Occultation event with (21601) 98XO89, event index number 3640
Regions able to see the event: SAfrica
Geocentric closest approach at 2026/04/15 17:46:39 UTC
J2000 position of star is 13:32:51.4 -30:20:32
Equinox of date position of star is 13:34:20.4 -30:28:35
Star is 145 degrees from the moon. Moon is 4% illuminated.
Stellar brightness G=14.8, 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 9.6 per integration for unocculted signal
Expected flux drop is 52% with SNR of 5.0 for the occulted depth (per occulted point)
Apparent velocity is 16.8 km/sec on the sky relative to the star, or, 19.3 arcsec/hr.
Position angle of asteroid motion is 117.4 degrees
The recommended exposure time corresponds to 13.4 km per image.
The 1-sigma error in the time of the event is 1.3 seconds.
The 1-sigma cross-track error in the shadow position is 28.6 km.
The sky-plane scale is 3123.1 km/arcsec.
Diameter estimates:
60.0 km assuming a 5% albedo, maximum of 3.6 sec for a central chord
24.5 km assuming a 30% albedo, maximum of 1.5 sec for a central chord
Cross-track diameter of 54.9 km used for deployment plan.
Star training set for 21601_98XO89, (2026/04/15 17:47UT) Object RA Dec mag sep mel Spica 13:26:34.9 -11:17:52 1.0 19.26 158 Iot Cen 13:22:05.1 -36:51:00 2.8 6.86 142 PPM 261770 13:34:04.2 -28:49:39 5.7 1.65 147 PPM 291494 13:33:17.2 -31:11:24 7.6 0.75 145 PPM 291500 13:33:34.4 -30:36:12 9.1 0.21 145 21601_98XO89 13:34:20.4 -30:28:35 14.9 145 Positions are for equinox of date
Star training set for 21601_98XO89, (2026/04/15 17:47UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 19.26 158 Iot Cen 13:20:35.1 -36:42:46 2.8 6.86 142 PPM 261770 13:32:35.7 -28:41:35 5.7 1.65 147 PPM 291494 13:31:48.1 -31:03:20 7.6 0.75 145 PPM 291500 13:32:05.4 -30:28:08 9.1 0.21 145 21601_98XO89 13:32:51.4 -30:20:32 14.9 145 Positions are for J2000