Occultation event with (18054) 99SW7, event index number 4284
Regions able to see the event: Europe
Geocentric closest approach at 2026/09/22 02:43:24 UTC
J2000 position of star is 05:55:07.8 +08:28:03
Equinox of date position of star is 05:56:35.3 +08:28:13
Star is 140 degrees from the moon. Moon is 79% illuminated.
Stellar brightness G=15.2, 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 7.6 per integration for unocculted signal
Expected flux drop is 77% with SNR of 5.8 for the occulted depth (per occulted point)
Apparent velocity is 12.3 km/sec on the sky relative to the star, or, 11.6 arcsec/hr.
Position angle of asteroid motion is 109.1 degrees
The recommended exposure time corresponds to 8.6 km per image.
The 1-sigma error in the time of the event is 0.1 seconds.
The 1-sigma cross-track error in the shadow position is 33.8 km.
The sky-plane scale is 3803.5 km/arcsec.
Diameter estimates:
42.9 km assuming a 5% albedo, maximum of 3.5 sec for a central chord
17.5 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 36.2 km used for deployment plan.
Star training set for 18054_99SW7, (2026/09/22 02:43UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.2 +07:24:35 0.4 1.06 140 Bellatrix 05:26:34.0 +06:22:18 1.6 7.73 133 PPM 149523 05:51:31.0 +09:52:37 6.4 1.88 140 PPM 149627 05:55:56.0 +08:03:27 7.2 0.44 140 PPM 149621 05:55:47.2 +08:23:27 9.1 0.21 140 PPM 149646 05:56:54.1 +08:24:49 11.1 0.10 140 18054_99SW7 05:56:35.3 +08:28:13 16.5 141 Positions are for equinox of date
Star training set for 18054_99SW7, (2026/09/22 02:43UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 1.06 140 Bellatrix 05:25:07.8 +06:20:58 1.6 7.73 133 PPM 149523 05:50:02.7 +09:52:15 6.4 1.88 140 PPM 149627 05:54:28.7 +08:03:15 7.2 0.44 140 PPM 149621 05:54:19.8 +08:23:15 9.1 0.21 140 PPM 149646 05:55:26.6 +08:24:40 11.1 0.10 140 18054_99SW7 05:55:07.8 +08:28:03 16.5 140 Positions are for J2000