Occultation event with (39264) 00YQ139, event index number 1118
Regions able to see the event: SAmericaN,SAmericaS
Geocentric closest approach at 2025/07/07 23:12:29 UTC
J2000 position of star is 10:20:36.4 -01:27:26
Equinox of date position of star is 10:21:54.5 -01:35:11
Star is 94 degrees from the moon. Moon is 92% illuminated.
Stellar brightness G=15.1, apparent brightess of occulting body is G=16.7
Use an exposure time of 0.30 seconds with the standard RECON-QHY system.
SNR of 4.3 per integration for unocculted signal
Expected flux drop is 82% with SNR of 3.5 for the occulted depth (per occulted point)
Apparent velocity is 31.4 km/sec on the sky relative to the star, or, 26.3 arcsec/hr.
Position angle of asteroid motion is 349.9 degrees
The recommended exposure time corresponds to 9.4 km per image.
The 1-sigma error in the time of the event is 2.0 seconds.
The 1-sigma cross-track error in the shadow position is 15.7 km.
The sky-plane scale is 4289.4 km/arcsec.
Diameter estimates:
41.1 km assuming a 5% albedo, aximum of 1.3 sec for a central chord
16.8 km assuming a 30% albedo, maximum of 0.5 sec for a central chord
Cross-track diameter of 41.1 km used for deployment plan.
Star training set for 39264_00YQ139, (2025/07/07 23:12UT) Object RA Dec mag sep mel Regulus 10:09:43.7 +11:50:29 1.3 13.76 103 PPM 193381 10:24:50.2 -03:46:22 6.4 2.31 92 PPM 178145 10:19:34.0 -01:22:24 8.0 0.62 95 PPM 178157 10:22:29.9 -01:47:07 9.5 0.25 94 PPM 178156 10:22:00.3 -01:36:01 10.1 0.03 94 39264_00YQ139 10:21:54.5 -01:35:11 16.7 94 Positions are for equinox of date
Star training set for 39264_00YQ139, (2025/07/07 23:12UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 13.76 103 PPM 193381 10:23:32.7 -03:38:34 6.4 2.31 92 PPM 178145 10:18:15.9 -01:14:41 8.0 0.62 95 PPM 178157 10:21:11.8 -01:39:22 9.5 0.25 94 PPM 178156 10:20:42.2 -01:28:16 10.1 0.03 94 39264_00YQ139 10:20:36.4 -01:27:26 16.7 94 Positions are for J2000