Occultation event with (5144) Achates, event index number 1115
Regions able to see the event: SAmericaN,SAmericaS
Geocentric closest approach at 2025/07/07 09:27:17 UTC
J2000 position of star is 03:09:47.7 +25:58:54
Equinox of date position of star is 03:11:18.4 +26:04:38
Star is 166 degrees from the moon. Moon is 88% illuminated.
Stellar brightness G=14.4, apparent brightess of occulting body is G=15.0
Use an exposure time of 0.45 seconds with the standard RECON-QHY system.
SNR of 9.9 per integration for unocculted signal
Expected flux drop is 65% with SNR of 6.4 for the occulted depth (per occulted point)
Apparent velocity is 29.5 km/sec on the sky relative to the star, or, 25.3 arcsec/hr.
The recommended exposure time corresponds to 13.3 km per image.
The 1-sigma error in the time of the event is 1.1 seconds.
The 1-sigma cross-track error in the shadow position is 15.0 km.
The sky-plane scale is 4200.7 km/arcsec.
Diameter estimates:
87.5 km assuming a 5% albedo, aximum of 3.0 sec for a central chord
35.7 km assuming a 30% albedo, maximum of 1.2 sec for a central chord
Cross-track diameter of 87.5 km used for deployment plan.
Star training set for 5144_Achates, (2025/07/07 09:27UT) Object RA Dec mag sep mel Aldebaran 04:37:23.3 +16:33:30 0.8 22.15 169 44Zet Per 03:55:44.5 +31:57:26 2.8 11.35 173 52 Ari 03:06:56.8 +25:21:10 6.1 1.22 165 PPM 092237 03:10:21.4 +25:27:50 8.2 0.65 166 PPM 092231 03:09:57.8 +26:04:00 8.8 0.30 166 PPM 092260 03:11:49.0 +26:11:21 10.8 0.16 166 5144_Achates 03:11:18.4 +26:04:38 15.0 167 Positions are for equinox of date
Star training set for 5144_Achates, (2025/07/07 09:27UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 22.15 169 44Zet Per 03:54:07.9 +31:53:01 2.8 11.35 173 52 Ari 03:05:26.7 +25:15:19 6.1 1.22 165 PPM 092237 03:08:51.0 +25:22:04 8.2 0.65 166 PPM 092231 03:08:27.1 +25:58:13 8.8 0.30 166 PPM 092260 03:10:18.2 +26:05:37 10.8 0.16 166 5144_Achates 03:09:47.7 +25:58:54 15.0 166 Positions are for J2000