Aṃśu (अंशु).
The name of the sun in the month of Saha (Mārgaśīrṣa).
the Āditya of the month Citra, possessing 7000 rays.

Aṃśu (अंशु) or Ambu is the name of a deity who was imparted with the knowledge of the Aṃśumadāgama by Sadāśiva through parasambandha, according to the pratisaṃhitā theory of Āgama origin and relationship (sambandha).

The aṃśumada-āgama, being part of the ten Śivabhedāgamas, refers to one of the twenty-eight Siddhāntāgamas: a classification of the Śaiva division of Śaivāgamas.
The Śaivāgamas represent the wisdom that has come down from lord Śiva, received by Pārvatī and accepted by Viṣṇu.
Ambu in turn transmitted the Aṃśumadāgama (through mahānsambandha) to Ugra, who then transmitted it to Ravi who then, through divya-sambandha, transmitted it to the Devas who, through divyādivya-sambandha, transmitted it to the Ṛṣis who finally, through adivya-sambandha, revealed the Aṃśumadāgama to human beings (Manuṣya).

Aṃśu (अंशु) refers to the “rays” (of the moon), according to the Bṛhatsaṃhitā (chapter 4), an encyclopedic Sanskrit work written by Varāhamihira mainly focusing on the science of ancient Indian astronomy astronomy (Jyotiṣa).
Accordingly, “If the disc of the moon that regularly waxes and wanes should appear white resembling the colour of the Kumuda flower or that of the stem of the lotus or if the moon’s course or disc or rays [i.e., aṃśu] should suffer no irregular change there will be prosperity in the land. During the waxing moon, the Brāhmins, the Kṣatriyas and mankind at large will prosper; and during the waning moon, they will suffer miseries.
The increase of prosperity will commence after the new-moon and of adversity after the full moon”.

Aṃśu (अंशु)
A ray, beam of light;
hot-rayed the Sun
Lustre, brilliance
A point or end.
A small or minute particle.
End of a thread.
A filament, especially of the Soma plant (Ved.)
Garment; decoration.
a kind of Soma libation,
Speed, velocity (vega).

Aṃśu (अंशु).
A minute particle or atom.
The source and the end

Like the flow of Agamas and the Sun rays and moonbeams, this shows the flow of grace from Ravi (Sun) to Manushya in this solar system that we live in and the ten million other solar systems, the grace touches every living being.
Creation is unconditional, creation is non-discriminative…

To scorch in the summer heat or dance in the rain is our choice…

Salutations to Sahasra Amsu !