Would start as a pin point of colored light and expand into a circular shape covering a large portion of the sky.

I would have been about 23 years old at time of this incident. I was leaving home for work and as I approached my car something caught my eye and as I looked up to my right in the sky I saw a pinpoint of light ( red, green, blue) that would semi-slowly expand into a large circular smoke ring type of shape before dissipating away. This would repeat multiple times and each time it would be change it's color.
I stood there totally freaked out by this. One of my first thoughts was that 'I need a witness to this' because there was no other traffic on the street in the neighborhood at that time of morning. So I went back into the house and woke up my land-lady and pleaded with her to come and see this spectacle, which she begrudgingly did. Once back outside, it was still taking place and we both saw it. These circles or rings would cover a huge expanse of sky before they would fade away.
As noted in my report the circle would get as large as a bicycle tire at arms length. I lived about 3 miles from Andrews AFB during this time and there are aircraft visible day and night around the entire DC metro area. There were no aircraft visible around the area of sky where this was taking place. I do not remember if the event ended while we watched but because of having to get to work I did get in my car and leave at some point.
Later that morning, WTOP radio actually reported on what I had witnessed, apparently getting multiple calls about the incident. I don't know their source, but they reported that NOAA was doing some kind of atmospheric testing that caused this effect. I have always been skeptical about that but who knows. I later did some internet research and have never found anything to explain it to my satisfaction.
I have never witnessed the northern lights in person but have seen videos of the northern lights, and what I saw was very uniform in nature. It never changed it's location in the sky and did not waver from how it displayed itself. A single point of light expanding in a circular motion repeatedly and changing colors each time it did this. I have been in this area for 50+ years and have never seen anything like it before or since. And as a final note I should mention that this took place on a clear and starry night.