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Large Sun at sunset

Ursa Major

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On the way back from the French city Carcassonne to Bizanet (a village where we are on holiday), I looked back to the west to see the sun set. I noticed that it was unusually yellow for the time. It was a little to bright to see the disc clearly.

I was a bit of a hazy day. and there were some high clouds in the west.

The sun sunk beneath these clouds and after about 5 mins it emerged under the clouds. Now it took on a very orange colour and was, I’m not joking, twice the size of the size you normally see the sun.

It was amazing!

I seem to remember that this could happen with the moon as well but I have never really noticed it before.

Perhaps Olly P, you might have seen it as you live fairly near.

Hopefully someone will be able to shed a little light on how this happens.


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This is an interesting effect. Indeed one of my neighbours examined it in her final year psychology thesis. The reddening is easy to explain; quite simply the atmosphere scatters all but the longest wavelength (red) light when the sun is very low and its rays are passing through the most atmosphere en route to your eye.

However, the rise in apparent size is purely psychological and applies, also, to the moon. Exclude everything else from the view (by using a telescope) and the size looks unchanged. I enjoy watching sunsets in the Ha solar scope because I like the trees etc silhoutted against the disk and the relief this gives to prominences etc. But the sun doesn't look any bigger! Step back from the scope and it does, though.

Have a care when looking at the sun, even when it's low.


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Thanks Olly,

I still find it weird that it has rarely happened on the many sunsets I have observed in the past.

Maybe it was something to do with being in a car. The looking through the back window (not the normal place to be viewing a sunset) may have tricked my mind.

I was sure it was some kind of atmospheric phenomenon. :)

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  • 4 weeks later...

Olly is right. Take your little finger, extend your arm out full length, and use the little finger to cover the sun or moon. No matter where you see them, you will always be able to cover them with your "pinkie" !

Jim S.

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