(1) Tithi and Nakshatra & its Pada find important role not only in Vedic Jyotish but also in deciding almost all the Vedic festivals except Sankranti Festivals.

(2) Tithi & Nakshatra is equally useful to perform the astrological remedies.

(3)In English the Tithi is kanown as lunar date & Nakshatra the Constellation.

(4) In this article I tell the simple way to calculate the Tithi & Nakshatra for the benefit of learners & researchers of Vedic Jyotish.

** **

**Part 1. Calculation Of Tithi In Simple Way**

(5) To calculate Tithi all you need is the longitudes of Sun and Moon. This process of calculating the Tithi holds good for both Sidereal & tropical longitudes of Sun & Moon.

(6) For example, today on Monday, February 20, 2017 at the time of Sunrise in almost all the areas near New Delhi the national capital of India the Sidereal Longitudes of Sun and Moon are Aquarius 07⁰ 30’ 21” and Scorpio 21⁰ 04’ 08”

(7) Solar Sidereal Longitude Aquarius 07⁰ 30’ 21” when changed to degrees becomes = 307.50583333333333333333333333333⁰

(8) Lunar Sidereal Longitude Scorpio 21⁰ 04’ 08” when changed to degrees becomes= 231.06888888888888888888888888889⁰

(9) The Formula to calculate Tithi = (Lunar Longitude – Solar Longitude) ÷ 12

(10) In the formula to calculate Tithi add 360⁰ if (Lunar Longitude – Solar Longitude) is less than zero or possesses negative value.

(11) Now putting the values of Lunar & Solar longitudes in degrees in the formula given under (9)

(12) Tithi = (Lunar Longitude In Degrees – Solar Longitude In Degrees) ÷ 12

= (231.06888888888888888888888888889 – 307.50583333333333333333333333333)⁰ ÷ 12

= (-76.436944444444444444444444444443)⁰ ÷ 12, in bracket the value is with minus so add 360⁰

= (360 -76.436944444444444444444444444443)⁰ ÷ 12

=283.56305555555555555555555555556⁰ ÷ 12

= 23.63025462962962962962962962963⁰, this value comes out more than 23 so it is 24^{th} and thus the Tithi or Lunar date at the time of Sunrise as described under (6) is 24^{th}.

(13)If the number after calculation as described under (12) comes out to be less than 15 then the Tithi is of Bright half otherwise the Tithi is of Dark Half.

(14) In this present case the number is 24 and it is more than 15 so subtract 15 from 24. It comes out to be 9 so the Tithi at the time of Sunrise as described under (6) is 9^{th} of Dark Half or Krishana Navmi.

(15) Take the final value 23.63025462962962962962962962963 as written under (12) again and take its right hand side decimal value by leaving the left hand side value and you get 0.63025462962962962962962962963 and now subtract this value from 1 or

(16) 1 – 0.63025462962962962962962962963 = 0.36974537037037037037037037037

(17) By multiplying the value written under (16) you get the percentage of Tithi left at the time of that Sunrise

= 0.36974537037037037037037037037 × 100 = 36.974537037037037037037037037% or about 36.97%

(18) 36.97% of 9^{th} of Dark Half left at the time of that Sunrise.

** **

**Part 2. Calculation Of Nakshatra & Its Pada In Simple Way**

(19) To calculate Nakshatra manually take only the Sidereal Lunar Longitude in Degrees which in this case is 231.06888888888888888888888888889⁰ and multiply it by 60 and then divide it by 800.

(20) Mathematically,

Nakshatra = {(Lunar Sidereal Longitude In Degrees) × 60} ÷ 800

(21) Putting the value in formula written under (20)

Nakshatra = {(231.06888888888888888888888888889) × 60)} ÷ 800

= {13864.133333333333333333333333333} ÷ 800 = 17.330166666666666666666666666667

Or **Nakshatra = 17.330166666666666666666666666667 or 18^{th}**

If the final value is 1^{st} the Nakshatra is Aswani, 2^{nd} Bharnai, 3^{rd} Kritika, 4^{th} Rohini, 5^{th} Mrigshira, 6^{th} Ardra, 7^{th} Punarvasu, 8^{th} Pushya, 9^{th} Aslesha, 10^{th} Magha, 11^{th} Poorvaphalgune, 12^{th} Uttaraphalgune, 13^{th} Hasta, 14^{th} Chitra, 15^{th} Swati, 16^{th} Vishakaha, 17^{th} Anuradha, 18^{th} Jyestha, 19^{th} Moola, 20^{th} Poorvaashada, 21^{st} Uttraashada, 22^{nd} Sharavan, 23^{rd} Dhansita, 24^{th} Shatbhisa, 25^{th} Poorvabhadrapada, 26^{th} Uttarbhadrapada and 27^{th} Revati.

In this case the **Nakshatra **come out to be *18 ^{t}*

*which means is*

^{h}**Jyestha**.

