It was about 10:30pm, i was fishing from a dock on lake austin. i had just landed a large carp and released it when i say back in a lounge chair and was looking at the stars. it had been mostly cloudy but here was a break in the clouds. a large one. i noticed movement and focused on a somewhat dim star. i watched and compared distances with other stars to confirm movement when i noticed 2 more stars moving at the same rate of speed. it was a perfect triangle. once i was sure it was moving i asked my girlfriend who was standing beside me on the dock and totally unaware of what i was doing,"is it me or is that moving?" i said nothing more. she replied, "it is moving, it's a triangle." we watched this thing move from the south to the north at a very slow speed. almost undetectable. you really had to be looking hard to notice it. there were trees behind us and we both watched it slowly close the distance between it and the trees. i'd say we watched it for 3-5 minutes before it disappeared into the trees. we both were excited by what we had both just witnessed. there is a clearing approx 40 yards behind us or to the north and i began to run up the stone steps from the dock to the lawn tripping over a sprinkler in the dark. my girlfriend was right behind me. we got to the clearing and waited. it never appeared. i'm still in awe by what we saw. i wanted to see if it would block out other stars as it got to them to confirm it was one solid object and not 3 separate ones. i didn't get the chance to do so. the 3 lights looked like stars. it blended in well. it was totally black and matched the night sky well also. to me it looked like it was way up there, out of our atmosphere high but i really don't know. if it was that high and it was one object them it had to be as big as texas. seriously. even if it was at 35 thousand feet, the altitude of a passenger jet and if it was one solid object then it was still very large. look at the thumb on hour hand and imagine the length of it being as long as one side of the triangle as you hold it up an arms length away. that's how big it was. i recently read something about a girl in houston that spotted a large black triangle and showed it to her boyfriend. they watched it for 15 minutes. this was also in aug of 2018. her description was dead on to what we witnessed. i hope our sighting and our story of what we saw will help you in some way. keep up the good work guys.