Three white lights in equilateral triangle move across night sky, multiple witnesses, summer camping trip 1974.

On our annual family camping trip near Chester, California, my sister, my cousin and I would occasionally see what we thought were satellites floating across the night sky. It has always bothered me that I have never seen anything similar to these "satellites" since then. After stumbling upon an online account of  "black triangles" I came to the realization that what we saw was probably NOT a satellite at all. In fact, I think is scientifically impossible for what we saw to be a satellite. So now, 38 years later, here is my belated report on the "three-star satellites" witnessed over the Potato Patch Campground near Chester, California in July/August of 1974.
I can remember it as if it were yesterday--one of those clear childhood memories that sticks with you in a very visual way. I remember talking about it with my sister as we lay there on our sleeping bags, looking up at the stars and wondering what those slowly moving triangle of stars were. We have talked about this as adults, though not in recent years.
The first time we saw them, it must have been between 9-10 PM, as it was fully dark and the stars were out. We were just lying there, looking up at the night sky when we saw what looked like stars formed in the shape of an equilateral triangle drifting overhead. There were three white lights, one in each corner of a triangle. I could not see any body or an edge to a triangle, just the three lights. What made them unusual is that they moved, and that they moved together in such a way that you knew they were physically connected. It must have been really high up, because the lights looked the same size as the stars, slightly bigger, but also slightly brighter than the stars. Anyways, it moved slowly against the other stars in what I think was a northern direction. The three unified lights would speed up then slow down along it's path and slowly turn or rotate around itself. The movement was very graceful, not at all like an airplane. It just looked like it was floating and spi! nning past us up there in the night sky. It seems like it took about 2 minutes before it went behind the trees.
I can remember seeing this at least twice for certain, and probably more like 3-5 times though I can't recall the exact instances of each. I do remember that it became commonplace for us to see these that summer. I remember that we would lay out and look for satellites, and we were successful several times. We were not all excited about the satellites. I am sure a shooting star would have been more exciting. We certainly didn't think we had seen a UFO. We just figured they were "three-star satellites" (that's what I called them) orbiting the earth. But, satellites don't speed up and slow down, and as far as I know satellites don't come in sets of three that move synchronously about at various speeds across the night sky. In retrospect, If it were indeed a satellite, then it would have had to be miles wide.
I have not mentioned this Black Triangle correlation to my sister. Though we have discussed the satellite sitings as adults, I have not discussed this with her in any detail within the last 10 or 15 years. It would be interesting if a third party could interview her to correlate the details of this story as I remember them.
Witness indicates that the date of the sighting is approximate.  PD