There was a question in Facebook as a comment on Sraddha as whether Sraddha procedures were laid down in the Vedas.
I replied that, to the best of my knowledge , the procedure for Sraddha is laid down in the Smritis and that I do not find a reference to it in the Veda.
While making this comment I made a remark that I was not sure whether Sandyavandana procedure was mentioned in the Vedas.
I received a feedback that Vedas and Upanishads do mention Sandhyavandana.
I have been able to locate the reference, which I reproduce.
Students performing Sandhyavandana in Veda Patashala.
“There are references in the vedas regarding Sandyavandanam. A reference occurs in “Second prasna, Second Anuvaka of Thaithria Aranyaka (Yajur Veda)”, explaining procedure of worship. The procedure of worship indicated is by offering “Arghya” (water in the palms of both hands thrown up), at the time of sunrise and sunset, meditating on Aditya (Sun).
Verses 15 & 16 of Ishvashya upanishad of Shukla Yajurveda also refers to Sun worship as above at sunrise and sunset.
Chandogya upanisad (Chapter 2 Section ix) discusses “Aditya vidya” explaining the importance of meditation of Sun or Aditya at sunrise and sunset, bringing out also the points mentioned above. Chapter 3, Section xii, of this upanishad explains meditation of aditya through gayatri. It also explains that the sun in the horizon outside and the sun element inside us are one and the same and there is no difference. The identity should be kept in mind while meditating through gayatri. This is the meaning of “Asavadityao brahma” recited during sandyavandanam.
These views are also echoed in Aditya Hridaya of the Yuddakanda of Ramayan. Agasthya explains to Sri Rama, the merits of worshipping Aditya. Aditya protects everyone, helps them in their duties, gives lustre, removes ignorance and provides happiness. He is friend of water and resides in every living thing.
Various Rishis set the procedures. Variations are there in Rig, Yajur and Sama Santhyavanthanam and Madhyaniham procedures. Various Sutras difined various procedures. Apastamba, Boudhayana, Parasara and Yajnvalkya sutras are some of them. “
1.Verses 15 and 16 of Isavasya Upanishad refer only to the extent that the Sun is to be worshiped.
2.References in Chandogya Upanishad.
Section 2 Chapter 9 says thus,
हिरण्मयेन पात्रेण सत्यस्यापिहितं मुखम् ।
तत्त्वं पूषन्नपावृणु सत्यधर्माय दृष्टये ॥१५॥
hiranmayena patrena satyasyapihitam mukham ।
tattvam pusannapavrnu satyadharmaya drstaye ॥ 15॥
The face of truth is covered with a
golden disc. Unveil it, O Pushan, so that I
who love the truth may see it.
16.पूषन्नेकर्षे यम सूर्य प्राजापत्य व्यूह रश्मीन् समूह तेजः ।
यत्ते रूपं कल्याणतमं तत्ते पश्यामि योऽसावसौ पुरुषः सोऽहमस्मि ॥१६॥
pusannekarse yama surya prajapatya
vyuha rasmin samuha tejah ।
yatte rupam kalyanatamam tatte pasyami
yo’savasau purusah so’hamasmi ॥ 16॥
16. O Pushan, the sole seer, O Controller,
O Sun, offspring of Praja-pati, spread forth
your rays and gather up your radiant light
that I may behold you of loveliest form.
Whosoever is that person that also am.
I do not think this is a Procedure for Sandhyavandana.
Chandogya Upanishad Section 2,Chapter 9, says thus,
1. One should meditate on the sevenfold Saman as yonder sun. The sun is the Saman because he is always the same (sama). He is the Saman because he makes everyone cherish the same thought: “He faces me,” “He faces me.”
2. One should know that all beings depend upon him (i.e. the sun). What he is before his rising is the syllable Him. The animals depend upon it (i.e. Him). Therefore the animals say “Him” before the sunrise, for they partake of the syllable Him of the Saman (sun).3. What he (the sun) is just after he has risen, that is the Prastava. Men depend upon it. Therefore men love praise (prastuti) and eulogy, for they partake of the Prastava of that Saman.
4. What he is when the rays go forth, that is the Adi. Birds depend upon It. Therefore birds hold themselves without support in the sky and fly about, for they partake of the Adi of that Saman.
5. What he is just at midday, that is the Udgitha. The devas (gods) are dependent upon it. Therefore they are the best of the offspring of Prajapati, for they partake of the Udgitha of that Sa man.
