Occultation event with (12242) Koon, event index number 4927
Regions able to see the event: SAfrica
Geocentric closest approach at 2026/11/29 01:38:43 UTC
J2000 position of star is 06:07:28.0 -02:42:37
Equinox of date position of star is 06:08:49.0 -02:42:56
Star is 45 degrees from the moon. Moon is 74% illuminated.
Stellar brightness G=16.1, apparent brightess of occulting body is G=16.1
Use an exposure time of 0.60 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 51% with SNR of 1.6 for the occulted depth (per occulted point)
Apparent velocity is 18.2 km/sec on the sky relative to the star, or, 20.1 arcsec/hr.
Position angle of asteroid motion is 59.1 degrees
The recommended exposure time corresponds to 10.9 km per image.
The 1-sigma error in the time of the event is 0.4 seconds.
The 1-sigma cross-track error in the shadow position is 32.8 km.
The sky-plane scale is 3271.8 km/arcsec.
Diameter estimates:
39.8 km assuming a 5% albedo, maximum of 2.2 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, (2026/11/29 01:39UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.8 +07:24:35 0.4 10.57 43 Saiph 05:49:02.0 -09:39:44 2.1 8.51 53 PPM 188806 06:07:58.9 -04:11:55 5.4 1.50 46 PPM 188810 06:08:16.9 -03:20:46 7.5 0.64 45 PPM 188817 06:08:25.0 -02:37:18 9.5 0.14 45 12242_Koon 06:08:49.0 -02:42:56 16.1 44 Positions are for equinox of date
Star training set for 12242_Koon, (2026/11/29 01:39UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 10.57 43 Saiph 05:47:45.4 -09:40:11 2.1 8.51 53 PPM 188806 06:06:38.7 -04:11:38 5.4 1.50 46 PPM 188810 06:06:56.2 -03:20:28 7.5 0.64 45 PPM 188817 06:07:03.9 -02:37:00 9.5 0.14 45 12242_Koon 06:07:28.0 -02:42:37 16.1 45 Positions are for J2000