Comments on: Illusion-o-rama

By: Al

Al — Tue, 15 Jul 2008 11:17:13 +0000

The blind spot is where the optic nerve goes through the retina. As the nerve connections (also blood vessels) are situated in front of the light-sensitive cells, there is a gap in the coverage to accommodate them.

By: Michael L

Michael L — Tue, 15 Jul 2008 09:20:40 +0000

So, on the flip side of this, what causes the blind spot?

By: CanadianLeigh

CanadianLeigh — Tue, 15 Jul 2008 08:32:18 +0000

Hi Brian, regarding Michael L’s question. I had noticed one exception to averted vision giving better vision at night and that is when I was trying to split doubles. They seem to blur together when you avert your vision. I finally understood why this happens when I read the article by Stephen James O’Meara in August’s issue of Astronomy. The article is titled Vanishing Acts, part 2. As splitting doubles is one of my fun pastimes when out observing, I found the article very interesting and instructive. As explained in greater detail in the article, direct vision will only work better if the stars are both bright enough and not to different in brightness. Before reading this article I just thought my eyes were getting too old.

By: MaDeR

MaDeR — Tue, 15 Jul 2008 06:39:27 +0000

Wow, what for here sticked climate troll?

By: madge

madge — Tue, 15 Jul 2008 05:19:45 +0000

Doh Brian beat me too it

By: Brian

Brian — Tue, 15 Jul 2008 02:19:25 +0000

Michael L: That’s because the color-sensitive cones are mostly jammed into a little circle at the center of your retina. The rest of the retina has a higher population of rods, which can only see in black-and-white but are more sensitive to faint amounts of light.

By: A Real Climatologist

A Real Climatologist — Tue, 15 Jul 2008 00:21:12 +0000

Then you must love the illusion of globull warming. Stick to what you know best; astronomy. You know little about earth science.

By: Another Eric

Another Eric — Mon, 14 Jul 2008 21:56:46 +0000

Thanks a lot, now I can’t drive home for at least 15 minutes!!!

By: Michael L

Michael L — Mon, 14 Jul 2008 21:15:05 +0000

Blind spot is weird, which brings an astronomy question up: When looking at a star with the naked eye, why is it that if you turn your eyes slightly away, you will actually see it with more clarity, even being able to distinguish if it is actually a double star?

I used to know tha answer to this, but I have forgotten.

By: Michael L

Michael L — Mon, 14 Jul 2008 21:07:32 +0000

That “Eclipse of Mars was cool, but now I have a big glowing cyan spot in front of my eyes and can hardly see my keyboard.

By: Michelle

Michelle — Mon, 14 Jul 2008 20:36:46 +0000

http://www.skytopia.com/project/illusion/blind.gif

…Okay you know what? that blind spot one just freaks me out.

By: Michelle

Michelle — Mon, 14 Jul 2008 20:27:27 +0000

sweet! I love illusions! It’s so fun to… um, get a headache.

By: C Arnoldus

C Arnoldus — Mon, 14 Jul 2008 20:19:26 +0000

Oh great, now I have a huge cyan dot in the middle of my field of vision.

By: Kaptain K

Kaptain K — Mon, 14 Jul 2008 20:17:30 +0000

My head hurts!

By: Michael L

Michael L — Mon, 14 Jul 2008 20:14:25 +0000

Funny you bring this up, Phil. I was getting ready to have my breakfast toast this morning, and this popped out…

http://photos-a.ak.facebook.com/photos-ak-snc1/v263/63/94/701429991/n701429991_998584_8945.jpg

By: Cory Albrecht

Cory Albrecht — Mon, 14 Jul 2008 19:52:11 +0000

Oi. You goignto supply aspirin for that link, too? Still, it is way cool,

By: MattGS

MattGS — Mon, 14 Jul 2008 19:26:43 +0000

Uh, I love illusions, too. Some of them are quite hard on the eyes though … they shouldn’t have put all of them on one page, I think.

By: Caleb

Caleb — Mon, 14 Jul 2008 19:13:11 +0000

One of my favorites:
http://web.mit.edu/persci/people/adelson/checkershadow_illusion.html

I know that A and B are the same shade (using a digital color dropper to compare the hex values), but no matter how many times I look at it, my mind tells me A and B are difference shades.

By: Viewer 3

Viewer 3 — Mon, 14 Jul 2008 19:13:03 +0000

As long as they’re more impressive than that waste-of-time “audio illusion” you had a while back.

By: Ken B.

Ken B. — Mon, 14 Jul 2008 19:04:33 +0000

I really like the checkerboard shadow illusion. I saw a very similar one (probably linked to by you) at http://www.illusion-optical.com/Optical-Illusions/ChessboardShading.php but this one is much stronger. I had to load it into my photo editor to prove it to myself. I grabbed a section of “square” B and dragged it off the board, and it got darker as I moved it!

By: Jeremy Lusk

Jeremy Lusk — Mon, 14 Jul 2008 19:00:41 +0000

Wow, great link! I’ve been looking for something like this for a while now – and this is the jackpot.

Cheers,
Jeremy

By: Craig

Craig — Mon, 14 Jul 2008 18:49:14 +0000

Is that pronounced “sky-TOE-pia” or “sky-toe-PIA”?