Several of us have played with these pinhole long-exposure images following a presentation by one of our NASS members at a conference two years ago. The practitioners call this "solargraphy" although it should probably be called heliography so as not to mix Latin and Greek. The photos are expected to be somewhat funky with random defects and whatever false-color photoshop or painterly effects you feel like introducing.
While only tangentially related to sundials, this is a very accessible art form, requiring mainly an empty can some photographic film and a way of making a very fine pinhole. Ideally, the dimension of the pinhole should be a function of the focal length of the can's interior. Here are two that I did: The first one was taken from a rooftop terrace in Brooklyn. The second is a friend's house from across his pond. http://chezaubert.net/brooklyn2.jpg http://chezaubert.net/froggy2.jpg The sun tracks are really more of a secondary decoration than the point of the photos. Jack Aubert -----Original Message----- From: sundial [mailto:sundial-boun...@uni-koeln.de] On Behalf Of rmallett Sent: Monday, May 05, 2014 2:42 PM To: Bill Gottesman; John Foad Cc: Sundial list Subject: Re: Sun tracks On 05/05/2014 14:03, Bill Gottesman wrote: > Here is what I think: > The can is laying on its side with its axis oriented north-south. A > pinhole is made on the west side of the can (assuming this location is > in the northern hemisphere, and that the zenith of the sun is toward > the south), pointing upward at about 45 degrees. It captures the sun > before it has reached solar noon, then tracks it all the way to sunset > in the west. The tracks of the morning sun at the top of the picture > appear to converge; this effect comes from that edge of the film being > so close to can's the pin-hole, where all light rays converge at their > origin. (The film is wrapped around the inside of the can) > > -Bill More conventional sunrise to sunset six month pinhole camera solargraphs periodically appear at www.space-weather.com (and of course Google will find loads more) -- -- Richard Mallett Eaton Bray, Dunstable South Beds. UK --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
