Doug DeHaven Items like this where needed before the prevalence of laser pointers we have today, these are mini handheld projectors, with a cute metal disk called a Gobo, with a light behind it and a lens to focus the small metal plate image onto the screen.
This unit was from an old planetarium, and was used by the presenters to point out the stars and star constellations on the dome!
Here is a video showing it in operation! ( Had to hunt down a replacement 12V incandescent light bulb for it!
Here are some closeup photos.
Here is the bulb I found close enough to work, and how it comes apart if you even happen to need to change the bulb in one!
Some History, These seem to be the first every design of this style of arrow projection, this model was designed for first use in the Adler Planetarium in Chicago by Curt Richter, who was prominent in cinema optics and projection.
“Electric Arrow Optical Pointer-The problem of illustrating public lectures at the Adler Planetarium prompted C. P. Richter to develop the Electric Arrow Optical Pointer which projects a white or red arrow on any surface from distances of 5-75 feet. The pointer, therefore, does not interfete with the view of the audience. It is constructed of light weight aluminum castings and operates on 110 volts A.C. or D.C. The Electric Arrow Optical Pointer is available from C. P. Richter, 2622 Farwell Ave., Chicago 45, Illinois.”
from page #111 in the below article.
https://scholarlycommons.law.northwestern.edu/cgi/viewcontent.cgi?article=4234&context=jclc
