Version 5.6

OccultWatcher

OccultWatcher is a free Windows program for asteroidal occultation observers. It tracks the occultation predictions published by many prediction feeds, finds the events that are observable from your sites, and lets you announce your stations so that observers around the world can coordinate their efforts.

The OccultWatcher main window listing upcoming events

What OccultWatcher does

Finds your events

Subscribe to the prediction feeds you are interested in and OccultWatcher will show the events that match your distance, star magnitude, magnitude drop, duration and other filters for your home and saved sites.

Coordinates observers

Announce a station for an event and see where other observers are going to be, so that chords can be spread across the predicted path. The "Planned Observations" feed shows every event someone has already announced a station for.

Helps you plan the night

Alerts and reminders for upcoming events, a shadow path plot with the predicted cloud cover at your home site for the next 3 days, and detailed information about the star and the asteroid, including double asteroids and past observations.

Reports your observations

Report your positive or negative observation directly from OccultWatcher, including for events that have already passed, and see the reported results of other observers.

Works with OccultWatcher Cloud

Events you add to My Events on OccultWatcher Cloud appear in OccultWatcher automatically, you can import your saved sites from it, and choose there which Community Tags you want to receive.

Extensible with add-ins

Draw star charts with C2A, open events in Occult and use the other add-ins, or write your own using Microsoft .NET.

Prediction feeds

OccultWatcher shows predictions computed on the cloud and also uploaded by feed maintainers and professional groups. You can also add your own personal predictions produced by Occult.

Observation Campaigns

Events that are currently part of an active observation campaign. They are available in OccultWatcher under the "Observation Campaigns" feed. See the current campaigns on OccultWatcher Cloud.

Lucky Star

Events from the Lucky Star project led by Bruno Sicardy at Paris Observatory. Converted to OccultWatcher format by Dave Gault, Australia.

Suspected Moons

Asteroids with a suspected, or suspected new, moon. Events selected by Dave Gault.

ACROSS

Challenging occultations by Near Earth Asteroids, supporting NASA's DART and ESA's Hera missions, including the asteroid Didymos. Run by Observatoire de la Côte d'Azur.

CBET Moons

Asteroids with confirmed or suspected moons. Events selected by Dave Gault and Peter Nosworthy.

GaiaMoons

Observing and characterising binary asteroids with stellar occultations. A collaboration between Paris Observatory (IMCCE), Observatoire de la Côte d'Azur (Lagrange) and Poznań University.

ESA JUICE

Occultations by Kallichore, a target of ESA's JUICE mission. Events selected by Jose L. Ortiz, Yucel Kilic and Juan Luis Rizos, Instituto de Astrofísica de Andalucía, Spain.

RECON

The Research and Education Collaborative Occultation Network at the Southwest Research Institute, measuring the sizes of cold classical Kuiper Belt Objects.

New style predictions

Community Tags

Events tagged by OccultWatcher community members as being of interest. Choose which tags you receive from your OccultWatcher Cloud user profile.

Planned Observations

All events for which someone has already announced a station, from any feed, even if you are not subscribed to it.

Old style predictions

IBEROC

All kinds of occultations visible from the Iberian Peninsula, the Balearic and Canary Islands and parts of north-west Africa. Maintained by Carlos Perelló.

UKOCL

Occultations for the United Kingdom and Ireland, many of which also cross mainland Europe and Scandinavia. Maintained by John Talbot.

NA Low Mag

North America events of 50km+ asteroids with combined magnitudes of near 11 to not less than 12.9; many have a magnitude drop <1. Maintained by Steve Messner.

Comet Occultations

Occultations involving comets. Maintained by Carlos Perelló.

Other

Planet Satellites (SatWatcher)

Occultations and eclipses involving the satellites of Jupiter, Saturn and Uranus. Maintained by Hristo Pavlov, Australia.

The OccultWatcher family

OccultWatcher Cloud

Search events, manage your sites and My Events, follow observation campaigns and community tags from any browser. cloud.occultwatcher.net

OccultWatcher Mobile

Your events, sites and reminders on your phone, using the same OccultWatcher account. OccultWatcher Mobile help

New to asteroidal occultations?

These online resources are a good place to start:

  • IOTA - International Occultation Timing Association
  • IOTA-ES - International Occultation Timing Association, European Section
  • IOTAoccultations - the IOTA discussion group
  • RASNZ Occultation Section - Australia and New Zealand occultation observers
  • Occult - Windows software by Dave Herald for predicting and reducing asteroidal occultations and many other phenomena
  • asteroidoccultation.com - asteroidal occultation predictions by Steve Preston

Requirements

Software

  • Windows 10 or Windows 11
  • Microsoft .NET Framework 4.5 or later (included with Windows 10 and 11)

Internet connection

Needed to download predictions from the feeds and to announce stations. Any connection that can display Google Maps without long delays is enough.

Account

OccultWatcher and an OccultWatcher account are free. You need an account to announce stations, report observations and use OccultWatcher Cloud.