Occultation event with (12242) Koon, event index number 1171
Regions able to see the event: SAfrica
Geocentric closest approach at 2025/07/27 03:28:13 UTC
J2000 position of star is 03:56:48.0 +16:19:00
Equinox of date position of star is 03:58:15.3 +16:23:21
Star is 93 degrees from the moon. Moon is 6% illuminated.
Stellar brightness G=13.3, apparent brightess of occulting body is G=16.6
Use an exposure time of 0.13 seconds with the standard RECON-QHY system.
SNR of 9.7 per integration for unocculted signal
Expected flux drop is 96% with SNR of 9.3 for the occulted depth (per occulted point)
Apparent velocity is 25.5 km/sec on the sky relative to the star, or, 23.0 arcsec/hr.
The recommended exposure time corresponds to 3.3 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 18.7 km.
The sky-plane scale is 3975.2 km/arcsec.
Diameter estimates:
39.8 km assuming a 5% albedo, aximum of 1.6 sec for a central chord
16.2 km assuming a 30% albedo, maximum of 0.6 sec for a central chord
Cross-track diameter of 39.8 km used for deployment plan.
Star training set for 12242_Koon, (2025/07/27 03:28UT) Object RA Dec mag sep mel Aldebaran 04:37:23.5 +16:33:31 0.8 9.38 84 44Zet Per 03:55:44.7 +31:57:27 2.8 15.58 90 PPM 119433 03:54:38.0 +17:24:05 6.0 1.33 94 PPM 119451 03:55:55.8 +16:41:18 7.6 0.63 94 PPM 119476 03:57:50.5 +16:19:42 9.8 0.12 93 12242_Koon 03:58:15.3 +16:23:21 16.6 93 Positions are for equinox of date
Star training set for 12242_Koon, (2025/07/27 03:28UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 9.38 84 44Zet Per 03:54:07.9 +31:53:01 2.8 15.58 90 PPM 119433 03:53:10.3 +17:19:37 6.0 1.33 94 PPM 119451 03:54:28.4 +16:36:53 7.6 0.63 94 PPM 119476 03:56:23.3 +16:15:20 9.8 0.12 93 12242_Koon 03:56:48.0 +16:19:00 16.6 93 Positions are for J2000