Occultation event with (12242) Koon, event index number 4480
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/10/25 07:09:43 UTC
J2000 position of star is 06:17:15.0 +00:16:54
Equinox of date position of star is 06:18:37.6 +00:16:12
Star is 77 degrees from the moon. Moon is 99% illuminated.
Stellar brightness G=16.5, apparent brightess of occulting body is G=16.4
Use an exposure time of 1.00 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 47% with SNR of 1.4 for the occulted depth (per occulted point)
Apparent velocity is 14.4 km/sec on the sky relative to the star, or, 14.7 arcsec/hr.
Position angle of asteroid motion is 10.7 degrees
The recommended exposure time corresponds to 14.4 km per image.
The 1-sigma error in the time of the event is 2.0 seconds.
The 1-sigma cross-track error in the shadow position is 16.6 km.
The sky-plane scale is 3508.4 km/arcsec.
Diameter estimates:
39.8 km assuming a 5% albedo, maximum of 2.8 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, (2026/10/25 07:10UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.5 +07:24:35 0.4 9.00 71 34Del Ori 05:33:22.7 -00:16:53 2.2 11.33 66 PPM 176187 06:16:56.1 -00:31:28 6.2 0.90 77 PPM 150247 06:19:21.2 +00:12:45 7.4 0.19 78 PPM 150220 06:18:27.9 +00:13:30 8.8 0.06 77 12242_Koon 06:18:37.6 +00:16:12 16.4 78 Positions are for equinox of date
Star training set for 12242_Koon, (2026/10/25 07:10UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 9.00 71 34Del Ori 05:32:00.4 -00:17:57 2.2 11.33 66 PPM 176187 06:15:34.0 -00:30:50 6.2 0.90 77 PPM 150247 06:17:58.7 +00:13:29 7.4 0.19 78 PPM 150220 06:17:05.3 +00:14:11 8.8 0.06 77 12242_Koon 06:17:15.0 +00:16:54 16.4 77 Positions are for J2000