Occultation event with (12242) Koon, event index number 4370
Regions able to see the event: Australia
Geocentric closest approach at 2026/10/09 17:54:35 UTC
J2000 position of star is 06:16:50.6 +01:47:39
Equinox of date position of star is 06:18:14.0 +01:46:58
Star is 90 degrees from the moon. Moon is 1% illuminated.
Stellar brightness G=16.5, apparent brightess of occulting body is G=16.5
Use an exposure time of 1.00 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 50% with SNR of 1.6 for the occulted depth (per occulted point)
Apparent velocity is 15.5 km/sec on the sky relative to the star, or, 15.3 arcsec/hr.
Position angle of asteroid motion is 162.2 degrees
The recommended exposure time corresponds to 15.5 km per image.
The 1-sigma error in the time of the event is 2.1 seconds.
The 1-sigma cross-track error in the shadow position is 1.4 km.
The sky-plane scale is 3658.3 km/arcsec.
Diameter estimates:
39.8 km assuming a 5% albedo, maximum of 2.6 sec for a central chord
16.2 km assuming a 30% albedo, maximum of 1.0 sec for a central chord
Cross-track diameter of 37.9 km used for deployment plan.
Star training set for 12242_Koon, (2026/10/09 17:55UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.3 +07:24:35 0.4 7.79 96 34Del Ori 05:33:22.5 -00:16:53 2.2 11.40 101 PPM 150341 06:22:49.4 +02:15:14 6.5 1.24 89 PPM 150234 06:18:59.6 +01:45:46 7.4 0.19 89 PPM 150219 06:18:27.1 +01:40:31 8.6 0.12 90 12242_Koon 06:18:14.0 +01:46:58 16.5 89 Positions are for equinox of date
Star training set for 12242_Koon, (2026/10/09 17:55UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 7.79 96 34Del Ori 05:32:00.4 -00:17:57 2.2 11.40 101 PPM 150341 06:21:25.7 +02:16:06 6.5 1.24 89 PPM 150234 06:17:36.2 +01:46:29 7.4 0.19 89 PPM 150219 06:17:03.7 +01:41:13 8.6 0.12 90 12242_Koon 06:16:50.6 +01:47:39 16.5 90 Positions are for J2000