Occultation event with (21601) 98XO89, event index number 1699
Regions able to see the event: NZ
Geocentric closest approach at 2025/12/19 15:03:23 UTC
J2000 position of star is 13:31:02.5 -26:39:06
Equinox of date position of star is 13:32:29.2 -26:47:06
Star is 52 degrees from the moon. Moon is 0% illuminated.
Stellar brightness G=15.7, apparent brightess of occulting body is G=15.8
Use an exposure time of 0.45 seconds with the standard RECON-QHY system.
SNR of 3.4 per integration for unocculted signal
Expected flux drop is 52% with SNR of 1.8 for the occulted depth (per occulted point)
Apparent velocity is 29.4 km/sec on the sky relative to the star, or, 25.7 arcsec/hr.
Position angle of asteroid motion is 120.9 degrees
The recommended exposure time corresponds to 13.2 km per image.
The 1-sigma error in the time of the event is 0.8 seconds.
The 1-sigma cross-track error in the shadow position is 26.7 km.
The sky-plane scale is 4118.5 km/arcsec.
Diameter estimates:
60.0 km assuming a 5% albedo, aximum of 2.0 sec for a central chord
24.5 km assuming a 30% albedo, maximum of 0.8 sec for a central chord
Cross-track diameter of 54.9 km used for deployment plan.
Star training set for 21601_98XO89, (2025/12/19 15:03UT) Object RA Dec mag sep mel Spica 13:26:33.9 -11:17:46 1.0 15.55 59 Iot Cen 13:22:04.0 -36:50:54 2.8 10.30 52 PPM 261689 13:29:28.2 -26:32:10 6.5 0.72 53 PPM 261767 13:33:58.3 -26:47:25 8.9 0.33 52 21601_98XO89 13:32:29.2 -26:47:06 15.8 52 Positions are for equinox of date
Star training set for 21601_98XO89, (2025/12/19 15:03UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 15.55 59 Iot Cen 13:20:35.1 -36:42:46 2.8 10.30 52 PPM 261689 13:28:01.9 -26:24:08 6.5 0.72 53 PPM 261767 13:32:31.6 -26:39:27 8.9 0.33 52 21601_98XO89 13:31:02.5 -26:39:06 15.8 52 Positions are for J2000