Equilateral triangle with 6 lights on underside

This is the first time I have had a UFO sighting.  What I saw was not my normal.  This occurred in the early morning hours of 8/13/2018 at about 3:40 a.m.  I had awoken about 3:00 a.m. and decided to go out on my deck in the backyard to see if I could observe the Perseid meteor showers, even though I was in the brighter city limits.
Constantly looking straight up to the sky, I had been outside about 40 minutes when I had the pleasure of seeing two meteors.  I was about to call it good and go inside when I glimpsed a very intense bright white light coming over the roof line to my south.  My first thought was jokingly "Oh, this ought to be a great meteor," and then my mind instantly realized, of course, it better not be a meteor!  
In the seconds I had this thought and was still looking up at the white brightness increasing and moving over the roof line, I saw an equilateral triangle shape of 6 round-shaped white lights arranged in 3 rows (one in leading front, two in next row and three in last row) - no pulsating or different colors.  It appeared to be a set of 6 lights moving in perfect formation and unity; I could not see an outline of a structure or frame that contained the lights but I had the sense the ‘edges’ were rounded and not sharp. I could not see the top of the craft, I only saw it from underneath so I don't know if there was a dome or viewing window(s).  I guesstimated the size around 9-10 feet.
It moved slowly over the space above me at a level and steady pace, making no noise, and moving from the south to the north near the tree line - which I later estimated to be about 100 feet high. It did not light up the ground area which remained dark.  The entire event took about 10-12 seconds before I could no longer track it due to it disappearing through the trees in the yard.  My thought was "what the heck was that?"  I stayed outside for about 5 more minutes before going inside as I started feeling a little uneasy.  A couple of days later I reported it to the Oregon Mufon Group.