- #36
sophiecentaur
Science Advisor
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Semantic? It's what you wrote and, if it were just a semantic issue, why didn't you mention it ten years ago?
I kept saying that it was other visual clues that 'told you' the rainbow was in the cloud. Now you seem to be agreeing. Why not agree earlier?
An Image is something you see. If its position can be identified rigorously (e.g. by parallax haha) then that's the Image Position - just like in a mirror. In the case of a rainbow, this will be at infinity (in the absence of other 'clues').
There was no point in suggesting an article other than that wiki one. It did not define an image, in any case. It was a simple set of ray diagrams for a couple of lenses, such as one draws in school.
If you ask me to draw a diagram showing how an image in a mirror appears where it does, I could do it. If you ask for one to show how and where a concave or convex lens produces an image, I could do it. I could even give an explanation of how a hologram works, with diagrams and how an image can be seen. If you shine a lamp on a piece of paper, I can also show how the paper appears to be where it is. No need for me to do this because the web is full of such diagrams. You have seen some. All I am asking is that you should be able to draw an equivalent, valid diagram to show how we 'see' a rainbow as being in a nearby rain shower / spray if we can't actually identify the position of the drops first. I don't need to see a mirror in order to identify where the reflected image is. Are you really determined not to acknowledge the existence of Parallax?
You are very choosy about which words of mine that you read (or remember). If you read carefully you will see that I referred to all drops on a radius from "that cone" deviate the 800nm rays by the same amount. This happens to be is true. Why state the obvious about conical rays rather than parsing my sentences with more care? I think you need to get the geometry of the situation straight - and then deliver a crushing blow to my ideas by producing that diagram. Without a diagram, there is no argument to support your view; it's just whimsy.
You can't 'gainsay' parallax. I don't think you can even say it.
I kept saying that it was other visual clues that 'told you' the rainbow was in the cloud. Now you seem to be agreeing. Why not agree earlier?
An Image is something you see. If its position can be identified rigorously (e.g. by parallax haha) then that's the Image Position - just like in a mirror. In the case of a rainbow, this will be at infinity (in the absence of other 'clues').
There was no point in suggesting an article other than that wiki one. It did not define an image, in any case. It was a simple set of ray diagrams for a couple of lenses, such as one draws in school.
If you ask me to draw a diagram showing how an image in a mirror appears where it does, I could do it. If you ask for one to show how and where a concave or convex lens produces an image, I could do it. I could even give an explanation of how a hologram works, with diagrams and how an image can be seen. If you shine a lamp on a piece of paper, I can also show how the paper appears to be where it is. No need for me to do this because the web is full of such diagrams. You have seen some. All I am asking is that you should be able to draw an equivalent, valid diagram to show how we 'see' a rainbow as being in a nearby rain shower / spray if we can't actually identify the position of the drops first. I don't need to see a mirror in order to identify where the reflected image is. Are you really determined not to acknowledge the existence of Parallax?
You are very choosy about which words of mine that you read (or remember). If you read carefully you will see that I referred to all drops on a radius from "that cone" deviate the 800nm rays by the same amount. This happens to be is true. Why state the obvious about conical rays rather than parsing my sentences with more care? I think you need to get the geometry of the situation straight - and then deliver a crushing blow to my ideas by producing that diagram. Without a diagram, there is no argument to support your view; it's just whimsy.
You can't 'gainsay' parallax. I don't think you can even say it.