Occultation event with (12242) Koon, event index number 4386
Regions able to see the event: Europe
Geocentric closest approach at 2026/10/13 04:24:15 UTC
J2000 position of star is 06:17:11.7 +01:27:37
Equinox of date position of star is 06:18:35.0 +01:26:55
Star is 128 degrees from the moon. Moon is 7% illuminated.
Stellar brightness G=15.4, apparent brightess of occulting body is G=16.5
Use an exposure time of 0.60 seconds with the standard RECON-QHY system.
SNR of 5.4 per integration for unocculted signal
Expected flux drop is 73% with SNR of 3.9 for the occulted depth (per occulted point)
Apparent velocity is 15.0 km/sec on the sky relative to the star, or, 14.9 arcsec/hr.
Position angle of asteroid motion is 168.2 degrees
The recommended exposure time corresponds to 9.0 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 4.6 km.
The sky-plane scale is 3623.8 km/arcsec.
Diameter estimates:
39.8 km assuming a 5% albedo, maximum of 2.7 sec for a central chord
16.2 km assuming a 30% albedo, maximum of 1.1 sec for a central chord
Cross-track diameter of 37.9 km used for deployment plan.
Star training set for 12242_Koon, (2026/10/13 04:24UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.4 +07:24:35 0.4 8.09 136 34Del Ori 05:33:22.6 -00:16:53 2.2 11.43 137 PPM 150341 06:22:49.5 +02:15:14 6.5 1.33 128 PPM 150254 06:19:39.2 +01:33:03 8.4 0.29 128 PPM 150231 06:18:50.8 +01:19:55 9.0 0.13 128 12242_Koon 06:18:35.0 +01:26:55 16.5 128 Positions are for equinox of date
Star training set for 12242_Koon, (2026/10/13 04:24UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 8.09 136 34Del Ori 05:32:00.4 -00:17:57 2.2 11.43 137 PPM 150341 06:21:25.7 +02:16:06 6.5 1.33 128 PPM 150254 06:18:15.8 +01:33:47 8.4 0.29 128 PPM 150231 06:17:27.6 +01:20:37 9.0 0.13 128 12242_Koon 06:17:11.7 +01:27:37 16.5 128 Positions are for J2000