<p>I was recently reminded of when, while with some friends 20some years ago, we happened to look up and see a circle of what seemed to be light (in the sky of course).</p>

<p>The circle was "empty" (only the circumference was lit up), parallel to the ground, and it seemed rather large from our point of view. I can only speculate on its altitude, in that it may have seemed closer to earth than space, but not that close.
In particular, it looked fantastically precise, as if drawn with a compass.
It did not look like a projection or a bat signal of sorts. I cannot reliably say if there were any clouds, if pressed I would venture a no.</p>

<p>This happened in southern Europe (near Rome).
We have lived here about 40 years, and do not recall anything similar before or since.</p>

<p>What might we have been looking at (googling "circle of light in the sky" is kind of a lost cause) ?</p>

<p>I am ashamed to admit that our reaction as Young Dynamic People was "Maaaan" and off to the pub, so we didn't hang around to see if it would fade or what else.</p>

<p>Tagging is tentative, suggestions are welcome.</p>

CC BY-SA 3.0
2017-08-30T07:11:06.673Z
Could it be a [sun dog](https://en.wikipedia.org/wiki/Sun_dog)? [Anthelion](https://en.wikipedia.org/wiki/Anthelion)? There are a number of rare [halo](https://en.wikipedia.org/wiki/Halo_(optical_phenomenon)) phenomena that could fit the description.
user2821
CC BY-SA 3.0
2017-08-30T07:11:51.377Z
All I can think of is a halo. https://en.wikipedia.org/wiki/Halo_(optical_phenomenon)
Communisty
CC BY-SA 3.0
2017-08-30T14:02:45.257Z
2 major differences: "mine" did not have a light in the middle to be the halo of, and was facing down.
deg
CC BY-SA 4.0
2021-05-21T01:24:51.350Z
There are [various halos](https://weather.com/science/weather-explainers/news/halos-new-mexico-photo-jan2015). By "parallel to the ground" do you mean centered on the zenith?
Keith McClary
CC BY-SA 4.0
2021-05-22T14:56:21.167Z
@KeithMcClary Alas, I don't know what centered on the zenith means. But I mean it was (or seemed to be) facing down, flat.
deg
CC BY-SA 4.0
2021-05-22T15:20:34.390Z
Zenith just means straight up. There are [Circumzenithal arc](https://en.wikipedia.org/wiki/Circumzenithal_arc) and [Parhelic circle](https://en.wikipedia.org/wiki/Parhelic_circle).
Keith McClary
CC BY-SA 4.0
2021-12-16T11:50:20.823Z
@KeithMcClary It looked not entirely unlike a parhelic circle, though the ice crystals requirement seems a bit off in a mediterranean summer evening.
deg
CC BY-SA 4.0
2021-12-16T17:28:35.107Z
A parhelic circle goes through the sun (or possibly the moon).
Keith McClary
CC BY-SA 4.0
2021-12-18T20:34:07.990Z
@KeithMcClary Then no, the sun was low or had set and there was no visible moon. As I recall it the circumference was complete and unobstructed.
deg
<astronomy><light>
Identifying circle of light in night sky
deg
# Identifying circle of light in night sky

(Asked by: username_0 on 2017-08-30)

I was recently reminded of when, while with some friends 20some years ago, we happened to look up and see a circle of what seemed to be light (in the sky of course).

The circle was "empty" (only the circumference was lit up), parallel to the ground, and it seemed rather large from our point of view. I can only speculate on its altitude, in that it may have seemed closer to earth than space, but not that close.
In particular, it looked fantastically precise, as if drawn with a compass.
It did not look like a projection or a bat signal of sorts. I cannot reliably say if there were any clouds, if pressed I would venture a no.

This happened in southern Europe (near Rome).
We have lived here about 40 years, and do not recall anything similar before or since.

What might we have been looking at (googling "circle of light in the sky" is kind of a lost cause) ?

I am ashamed to admit that our reaction as Young Dynamic People was "Maaaan" and off to the pub, so we didn't hang around to see if it would fade or what else.

Tagging is tentative, suggestions are welcome.

**Tags:** astronomy, light

> **Comments:**
> **username_1**: Could it be a [sun dog](https://en.wikipedia.org/wiki/Sun_dog)? [Anthelion](https://en.wikipedia.org/wiki/Anthelion)? There are a number of rare [halo](https://en.wikipedia.org/wiki/Halo_(optical_phenomenon)) phenomena that could fit the description.  
> **username_2**: All I can think of is a halo. https://en.wikipedia.org/wiki/Halo_(optical_phenomenon)  
> **username_0**: 2 major differences: "mine" did not have a light in the middle to be the halo of, and was facing down.  
> **username_3**: There are [various halos](https://weather.com/science/weather-explainers/news/halos-new-mexico-photo-jan2015). By "parallel to the ground" do you mean centered on the zenith?  
> **username_0**: @username_3 Alas, I don't know what centered on the zenith means. But I mean it was (or seemed to be) facing down, flat.  
> **username_3**: Zenith just means straight up. There are [Circumzenithal arc](https://en.wikipedia.org/wiki/Circumzenithal_arc) and [Parhelic circle](https://en.wikipedia.org/wiki/Parhelic_circle).  
> **username_0**: @username_3 It looked not entirely unlike a parhelic circle, though the ice crystals requirement seems a bit off in a mediterranean summer evening.  
> **username_3**: A parhelic circle goes through the sun (or possibly the moon).  
> **username_0**: @username_3 Then no, the sun was low or had set and there was no visible moon. As I recall it the circumference was complete and unobstructed.  

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## 0 answers

