Two strange lights (similar to satellites) following eachother and varying in brightness.

We were stargazing and looking for meteors in the early morning hours.  We had seen a couple satellites pass over, when suddenly in the distance there were two lights that were very dim, then grew in brightness.  They moved like a satellite, as you could tell they were very far away, but they had no blinking lights of any kind.  I'm an avid stargazer and have no trouble whatsoever telling the difference between satellites and anything else.  They appeared in the north.  They were two lights, perfectly in sync, about a thumbs distance apart when you hold your arm out in front of you.  They were so synced I began to think it was part of the same object-if so, it would have had to be HUGE.  The leading light stayed the same amount of brightness for about 15 seconds, but the second light became VERY bright.  Easily the brightest thing in the sky.  The other two in my group all stood up to try to get a better view.  And the.  It was gone.  The second light went out completely! , and the first gradually dimmed until it was out of our field of view.  It was not an Iridium Flare, and two satellites do not follow that close together in perfect sync in orbit.  I've never seen anything like it, and stil can't figure out what it was.