Sundial at the Very Large Array made from parts of an old
radio telescope.
http://news.stanford.edu/thedish/2013/10/02/worlds-first-radio-sundial-dedicated-in-memory-of-ron-bracewell/
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https://lists.uni-koeln.de/mailman/listinfo/sundial
http://pollux.nss.nima.mil/calc/degree.html
this page will compute the size of a degree of
latitude and longitude
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I've been given an Aquitaine ring sundial. I'd like to
know how to compute one, but have been unable to
find information in my sundial book collection or
on any sundial web sites.
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For pinhole imaging, the optimal diameter of a pinhole
is one where the pinhole is the same size as the
diffraction disk it produces.
There is a calculator at:
http://www.mrpinhole.com/calcpinh.php
and a lot of information at:
http://www.pinholeresource.com/pinhole.html
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Amateur astronomers also deal with polar alignment when they have to
set up an equitorial mount. This is usually done with a low power
finder scope (6 to 8 power). If you can attach a finder scope to the
sundial, this would be much better than trying to align by eye.
Some finder scopes just
The photo-3d list people maintain a different list sell-3d for
commercial postings.
There's a web page on rainbows and halos at:
http://ds.dial.pipex.com/lc/atoptics/phenom.htm
Thomas Harvey posted a picture to the pinhole photography mailing list
of a sundial in Portland Oregon.
http://web.pdx.edu/~harveyt/USsundialPin.jpg
There's an 8 page article about sundials in the July/August issue
of Weatherwise magazine.
People on this list may be interested in the Moonstick
slide rule moon phase calculator.
www.moonstick.com
The normal procedure when photographing the sun is to use
a neutral density filter of density 5.0, which reduces the
light by a factor of 100,000. So even of you took a picture
a week through this filter, it's nowhere near the exposure
needed to register the foreground image.
The eye/brain is very good at seeing lines, and can see lines thinner
than the usual 1 arcminute given as the resolution of the eye.
20/20 vision is based on reading letters that are 5 arcminutes high
that have 1 arcminute features (line width and gaps). So this might
give you an idea of how big
Somebody was interested in the Sundicator. I've got one.
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