page_title: Astronomical rings
hierarchical_section_title: Astronomical rings
caption_attribution_description: Astronomical ring dial
context_page_description: Astronomical rings, also known as Gemma's rings, are an early astronomical instrument. The instrument consists of three rings, representing the celestial equator, declination, and the meridian.
  It can be used as a sun dial to tell time, if the approximate latitude and season is known, or to tell latitude, if the time is known or observed. It may be considered to be a simplified, portable armillary sphere, or a more complex form of astrolabe.
context_section_description: Astronomical rings (Latin: annuli astronomici), also known as Gemma's rings, are an early astronomical instrument. The instrument consists of three rings, representing the celestial equator, declination, and the meridian.
  It can be used as a sun dial to tell time, if the approximate latitude and season is known, or to tell latitude, if the time is known or observed (at solar noon). It may be considered to be a simplified, portable armillary sphere, or a more complex form of astrolabe.
caption: Diagram of astronomical rings (Johannes Dryander, Annulorum trium diversi generis..., published Marburg, 1537)
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