enter image description here

I took this picture a few minutes ago (35 minutes ago, currently 1828 here)

As you can see there's a VERY bright spot on the right that shows a spectrum on the one side.

I am pretty confident it's the reflection from a large body of water there are quite a few reservoirs around.

However I do have some questions:

  1. Why do the colours band only on one side
  2. Why does it move (when the sun sets approximately 35 degrees to the right of where it is now this shape can appear to the right of the sun, not left!)
  3. Why is it only sometimes there? (Perhaps it is blocked by hills sometimes?)

Most importantly:

How can I model where it is?

I took a picture 15 minutes later and both the sun and the bright spot had gone lower in the image. I could try and model this as a point light hitting something on a plane and approximate the height of clouds and such but sun isn't a point and the earth isn't a plane.

I have spotted this thing elsewhere and have been pondering on modeling such things for a while. I've gotten no where. It's not an urgent question but it is a curiosity.

  • 1
    $\begingroup$ en.wikipedia.org/wiki/Sun_dogs All you need to know is there. $\endgroup$
    – Sanchises
    Commented Sep 28, 2015 at 17:48
  • 1
    $\begingroup$ There doesn't seem to be a pair of them, but reading more now - thanks @sanchises - my searches for "bright spot in the sky" didn't go well. $\endgroup$
    – Alec Teal
    Commented Sep 28, 2015 at 17:50
  • $\begingroup$ Note that there needs to be ice in the air where you see the sun dog. If you live near a body of water, that may be reason there's often a lot of moisture in the air there for ice crystals to form, where that may not be the case at the other side of the sun in your location. $\endgroup$
    – Sanchises
    Commented Sep 28, 2015 at 17:51
  • $\begingroup$ @sanchises I'll look into that, the temperature has been 13-16 (C) today, but I've seen this on scorching days near mid-day in coventry. I'll keep an eye out now I know what to look for (air temp and the feeling of warmth are separate after all, thanks for the link) $\endgroup$
    – Alec Teal
    Commented Sep 28, 2015 at 17:53
  • 3
    $\begingroup$ "There doesn't seem to be a pair of them" Not unusual. It just means that the atmosphere is not uniform in the icy layer. $\endgroup$ Commented Sep 28, 2015 at 18:11


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