Silent saucer seen hovering over pine trees then zoomed away.

I was about 7 years old and my sister was about 9 when we were playing outside on our deck.  We lived right on Scenic Hwy.  My sister said to me, "Look at that" and I looked up and saw a silver saucer shaped large object hovering just above the pine trees.  We both just stared at it for a minute.  There was no sound, it was stationary.  I remember noticing some type of lights that went around the middle of the object.  The object had a large saucer shape topped by a smaller section on top.  I ran inside to get our older brother but when we got back outside, the object had gone.  My sister said it zoomed off fast just like that.  Our older brother never believed us and still doesn't to this day, even though we both described the same thing independently.  My dad told us it was probably something from Dobbins AFB.  To this day I can see the object as clearly in my head as I saw it then and so can my sister.  I have approximated the dates as I can't remember the exact time.  I just know it had to have been 77-78 since I remember it well.
Source of report indicates that the date of the incident is approximate.  PD