen

omen

on?

We

mig

ht s

umm

ariz

e it

as b

eing

stro

ngly

sug

gest

ive,

but

def

inite

ly n

ot

conc

lusi

ve.

Tre

atm

ent o

f Ksh

aya

Mon

ths40

W

e m

ay c

ompl

ete

our

disc

ussio

n of

ksh

aya

mon

ths

by d

escr

ibin

g th

e th

ree

Ksh

aya

Scho

ols o

f tho

ught

.

The

Nor

th W

este

rn S

choo

l is

fol

low

ed in

the

nor

th-w

este

rn p

art

of t

he c

ount

ry,

pres

umab

ly

in

Guj

arat

an

d/

or

Raj

asth

an,

whe

re

the

luni

sola

r ca

lend

ar

is us

ed.

Esse

ntia

lly, t

he N

orth

Wes

tern

Sch

ool t

reat

s the

adh

ika

mon

th b

efor

e ks

haya

as

a no

rmal

mon

th a

nd t

he o

ne a

fter

the

ksha

ya m

onth

to

be i

nter

cala

ry.

This

con

trast

s w

ith t

he

East

ern

Scho

ol w

here

the

rev

erse

is

follo

wed

; th

e ad

hika

mon

th b

efor

e th

e ks

haya

is

deem

ed i

nter

cala

ry,

whi

le t

he o

ne a

fter

it is

deem

ed n

orm

al.

The

East

ern

Scho

ol i

s

follo

wed

in th

e ea

ster

n pa

rts o

f the

cou

ntry

, whe

re th

e lu

niso

lar c

alen

dar i

s fo

llow

ed. T

he

final

of

the

trio,

the

Sou

ther

n Sc

hool

, tre

ats

both

adh

ika

maa

sas

as i

nter

cala

ry,

inst

ead

reck

onin

g th

e ks

haya

mon

th a

s a

“jug

ma”

, i.e

., th

e fir

st h

alf o

f the

thith

i of t

his

mon

th is

deem

ed t

o be

tha

t of

the

firs

t m

onth

, and

the

sec

ond

half

as t

hat

of t

he s

econ

d m

onth

.

This

is p

resu

mab

ly f

ollo

wed

in

the

Sout

hern

par

ts o

f th

e co

untr

y w

here

the

lun

isola

r

cale

ndar

is fo

llow

ed.

40 C

hatte

rjee,

SK

. p 3

7- 4

0

Page 20: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 2

5

Epi

logu

e –

Th

e B

egin

ning

By th

is ti

me,

onl

ooke

rs a

ll si

des

gath

ered

aro

und

the

two.

The

y we

re a

ttent

ivel

y

liste

ning

to th

e co

nver

satio

n be

twee

n th

em. A

long

with

Apa

ra G

anita

, the

y we

re w

aitin

g

for

the

dwar

a pa

lika

to a

sk o

nce

agai

n. B

ut s

he d

idn’

t. Sh

e st

ood

and

smile

d. H

er fa

ce

was

radi

ant,

glow

ing

like

the

moo

n on

a P

urni

ma

and

the

hars

h su

mm

er su

n en

teri

ng th

e

Mith

una

raas

i.

Sh

e st

ill s

aid

noth

ing.

She

got

up

and

walk

ed a

way

from

the

crow

d. S

till s

mili

ng.

Still

gra

cefu

l.

Th

e sp

arks

cam

e sl

owly

, bu

t su

dden

ly.

All

arou

nd t

hem

, th

e la

ndsc

ape

was

chan

ging

. The

gat

e wa

s mel

ting

into

the

walls

, the

wal

ls in

to th

e gr

ound

. The

gro

und

was

chan

ging

into

gra

ss, t

he g

rass

cov

erin

g th

e en

tire

grou

nd.

Exce

pt t

he g

roun

d un

dern

eath

Apa

ra G

anita

. H

e fo

und

him

self

stan

ding

on

an

elev

ated

pod

ium

, fac

ing

liste

ners

all

arou

nd h

im, a

ll wa

iting

to h

ear h

im sp

eak.

For o

nce,

he

didn

’t kn

ow w

hat t

o sa

y.

Page 21: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 2

6

Bib

liogr

aphy

1.

S.K

. Cha

tterje

e. In

dian

Cal

endr

ic S

yste

m, P

ublic

atio

ns D

ivis

ion,

Min

istry

of

Info

rmat

ion

and

Bro

adca

stin

g, G

over

nmen

t of I

ndia

, 198

8.

2.

C

hakr

avar

ty,

Apu

rba

Kum

ar a

nd S

K C

hatte

rjee.

“In

dian

Cal

enda

r fro

m P

ost-

Ved

ic P

erio

d to

AD

190

0” in

Hist

ory

of A

stro

nom

y in

Ind

ia, e

d. S

.N. S

en a

nd

K.S

. Shu

kla,

. Ind

ian

Nat

iona

l Sci

ence

Aca

dem

y, N

ew D

elhi

, 198

5.

