Rainbow at sunset

cavedave

Have you seen a small part of a rainbow at sunset before? There was no rain in the area. It was North Antrim this weekend.


What causes this?

mike65

Well not all moisture is rain, it looks like a vapour trail that the sun caught at the right angle.

cavedave

Good point Mike the light must be reflecting off some vapor. Is this form of rainbow common? Googling images of 'rainbow at sunset' you get similar images.

Hal1

Looks like a 'Sundog'.

http://en.wikipedia.org/wiki/Sun_dog

'A sun dog or sundog (scientific name parhelion, plural parhelia, for "beside the sun") is a common bright circular spot on a solar halo. It is an atmospheric optical phenomenon primarily associated with the reflection or refraction of sunlight by small ice crystals making up cirrus or cirrostratus clouds. Often, two sun dogs can be seen (one on each side of the sun) simultaneously.'

Good cap there.

cavedave

They seem fairly common. Here is another photo from flickr


If it is a sun dog you'd expect to see a matching one on the opposite side. I'll know to look for that if i see it again.

pauldry

i tell normal non weather people about these and they look at me weird

gillo_100

I am just completely guessing here.

But could it be something to do with the angle the suns ray are making with the atmosphere. As its such a low angle the moisture could be much further away possibly even over the horizon but still have an effect splitting the light.

My name is URL

Could it be a Circumhorizontal arc?

M.T. Cranium

Yes these are sundogs, they are refracted sunlight from the ice crystals in cirrus clouds. We see these very frequently in the winter or any colder weather patterns in Canada when the sun is rising or setting through cirrus layers in high pressure. That kind of weather prevailed this past weekend in Ireland. You probably don't see them as often because of the maritime nature of your climate. A similar feature is the lunar or solar halo that sometimes appears when ice crytal clouds partially obscure the moon or sun. These lack the colour of sundogs (usually).

nilhg

They can be quite spectacular