Cari Amici
(Dear Friends),
However, it was not
until Alhazen (nicknamed "Ptolemy
the Second”) that it was put together that the projected image
on the screen was actually the rearranged (upside down) image of the light from
the other side of the aperture (pinhole). Alhazen was a mathematician, scientist, and
astronomer who made many advances in optics.
He was even studying the magnifying power of a lens. Alhazan is thought to have died in Cairo,
Egypt in 1040 A.D.
Leonardo da
Vinci took his turn describing the optics effects and suggested their use by
artists as an aid in drawing. By the
mid-1500s, another Italian Giambattista
della Porta began publishing a series of books (“Magia Naturalis,” starting in 1558) about many topics, including the
use of a convex lens and he receives credit for having perfected the camera
obscura. He also explained in popular
terms how the lens of the eye was similar to the lens of the camera obscura,
increasing the latter’s fame.
While in Bristol,
England, last week, I got to see the famous Clifton Suspension Bridge: In person and on foot, but also, with a large
camera obscura! There is a nearby
Observatory that houses a camera obscura.
The building is 337 feet above the gorge and river below. Oddly enough, I took most of the images from
inside the Observatory near the bridge (vs. of the observatory itself), and the image of it was taken from the bridge. You will just see the tops of this building
that once was a snuff mill.
The mill suffered a
huge fire and lay dormant for decades until an artist, William West, rented it
as a studio in 1828. During his time
there, he installed the camera obscura that is still there today. The 5-inch convex lens and sloping mirror
project an image of the surrounding areas outside (including the suspension
bridge), but not a mirror image, onto a large white disk. I was surprised by how bumpy this surface
was.
When my friend Wendy
and I entered the tower room with the camera obscura and its projected image,
it was dark and there were two women and three children enjoying the
experience. Of course, the entire space
would have to be painted dark, with no other windows in order to clearly see
the projected image. I was surprised at
how sharp the image was and on a bright day it is said to be even better.
The Observatory
is listed on the “Buildings at Risk Register” by English Heritage. Perhaps the small donation is enough to keep
the doors open… or at least, keep a person employed for a bit. The Observatory also houses the entrance that
artist William West built to a cave that opens out on the face of the cliff
overlooking the gorge. We did not visit
that, preferring to do some plein air painting instead.
Follow these links for more information about the camera obscura in Bristol, England:
http://en.wikipedia.org/wiki/Observatory,_Bristol
http://visitbristol.co.uk/things-to-do/clifton-observatory-camera-obscura-and-cave-p24651
In general, the camera obscura information (ie, not just the Bristol c.o.):
http://en.wikipedia.org/wiki/Camera_obscura
http://brightbytes.com/cosite/what.html
Alhazen, mathematician and scientist interested in optics:
http://en.wikipedia.org/wiki/Alhazen
Giambattista della Porta, scientist who perfected the camera obscura and also invented a way to sneak messages to prisoners using eggs (mid-1550s):
http://en.wikipedia.org/wiki/Giambattista_della_Porta
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