Welcome to OpenAstronomyLog, a free and open XML schema definition for all kinds of astronomical observations. Software that supports this schema enables an observer to share observations with other observers or move observations among software products.

The schema (formerly known as COMAST schema) was primarily developed by the German "Fachgruppe für Computerastronomie" (section for computerastronomy) which is a subsection of Germany's largest astronomy union, VDS (Vereinigung der Sternfreunde e.V.) Starting with version 2.0 the schema was renamed from COMAST (abbr. for Computer Astronomy) to OpenAstronomyLog, or <OAL>.

The schema is released under the APACHE Software License 2.0 and is currently supported in both open source and commercial software. The complete schema is available in the Downloads section.