originally posted by: PlasticDreams
a reply to: Soylent Green Is People
To the person who took this image, the moon probably looked a lot bigger in person than it did in the image.
Why? 30 mm still provides more zoom than human eyes.
First of all, it is a fact that the Moon appears smaller in a photo I take with my mobile phone than I think it should look -- i.e., it seemed bigger
in person than in the photo. I'm sure I'm not the only person who notices that illusion about pictures taken with a standard camera and lens.
I think that is at least partially due to our eyes being able to "see" a wide angle scene, but our brains really concentrate on the center of the
scene more than the periphery. The camera, on the other hand, picks up the entire scene in front of me under the same "level of perception" --
because the camera generally perceives the periphery of the image it is taking the same way it perceives the center of that image, and presents the
entire scene in a single homogenously-perceived image.
I don't get it, sometimes the moon is very small and distant and I can't see the "geography" on it and sometimes it seems very close and big
and I can see very clear detail.
I think the size issue and the "see every detail" issue are two different things.
When the Moon looks huge on the horizon but looks smaller when it is high in the sky, that is due mostly to optical illusions. There is still some
question as to exactly what illusion is the cause, but you yourself can verify that it is ONLY and illusion (and that the Moon is not actually larger
on the horizon than it is in the sky) with a simple experiment: the next time the Moon looks huge on the horizon, take a ruler or measuring stick and
hold it at arm's length in front of you and measure the apparent diameter of the moon. Second, wait a few hours until the Moon is more over your head
(and probably looing smaller), and measure it again using the same technique....
...You will discover that the two measurements will be the same. That is, the Moon on the horizon looking larger was only due to an optical
One possible explanation for this illusion that people have suggested is the way our brains try to gauge the distance of things. Our brains take
clues from the rest of the scene it is observing trying to determine how far away something is. It has been suggested that the brain sometimes thinks
the Moon must be closer than it is given the other visual clues around it, and thus make us perceive it as larger.
Such as the images below. The Moon is the same size in both images.
Or maybe it also has something to do with how our brain perceives relative sizes of objects, and our brains are gauging the size of the moon relative
to the objects near the horizon. The Ebbinghaus Illusion (below) is an example of this relative size illusion. In the below graphic, the orange
circles are the exact same size:
As for being able to see more detail sometimes than other times, I think that is due to the contrast between the apparent brightness of the moon and
the brightness (or darkness) of the sky. When the Moon is seen against a dusk sky, the contrast between the Moon and the sky is less, so our eyes
(being accustomed to the relative brightness of the dusk sky) can see details on the Moon better.
However, when the sky is black, our eyes have a tougher time adjusting to the greater contrast between the dark sky and the bright Moon -- even if the
Moon was just as bright as it was in the dusk sky.
This is obviousy not caused by an illusion and the moons orbital motions cannot account for this huge difference since even with a supermoon
the increase in apparent diameter is only 14% according to science.
Well, as I said above, I think some of it (the apparent large size in the horizon) is an illusion, but some of it could be the
I wouldn't say it "obviously is not an illusion".
edit on 5/5/2017 by Soylent Green Is People because: (no reason given)
edit on 5/5/2017 by Soylent Green Is People because:
(no reason given)