Occultation event with (21601) 98XO89, event index number 3649
Regions able to see the event: Australia,NZ
Geocentric closest approach at 2026/04/17 12:35:28 UTC
J2000 position of star is 13:31:54.6 -30:14:03
Equinox of date position of star is 13:33:23.6 -30:22:08
Star is 164 degrees from the moon. Moon is 0% illuminated.
Stellar brightness G=15.3, apparent brightess of occulting body is G=14.9
Use an exposure time of 0.80 seconds with the standard RECON-QHY system.
SNR of 6.5 per integration for unocculted signal
Expected flux drop is 41% with SNR of 2.7 for the occulted depth (per occulted point)
Apparent velocity is 16.9 km/sec on the sky relative to the star, or, 19.5 arcsec/hr.
Position angle of asteroid motion is 118.5 degrees
The recommended exposure time corresponds to 13.5 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 28.4 km.
The sky-plane scale is 3120.9 km/arcsec.
Diameter estimates:
60.0 km assuming a 5% albedo, maximum of 3.5 sec for a central chord
24.5 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 54.9 km used for deployment plan.
Star training set for 21601_98XO89, (2026/04/17 12:35UT) Object RA Dec mag sep mel Spica 13:26:34.9 -11:17:52 1.0 19.14 176 Iot Cen 13:22:05.1 -36:51:01 2.8 6.89 157 PPM 261770 13:34:04.2 -28:49:39 5.7 1.55 166 PPM 261768 13:34:03.1 -29:41:59 6.9 0.68 165 PPM 291485 13:32:57.0 -30:19:19 9.9 0.11 164 21601_98XO89 13:33:23.6 -30:22:08 14.9 164 Positions are for equinox of date
Star training set for 21601_98XO89, (2026/04/17 12:35UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 19.14 176 Iot Cen 13:20:35.1 -36:42:46 2.8 6.89 157 PPM 261770 13:32:35.7 -28:41:35 5.7 1.55 166 PPM 261768 13:32:34.3 -29:33:55 6.9 0.68 165 PPM 291485 13:31:28.1 -30:11:14 9.9 0.11 164 21601_98XO89 13:31:54.6 -30:14:03 14.9 164 Positions are for J2000