ILLUSTRATIONS & OBSERVATIONS
ABOUT THE "MOON ILLUSION"
"Believing is Seeing"
 
MOON ILLUSION: Illusion claimed to exist that moon near or on the horizon looks "larger" than the moon we recall seeing high up in the night sky on other occasions.
This illusion has been reported for thousands of years by various cultures. Usually attributed to clues or perspective from objects seen on horizon [causing a realization moon is further away than we thought -- therefore, to be that size of a circle in our eye and be that far away, it must be larger than we thought.] The realization causes us to "see "what we realize, or a "believing is seeing" illusion.
 

 
The illusion above (which I modified from the Ponzo illusion, shown later below) seems to work (mildly) based on the amount of area surrounding the circle -- the more area, the smaller the circle will seem by comparison. The zenith moon may seem small compared to the vast expanse of sky area surrouding it..
But when I substitute moons in place of the circles, then this is the view:

The illusion above no longer seems to work. Both moons seem equal sized. No reason for it comes to mind. So I decided to go back to the original Ponzo illusion (just below).