Occultation event with (12242) Koon, event index number 4508
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/10/29 06:17:19 UTC
J2000 position of star is 06:16:51.5 -00:05:57
Equinox of date position of star is 06:18:13.9 -00:06:39
Star is 33 degrees from the moon. Moon is 87% illuminated.
Stellar brightness G=12.5, apparent brightess of occulting body is G=16.4
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 15.3 per integration for unocculted signal
Expected flux drop is 97% with SNR of 14.9 for the occulted depth (per occulted point)
Apparent velocity is 14.5 km/sec on the sky relative to the star, or, 15.1 arcsec/hr.
Position angle of asteroid motion is 17.9 degrees
The recommended exposure time corresponds to 1.7 km per image.
The 1-sigma error in the time of the event is 1.8 seconds.
The 1-sigma cross-track error in the shadow position is 19.8 km.
The sky-plane scale is 3473.4 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, (2026/10/29 06:17UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.5 +07:24:35 0.4 9.25 23 34Del Ori 05:33:22.7 -00:16:53 2.2 11.21 29 PPM 176187 06:16:56.1 -00:31:28 6.2 0.53 33 PPM 176195 06:18:12.5 -00:08:51 8.5 0.04 33 12242_Koon 06:18:13.9 -00:06:39 16.4 33 Positions are for equinox of date
Star training set for 12242_Koon, (2026/10/29 06:17UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 9.25 23 34Del Ori 05:32:00.4 -00:17:57 2.2 11.21 29 PPM 176187 06:15:34.0 -00:30:50 6.2 0.53 33 PPM 176195 06:16:50.1 -00:08:10 8.5 0.04 33 12242_Koon 06:16:51.5 -00:05:57 16.4 33 Positions are for J2000