Black silhouetted object against glow of distant town. Flashing light on one edge. Hovers then drops down out of sight.

My hobby was Astronomy and I would get up late at night to look out of my window at the stars.  It was a summer night I believe in August of 1957. I was looking south toward the massachusetts turnpike and toward the town of Indian Orchard, Mass which cast a glow into the night sky. I was ten years old at the time.  My stargazing was interrupted by a rapidly flashing bluish white light.  I thought it was some kind of firefly but when I looked directly at it I saw that it was on one edge of a black silhouetted cigar shaped object.  It reminded me of a weapon discharge such as a machine gun.  It was 'firing' in the same direction of travel as the object and appeared to be slowing the object down as if it were a retrorocket.  The object (which I estimated to be large...at least several hundred feet long) slowed to a halt over the hill.  The blue-white light ceased to discharge.  After a few seconds it slowly descended behind the hill and out of sight (there is a valley there where the Ludlow River (it may be called the Chicopee River actually) flows.  I watched for hours but it never came up into view again.  I had heard that the Ludlow police had seen it in a different area that night at about 3am but never verified this in newspapers recently.
Date in 1957 is approximate.  We have assigned an arbitrary date in August 1957.  PD