Occultation event with (21601) 98XO89, event index number 945
Regions able to see the event: Australia
Geocentric closest approach at 2025/05/03 08:35:36 UTC
J2000 position of star is 10:55:06.5 -17:15:44
Equinox of date position of star is 10:56:21.5 -17:23:52
Star is 59 degrees from the moon. Moon is 37% illuminated.
Stellar brightness G=14.0, apparent brightess of occulting body is G=15.3
Use an exposure time of 0.30 seconds with the standard RECON-QHY system.
SNR of 10.0 per integration for unocculted signal
Expected flux drop is 76% with SNR of 7.6 for the occulted depth (per occulted point)
Apparent velocity is 10.2 km/sec on the sky relative to the star, or, 11.3 arcsec/hr.
Position angle of asteroid motion is 108.7 degrees
The recommended exposure time corresponds to 3.1 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 36.8 km.
The sky-plane scale is 3267.7 km/arcsec.
Diameter estimates:
60.0 km assuming a 5% albedo, aximum of 5.9 sec for a central chord
24.5 km assuming a 30% albedo, maximum of 2.4 sec for a central chord
Cross-track diameter of 60.0 km used for deployment plan.
Star training set for 21601_98XO89, (2025/05/03 08:36UT) Object RA Dec mag sep mel Regulus 10:09:43.1 +11:50:33 1.3 31.43 32 4Gam Crv 12:17:06.8 -17:40:57 2.6 19.24 74 PPM 223760 11:00:46.2 -16:29:24 5.3 1.39 59 PPM 223690 10:58:00.9 -17:35:20 8.1 0.44 59 PPM 223649 10:56:18.0 -17:17:16 9.6 0.11 59 21601_98XO89 10:56:21.5 -17:23:52 15.3 59 Positions are for equinox of date
Star training set for 21601_98XO89, (2025/05/03 08:36UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 31.43 32 4Gam Crv 12:15:48.1 -17:32:30 2.6 19.24 74 PPM 223760 10:59:30.8 -16:21:13 5.3 1.39 59 PPM 223690 10:56:45.9 -17:27:11 8.1 0.44 59 PPM 223649 10:55:03.0 -17:09:08 9.6 0.11 59 21601_98XO89 10:55:06.5 -17:15:44 15.3 59 Positions are for J2000