Talk:Haidinger's brush

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Hm, I cannot see the simulated Haidinger effect in the current Wikipedia simulation picture. --Abdull 11:19, 5 August 2006 (UTC)

It's there. It's in the center of the picture, in the white area to the left and slightly above the word BROWSE, oriented with the yellow brush vertical.

The real Haidinger effect is pretty hard to see (are you able to see it?) and so is the simulated effect. It's likely that it's more or less visible depending on your monitor settings. Dpbsmith (talk) 13:57, 5 August 2006 (UTC)

It is very subtle. I generally cannot see it straight-off, but if I look at a blank white LCD screen and tilt my head from side to side, I notice the brush pattern moving with the motion of my head. I can see the yellow nodes quite clearly, but the blue nodes aren't quite as clear. --Mdwyer 22:22, 5 August 2006 (UTC)

Thank god for this article! I was about to RMA my monitor! --Generalmiaow 22:58, 24 October 2006 (UTC)

Can we add the size Haidinger's brush takes up on ones field of view? I calculated about 3 degrees for the yellow part and me, but I'm not sure if I'm even seeing that thing properly. Comments? Peter S. 17:16, 2 June 2007 (UTC)

How do you see this brush? Is it everywhere on the screen? --HappyCamper 17:37, 2 June 2007 (UTC)

I can also see it more readily by popping my glasses on and off. Perhaps this is made more prominent by the high degree of astigmatism in my vision. algocu (talk) 22:51, 14 February 2008 (UTC)

[edit] Sublety not effective

I have been able to see this effect for some time now, both in the sky and on LCD displays, after an article about it appeared in Sky and Telescope magazine. I am also an "expert" video observer. Even on my properly-adjusted display, the "Simulated appearance of a computer screen" is impossible to discern -- the actual effect is, in fact, more easily visible. For that reason, I recommend removing it or exaggerating it to become more visible. algocu (talk) 22:49, 14 February 2008 (UTC)

[edit] Xantophylla is the responsible of the Brush...

I think that a very important thing to point out is that H's brush is mainly due to xantophylla visual pigment. Human vision in based upon four visual pigments: lutein (viz xantophylla), heomoglobine, ferrohemoglobine and ferrihemoglobine. The first one has three particular features we are interested in:

1) absorbs in the blue range of spectrum 2) Has a very anisotropical shape (it's a rod...); radiation stimulates both electronic states and

  molecular vibrational states, which are mainly disposed along with the molecule direction. That
  means that xantophylla is sensitive to the polarization of the light.

3) Xantophylla pigments tend to be parallel to visive nerves; these, because of the fact that fovea

  is not flat, are almost orthogonal to the fovea in its central part, and nearly parallel in its
  outern region. This means that two different areas of the fovea are mainly sensible to two different degrees of polarization.

Point 1) tells us that H's brush should be visible in the blue/violet spectral range.

If you think we should fix all this, please tell me; I can provide sufficient bibligraphy, too (Raman's peapers about visual perception)--CAPITANEVS (talk) 22:15, 25 April 2008 (UTC)