Cylinder shaped object hoovering within 80 feet of me on a clear evening sky.

I was in the military on active duty with the Coast Guard in Oakland, CA, but on Governor's Island, which is an estuary.  
I was on a second floor barracks facing south when I looked out the window and saw a disc shaped object hoovering above a building across the street from my barracks window.  The object was only 20 feet above the building which gave me a perfect viewing. 
I opened the window and looked at how close this object was.  I saw no windows but multicolored lights circumnavigating the object like you would see on an outdoor theater displaying the features at the show.  The disc reminded me of a football shape.  
I shouted at a guard passing on the same side of the street to come across the street and look up.  He witnessed it as well.  
I ran down the stairs of the barracks to alert the watchman and by the time we both observed this object we saw it jet upwards at an angle with no sound and disappear into the night sky like an open shutter on a camera, leaving a trail of light behind it.  
I have been an avid UFO watcher with interest since I was a teenager.  I have shared this story with hundreds of people and even an astronaut that visited our neighboring community several years ago.  He walked on the moon and said he had witnessed UFO's himself.  I am a true believer!