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International Sunbeam and Shadow Project
“Sun 45 Equi-umbra”

-since 2009 International Year of Astronomy
Sun-Earth Connection: Science, Culture and Heritage Care

 
sun
Equiumbra Sun 45 Sundial
When: height=length
Sun Altitude = 45 degrees
sunbeam box
Equi-umbra Sun45 Sunbeam Box
When: hole height - spot height = length
 Sun Altitude = 45 degrees
 
 Summary

Following the Sun without looking at it directly.
Using simple ancient methods

  • from midwinter to midsummer solstice or vice versa
    as the sun appears to move from North to South.

  • in places of different latitude from North to South across the World.    
Comparing observations with the latest scientific
predictions.

Activities:

    • Construct (quickly, easily and cheaply):
    • a circular sun 45 sundial (a vertical post surrounded by a horizontal circle )

    • a sunbeam box (a rectangular cardboard box with a hole in the end)

  • Observe the sunbeams and shadows on different days and at different times, as autumn and winter approach in the northern hemisphere and spring and summer in the south.

  • Record the time and the date when the sun is at, or near, an angle of 45 degrees (Equi-umbra) in the morning or in the afternoon and, if possible when this occurs at midday.

  • Obtain the latitude and longitude of the place, the local time and the time at Greenwich.

  • Compare notes of the dates and times with the latest sun information from the internet.

Possible Additional Activities:

  • Construct a simple and safe sun inclinometer and/or a shadow plumbline.

  • Look for unintentional (casual) sundials (flagpoles, posts, monuments, buildings etc) locally and using the internet.

  • Collect related photos from magazines etc. and from the internet. which contain indications of the direction in which they were taken, and where the latitude and longitude of the place and the date and time are known or can be found.

  • Compile a group, or personal, sun diary (almanack) containing local information (maps etc) together with sun 45 information and related images for different days of the year.

  • Learn more about the sun and its role in the development of clocks and calenders, in culture, in navigation, surveying, climate change and health

  • Investigate the possibility of constructing sun45 dials in public spaces

Arriba © Ciencias y Artes Patagonia, 2009 last update :090515