Purport

After revealing He(Shri Krsihna) existing in every living being as the soul, Bhagvan Shri Krishna now revels his first form. And the very first form Shri Krishna mentioned is Bhagvan Shri Vishnu. Bhagvan Vishnu, the supreme personality of Godhead of which Bhagvan Shri Krishna is the incarnation.

Bhagvan Vishnu here mentioned as one of the Adityas. The Aditya has many interpretations in Sanatan Scriptures and also the numbers. In Vedas there are 8 Adityas, in Purana there are 12 Adityas. Yet in Bramha Purana there are 9 groups of 12 Adityas each, making it all 108. In Vedas, Adityas are the main deities. Another interpretation of Aditya is those who was the son of lady Aditi.

Bhagvan Vishnu incarnated as the son Devi Aditi and Sage Rishi Kashyap as Vamana(Dwarf) and for this reason, he is also called as Aditya. This is similar to Shri Ram called as Raghupati for being in the family of king Raghu, Shri Krishna called as Vasudeva, because He was the son of Vasudev.

In this Shloka Bhagvan Shri Krishna mentioned other forms. Of the lights that shine in the countless universes Lord Krishna's Vibhuti is the solar group consisting of all suns. Of the 7 Maruts being Avaha, Prahava, Nivaha, Purvaha, Udvaha, Samvaha and Parivaha who are different varieties of winds blowing throughout space, Lord Krishna's Vibhuti is the chief wind known as Parivaha who bears the name Marici the primal wind which precedes all the others. Of all constellations, Lord Krishna's Vibhuti is the moon. The genitive case of the word "sasi" meaning the moon is not referring to one out of many but is specifying one overall. Thus naksatranam aham sasi refers to the moon as being the Lord over all the constellations. This will also be exemplified similarly in the next verse where He states His Vibhuti is the consciousness in all beings which means that what exists as consciousness apart from intelligence is His Vibhuti also.