6. What he is after midday and before afternoon, that is the Pratihara. The foetuses depend upon it. Therefore they are held in the womb after being conceived and do not fall, for they partake of the Pratihara of the Saman.
7. What he is after the afternoon and before sunset, that is the Upadrava. The animals of the forest depend upon it. Therefore they run (upadravanti) to the forest and their caves when they see a man, for partake of the Upadrava of that Saman.
8. What he is just after the sunset, that is the Nidhana.,The Manes depend upon it. Therefore they put them (i.e. the Manes) down (nidadhati), for they partake of the Nidhana of that Saman. Thus a man meditates on the sevenfold Saman as the sun.
Chandogya Section3, Chapter 3.
Meditation on the Udgitha as the Sun and the Vyana
1. Now is described the meditation on the Udgitha with reference to the gods: One should meditate on the Udgitha as the sun who gives warmth. When he (the sun) rises he sings the Udgitha for the benefit of all creatures. When he rises he destroys darkness and fear. He who knows this becomes the destroyer of darkness and fear.
2. This prana and that sun are the same. This is warm and that is warm. This they call svara (what goes out) and that, pratyasvara (what returns). Therefore one should meditate on the Udgitha as this and that.
3. One should meditate on the Udgitha as the vyana. That which one breathes out is the prana and that which one breathes in is the apana. That which is the junction of the prana and the apana is the Vyana. This vyana is speech. Therefore when one utters speech one stops the prana and the apana.
4. That which is speech is the Rik. Therefore when a man utters a Rik he neither breathes out nor breathes in. That which is the Rik is the Saman. Therefore when a man sings a Saman, he neither breathes out nor breathes in. That which is the Saman is the Udgitha. Therefore when a man sings the Udgitha he neither breathes out nor breathes in.
5. And other works also which require strength, such as the kindling of fire by rubbing, running a race and stringing a strong bow, are performed without breathing out or breathing in. Therefore one should meditate on the Udgitha as the vyana.
6. One should meditate on the letters of the word Udgitha (i.e. ut, gi and tha). Ut is the prana, for a man rises (uttishthati) by means of the prana. Gi is speech, for speeches are called girah. Tha is food, for all this subsists (sthita) on food.
7. Ut is heaven, gi the mid—region and tha the earth. Ut is the sun, gi the air and tha fire. Ut is the Sama—Veda, gi the Yajur—Veda and tha the Rig—Veda. To him who thus meditates speech yields milk and milk is speech. He who knows this and meditates on the letters of the Udgitha becomes the possessor of food and the eater of food.
8. Next follows the fulfilment of prayers. One should thus meditate on the object one wishes to obtain through meditation: he (i.e. the udgatri priest) should meditate on the Saman with which he is going chant the praise.
9. He (the udgatri priest) should meditate on the Rik in which that Saman occurs, on the rishi to whom it was revealed and on the deity whom he is going to praise.
10. He (the udgatri priest) should meditate on the metre in which he is going to chant the praise; he should meditate on the hymn by which he is going to chant the praise.
11. He (the udgatri priest) should meditate on the quarter of space facing which he is going to chant the praise.
12. Finally, he (the udgatri priest) should meditate on himself and then on the object desired and chant the praise correctly. Thus will be quickly fulfilled for him the desire, desiring which he may offer the hymn of praise, yea, desiring which he may offer the hymn of praise.
There are more references cited as below in some web sites on this subject.
Rig Veda Samhita 3.62.10
Here one finds a reference to Gayathri Mantra, no procedures.
Again The Taitriya Aranyaka says,
Pancha Maha Yajna
Pancha vaa ete mahayajnaassatati
Prataayante satati santishtante
Manushya yajno brahmayajna iti
These are the five great sacrifices which are to be performed on a daily basis and completed.
deva yajna, pitr
u yajna, bhuta yajna, manushya yajna
brahma yajna 2.10.
2.11 goes on to describe the Gayatri Mantra recitation procedure.
No procedures for Sandhyavandan as a whole.
As to Agasthya instructing Rama, this too stresses the importance of Sun worship, no procedures.
One may well remember that Rama had Upanayana performed much before Yuddha Kanda and as such should have known the Sandhya vandana.
Again, No procedure.
All these do not constitute a procedure for performing Sandhyavandana.
References to worship of the Sun is mentioned, no procedures to be followed are set.
As I said of Sraddham, these procedures are set by Smriti, not by Sruthi.
Inputs clarifications welcome.