Occultation event with (12242) Koon, event index number 5160
Regions able to see the event: Australia
Geocentric closest approach at 2026/12/10 13:14:38 UTC
J2000 position of star is 06:01:45.0 -03:23:59
Equinox of date position of star is 06:03:05.7 -03:24:05
Star is 149 degrees from the moon. Moon is 2% illuminated.
Stellar brightness G=15.2, apparent brightess of occulting body is G=16.0
Use an exposure time of 0.45 seconds with the standard RECON-QHY system.
SNR of 5.1 per integration for unocculted signal
Expected flux drop is 67% with SNR of 3.4 for the occulted depth (per occulted point)
Apparent velocity is 19.1 km/sec on the sky relative to the star, or, 21.2 arcsec/hr.
Position angle of asteroid motion is 68.9 degrees
The recommended exposure time corresponds to 8.6 km per image.
The 1-sigma error in the time of the event is 0.1 seconds.
The 1-sigma cross-track error in the shadow position is 33.3 km.
The sky-plane scale is 3238.6 km/arcsec.
Diameter estimates:
39.8 km assuming a 5% albedo, maximum of 2.1 sec for a central chord
16.2 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 37.9 km used for deployment plan.
Star training set for 12242_Koon, (2026/12/10 13:15UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.9 +07:24:35 0.4 10.93 159 Saiph 05:49:02.1 -09:39:43 2.1 7.17 142 PPM 188676 06:01:24.3 -03:04:31 4.7 0.53 149 PPM 188692 06:02:18.6 -03:24:36 8.5 0.20 149 12242_Koon 06:03:05.7 -03:24:05 16.0 149 Positions are for equinox of date
Star training set for 12242_Koon, (2026/12/10 13:15UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 10.93 159 Saiph 05:47:45.4 -09:40:11 2.1 7.17 142 PPM 188676 06:00:03.4 -03:04:29 4.7 0.53 149 PPM 188692 06:00:57.9 -03:24:32 8.5 0.20 149 12242_Koon 06:01:45.0 -03:23:59 16.0 149 Positions are for J2000