A Fibre Optic Vertical Illuminator for Stereo Microscopes
by Ian MacGregor, Burnaby, BC, Canada
One of the problems with ordinary stereo microscope illuminators is that you cannot light deep recesses, or in my case, the bottom of an arrowhead socket. Photo 1 is a typical end view of an Early Iron Age ( ca. 300 BCE ) bronze arrowhead illuminated by a regular ring light ... basically you are looking into a black hole where the majority of details are hidden in the shadows.
Photo 1: Typical end view of a deep arrowhead socket using a ring light.
What is needed is an vertical illuminator, so I constructed this attachment to fit over the objective of my stereo 'scope There is nothing new about this type of illuminator but they are rare on the used microscope parts market. This design proved to be a very simple machining job and inexpensive to make.
Photo 2: Top view of the vertical illuminator
Photo 3: Bottom view of the vertical illuminator showing the 5 mm 45 degree prism that directs the light beam 90 degrees downward.
Photo 4: The vertical illuminator in operation. When the prism holder is positioned properly, it is invisible in the field of view.
Photo 5: Those details in the dark are revealed after 2300
years! Shiny black deposits adhere to the socket's internal wall of the arrowhead pictured in Photo 4
and they may be remnants of pitch used for hafting.
As far as I know, no one has ever reported this find in the academic literature ..... probably because they never looked or if they did, they didn't have a vertical illuminator. Please feel free to e-mail me, Ian MacGregor , if you any questions or comments.
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