Explain breifly about chandas and abhimany devthas
like for gaythri mantra its gaythri chands, savitha devaatha rshi is vishwa mitra
one chandas how many letters how one should refer or add for missing letters in chandas while doing yagya
- I am going to say this is related to hinduism.stackexchange.com/questions/30171/…. Check if hinduism.stackexchange.com/questions/17783/… answers you? – Ambi Dec 30 '18 at 11:00
Major metres
The major Vedic Chandahs are 7 in number. They are - Gayatri, Ushnik, Anushtup, Brihati, Pangkti, Trishtup and Jagati.
Sometimes Pangkti is also called Virat.
The number of syllables or Aksharas in the Mantra determines to which Chandah (or metre) it belongs.
Given below are the distributions, variants and total number of Mantras (for a particular Chandah in the Vedas):
Chandah name - Distribution - Number of variants it has - total number of mantras that are in this particular Chandah
Gayatri - 8|8|8 - 10 - 2456
Ushnik - 8|8|12 - 7 - 398
Anushtup - 8|8|8|8| - 7 - 850
Brihati - 8|8|12|8 - 11 - 427
Pangkti - 8|8|8|8|8 - 7 - 499
Trishtup - 11|11|11|11 - 14 - 4258
Jagati - 12|12|12|12 - 3 - 1353.
So, while Gayatri Chnadah will have 24 syllables, Anushtup will have 32 syllables, a Pangkti Chandah will have 40 syllables and so on.
The number of Trishtup Chandah Mantras is the highest (4258) followed by Mantras in Gayatri Chandah.
The Chandah called Pangkti-Virat has 40 aksharas (syllables) and it's distribution is 10|10|10|10.
But for Gayatri there are as many as 10 variants and not all of them have exactly 24 syllables.
Some such variants are: 5|5|5|5|6, 5|5|5|4|6, 6|7|11, 7|7|7|, 7|6|6 etc and all of them belong to the Gayatri family of metres.
Minor metres
There are some minor Vedic metres as well like Atijagati, Dhriti, Ati Dhriti etc. A similar list for them is as given below:
Atijagati - 12|12|12|8|8 - 17
Shakvari - 8|8|8|8|8|8|8 - 19
Atishakvari - 16|16|12|8|8 - 10
Ashith - 16|16|16|8|8 - 7
Atyashith - 12|12|8|8|8|12 - 82
Dhriti - 12|12|8|8|8|16|8 - 2
Ati Dhriti - 12|12|8|8|8|12|8|8 - 76
Source - Essentials of Rig Veda, R.L.Kashyap ( Sri Aurobindo Kapaly Shastry Institute of Vedic culture).
- To clarify, when you mean 'major Chandahs', you mean the 'major vedic Chandahs', correct? – user1952500Dec 31 '18 at 2:49
- 1
Vedic meter or Chanda" (छन्द ) points towards how a mantra or verse is constructed in some definite rules.. A Chandas is having rule of how many letters are there in it and how theese letters are divided into different parts called Paadas . Chandas is one among six Vedangas or parts of Vedas.
There are a number of Chandas used in Vedas , Mainly there are Seven Chandas used in Vedas and those are are:
Gayatri: This Chandas has 24 Letters/Aksharas in each stanza/mantra divided into 3 Paadas (parts/legs) of 8 Letters/Aksharas.
Examples of Gayatri Chanda.:-
Gayatri Mantra 
Rudra Gayatri Mantra
Ushnik : This Chandas has 28 Letters/Aksharas in each stanza/mantra divided into 4 Paadas of 7 Letters/Aksharas
Anustup: This Chandas has 32 Letters/Aksharas in each stanza/ mantra divided into 4 Paadas of 8 Letters/Aksharas. Most of the Slokas in typical classical Sanskrit uses this Chandas, most often recited being.
Example of Anustup Meter -: 
Brihati : This Chandas has 36 Letters/Aksharasin each stanzas or mantra divided into four 4 Paadas (8 + 8 + 12 + 8) Letters/Aksharas.
Pankti : This Chandas has 40 Letters/Aksharas in each stanza divided into 4 Paadas of 10 Letters each (sometimes 5 Padas of 8 letters each)
Tristup: This Chandas has 44 Letters/Aksharas in each stanza divided into 4 Paadas of 11 Letters/Aksharas.
Jagati: This Chandas has 48 Letters/Aksharas in each stanza divided into 4 Paadas of 12 Letters/Aksharas.
Each of these Chandas has distinct rules for how the letter patterns are formed. According to scholars Vedic mantras are much older than coming of Sanskrit grammar rules ,so its difficult to apply exact rules always.There are Gayatris with different no. letters other than 24 letters is having different names. In this case the rishi or the seer of the mantra is having his distinct way how the mantra shall be recited a Then they also teach their students how to recite that. And these information got passed on in this way from Teacher to students. For one must enquire qualified techer in a Veda-Pathshala or Vedic learning centre.
Here is Information about Chandas / Upa chandas , sub meters used in Rig-Veda. Link 1
Link 2
Below are some of the variation of main chandas.
Anustupa अनुष्टुप् क. -कविराट अनुष्टुप् Kaviraat Anustupa , ख - कृति अनुष्टुप् kruti Anustupa , न -नष्टरूपी अनुष्टुप् Nastarupi Anustupa , घ - विराट अनुष्टुप् Virat Anustupa.
उष्णिक Ushnika क. - अनुष्टुप् गर्भा उष्णिक Anustupa Garbha Ushnika , ख - ककुप उष्णिक Kakupa Ushnika , ग - तनुषिरा उष्णिक Tanushira Ushnika , घ - पुर उष्णिक Pur Ushnika
गायत्री Gayatri क - द्विपदा विराट गायत्री Dwipada Virat Gayatri , ख - पाद् निचृत् गायत्री Pada Nichrut Gayatri , ग - प्रतिष्ठा गायत्री Pratistha Gayatri.
जगति Jagati क - महापन्क्ति जगति Mahapankti Jagati
त्रिष्टुप् Trishtupa क - महाब्रुहति त्रिष्टुप् Mahabruhati Trishtupa , ख - यवमध्या महाब्रुहति त्रिष्टुप् Yavamadhya Mahabruhati Trishtupa.
पंक्ति Pankti क - चतुष्पदा विराट पंक्ति Chatuspada Virat Pankti , ख - प्रस्तार पंक्ति प्रगाथ pragatha
बृहती Bruhati क -विष्टार बृहती बृहती Vishtaar Bruhati Bruhati , ख - स्कन्धोग्रीवी बृहती skandhogrivi Bruhati AtiShakvari - अतिशक्वरी , Atijagati अतिजगति