Sphere was hoovering over grandpa's house when I was 10-12 in 1970ish with green and orange lights don't remember it leaving.

I lived on a hill next to the courthouse that overlooks the Missouri river. I was about 10 to 12 years old. I was in my yard and turned opposite the river to face downhill. Across the street silently hoovering above my grandfathers house was a saucer shaped craft with half egg shapes on the top and bottom. There were green and orange lights on top and I'm not sure those colors are correct since I've put the memory away a long time. It was early evening the light was waning but the ship was clear to see because it was so close. I can't remember how long I stood there and stared at it. I guess I was mesmerized. I don't remember any fear or panic. The weird part is my mother and her best friend were 100 feet behind me looking out over the river engaged in coversation. I remember later telling her what had happened. I don't remember the ship leaving. Years later she had no memory of me telling her any such story. I told my grandfather the story at a family get together when I was 30. He was a no nonsense German Catholic who believed in hard work. He said years earlier when my mother was young, she and a sister and brother were in the back seat of grandfathers car when they saw a UFO in a field outside of town. He pulled the car over and watched until it left. He said it matter of fact like watching a flock of birds leave. My mother doesn't remember this either. This is my only sighting.
Date is approximate.  PD