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Speaking
of the "dark room" photograph effect, I discovered I had the
camera obscura effect, but I didn't know what it was at first.
The difficulty came from the small size (only 3/16"
approximately) of the sun spot on the target paper. I noticed
what only appeared to be a couple of small lines in the spot.
Their orientation changed as the day progressed. It wasn't until Bob Kellogg added the paragraph noting that the pinhole turns the virtual image of the scene (including the sun's disk) into a real image -- as in a camera obscura -- that I understood. What I was seeing was a tiny image of the scene that included the dark lines of the gazebo's roof in addition to the brightness of the sun. On 2/16/2012 3:28 PM, ruben nohuitol wrote: If it's usefull for you the pinhole of my analema (on the roof) is 3/16" which hapened to be very good. Let me tell you that, today, feb 16, even when is partially clouded, the sun beam went into the room, making a "dark room" photography effect, thus, even when the direct mark was 1 1/2" in the floor, the round spect formed for this spect, was fifteen inches, allow us to see the clouds around the sun, moving fast and fascinating.www.ruben.mx --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial |
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