[AlexP]

Sun disc size in physical sun and sky, e.g. for "large sun" sunsets

[moreschipaolo]

+1000

[Bubbaloo]

Focal length.

When photographers want this effect, do they enlarge the sun?

[eric nixon]

Actually there isnt a sun disc in the maxwell sky, is there? just the glare from a bright point, or am I mistaken.

Making a sun doesnt seem so hard, I think a circle shape would do it? maybe targeted towards cam....

[AlexP]

There is bright sun circle as sun disc, about 18EV brighter then sky, so we can take it as sun disc.

But my bad, didn't know that larger sun is an illusion:
http://en.wikipedia.org/wiki/Sunset
"The Sun also appears larger on the horizon, an optical illusion, similar to the moon illusion."

[polynurb]

sun "diameter" goes hand in hand with the physical sky settings.

sun diameter is always constant (not like moon which actually does get significantly closer at times)
so the appearance of the sun diameter is related to atmospheric properties and not the sun "size" itself.

adjust turbidity coefficient between ,2 and ,02 to get differently sized discs.
however i can understand the need to adjust this property independently from the other aspects of "turbidity"

so +1

[Polyxo]

Should M~R be limited to rendering stuff on earth?
The sun will already have considerable size on planet Mercury...

[Bubbaloo]

Should M~R be limited to rendering stuff on earth?
The sun will already have considerable size on planet Mercury...

Very true!