Astronomical Units of Time Measurement      By Govind Kumar  

                                   

We find Yuga cylces mentioned not only in astronomical works, but also in mythological works in India. 

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Kali Yuga began on the midnight of 17th Feb 3102 BCE and the duration of this Kali Yuga is said to be 4.32 K solar years. Dwapara is 2*Kali Yuga years. Treta is 3*K Y and Krita Yuga is 4*K Y. 


Krita Treta Dwaparascha Kalischaiva Chaturyugam 
Divya Dwadasabhir varshai savadhanam niroopitham 


Thus an Equinoctial Cycle, Mahayuga is equal to 4+3+2+1 = 10 KYs. 

E C = 10 KYs. 

A Greater Equinoctial Cycle ( Manvantara ) = 71 Equinoctial Cycles 

There are cusps happening in between Manvantaras, each equal to a Krita Yuga in duration. A Krita is equal to 4 KYs or 2/5 of a Maha Yuga. Since there will 15 such cusps happening amongst the Fourteen Manvantaras, they are equal to 15*2/5 = 6 Mahayugas. 

Hence 14*71+6 = 1000 Mahayugas = 4.32 Billion Years 

Sahasra yuga paryantham 
Aharyal brahmano vidu 
Ratrim yugah sahasrantham 
The Ahoratra vido janah ( The Holy Geetha ).
 

This is one Cosmological Cycle, called Brahma Kalpa. 

Chaturyuga sahasram indra harina dinam uchyathe 


From one second, it can be logarithmically shown, upto 10^22 seconds. This is what the above diagram shows. This diagram is by courtesy of Wikipedia. 

From 10^0 it goes upto 10^22 seconds. One day of Brahma is 4.32 billion years and 100 years of Brahma therefore is 311.04 trillion years, which is shown logarithmically above. 

One Asu is 4 seconds, one Vinadi is 24 seconds and one Nadi is 24 minutes. 60 such Nadis make up one day. This is the Sexagesimal division of a day into 60 Nadis ! In Astronomy, one degree is sixty minutes and one minute is sixty seconds. Hence sexagesimal division is justified ! 365.25 such days constitute a year and Hindu calculation goes upto 311.04 trillion years ! 

 
Mean and true planetary longitudes in the Zodiac is computed by Nine Orbital Elements, in Indian Astronomy. 


Mean longitude of Planet, Graha Madhyama , M 
Daily Motion of the Mean Longitude, Madhyama Dina Gathi, Md 
Aphelion, Mandoccha, Ap 
Daily Motion of Aphelion, Mandoccha Dina Gathi, Apd 
Ascending Node, Patha, N 
Daily Motion of Ascending Node, Patha Dina Gathi, Nd 
Heliocentric Distance, Manda Karna, radius vector, mndk 
Maximum Latitude, L, Parama Vikshepa 
Eccentricity, Chyuthi,e 


In Western Astronomy, we have six orbital elements 

Mean Anomaly, m 
Argument of Perihelion, w 
Eccentricity, e 
Ascending Node, N 
Inclination, i, inclinent of orbit 
Semi Major Axis, a 

With the Nine Orbital Elements, true geocentric longitude of the planet is computed, using multi step algorithms. 

There is geometrical equivalence between both the Epicycle and the Eccentric Models. 

The radius of the Epicycle, r = e, the distance of the Equant from the Observer.