I was tracking the ISS using the Virtual Sky app on my iPad. As the ISS came into view from the west I could watch it with the naked eye. The sky was well lit by the super moon and the very few large clouds were at around 5-8 thousand feet. Other than that the sky was clear. I was facing south just as the ISS passed overhead. It was travelling at a steady pace with what looked like a smaller service module just ahead of it. As the ISS passed just to the left of the moon 3 very bright lights in a perfectly symmetrical triangle faded into view. They were huge like watching a constellation but slowly ascending in the southern sky almost parallel to the moon. I tried aiming my iPad at it a few times to see if it was an object of interest in the Virtual Sky app but nothing was showing up. The ISS was now heading well into the south east and after approximately 10 seconds the lights began to fade out all the while steadily ascending and maintaining their perfect triangular formation. I am an amateur astronomer, keen aircraft enthusiast and like to think I have a pretty good grasp of most things that fly. I have seen many satellites, meteors, iridium flares, rocket launches and even a few comets. This event was none of the above. It was definitely not aircraft(that I know of) or Chinese lanterns due to its size and brightness.I mentioned seeing the ISS on social media when a friend nearby sent me a message asking if I had seen anything else? It turns out he had also seen these lights.