Sun Angle Calculator-the 1951 original!

Item Details

Toledo, Ohio, Libbey-Owens-Ford Glass Company, 1951

VG

The very first commercially available solar tool designed for solar architects & engineers, who, in the mid-twentieth century, were pioneering the potential use of solar energy in modern homes, though they still saw it as a “supplementary” source of energy, providing more heat in the winter & designing windows to best control the sun’s heat in the summer & save on air conditioning. Designed to alleviate the need to make mathematical calculations, the calculator was promoted as a quick tool to demonstrate to clients how to "get the amount of sun they want, where & when they want it" with the proper home design. The device allowed them to directly read the projections of the sun’s rays with reference to buildings, using the calculator, comprised of 4 stiff plastic 6” x 6” squares attached in the center with a gold-colored screw, along with a plastic dial/pointer that could spin to reveal the “true altitude angle.”  It was compactly housed in a tri-fold envelope along with a 31-page booklet of instructions, “How to Use the Sun Angle Calculator.” Created by physicists & mathematicians at the Libbey-Owens-Ford glass company, in consultation with practicing architects & engineers, & manufactured by Aeronautical Services, Inc. (Washington, D.C.), selected for their expertise in the field of navigation introduction.

Condition is VG: blue paper wrappers are clean, with creasing at corners & slight tearing at lower spine/rubbing to all extremities. The sturdy silver snap clasp is secure & fully functional. The interior contents are FINE: booklet is pristine, appears never opened, & plastic calculator is clear with no yellowing, central screw mechanism moves easily, but is completely secure. One sheet order form is Near Fine, with a tad of very shallow folding to one long edge. There are 2 sheets, each 16" x 16", that fold in quarters: Appendix III: Chart for Determining Direct Solar Energy; Appendix IV: Chart for Determining Sky (Diffuse) Energy. These are both Fine: flawless & apparently never unfolded. Appendix I & II are bound into the booklet--nothing is missing!

WorldCat lists 19 copies worldwide of the instructional booklet only: 0 of the complete set. Later versions from the 1970s are available in the trade, but none of this First Edition located (7/25).

 

 

 

• “Solar House History” blog, 2013. Anthony Denzer