Occultation event with (12242) Koon, event index number 4426
Regions able to see the event: Australia
Geocentric closest approach at 2026/10/17 19:16:45 UTC
J2000 position of star is 06:17:26.3 +01:00:36
Equinox of date position of star is 06:18:49.3 +00:59:54
Star is 152 degrees from the moon. Moon is 42% illuminated.
Stellar brightness G=16.2, apparent brightess of occulting body is G=16.5
Use an exposure time of 0.70 seconds with the standard RECON-QHY system.
SNR of 3.2 per integration for unocculted signal
Expected flux drop is 56% with SNR of 1.8 for the occulted depth (per occulted point)
Apparent velocity is 14.6 km/sec on the sky relative to the star, or, 14.7 arcsec/hr.
Position angle of asteroid motion is 176.7 degrees
The recommended exposure time corresponds to 10.2 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 9.1 km.
The sky-plane scale is 3578.6 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, (2026/10/17 19:17UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.4 +07:24:35 0.4 8.47 155 34Del Ori 05:33:22.6 -00:16:53 2.2 11.43 145 PPM 176187 06:16:56.1 -00:31:28 6.2 1.59 151 PPM 150202 06:17:44.1 +01:04:09 6.7 0.28 152 PPM 150224 06:18:33.8 +00:59:20 9.6 0.07 152 12242_Koon 06:18:49.3 +00:59:54 16.5 152 Positions are for equinox of date
Star training set for 12242_Koon, (2026/10/17 19:17UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 8.47 155 34Del Ori 05:32:00.4 -00:17:57 2.2 11.43 145 PPM 176187 06:15:34.0 -00:30:50 6.2 1.59 151 PPM 150202 06:16:21.0 +01:04:49 6.7 0.28 152 PPM 150224 06:17:10.8 +01:00:02 9.6 0.07 152 12242_Koon 06:17:26.3 +01:00:36 16.5 152 Positions are for J2000