Occultations by Trans-Neptunian Objects including Pluto, Charon, Hydra and Nix

Description of the maps

The maps, generated by Bruno Sicardy from predicitons of the RIO Team, contain a number of informations. This will give you a first of planning the observation.

Above the graphic, you will find

• Name of object

• Distance of the dots in the shadow in km and seconds

• Offsets used in in the predcitions in mas

Below the graphic you will find

• day, month and year of occultation

• UT time of occultation (big dot in the shadow)

• J2000 position of star in RA and DEC

• geocentric closest approach, in arcsec

• planet position angle wrt to star at C/A, in deg

• velocity in plane of sky in km/sec

• distance of occulting object to earth in AU

• R-Magnitude, corrected for velocity

• K-magnitude, corrected for velocity

• central longitude of the event

The magnitudes are corrected for the relative velocity in a way, that a movement with 20km/sec does not result in a correction. If the velocity is faster, the magnitude given is lower, because to get the same spatial resolution, you need a shorter exposure time. If it is slower, you get a fainter magnitude, because of the opposite effect. The slower the velocity is, the fainter stars you can observe keeping the resolution constant!