Occultation event with (21601) 98XO89, event index number 1092
Regions able to see the event: Australia,NZ
Geocentric closest approach at 2025/06/24 09:03:49 UTC
J2000 position of star is 11:08:00.1 -14:57:22
Equinox of date position of star is 11:09:16.4 -15:05:40
Star is 97 degrees from the moon. Moon is 2% illuminated.
Stellar brightness G=13.3, apparent brightess of occulting body is G=15.7
Use an exposure time of 0.13 seconds with the standard RECON-QHY system.
SNR of 9.6 per integration for unocculted signal
Expected flux drop is 90% with SNR of 8.7 for the occulted depth (per occulted point)
Apparent velocity is 19.7 km/sec on the sky relative to the star, or, 18.8 arcsec/hr.
Position angle of asteroid motion is 359.4 degrees
The recommended exposure time corresponds to 2.6 km per image.
The 1-sigma error in the time of the event is 2.2 seconds.
The 1-sigma cross-track error in the shadow position is 19.5 km.
The sky-plane scale is 3786.6 km/arcsec.
Diameter estimates:
60.0 km assuming a 5% albedo, aximum of 3.0 sec for a central chord
24.5 km assuming a 30% albedo, maximum of 1.2 sec for a central chord
Cross-track diameter of 60.0 km used for deployment plan.
Star training set for 21601_98XO89, (2025/06/24 09:04UT) Object RA Dec mag sep mel Regulus 10:09:43.6 +11:50:30 1.3 30.71 71 4Gam Crv 12:17:07.2 -17:41:00 2.6 16.47 113 PPM 223779 11:01:27.8 -14:13:15 5.8 2.08 95 PPM 223962 11:08:36.9 -15:29:51 8.1 0.43 97 PPM 223998 11:10:06.5 -14:52:14 9.8 0.30 97 21601_98XO89 11:09:16.4 -15:05:40 15.7 97 Positions are for equinox of date
Star training set for 21601_98XO89, (2025/06/24 09:04UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 30.71 71 4Gam Crv 12:15:48.1 -17:32:30 2.6 16.47 113 PPM 223779 11:00:11.7 -14:05:01 5.8 2.08 95 PPM 223962 11:07:20.7 -15:21:34 8.1 0.43 97 PPM 223998 11:08:50.1 -14:43:56 9.8 0.30 97 21601_98XO89 11:08:00.1 -14:57:22 15.7 97 Positions are for J2000