Cora»Occultations

Occultation events / predictions

Start Date:		(Start date, Format: yyyy-mm-dd or yyyy-mm or yyyy)
End Date:		(Ende date, Format: yyyy-mm-dd or yyyy-mm or yyyy)
Date filter:		(If checked the date filter is active. Otherwise query the whole db date range)
Site Coord:		(Longitude Latitude in deg (Lng. > 0 to the East) OR MPC code (XXX))
Site Name:		(Free name, just for the header. Optional)
Min P1:		(Show events with this minimum occultation probability 0-100% at observer site. See info below !)
Max Sun:		(Show events with maximum altitude of the sun at observing site below this limit (for t0))
Site filter:		(If checked the site filter constraints are active. If unchecked => 'worldwide')
Object:		(Filter for object name: examples: (41), Pallas, 1997 RB7)
Min Diam:		(Show events with object diameter larger than this)
Max Smag:		(Show events down to this star magnitude)
Sso tags:		(Just objects with selected tag)
Sort by:		(Sort resulting table according to this criteria)
Occ db:		(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.

Min P1: For asteroids, a high P1 (~ 50% or more) filters events close to your site. For CeTNOs, Comets, PHAs, and NEOs, use a much lower P1 (~ 3-10% or less), as their probabilities are generally small(er). P1 is computed on the fundamental plane, not on the Earth’s surface, so it may be imperfect. If too few events appear, lower P1 or disable the distance filter.

Occultation Databases

Asteroids: The main (default) database contains worldwide predictions of stellar occultations by asteroids (currently for about three 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 DR3 stars brighter than G = 15 mag.

CeTNOs: This database contains occultations by Centaurs (diam > 50 km) and TNOs (diam > 150 km) for the whole year. Gaia DR3 stars brigther than G = 18 mag.

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.

NEOs & PHAs: Contains those objects listed in the corersponding MPC files NEA.txt and PHA.txt. These DBs are seperated, but overall are a subset of the Asteroids DB.

Several other databases for special purposes or dedicated projects.

Orbits and ephemerides: JPL Horizons (JPLH) ephemerides are used by default. CORA bulk ephemerides, which are also high precision due to a sophisticated integrator and dynamic model, use astorb.dat elements (Moskovitz+2022) and are indicated by "PEE+ASTORB(epoch)" as the orbit reference. CORA's own orbit solutions are indicated by "CORA+some version indicator".

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