Occultation event with (18054) 99SW7, event index number 1263
Regions able to see the event: SAfrica
Geocentric closest approach at 2025/09/03 03:57:28 UTC
J2000 position of star is 03:58:22.1 -00:29:44
Equinox of date position of star is 03:59:40.8 -00:25:25
Star is 128 degrees from the moon. Moon is 77% illuminated.
Stellar brightness G=15.6, apparent brightess of occulting body is G=16.4
Use an exposure time of 0.90 seconds with the standard RECON-QHY system.
SNR of 6.0 per integration for unocculted signal
Expected flux drop is 66% with SNR of 3.9 for the occulted depth (per occulted point)
Apparent velocity is 9.9 km/sec on the sky relative to the star, or, 9.7 arcsec/hr.
Position angle of asteroid motion is 135.3 degrees
The recommended exposure time corresponds to 8.9 km per image.
The 1-sigma error in the time of the event is 1.4 seconds.
The 1-sigma cross-track error in the shadow position is 28.9 km.
The sky-plane scale is 3638.6 km/arcsec.
Diameter estimates:
42.9 km assuming a 5% albedo, aximum of 4.4 sec for a central chord
17.5 km assuming a 30% albedo, maximum of 1.8 sec for a central chord
Cross-track diameter of 36.2 km used for deployment plan.
Star training set for 18054_99SW7, (2025/09/03 03:57UT) Object RA Dec mag sep mel Aldebaran 04:37:23.8 +16:33:32 0.8 19.36 145 Menkar 03:03:37.5 +04:11:20 2.5 14.74 119 PPM 175430 04:03:55.8 -00:12:04 5.6 1.09 129 PPM 175431 04:03:57.0 -00:43:53 6.9 1.11 129 PPM 175423 04:00:44.1 -00:20:14 9.2 0.28 128 PPM 175420 04:00:17.9 -00:14:43 11.9 0.24 128 18054_99SW7 03:59:40.8 -00:25:25 16.4 128 Positions are for equinox of date
Star training set for 18054_99SW7, (2025/09/03 03:57UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 19.36 145 Menkar 03:02:16.8 +04:05:21 2.5 14.74 119 PPM 175430 04:02:37.0 -00:16:15 5.6 1.09 129 PPM 175431 04:02:38.5 -00:48:04 6.9 1.11 129 PPM 175423 03:59:25.3 -00:24:31 9.2 0.28 128 PPM 175420 03:58:59.1 -00:19:01 11.9 0.24 128 18054_99SW7 03:58:22.1 -00:29:44 16.4 128 Positions are for J2000