There was a faint dull silver green luminous oval object flying in a clockwise rotation, spanning over the river and neighboring houses.I was taking my dog outside for a walk. When I noticed the sky had a purple blue tint and there was a faint dull silver-green luminous object flying from the lower end of my backyard crossing over the Connecticut River. At first I thought it was a helicopter or a stealth jet or a light beacon due to the air base being near by or a looping shooting star or meteor. But there was no sound emitting ,nor was there a streamed light source connecting to the sky. The object was circling in clockwise rotation it reached a full circle in every 3-4 in a half seconds. The phenomena lasted for roughly 15-20 mins begining from 8:26pm. It made roughly 60-70 rotations. This has been the first sighting that I have ever witnessed this irregularity to happen in this area.