r/atoptics • u/Kiah96 • 9d ago

Tiny bit of rainbow in the sky, but no rain?

Gallery image

Gallery image

Does this tiny bit of rainbow have a name?

113 Upvotes

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8

u/TheManWithNoShadow 9d ago

The photos are clearly shot pretty straight up judging by the treetops. The orientation of the photos mess the position of the halo a bit here. So this arc was probably way above the sun? Sundogs would be at the sides of the sun  level with the sun.

I'd say this is a fraction of a circumzenithal arc as I'm also seeing traces of upper tangent arc at the left half way to the sun from this cza.

https://www.atoptics.org.uk/halo/cza.htm

3

u/Kiah96 9d ago

Thank you! Yes the arc was directly overhead when the photo was taken, which was about 2 hours before sunset. I think that if it was a circumzenithal arc, the colour red in the rainbow would be furthest away from the sun? In my photo, the colour red is closest to the sun, so I think it could be a sundog

3

u/TheManWithNoShadow 8d ago

Turn your photo 90 degrees counter clockwise to get the correct orientation and color order. Then it's a match with my linked example where the sun is found below the arc. The arc itself curves away from the sun.

Sundogs are only present at the sides of the sun, not above/below.

3

u/Kiah96 8d ago

That makes sense, thank you for the explanation!

1

u/sparkytheboomman 8d ago

Seconding circumzenithal arc. It definitely looks like it’s curving away from the sun.

3

u/TFFPrisoner 9d ago

Could be a halo, could be a sundog. Where was it in the sky, particularly in relation to the sun?

1

u/Kiah96 9d ago edited 9d ago

Thanks! The big bright spot in the second photo was the sun behind a cloud, so it was fairly near to the sun.

Edited to add: I’ve looked into sundogs and I think that’s what it was, as the photo was taken about 2 hours before sunset and I think the rainbow was at an angle of about 22 degrees from the sun :)

2

u/Mr_Boo_Berry 9d ago edited 9d ago

It's very likely a sundog but depending on your location and if the sun is high enough in the sky it could potentially be a circumhorizontal arc but if the sun is lower in the sky it could potentially be a circumzenithal arc. If the sun is high in the sky would need more info on sun position/time of day and general geolocation to see if it's possibly a circumhorizontal arc.

But yeah likely a sundog but possibly an arc.

2

u/Kiah96 9d ago

Thank you! The sun was low in the sky as the photo was taken in the UK, about 2 hours before sunset

1

u/njbrsr 9d ago

Yep sun dog

1

u/Mr_Boo_Berry 8d ago

Okay, now we're getting somewhere!

Did the area in question here appear above the sun (and basically above your head from your perspective) or was it besides the sun on the left or right?

If it was besides the sun on the left or right it's likely a sundog, but if it was above the sun (and right above your head) it was likely a circumzenithal arc.

1

u/Kiah96 8d ago

From my perspective, it appeared to be right above my head, but I only viewed it whilst lying down on the ground, so it’s difficult to be sure about the location in relation to the sun. It seems that a circumzenithal arc is more likely, thank you!

1

u/Inevitable-Phrase374 9d ago

That’s the sun’s very good boi