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Pilkington Sun Angle Calculator (SAC)

Assembly of Sun Angle CalculatorsThe former LOFSAC (Libbey-Owens-Ford Sun Angle Calculator) is available again! This handy tool provides a relatively simple method of determining solar geometry variables for architectural design, such as designing shading devices or locating the position of the sun relative to a particular latitude and time. The Sun Angle Calculator is a quick and accurate tool and has been used extensively by educators, researchers, and design professionals for the past 50 years. Permission to reproduce and distribute the Sun Angle Calculator has been provided by Pilkington to the Society of Building Science Educators (SBSE). The Sun Angle calculators are now printed on a high quality styrene and have a nylon screw and nut for quick assembly (no more chasing the little brass screws all over the lecture hall!).

Contents of the Pilkington Sun Angle Calculator

Each Pilkington Sun Angle Calculator contains the following items, which will be sent to you for collation and assembly:

  • Sunpath charts for 24, 28, 32, 36, 40, 44, 48 and 52 North latitudes
  • 1 profile angle (red) overlay
  • 1 equidistant altitude cursor
  • assembly screw and nut

Please note that the instructional manual for the Pilkington Sun Angle Calculator is not included with the above package, but is available on the World Wide Web (see below).

The Libbey-Owens-Ford company was acquired in 1986 by the largest global glass manufacturer, Pilkington, and is now referred to as Pilkington North America (PNA). No portion of the Sun Angle Calculator package (including the manual) may be reproduced, translated, or transmitted in any form or manner by any means -- including but not limited to graphic, electronic, and mechanical methods without explicit written consent from Pilkington.

Please note that the daylight availability overlays were too numerous to reproduce, but are available in the appendices of Fuller Moore's book Concepts and Practice of Architectural Daylighting (Van Nostrand Reinhold Company, 1985).  Please see external reflected component dot charts B-10 to B-18, and Appendix C: Exterior Illuminance Overlays.

Order Your SAC Today!
Pilkington Sun Angle Calculators are available for purchase at the following price structure:
A. Quantities of 1 to 5: $28/each
B. Quantities of 6 or more: $24/each
C. Bookstores only: $20/each (with your institutional account number for UPS or FedEx or a pre-paid shipping authorization for same. Each Pilkington Sun Angle Calculator contains the items noted above, which will be sent to you for collation and assembly and suggested shrink wrapping.)
Prices includes shipping and handling via USPS within the continental U.S.
Please call CERES at (765) 285-1135 to arrange Alaska, Hawaii, international, expedited, or bookstore orders. Please note SBSE cannot process returns or replacement parts. If ordering for a class, faculty are requested to place a single order to expedite the process.

Ordering information

Sun Angle Calculators must be ordered using the link below:

Important! Orders will no longer be accepted over the phone, by fax or via email. All orders must be processed through the online system.

Payment may be made via credit card only (Discover, MasterCard or Visa only). You will receive confirmation of your order via e-mail once your credit card has been processed. Your order will then be shipped.

If you have questions regarding ordering contact:

Office of the Director / CERES
Ball State University
Phone: (765) 285-1135 [8:00am - 5:00pm EST, Monday - Friday]

Fax: (765) 285-5622

Instruction Manual
The instructional manual that accompanies the Sun Angle Calculator -- "Designing with the Pilkington Sun Angle Calculator" -- is now available in electronic format and may be downloaded. Download PDF Manual (1.8 MB)
Update for magnetic variation. Download Magnetic Variation PDF (200 kb)

Plot Your Own Sun Path Charts
The University of Oregon Solar Radiation Monitoring Laboratory developed a sun path chart program that is a very handy resource! Just put in latitude and longitude or zip code for U.S. locations, time zone, and it prints out a pdf!  Contact Lab Director Frank Vignola <> for further information.

SBSE: Society of Building Science Educators, 2014
Comments about this page can be sent to Martha Bohm