Posts Tagged ‘sundials’

Diptics: Henry Moore Sundial Sculpture

January 23, 2012

The following gallery of four-panel diptychs features several photos of the Henry Moore Sundial Sculpture, Sundial Plaza, Adler Planetarium & Astronomy Museum, Chicago, Illinois USA. The sculpture is a type of sundial that is sometimes referred to as a “bowstring” equatorial sundial. See also an annotated photo of the sculpture that illustrates how a “bowstring” equatorial sundial is simply a reduced model of the Earth.

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Tech Tips: The preceding composite images were created using Apple “Aperture,” Adobe “Photoshop,” and “Diptic” app for Apple iOS mobile devices. For details, see “Advanced technique for creating Diptic ‘photo tiles’” (one of my recent Posterous posts). The border is five (5) pixels wide, rather than my usual preference of 10 pixels.

Copyright © 2012 Walter Sanford. All rights reserved. www.wsanford.com

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Diptics: University of Colorado Boulder

January 21, 2012

For more than a decade, I was actively involved with several K-13 education outreach initiatives of the American Meteorological Society. I was fortunate to be able to visit Boulder, Colorado USA for several in-service training workshops for science teachers. We stayed at Kittredge Complex, University of Colorado, for every workshop.

The following gallery of three-panel diptychs features several photos of the University of Colorado Boulder campus. Shown clockwise from the top: Kittredge Complex, with a spectacular view of the Flatirons in the background (part of the Front Range of the Rocky Mountains); the John Garrey Tippit Memorial Sundial, an equatorial sundial; and the Colorado Scale Model Solar System (notice my reflection and the Fiske Planetarium and Science Center behind me).

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Tech Tips: The preceding composite images were created using Apple “Aperture,” Adobe “Photoshop,” and “Diptic” app for Apple iOS mobile devices. For details, see “Advanced technique for creating Diptic ‘photo tiles’” (one of my recent Posterous posts). The border of Photos 1 and 3 is five (5) pixels; 10 pixels for Photos 2 and 4.

Copyright © 2012 Walter Sanford. All rights reserved. www.wsanford.com

Diptics: "Bowstring" equatorial sundials

January 19, 2012

The following gallery of four-panel diptychs features photos of two “bowstring” equatorial sundial sculptures: 1) the Robert Adzema Hyatt Regency Jersey City Sundial, Jersey City, New Jersey USA, a combination “bowstring” equatorial sundial, noon mark solar calendar, and horizontal sundial (shown in the two upper panels); and 2) the Henry Moore Sundial Sculpture, Sundial Plaza, Adler Planetarium & Astronomy Museum, Chicago, Illinois USA (shown in the two lower panels).

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Tech Tips: The preceding composite images were created using Apple “Aperture,” Adobe “Photoshop,” and “Diptic” app for Apple iOS mobile devices. For details, see “Advanced technique for creating Diptic ‘photo tiles’” (one of my recent Posterous posts). The border is five (5) pixels wide, rather than my usual preference of 10 pixels.

Photos © Copyright 2012 Walter Sanford. All rights reserved. www.wsanford.com

Lost & Found: Another Alexandria, VA USA sundial

January 17, 2012

The North American Sundial Society Sundial Registry listing for Virginia Alexandria Dial #253 says, “May have been removed; could not be located 8/2005. Contacted historical society 12/2008 to confirm placement but no reply.” I’m happy to report the sundial is in fact right where it’s supposed to be! Well, sort of. The Sundial Registry lists the location of Dial #253 as, “NW corner of King & Cameron St.” That is, in a word, impossible: Cameron- and King Streets are parallel streets, as shown by a zoomed-in map of Old Town Alexandria. The actual location of the vertical sundial is the corner of Cameron- and N. Washington Streets, as shown by a geotagged full-size version of the photo and verified by the following screen captures from Google Maps Street View: facing east along Cameron Street toward N. Washington Street; corner of Cameron- and N. Washington Streets; facing west along Cameron Street toward N. Columbus Street.

