Description

I want to share something seen in the sky in Boulder Colorado. I went to a free telescope viewing night at the CU observatory which they host sometimes. It was around 9:00pm on 12/7/2018.

The telescope viewing was on a large deck with a retractable roof. I was waiting in line for one of the telescopes and looking up at the sky, when I saw something crossing overheard from roughly South to Northeast. It lasted about 15 seconds and crossed about 150 degrees of sky by a rough measurement using my hand, before disappearing from view behind the building.

The object itself appeared to consist of approximately 3 orb-like spots in the sky moving in a fast screwy swirling loopy sort of motion. They were not brightly illuminated and were only dimly noticeable. They reminded me of a group of fast-moving jellyfish.

Another man and woman saw it as well. One of them thought it was birds and the other thought it was drones. I didn't think it was either of those. It was pretty cold and late at night for birds, and there was no buzzing sound as would be expected from drones. It was very quiet and I heard no sound at all. They looked more like oscillating disks than birds to my eye. Also I feel they would have been going very fast for birds and I've never seen drones move together as a group in that way.

There was little to no wind at surface level, so I didn't think balloons either. I've seen when people put LEDs in balloons and it didn't look like that either. The swirling motion wasn't like balloons drifting, it looked like powered motion to me and almost bouncy. The distance between them was not solid, they looked like 3 independent objects swirling together in a group. If it was balloons, the wind would've been very intense aloft while almost calm on the ground. The weather was mild overall, including in the days before and after.

In the picture, the trails I drew weren't actually visible and are included as a rough indication of the wavy motion. I was looking directly overhead and tried to recreate the view. If I had to assign a 'frequency' to the motion, I'd say maybe 2 cycles per second, with an 'amplitude' of maybe 0.5-1.0 degree. I don't know the altitude and it's hard to guess.

For background I am a hobby astronomer, have flown drones, have a pilot's license, and in general spend a lot of time gawking at the sky but I've never seen anything quite like it, although it's not the only thing I've seen that I would call a UFO. I've been thinking about it frequently and wanted to share with as much detail as I could think of.

https://preview.redd.it/x1ngs9yv8r841.png?width=685&format=png&auto=w…