Collaborative Occultation Resources and Archive (CORA)

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Occultation events / predictions

(Start date, Format: yyyy-mm-dd or yyyy-mm or yyyy)
(Ende date, Format: yyyy-mm-dd or yyyy-mm or yyyy)
(If checked the date filter is active. Otherwise query the whole db date range)
(Longitude Latitude in deg (Lng. > 0 to the East) OR MPC code (XXX))
(Free name, just for the header. Optional)
(Show events with this minimum occultation probability 0-100% at observer site. See info below !)
(Show events with maximum altitude of the sun at observing site below this limit (for t0))
(If checked the site filter constraints are active. If unchecked => 'worldwide')
(Filter for object name: examples: (41), Pallas, 1997 RB7)
(Show events with object diameter larger than this)
(Show events down to this star magnitude)
(Just objects with selected tag)
(Sort resulting table according to this criteria)
(Select database with occultation events (see explanation at bottom))
(Depending on your input response may take some ten seconds!)

Basic information and usage

Usage: As quick start you only have to enter the latitude and longitude of your observing site in decimal degrees (long: + is east of Greenwich), seperated by a comma or space. Alternatively you can enter the 3-letter MPC station code (always in the form XXX, even for stations 000...099). In that case the site name will be taken from the MPC record.

Note P1: For asteroid predictions (db: asteroids) you can set minimum occultation probability at the observer site P1 to 50 or even higher to get just events close to your site. For CeTNOs and Comets you should set P1 very low (3-10), otherwise you will see almost no events as the probability in general is much lower for most of these occultations.The probability is computed using the distance of the site to the center line on the fundamental plane rather then on the Earth surface, thus it can be sometimes incorrect.

Occultation Databases

Asteroids: The main (default) database contains worldwide predictions of stellar occultations by asteroids (currently for about 2-6 months time span before a new run is made; otherwise the DB would be too large and it will take too much time to get the event list). Predictions are for asteroids (sometimes plus some special targets) with diam > 10 km and Gaia (e)DR3 stars brighter than G = 15 mag. JPL Horizons (JPLH) ephemerides are used by default.

CeTNOs: This database contains occultations by Centaurs (diam > 50 km) and TNOs (diam > 150 km) for the whole year. Gaia (e)DR3 stars brigther than G = 18 mag. JPL Horizons (JPLH) ephemerides are used by default.

Comets: A small list of numbered comets with expected diameter > 5 km (JPL SBDB). Currently ~25 comets. Gaia (e)DR3 stars brighter than G = 15 mag. JPL Horizons (JPLH) ephemerides are used by default.

Several other databases for special purposes or dedicated projects.