Occultation event with (24313) 99YR27, event index number 3801
Regions able to see the event: NZ
Geocentric closest approach at 2026/06/20 07:47:14 UTC
J2000 position of star is 11:26:31.8 +15:34:51
Equinox of date position of star is 11:27:54.6 +15:26:06
Star is 13 degrees from the moon. Moon is 34% illuminated.
Stellar brightness G=12.0, apparent brightess of occulting body is G=16.8
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 22.0 per integration for unocculted signal
Expected flux drop is 99% with SNR of 21.7 for the occulted depth (per occulted point)
Apparent velocity is 19.8 km/sec on the sky relative to the star, or, 17.1 arcsec/hr.
Position angle of asteroid motion is 137.7 degrees
The recommended exposure time corresponds to 2.4 km per image.
The 1-sigma error in the time of the event is 1.9 seconds.
The 1-sigma cross-track error in the shadow position is 4.0 km.
The sky-plane scale is 4160.6 km/arcsec.
Diameter estimates:
41.9 km assuming a 5% albedo, maximum of 2.1 sec for a central chord
17.1 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 34.6 km used for deployment plan.
Star training set for 24313_99YR27, (2026/06/20 07:47UT) Object RA Dec mag sep mel Regulus 10:09:46.7 +11:50:13 1.3 19.31 10 Denebola 11:50:24.5 +14:25:27 2.1 5.53 18 81 Leo 11:26:59.0 +16:18:38 5.8 0.90 14 PPM 128227 11:25:49.4 +15:44:18 8.1 0.59 13 PPM 128256 11:28:19.0 +15:49:30 9.4 0.40 14 24313_99YR27 11:27:54.6 +15:26:06 16.8 13 Positions are for equinox of date
Star training set for 24313_99YR27, (2026/06/20 07:47UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 19.31 10 Denebola 11:49:02.7 +14:34:16 2.1 5.53 18 81 Leo 11:25:36.1 +16:27:23 5.8 0.90 14 PPM 128227 11:24:26.5 +15:53:02 8.1 0.59 13 PPM 128256 11:26:56.2 +15:58:15 9.4 0.40 14 24313_99YR27 11:26:31.8 +15:34:51 16.8 13 Positions are for J2000