@Ann K's directions were perfectly adequate, and I agree with her conclusions, even from the rendering of the video that I saw. And the reason I'm not posting a screenshot of that is because for some unknown the reason (well, probably a shitty codec) the video played at completely the wrong aspect ratio and resolution, so half the window was repeated lines, and the other half of the window was a stretched version of the actual video. The light below - where in frame I cannot tell you as the video's mangled - moved in sync with the light above - ditto. That's what a reflection would do. Sorry I couldn't be of more help, but you might have more luck just viewing it yourself.Please show
I'd like to mention that not every aircraft will show up via the ADSB app I use. I know of one pilot who's helicopter never shows up. It passes inspection but every time we try to find it through flighttracker24, past or present, we can't.That's when I realised it was probably an aircraft, that I was seeing the landing lights of, so I checked an ADSB app and found it was a plane on approach to Manchester airport.