Telescope Reviews: Re: Some tid-bits obout the 2.3x40 Owl eyes

Patric ,

Once again , no need to excuse your faulty English .

Your posts always make more sense to me than many of my own , when I read them over again :-)

I've had a theory for several years now with regard to the optical illusion of objects not appearing as magnified as they truly are .

When we see , naked eye , for example a HOUSE FOR SALE sign against the background of the windows of the house , which appear to be the same apparant size as the sign .

When we look at the sign through 10x binoculars , the background window is also magnified 10x , as is everything else in the field of view ( or at least approximately so )

This has the effect of neutralising the actual enlargement .

In my example , if we could just magnify the sign , and nothing else , then we would easily see that the sign appeared 10x larger .

It's all about perspective -- as in the famous horizon moon ( and setting sun ) illusion !

Now the moon , when NOT on the horizon , is actually one of the very rare exceptions to situations where the above perspective theory applies .

Usually , when we view the moon , it against only perhaps a few visible stars , which do NOT appear any LARGER when viewed through binoculars , but they DO appear further separated than they did naked eye .

In this case , we should revert to EASILY seeing that the moon , through 10x binoculars , appears 10x larger ( or closer ) -- BUT -- I , for one , do NOT !

To my eyes ( or rather via my brain ) I get the optical illusion of the moon , when magnified by 10x , APPEARING to be magnified by a factor as if dividing 10 by pi ( 3.142 ).

In other words , if I had to GUESSTIMATE the apparant size of the moon , viewed through binoculars which were truly 10x magnification , but the magnification of which was kept secret from me , whilst not permitted to compare with one eye naked and the other through an eyepiece , I would be inclined to GUESS that the magnification was 10 / 3.142 or 3.182x APPARANT .

All of the above , of course , is a great example of how many of my posts can appear far more nonsensical than any of YOURS , in spite of your supposed language disadvantage ! :-)

But - it was something to think about on a lazy , damp , overcast , windy sunday afternoon !

Kind regards
Kenny

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Two eyes and a preference to use both

Zeiss 7 x 42 BGAT
Captain's Helmsman 7 x 50
Nikon 10 x 42 Superior E
Swift Audubon Kestrel 10 x 50
Helios 15 x 70 Observation
Strathspey 20 x 90
Televue 76 APO
Zeiss 85 Diascope
Helios 102 f5 refractor
Various eyepieces barlows tripods mounts etc.
Panasonic Lumix DMC - TZ5 digital camera

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