The Dent Dipleidoscope now offered on live auction appears to have a
curious hole or similar detail in the center of the removable round
cover; none of my Dent dipleidoscopes has such a hole in the cover and I
have never seen another one that does. I don't know what that detail
actually is nor its purpose. It could be an "aftermarket" modification!
You surely want the large area of the dipleidoscope exposed when you
place your head to observe the dipleidoscope image.
I have an original printed Dent booklet, with its included tables of
solar noon offset. This booklet is, of course, printed in black and
white. While it does include a drawing depicting how solar rays are
reflected within the dipleidoscope optics, understanding the ray paths
as shown and how they are used is difficult! In my presentation to NASS,
I expanded this drawing with labeled color line paths to help explain
the operation. Once understood, the dipleidoscope is a really simple
instrument!
Attached is a thumbnail image of the demonstration device I used to
depict the image seen in a Dent Dipleidoscope as solar noon approaches.
As I titled my presentation, the Dipleidoscope is a Sundial by Another
Name...
Larry McDavid
NASS Registrar
On 10/31/2014 9:44 AM, [email protected] wrote:
A copy of Dent's booklet on the use and design of the Dipleidoscope is
available on line from Google Books at:
http://books.google.com/books?id=9QlbAAAAQAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false
Dave
Sent from my iPad
...
--
Best wishes,
Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)
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