(22) To Calculate the Pada of any Nakshatra take the value of that Nakshatra which in this case is 17.330166666666666666666666666667

(23) Take the decimal side of the value written under (22) which in this case is 0.330166666666666666666666666667 and multiply this by 800

Or 0.330166666666666666666666666667 × 800 = 264.1333333333333333333333333336

If this values is within 0 to 200 it is first Pada, within 200 to 400 it is second Pada, within 400 to 600 it is 3^{rd} pada and within 600 to 800 it is 4^{th} pada.

(24) In this case the value 264.1333333333333333333333333336 is within 200 to 400 so Moon occupies **2 ^{nd} Pada** of

**Jyestha Nakshatra**at the time of that Sunrise.

(25) ** Conclusion**: Today on

**Monday, February 20, 2017**at the

**time**of

**Sunrise**in

**places near**to

**New Delhi**the national capital of India it was

**9**and that

^{th}of Dark Half**Sunrise**occurred in

**2**.

^{nd}Pada of Jyestha Nakshatra

Written on Monday, February 20, 2017 at 13:05 (IST) by

**Vishal Aksh**

Excellent an simple narration which very easy to learn. Thanks Guruji!

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Excellent explanation with example. I would like to learn more about astrology calculation. Can you guide me. Please

Thank you Guruji

Siva

Vancouver, Canada

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Hello Sir,

How did you calculate ‘Solar Sidereal Longitude” to degree (307.5058..) Is there any formula ?

“Solar Sidereal Longitude Aquarius 07⁰ 30’ 21” when changed to degrees becomes = 307.50583333333333333333333333333⁰”.

Please suggest me. Thanks in advance.

Best Regards

Kamlesh

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When sun is in Aquarius it means sun has already crossed 10 signs from aries to capricorn so we take, 10 sign and multiply it with 30 degrees like this

10 x 30 = 300 degrees

now we add the longitude of the sun in Aquarius like this

300 + 07⁰ 30’ 21 = 307⁰ 30’ 21

now if we convert this Degrees Minutes Seconds to Decimal degrees we get

307.50583333333333333333333333333

you can use the below link to convert the DMS to Decimal degrees

https://www.latlong.net/degrees-minutes-seconds-to-decimal-degrees

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I tried your equation works great except it jumps for 1 in a complete 30 day cycle this happens for purnima/amavasya index hence the calendar i tried could never show purnima/amavasya instead it shows the first one Prathama, below is the code/algorithm

string calcTithi(string ms, string md, string ss, string sd)

{

int tithi = 0;

try

{

var tDict = new Dictionary { {1, “Prathama”}, {2, “Dwitiya”}, {3, “Tritiya”}, {4, “Chaturthi”}, {5, “Panchami”}, {6, “Shashthi”}, {7, “Sapthami”}, {8, “Asthami”}, {9, “Navami”}, {10, “Dasami”}, {11, “Ekadashi”}, {12, “Dwadashi”}, {13, “Trayodashi”}, {14, “Chaturdashi”}, {15, “Purnima”}};

string astClient = System.Web.HttpContext.Current.Server.MapPath(“~/Content/astroclient”);

string rJ = string.Format(@”{0}\rashis.json”, astClient);

using (StreamReader r4 = new StreamReader(rJ))

{

string json4 = r4.ReadToEnd();

dynamic rashis = JsonConvert.DeserializeObject(json4);

int rnum = Convert.ToInt32(rashis[ms.ToLower()].ToString());

int mdeg = (rnum – 1) * 30;

rnum = Convert.ToInt32(rashis[ss.ToLower()].ToString());

int sdeg = (rnum – 1) * 30;

float mcd = float.Parse(md) + mdeg;

float scd = float.Parse(sd) + sdeg;

mcd = ConvertDegreeAngleToDouble((mcd.ToString().Contains(‘.’)) ? Convert.ToInt32(mcd.ToString().Split(‘.’)[0]) : Convert.ToInt32(mcd), (mcd.ToString().Contains(‘.’)) ? Convert.ToInt32(mcd.ToString().Split(‘.’)[1]) : 0, 0);

scd = ConvertDegreeAngleToDouble((scd.ToString().Contains(‘.’)) ? Convert.ToInt32(scd.ToString().Split(‘.’)[0]) : Convert.ToInt32(scd), (scd.ToString().Contains(‘.’)) ? Convert.ToInt32(scd.ToString().Split(‘.’)[1]) : 0, 0);

float diff = mcd – scd;

if (diff 15.0)

{

dh = true;

dth -= 15.0;

}

tithi = Convert.ToInt32(dth.ToString().Split(‘.’)[0]);

if (tithi == 0) tithi++;

string thi = tDict[tithi];

if (thi == “Purnima” && dh == true)

thi = “Amavasya”;

return string.Format(“{0}|{1}”, thi,(dh == true) ? “wanning” : “waxing”);

}

}

catch (Exception eX)

{

return eX.Message + tithi.ToString();

}

}

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