A sphere floating just above the ground, invisible in the dark but reflecting/emitting an infrared signal.

We were at a cottage in a remote rural part of Wales. It was around midnight and raining. I was using my night-vision binoculars to look for nocturnal wildlife before heading to bed. The binoculars emit an infrared light which illuminates the immediate area and is displayed on a screen.
I noticed that the image on screen was showing some kind of interference, with horizontal lines across the display.
When I looked into the field at the front of the cottage, I saw a sphere emitting or reflecting a very strong infrared signal to my binoculars. I lowered the binoculars and looked directly in the direction of the object. It was raining and, in the absence of any light other than that from the cottage, it was too dark for me to see anything. I looked again with the binoculars and the sphere was clearly visible.
I quite honestly felt incredibly spooked. I walked back into the cottage, told my family I'd seen a UFO and they laughed at me. I convinced myself the binoculars were faulty and went to bed.
Next day, the binoculars were working fine. There was nothing visible in daylight that could explain what I'd seen. It is a significant source of regret that I didn't record what I'd seen. All I had to do was press the record button but I was so spooked it didn't occur to me to do so.
Looking back, it was difficult to gauge distance but I think that the hill behind the field is about 150 m distant. My sense is that the sphere was about 10-15 m away which would put its diameter at about 1m. If the sphere was on the opposite side of the field, my estimate is that its diameter would have been more like 7-10m. There was no sound emitted by the object and no visible means of support. It was just floating above the ground. As the image was an infrared signal on a monochrome screen, I don't know the colour of the object. I don't subscribe to aliens whizzing about the planet, but can find no rational explanation for what I saw. The area is overflown by military aircraft from Anglesey but the location is civilian with no MOD connections I'm aware of.