They see the light of the day

These are described in the Chandogya as a pair of Rik-mantras. I don't know what that means, but they appear to be fragments handed down by tradition. One or two syllables are, according to the commentator, meaningless. So we are dealing with some very ancient words that have been passed down for centuries. I have given a literal translation here.

This is one of many meditations on the sun in the Upanishads. Whoever composed these mantras was moved to worship the sun, the source of life and light, and found in it a reflection of "the light that is ours", the light in the heart of our being.

आदित्पत्नास्य रेतसः ज्योतिः पश्यन्ति वासरम। पारो यदिध्यते दिवि ॥ ७ ॥

They see the light of the day, the everlasting source, that which shines supreme in the luminous heaven.

उद्वयन तमासपरी ज्योतिः पश्यनता उत्तरंग स्वः पश्यनता उत्तरं देवन देवत्रा सुर्यमागंमा ज्योतिरुत्तममिति ज्योतितुत्तामामिति ॥ ८ ॥

"We have seen beyond darkness the supreme light that is ours, have seen the supreme, he who is brightest among lights.
We have attained that sun that is the best of all lights, the best of all lights."
Chandogya III 17 7-8

I am struck once more by the simplicity of the Sanskrit, tricky as it is to tease out the meaning. It's hard to understand how the translation in the Advaita Ashrama edition has been arrived at:

In the supreme Brahman which is the oldest and is the source of the world, they (the knowers of Brahman) visualize everywhere that supreme Light which shines like the all-pervading daylight.
Having realised the Light (in the sun), which is the dispeller of ignorance, (and) which is non-different from the Light within our hearts-having visualized the Light which is higher than other lights-, we have attained the Sun, the Light that is the best of all lights, bright among the lights.

I am continually struck by how over-complicated the standard translations are. Shankara's 8th Century AD commentary is lucid, but he deliberately adds things to the text that are not there, in order to prove that the Upanishads are an expression of his Advaita Vedanta philosophy.
He's not wrong to find that philosophy in the Upanishads, but I think he does them a disservice when he tries to find only that philosophy.

We also read III, 19 today, a delightful creation myth involving an egg that becomes the universe, with the sun born out of it.