Alexandria Dial #254 is a horizontal sundial located at historic Christ Church on the opposite side of Cameron Street from Dial #253. The Sundial Registry listing for Dial #254 says, “Horizontal circular bronze dial appears to have been designed for 32 degrees N.” Read more about this issue in my last post, “Sundial at Christ Church, Alexandria, VA USA.”

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Picasa Web Album: Alexandria, VA Sundials

Tech Tips: All photos in the preceding slideshow were geotagged automatically by an Apple iPhone 4. Apple Computer does not support Adobe Flash on its mobile devices, so embedded slideshows from Picasa Web Albums (such as the one shown above) will not display properly on the iPod touch, iPhone, and iPad. For this reason, you may need to follow the hyperlink to the photo album, then click on the slideshow icon (shown upper-right corner). Learn more about Google Maps Street View. Locate the sundials using the following search string in Google Maps: “Christ Church Alexandria”

Sundial at Christ Church, Alexandria, VA USA

January 15, 2012

A horizontal sundial is located on the grounds of historic Christ Church in Old Town Alexandria, Virginia USA. The North American Sundial Society Dial Registry listing says, the “dial appears to have been designed for 32 degrees N.” In order to determine whether the sundial is in fact aligned properly, I examined a couple of photos that were geotagged by my Apple iPhone 4. (See “Tech Tips” for details, below.)

Similar to setting the correct time on an analog clock or wristwatch (by moving the hands of the timepiece into proper position), properly orienting a horizontal sundial will move the shadow of the gnomon (or style) into position so that the dial face displays the correct time.

  1. The dial plate should be horizontal.
  2. The shadow-casting edge of the gnomon should be parallel to the Earth’s axis, inclined at an angle equal to the latitude of the sundial.
  3. The tip of the gnomon should point toward the North Celestial Pole (i.e., Polaris, the North Star). More simply, the dial face should be aligned so that 12 noon points toward geographic north and the 12 noon hour line is aligned with your local meridian.

Photos 1-2 of 8 (shown below) verify that the dial plate is horizontal. Photos 3-4 show the gnomon is inclined at an angle of 31.86 degrees (~32 degrees); Photos 5-6 show the latitude of the sundial is 38 degrees 48 minutes 22.2 seconds. Photos 7-8 show the image direction is 218.4602 degrees, meaning the tip of the gnomon is pointing southwest rather than true geographic north (0, 360 degrees).

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Bottom line: The Christ Church sundial appears to have been made for another location and is aligned improperly for its new location. In other words, the sundial is strictly ornamental and will not tell time correctly.

Tech Tips: The iPhone Camera app works seamlessly with two built-in devices to geotag photos: the GPS sensor measures position on Earth; the digital compass measures “image direction.” PixelStick, an application for Mac OS X, was used to measure angles in one of the photos (see Photos 1-4, above). Apple “Preview” was used to display GPS info for both photos (see Photos 5-8, above).

Photos © Copyright 2012 Walter Sanford. All rights reserved. www.wsanford.com

Diptychs of Diptych Sundials

March 18, 2011

 

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Like “Drawing Hands,” the lithograph by M. C. Escher featuring one hand drawing another, I thought it would be interesting to create diptych photo collages using images of diptych sundials. Since I don’t have access to a collection of diptych sundials, I decided to take advantage of the laws related to intellectual property that allow liberal use of copyrighted materials for educational purposes: I repurposed several photos of diptych sundials from the National Maritime Museum for a mini-lesson on diptychs and diptych sundials. The diptychs (shown above) were created using Diptic app.

Terminology:

According to the Apple OS X “Dictionary” widget, a diptych is:

  1. a painting, esp. an altarpiece, on two hinged wooden panels that may be closed like a book.
  2. an ancient writing tablet consisting of two hinged leaves with waxed inner sides.

The British Sundial Society Glossary definition of a diptych sundial is as follows:

a portable (pocket) dial in which a vertical and horizontal dial are hinged together, and a common cord gnomon running between them also ensures that they open to a right angle [90 degrees]. [Diptych sundials are] latitude specific.

Related Resources:

Editor’s Note: I currently serve as chairperson of the North American Sundial Society (NASS) Education Committee. Educators interested in exploring ways to use sundials to enhance and/or enrich classroom instruction are encouraged to contact me.


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