Occultation event with (18054) 99SW7, event index number 4136
Regions able to see the event: SAmericaN,SAmericaS
Geocentric closest approach at 2026/08/31 09:24:10 UTC
J2000 position of star is 05:46:14.1 +08:57:08
Equinox of date position of star is 05:47:41.7 +08:57:38
Star is 71 degrees from the moon. Moon is 89% illuminated.
Stellar brightness G=14.4, apparent brightess of occulting body is G=16.6
Use an exposure time of 0.40 seconds with the standard RECON-QHY system.
SNR of 9.3 per integration for unocculted signal
Expected flux drop is 88% with SNR of 8.2 for the occulted depth (per occulted point)
Apparent velocity is 21.6 km/sec on the sky relative to the star, or, 19.2 arcsec/hr.
Position angle of asteroid motion is 98.2 degrees
The recommended exposure time corresponds to 8.6 km per image.
The 1-sigma error in the time of the event is 0.3 seconds.
The 1-sigma cross-track error in the shadow position is 33.1 km.
The sky-plane scale is 4038.8 km/arcsec.
Diameter estimates:
42.9 km assuming a 5% albedo, maximum of 2.0 sec for a central chord
17.5 km assuming a 30% albedo, maximum of 0.8 sec for a central chord
Cross-track diameter of 36.2 km used for deployment plan.
Star training set for 18054_99SW7, (2026/08/31 09:24UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.0 +07:24:35 0.4 2.70 74 Bellatrix 05:26:33.8 +06:22:18 1.6 5.84 66 PPM 149523 05:51:30.8 +09:52:37 6.4 1.31 72 PPM 149411 05:47:00.4 +09:19:33 8.5 0.40 71 PPM 149419 05:47:11.1 +08:43:38 9.7 0.27 71 PPM 149437 05:48:13.6 +08:45:56 10.8 0.24 71 18054_99SW7 05:47:41.7 +08:57:38 16.6 71 Positions are for equinox of date
Star training set for 18054_99SW7, (2026/08/31 09:24UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 2.70 74 Bellatrix 05:25:07.8 +06:20:58 1.6 5.84 66 PPM 149523 05:50:02.7 +09:52:15 6.4 1.31 72 PPM 149411 05:45:32.6 +09:19:01 8.5 0.40 71 PPM 149419 05:45:43.7 +08:43:06 9.7 0.27 71 PPM 149437 05:46:46.1 +08:45:27 10.8 0.24 71 18054_99SW7 05:46:14.1 +08:57:08 16.6 71 Positions are for J2000