Occultation event with (588) Achilles, event index number 1076
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/06/20 22:36:14 UTC
J2000 position of star is 10:36:47.9 +02:44:04
Equinox of date position of star is 10:38:06.8 +02:36:06
Star is 132 degrees from the moon. Moon is 27% illuminated.
Stellar brightness G=13.6, apparent brightess of occulting body is G=13.8
Use an exposure time of 0.20 seconds with the standard RECON-QHY system.
SNR of 9.2 per integration for unocculted signal
Expected flux drop is 55% with SNR of 5.1 for the occulted depth (per occulted point)
Apparent velocity is 23.2 km/sec on the sky relative to the star, or, 22.0 arcsec/hr.
Position angle of asteroid motion is 339.0 degrees
The recommended exposure time corresponds to 4.6 km per image.
The 1-sigma error in the time of the event is 1.6 seconds.
The 1-sigma cross-track error in the shadow position is 26.9 km.
The sky-plane scale is 3791.5 km/arcsec.
Diameter estimates:
135.5 km assuming a 5% albedo, aximum of 5.8 sec for a central chord
55.3 km assuming a 30% albedo, maximum of 2.4 sec for a central chord
Cross-track diameter of 135.5 km used for deployment plan.
Star training set for 588_Achilles, (2025/06/20 22:36UT) Object RA Dec mag sep mel Regulus 10:09:43.5 +11:50:30 1.3 11.61 122 30Bet Sex 10:31:35.6 -00:46:06 4.8 3.74 131 PPM 156997 10:37:20.3 +02:36:54 8.5 0.19 132 588_Achilles 10:38:06.8 +02:36:06 13.8 132 Positions are for equinox of date
Star training set for 588_Achilles, (2025/06/20 22:36UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 11.61 122 30Bet Sex 10:30:17.4 -00:38:14 4.8 3.74 131 PPM 156997 10:36:01.5 +02:44:51 8.5 0.19 132 588_Achilles 10:36:47.9 +02:44:04 13.8 132 Positions are for J2000