The Omnidoxical Encyclopaedia of Astronism is a post-disquisitional segment of the Omnidoxy within the Appendix of the Omnidoxy as part of the Original Omnidoxical Series solely written and organised by Cometan and published by the Astronist Institution. The Omnidoxical Encyclopaedia of Astronism provides an extensive series of encyclopaedic entries of one hundred of the most important beliefs and terms that emerged out of the Omnidoxy in relation to Astronism.
 
These encyclopaedic entries consist of a few paragraphs each exploring the meaning of the term in question, its position in Astronism, often considering its significance in relation to other terms and beliefs. The Omnidoxical Encyclopaedia of Astronism constitutes the first encyclopaedic reference guide to Astronism and its categorisation within the Omnidoxy provides it within even greater significance and authority.