Stanford Solar Center
About the SunFor StudentsFor EducatorsSpace Weather Monitors
Ancient ObservatoriesSolar FolkloreSolar Art & Literature

Viewing and Understanding the Analemma

Photographs by Anthony Ayiomamitis

What is an analemma?

If you looked at the Sun at the same time each day, from the same place, would it appear at the same location in the sky? If the Earth were not tilted, and if its orbit around the Sun were perfectly circular, then, yes, it would. However, a combination of the Earth's 23.5 degree tilt and its slightly elliptical orbit combine to generate this figure "8" pattern of where the Sun would appear at the same time throughout the year. The pattern is called an analemma.

The Sun will appear at its highest point in the sky, and highest point in the analemma, during summer. In the winter, the Sun is at its lowest point. The in-between times generate the rest of the analemma pattern. (See Analemma Curve.) Analemmas viewed from different Earth latitudes have slightly different shapes, as do analemmas created at different times of the day. Analemmas on the other planets have different shapes entirely!

Learn more about analemmas and the associated Equation of Time.

Click on each image for more details

08:00:00 UT+2
Jan 12/02 - Dec 21/02
Tholos,
Ancient Delphi, Greece
Larger image (78K)

12:28:16 UT+2
Jan 12/02 - Dec 21/02
Parthenon,
Athens, Greece
Larger image (43K)

16:00:00 UT+2
Jan 07/03 - Dec 20/03
Temple of Zeus,
Ancient Nemea, Greece
Larger image (163K)

10:00:00 UT+2
Jan 07/03 - Dec 20/03
Hephaisteion,
Athens, Greece
Larger image (194K)

15:00:00 UT+2
Jan 07/03 - Dec 20/03
Erechtheion,
Athens, Greece
Larger image (158K)

09:00:00 UT+2
Jan 07/03 - Dec 20/03
Temple of Apollo,
Ancient Corinth, Greece
Larger image (160K)

Why are Analemmas Hard to Photograph?

The analemma is considered one of the most difficult and demanding astronomical phenomenon to image. because it is never present all at once. It requires a a virtual image made at the same time of day on 30 to 50 days throughout the year.

The analemmas on this page were completed by Anthony Ayiomamitis of Greece (http://perseus.gr), in a marathon started in 2001 to document the complete range of analemmas from sunrise to sunset. These photographs are unique in representing the first analemmas ever imaged during a single calendar year and the first analemmas ever imaged in Greece.

The photographer first attached a filter to his camera to block out the extreme light coming from the Sun. This filter also blocks any light coming from the Greek ruins nearby, so only the Sun shows on his film. Then he went to exactly the same spot, at exactly the same time of day, throughout the year, and exposed the same film to the Sun each time (multiple exposures). He made one final trip to take a picture of the Greek ruins, this time without the filter and without the Sun in the sky.

More information about Conquering the Solar Analemma Challenge.

Where Can I Find Out More About Analemmas?


 

Home · Request Solar Posters · Site Map · Glossary · About Us · Contact Us
©2008 by Stanford SOLAR Center · Permitted Uses · Credits