Saucer shaped object with orange lights.

I can remember my UFO sighting as if it happened yesterday.  It was September 7, 1970. 11:10 p.m. I was about to start my senior year in high school.  We lived on a main highway just up from a very bad intersection where there were always accidents.  (Seven miles south of Pittsburgh, PA.)   
At 11:10 p.m. that night I was leaving one upstairs room to go into the bathroom when I noticed a light somewhat flickering on the sheer draperies.  I assumed it was another accident and the lights of a tow truck.  I walked to the window to look down at the intersection and saw nothing.  I realized the light was coming from above. 
I saw a huge circular metal craft with lights on the bottom.  It silently was hovering over my side yard at a slight angle so that I could only see the bottom of it.  It was just above the poplar tree tops along the border of our property.  I got a very close up look at it.  The bottom was slightly convex and a matte colored dark metal.  
There were what looked like semi opaque tempered glass panels on the bottom.  Similar to a bathroom window.  You can see light but glass is not transparent.  Those panels are where the amber lights emanated.  They were on constantly but yet had a slight pulsating flicker to them.  For some reason, although I don't know why, I thought it was due to the power source of the craft.  
I saw it for approximately 15 seconds as it hovered silently.  Then, faster than I could blink my eyes, it took off at a 45 degree angle to the west.  I was so terrified and will never forget what I saw.  
I am sending a drawing explaining what it looked like to the email listed on your website.  
If you call me I can give you exact locations and any other info you might want.
If it has any relevance I don't know, but I am was not very far from Bettis Atomic Power Laboratory.