I saw an aircraft flying over, about two hours after sunset with a pair of bright, large, constantly on, orange lights. I'm wondering what kind of aircraft this could have been.

More details:

  • Latitude - Longitude: 43.1, 25.4 (central Bulgaria)
  • Date: 8 August 2021
  • Time (approximately): 22:30 EEST (Sofia, Bulgaria)
  • Estimated direction: flying from NNE to SSW
  • Estimated height: unsure, but I'm guessing at least several kilometers up (see below)

Additional information:

We were stargazing with a group of adults and children, looking north towards the Perseus constellation, looking out for meteors from the Perseids meteor shower.

At some point we saw two bright orange lights approaching from the north at a constant speed. They were not blinking, but permanently on. They were also quite large (not the blinking green/red dots I'm used to seeing on airliners). And we could see them as round shapes, much bigger than stars or planets, but much smaller than the moon. They appeared about the size of the tip of a pencil eraser. The craft passed straight overhead and then continued flying in a straight line until it disappeared out of sight. I estimate we were able to see it for at least a minute. We were able to see a good portion of the night sky from our location, I estimate at least 120 degrees. We didn't hear any sound coming off it and with the naked eye there were no other lights. However, looking with binoculars, a regularly flashing white light was visible between the orange lights. This light was set a fraction to the rear of the craft, but more or less between the orange lights.

The orange lights appeared to me as circles all the time, while the craft was coming towards us, while overhead, and while flying away from us. So in my mind they must have been sphere shaped.

I checked where the ISS was at that time with this ISS Tracker and it appears that was above northwest Australia, so nowhere near.

What kind of aircraft could this have been?

  • 2
    $\begingroup$ related: aviation.stackexchange.com/questions/63851/… $\endgroup$
    – Jamiec
    Aug 10, 2021 at 10:07
  • 1
    $\begingroup$ Aircraft do not have blinking green lights. Not if they are functioning properly at least :) Blinking lights are either red (beacon) or white (strobe). $\endgroup$
    – Jpe61
    Aug 10, 2021 at 11:43
  • $\begingroup$ @Jamiec - thank you. Yes I'd seen and considered that question and its answers, but none seem satisfactory. $\endgroup$
    – Dvaeer
    Aug 10, 2021 at 11:52
  • $\begingroup$ @Jpe61 - thank you. So the green lights are always static? I didn't know that. Thanks. $\endgroup$
    – Dvaeer
    Aug 10, 2021 at 12:03
  • 3
    $\begingroup$ If a multi-rotor drone had amber LEDs on two of its rotors, that would explain why the lights appeared basically circular to observers throughout multiple viewing angles. And drones are quiet, and their height would be very difficult to gauge at night. $\endgroup$
    – CCTO
    Aug 12, 2021 at 4:43

1 Answer 1


The large size of the orange lights you saw-- "much bigger than stars or planets"-- suggests two fire balloons joined together, with a blinking white light between. The lack of sound is also consistent with this. For a powered aircraft to be flying so high that you couldn't hear the engine, and the lights to still appear "much bigger than stars or planets" from your vantage point, the lights would have to be enormous, which is implausible.

Note that on clear nights, a temperature inversion layer often sets up in the lower atmosphere, inhibiting mixing and allowing there to be strong winds aloft but little or no wind at the surface. Hence a balloon just a few hundred feet up-- or a few thousand feet up-- could travel much faster than you might expect based on the wind felt at ground level.

  • $\begingroup$ This sounds like a plausible explanation, but I have a few questions about it. The page you shared talks about using candles for the balloon, which would cause the air in the balloons to heat up. If candles were involved I'd expect some flickering in the lights, which I don't remember seeing. Although, if a prankster had made this and put a white flashing light in the middle, they could have also made larger lights at the sides. Also, it was going in such a straight line - like a ruler. Wouldn't you expect wind to cause some lateral movement? I appreciate your thoughts. $\endgroup$
    – Dvaeer
    Nov 20, 2021 at 12:27
  • 3
    $\begingroup$ @Dvaeer If what you saw was indeed two fire balloons, then they would have been completely still relative to the air, so there would be no relative wind to make them flicker. Likewise, their direction of motion would have been directly in line with the wind, so unless the wind suddenly changed for some reason, their flight path would be a straight line. $\endgroup$ Dec 22, 2021 at 1:14

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