The Sabian symbols are a set of 360 images, one for each degree of the zodiac. The term “Sabian” goes back thousands of years to Sumeria, where it’s thought that it referred to a tribe of Sun worshipers. You can view a more complete history of the origin of the term on the Sabian Assembly site.
Contemporary astrologers generally use a set of symbols elucidated by clairvoyant and Virgo, Elsie Wheeler (happy birthday, Elsie!), who in 1925 worked with Marc Edmund Jones to fashion a modern collection of images which could speak to a 20th century audience. Images such as airplanes, hospitals, schools, and more form a lexicon that was more accessible to astrologers of the day. Read a complete history of the Elsie Wheeler symbols on Lynda Hill’s site.
Metaphysicians have in fact been coming up with unique sets of degree meanings for thousands of years and continue to do so with an ever-widening set of techniques. David Cochrane, for instance, has derived a set of symbols based on theories of harmonic astrology in his work, Astrology for the 21st Century
Lynda Hill is by far the most renowned contemporary astrologer and writer integrating the Sabian symbols into her practice, and works with the degree meanings of Elsie Wheeler. I had the good fortune to hear her speak at the 2008 United Astrology Conference and was amazed at the many synchronicities she shares with Wheeler. Dena DeCastro recently conducted a great interview with Lynda about the symbols on her Evolutions of Astrology podcast.
The Sabian collages on this site are almost all drawn off of Elsie Wheeler’s symbols as presented by Dane Rudhyar in his work, An Astrological Mandala