Astronomy: Optical Illusions, eye physiology and psychology

The Moon Illusion• Effect: the moon APPEARS larger when near the

Horizon

• Effect: the moon APPEARS larger when near the Horizon

•Cause 1: Objects appear larger when seen in conjunction with a VANISHING POINT

The Moon Illusion

Cause 2• Our Mind tries to “flatten” the sky above

us, • So that we feel like the moon is closer

when above than on the horizon• Based on a lifetime of CLOUD

observations

•Cause 3: – Horizon has OBJECTS to

COMPARE to the moon’s size

The Moon Illusion

The visual environment can TRICK the Brain.

Ebbinghaus Illusion.

OPTICAL OPTICAL ILLUSIONSILLUSIONS

•TRICKS OF THE : LIGHT / EYE / MIND

TYPE 1TYPE 1•PROXIMITY Illusions–When seen in the right environment, size and direction can become mentally distorted

Müller-Lyer illusion

Hermann grid illusion

Scintillating grid illusion

Scintillating grid illusion

LateralInhibition-Your brain is trying to increase the CONTRAST of the image, and falsely concentrates the eyes, signals

café wall illusion

café wall illusion

Poggendorff Illusion – which color does the black line intersect?

White's Illusion – How many shades of grey here?

Cornsweet illusion

MACH Bands

VECTORIAL DOT CURVATURE ILLUSION

Zollner Illusion

NOW,READTHIS

“Forced Perspective” ToningGives illusion of movementMind interprets Dark=fartherLight = closer

Illusory Motion

Fra

ser S

pira

l

“FALSE BENDING”

If Straight Lines pass by an intensifying image,the brain will Either

“PUSH” the line out

Or “PULL” the line in

Jastrow Illusion – these are the same size

TYPE 2VISUAL IMPOSSIBILITES & FORCED PERSPECTIVE

The mind EXPECTS to see certain things, and objects can be drawn to Break those rules

• Front of the cube or Back of the cube?

Blivet

Ambihelix

TYPE 3•GESTALT / WHOLE PICTURE Illusions

•The mind can be focused on one image at a time, but recognize multiple images or composites.

Kanizsa Triangle

• Ready?...

Do you see a musician or a girl's face?

• Ready?...

• Ready?...

• Ready?...

old man's face or two lovers kissing?

• Ready?...

Old General orOld man and Young Mother at the Gate

• Ready?...

Buy a poster!

Don QuixoteNear and Far

• Ready?...

• Einstein or Marilyn?

“hybrid imaging.” 

Looks like Ex-President Bill Clintonand his Vice President Al Gore, right?Wrong... It's Clinton's face twice, with two different haircuts.

How many Wolves do you see?

Scintillating grid illusion

EYE Physiology

Light receptors at the back of your eye absorb photons + Convert into brain signals.Rods – Basic Light receptorsCones – Color Differentiation.

Both dependant on blood flow/Distribution and translation of Image to electrical signal

EYE FUNCTION• Given prolonged exposure,

the eye tries to compensate to the same types of photons on the same cells.

EYE FUNCTION• Given prolonged exposure,

the eye tries to compensate to the same types of photons on the same cells.

BRAIN COMPENSATION

Your brain will get used to a pattern of movement,And adjust its perception so that movement is “stable.”When that pattern is removed, your brain will perceive stillnessAs moving

The Skin-Crawling Spiral

The Skin-Crawling Spiral

The Skin-Crawling Spiral

“DEPTH” Vision•“3-D” vision can determine what objects are near vs. far away.

•To do this, your brain takes the info from 2 eyes and compares the differences.

http://www.jedisimon.com/optical_illusions_by_jedi_simon.htm