it was changing colors, like most of the rainbow colors, not flashing just changing but the intensity ... same.

The night was clear so when I got out of my car to go inside I took a few minutes to enjoy the stars. I was looking to the south and spotted a bright light moving to what appeared to be north. I didn't think to much about it cause we have Forbes Air Base and a police helicopter in town, but what caught my eye was that it was changing colors, like most of the rainbow colors, not flashing just changing but the intensity of the light stayed the same. NOW I was wondering why our police helo was changing colors as I have never seen it do that before. It was about the same brightness as Jupiter is on a good night but slightly brighter. I watched it for about 7-10 seconds then it stopped in mid-flight. When it stopped it also stopped changing colors and changed to a VERY brilliant white light, like twice the brightness of Jupiter. That lasted about 4-5 seconds and then all at once this thing took off to the stars so fast it was gone in less than 1 second, if I had blinked I would have missed it leaving. It did not go OVER the horizon it went straight up at about a 70 degree angle to the way it was flying when I watched it before it left. It went UP INTO the stars, not leaving a trail of any kind except a light trail, the kind you see if you move a flashlight beam across a wall VERY fast. At that moment I knew it wasn't something of earth as I have seen aircraft fly all my life and none ever acted like this thing.
Object was too far away to make out any shape so can't give one.
Date in June 1977 is approximate.  PD