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Occultations
A simple visual event can become a precise astronomical measurement when observers record it accurately.
What is an occultation?
An occultation occurs when one celestial body passes in front of another from the observer's point of view. For IOTA observers, the most useful events include stars occulted by asteroids and stars occulted by the Moon.
Why observe?
The disappearance and reappearance times define a chord across the occulting body's silhouette. Observations from multiple sites can be combined to reconstruct asteroid profiles and improve orbital information. Particularly precise observations may also reveal double stars or unexpected structure.
How to begin
- Choose a prediction.Find an upcoming event with a shadow path accessible to your location.
- Prepare equipment.Use a suitable telescope, detector and a reliable time reference.
- Observe the event.Record continuously around the predicted time and keep complete site/equipment notes.
- Reduce and report.Determine event timings and submit the observation in the accepted IOTA report format.