3.

M

.H. S

aha

and

N.C

. Lah

iri, R

epor

t of t

he C

alen

dar R

efor

m C

omm

ittee

, Cou

ncil

of S

cien

tific

and

Indu

stria

l Res

earc

h, N

ew D

elhi

, 199

2.

4.

Jaw

ad, A

la’a

H. “

How

Lon

g is

a Lu

nar M

onth

?” in

Sky

and

Tel

esco

pe, N

ovem

ber

1993

. 5.

A

bhay

anka

r, K

D. “

Our

Deb

ts t

o ou

r A

nces

tors

” in

Tre

asur

es o

f A

ncie

nt I

ndia

n A

stro

nom

y. e

d. K

D A

bhay

anka

r and

Dr.

BG

Sid

harth

. Aja

nta

Publ

icat

ions

, Del

hi.

1993

. 6.

Des

how

itz,

Nac

hum

and

Edw

ard

M.

Rei

ngol

d. C

alen

dric

al C

ompu

tatio

ns:

The

Mill

enni

um E

ditio

n. C

ambr

idge

Uni

veris

ty P

ress

, Cam

brid

ge. 2

001.

7.

Ven

kata

Ram

ana

Saas

tri,

Chi

vuku

la.

Kal

yana

Gan

itham

. Sr

inge

ri V

irupa

aksh

a Pe

etha

m, S

ringe

ri. 1

942.

(Thi

s is a

Tel

ugu

lang

uage

reso

urce

)

Page 22: Panchanga- Tantra - Department of Mathematics - National

Panc

hang

a- T

antra

: The

Mag

ic of

the I

ndian

Cale

ndar

Sys

tem / 2

7

Ack

now

ledg

emen

ts

Th

is re

port

is 51

50 w

ords

long

, mak

ing

it th

e bi

gges

t rep

ort I

’ve

ever

writ

ten.

It’s

been

in

the

mak

ing

for

the

last

one

-yea

r in

tw

o co

untri

es.

Obv

ious

ly,

ther

e ar

e m

any

peop

le w

ho’v

e he

lped

me,

and

I’d

like

to th

ank

ever

yone

of t

hem

.

Fi

rst,

I’d

like

to th

ank

Dr.

Hel

mer

Asl

akse

n, m

y re

sear

ch s

uper

viso

r; sir

, it’s

bee

n

a pl

easu

re w

orki

ng w

ith y

ou. I

t was

gre

at s

yner

gy a

ll th

e w

ay. A

khil

Deo

gar a

nd A

ksha

y

Pras

ad, t

he o

ther

two

stud

ents

who

wor

ked

on th

is, a

lso n

eed

a gr

atef

ul th

ank-

you

here

.

Way

to g

o gu

ys, w

e m

ade

it. T

o D

r. D

esho

witz

, for

hel

ping

me

out w

ith th

e ca

lend

rica

code

, jus

t w

hen

I w

as s

tuck

. To

Dr.

Subr

aman

yam

and

all

the

won

derf

ul p

eopl

e at

the

Dep

artm

ent

of A

stro

logy

, Po

tti S

riram

ulu

Telu

gu U

nive

rsity

, H

yder

abad

, it’

s be

en a

plea

sure

mee

ting

you

all a

nd I

’m g

rate

ful y

ou s

at th

roug

h m

y pr

esen

tatio

n on

that

col

d

Dec

embe

r ev

enin

g. T

o D

r. B

G S

iddh

arth

, Dire

ctor

Gen

eral

, BM

Birl

a Sc

ienc

e C

ente

r,

your

com

men

ts w

ere

inva

luab

le.

To D

r. V

alla

bh,

Prof

esso

r an

d H

ead,

Ast

rono

my

Dep

artm

ent,

Osm

ania

Uni

vers

ity, s

ir, I

tha

nk y

ou f

or s

pend

ing

som

e tim

e w

ith m

e. T

o

Dr.

Mad

ugul

a Si

vasr

i Sar

ma,

it’s

bee

n a

plea

sure

mee

ting

you

and

I’m

gra

tefu

l for

you

r

com

men

ts o

n th

e ru

les

for

fest

ival

s. To

Dr.

CV

L N

aras

imha

m,

for

thos

e w

onde

rful

even

ings

on

the

bank

s of

the

Riv

er M

usi d

iscus

sing

pan

chan

gam

trad

ition

s. A

nd la

st b

ut

not l

east

, I’d

like

to th

ank

my

pare

nts a

nd m

y lit

tle b

roth

er fo

r kee

ping

up

with

me

durin

g

all t

hose

late

-nig

ht se

ssio

ns I

spen

t pou

ring

over

cal

enda

rs.

I o

nce

agai

n th

ank

ever

yone

who

’s h

elpe

d m

e. O

f cou

rse,

it b

ears

no

need

to s

ay

that

all

erro

rs a

re m

ine.