re:homescope

[P3D Elliot Burke <elliotb@xxxxxxxxxxxxx>]

>        recently at an antique store I saw a small device called a
>Homesscope.  It was not typical 3-d but gave interesting results.
>Basically, it appeared to be a small wooden case with a small parabolic
>mirror (or concave perhaps) on the inside.  When the case was opened, one
>could place a picture postcard opposite the mirror and then, when one
>looked over the postcard into the mirror, the angle of the mirror gave a
>sort-of three dimensional effect.  The ordinary postcard seemed to have
>depth.  Has anyone seen one of these before and can anybody suggest a
>price?

These are referred to as biocular viewer, both eyes share a large exit pupil.  The 
simplest form is a makeup mirror: a concave mirror of large enough diameter and focal 
length of 12-18" or so. An object near the focus of the mirror can be seen with both 
eyes.  Appropriately focused there will be an erect virtual image with a reasonable 
amount of convergence.

It is a dramatic effect, but can't be used to make too much magnification.

Elliot Burke
HighTide Instruments
elliotb@xxxxxxxxxxxxx


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