Pulsating Circular Light in sky off Southern Maine Coast

I was on my porch looking out over York Harbor/Beach when I noticed a light blinking in the sky far above the horizontal line where the ocean meets the sky, visionally speaking. It looked like a star but was apparently in atmosphere and seemed to be pulsating. I watched from inside the house as it was cold but collected a few minutes of footage. It moved in a vertical motion slightly but remained in that vicinity for near an hr. It seemed like a giant drone from the way it was hovering and by size as it was like looking at a plane and knowing it’s proximity to you is much further than just a couple hundred yards. It was possibly the strangest thing I’ve witnessed in my life. I’ve shown others the videos and they are just as baffled.