Hi Marrish, I did miss this one, yes. Thanks for the 'heads-up'
Okay, so we have:
Pūṣann ekarṣe yama sūrya prājāpatya vyūha raśmīn samūha tejaḥ;
Yat te rūpaṃ kalyāṇatamaṃ tat te paśyāmi yo 'sāv asau puruṣaḥ so 'ham asmi.
- Pūṣan is the vocative singular of pūṣan- which is the name of a deity connected with the sun and, from here, it comes to just mean the sun. (The doubling of the n is due to saṃdhi)
- ekarṣe is the vocative singular of ekarṣi-, from eka- + ṛṣi-. This means the only/original/first ṛṣi/philosopher/sage.
- yama is the vocative singular of yama-
- sūrya is the vocative singular of sūrya-
- prājāpatya is the vocative singular of prājāpatya-, it means a descendent of Prajāpati, or someone relating to Prajāpati
- vyūha is a second person, singular, imperative - as marrish correctly points out. It is from vi- + ūh- (1P). The grammarians recognise ūh- as a separate root, although - as marrish says - it is almost certainly derived from (and very much related to) vah-. vyūh- means to disperse.
- raśmīn is the accusative plural of raśmi-, meaning ray
- samūha is - again - the second person, singular, imperative of sam- + ūh- (1P, 1A). It means gather.
- tejaḥ is the accusative singular of tejas-, light.
- yad is the accusative singular, neuter of the relative pronoun yad-. I'll come back to this. It becomes yat through saṃdhi.
- te is the enclitic form of the genitive singular of yuṣmad-. It means your/thy.
- rūpam is the accusative singular of rūpa-, form, beauty.
- kalyāṇatamam is the accusative singular of kalyāṇatama-, the superlative of kalyāṇa-, so it means the most beautiful
- tad is the accusative singular, neuter form of the relative pronoun tad-. I'll come back to this. It becomes tat through saṃdhi.
- paśyāmi is in the first person, singular, present tense and it means, I see, it is from the root paś (4P, 4A), which is used in place of the root dṛś (P, A) in the present stem.
- yaḥ is the nominative singular, masculine form of the relative pronoun yad-. It becomes yo due to saṃdhi with the following asau. The initial a of asau is dropped, leaving yo 'sau
- asau is the nominative singular, masculine form of the demonstrative pronoun adas-, meaning that. It becomes asāv due to saṃdhi with the following asau. Thus, we have yaḥ asau asau becoming yo 'sāv asau. For this reason, it cannot be vasau, because then we would have yo 'sau vasau. Also, there is no finite verb form vasau of the root vas that i know of. There are a couple of derived nouns vasa- and vasi-, which mean dwelling. Vasau would be the nominative/accusative/vocative dual of vasa- and the locative singular of vasi-, but neither of these seem to make much sense here anyway.
- puruṣaḥ is the nominative, singular of puruṣa- meaning man, human
- saḥ is the nominative, singular, masculine form of the relative pronoun tad-. It means he. It becomes so due to saṃdhi with aham (see above).
- aham is the nominative singular form of the personal pronoun asmad-, it means I
- asmi is the first person, singular, present form of the root as- (2P, 2A), meaning to be
So, to answer your 2nd question, व्यूह रश्मीन् समूह तेजः, means
disperse your rays, gather up your light
Now, for the rest of the translation. Pūṣann ekarṣe yama sūrya prājāpatya is simply a string of vocatives, referring to the subject of this verse. Pūṣan is a solar deity, or simply the sun and he nourishes. There is a lot of mythology I don't really know about present in this verse, but I suppose ekarṣi is the first ṛṣi, or the only/lonely ṛṣi. In the translations we get the idea that the only ṛṣi is the sole traveller in the heavens, the only journeyer, the only seer; so this must, then, be the sun also. We have the idea that the sun, as it journeys through the sky, is like a lonely, or - perhaps - original Seer/philosopher. Yama is the 'regulator,' or 'controller of all' and - I believe - was also born from the Sun. But I think here were just supposed to have the idea that the sun is the regulator. Sūrya is obviously the sun, and Prajāpati is a creator deity, i think also related to the Sun. So we have a lot of Vedic mythology at the start of this verse, which I'm afraid is a bit beyond my reach. If you know your Upaniṣadic mythology, perhaps you're already comfortable with this, if not, you may like to read up on it to fully understand this verse. I think, though, that it's safe to say that our sentence starts with a number of addresses to the sun. The sun is then asked to remove its rays and gather up its blinding light. So, perhaps the sun is too bright to be seen properly, so it's being asked to do these things so that it can be looked upon and its true form may be discerned. That would have been my interpretation, but I did a bit of reading, and some people seem to think that the sun is essentially being asked to distill its rays and light into its most perfect form and this is a metaphor for the truth that one comes to understand by reading the upaniṣads. Either way, the justification comes next. Here's where I have trouble.
This is my understanding. So, we have yad agreeing with rūpam in case, number and gender (accusative, singular, neuter) and I think that the rūpam is the object of the verb paśyāmi. We then have te qualifying rūpam and kalyāṇatamam as an adjective of rūpam. So, we have 'that form of yours which is most beautiful', we then have tad, agreeing with rūpam, as the correlative form and a repetition of the te. So, I'm not sure if this is clear, but i think the translation should be something like 'that form of yours which is most beautiful, that (is the form) of yours I see'. There may be an implied sense of 'so that', as we get in the second translation, but I think the first translation makes more sense grammatically. So the sun disperses its rays, it gathers its lustre, and now I see its most beautiful form.
If this is true, now we can explain asāv asau, asau is the nominative singular masculine of adas- and the nominative singular feminine of adas-. The locative singular masculine of adas- is amuṣmin and in the feminine its amuṣyām, so I don't think it can be locative. Instead I depart slightly from the translation, I think it might be something like 'that man who is beyond' (adas- can sometimes mean, 'yonder', 'beyond') or, perhaps 'that man who is that', or 'that man who is that (man)', with these two giving a sense of the eternal man, or the enlightened one. I think the idea that a few commentators have is that by reading the upaniṣads you gain a more perfect knowledge and the metaphor of this verse is that you see the sun more clearly, or in its most perfect form, and so the analogy is that you see the world in a more perfect form. Hence - 'he am I' (so 'ham asmi.)
You may want to look at Islam Kotob's 'Upanishads'. It was published by Islamic Books, I think.
