Occultation event with (24313) 99YR27, event index number 1559
Regions able to see the event: Europe
Geocentric closest approach at 2025/11/21 02:45:20 UTC
J2000 position of star is 11:49:27.5 +16:18:07
Equinox of date position of star is 11:50:47.6 +16:09:28
Star is 79 degrees from the moon. Moon is 1% illuminated.
Stellar brightness G=16.1, apparent brightess of occulting body is G=16.8
Use an exposure time of 0.65 seconds with the standard RECON-QHY system.
SNR of 3.2 per integration for unocculted signal
Expected flux drop is 64% with SNR of 2.0 for the occulted depth (per occulted point)
Apparent velocity is 23.2 km/sec on the sky relative to the star, or, 19.8 arcsec/hr.
Position angle of asteroid motion is 104.4 degrees
The recommended exposure time corresponds to 15.0 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 23.5 km.
The sky-plane scale is 4208.7 km/arcsec.
Diameter estimates:
41.9 km assuming a 5% albedo, aximum of 1.8 sec for a central chord
17.1 km assuming a 30% albedo, maximum of 0.7 sec for a central chord
Cross-track diameter of 34.6 km used for deployment plan.
Star training set for 24313_99YR27, (2025/11/21 02:45UT) Object RA Dec mag sep mel Regulus 10:09:44.9 +11:50:23 1.3 24.87 98 Denebola 11:50:22.7 +14:25:38 2.1 1.73 78 PPM 128581 11:50:34.9 +16:05:55 6.3 0.08 79 24313_99YR27 11:50:47.6 +16:09:28 16.8 78 Positions are for equinox of date
Star training set for 24313_99YR27, (2025/11/21 02:45UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 24.87 98 Denebola 11:49:02.7 +14:34:16 2.1 1.73 78 PPM 128581 11:49:14.9 +16:14:33 6.3 0.08 79 24313_99YR27 11:49:27.5 +16:18:07 16.8 79 Positions are for J2000