Occultation event with (5144) Achates, event index number 4294
Regions able to see the event: SAfrica
Geocentric closest approach at 2026/09/24 03:18:25 UTC
J2000 position of star is 05:27:54.1 +31:54:11
Equinox of date position of star is 05:29:38.3 +31:55:24
Star is 113 degrees from the moon. Moon is 93% illuminated.
Stellar brightness G=15.4, apparent brightess of occulting body is G=15.4
Use an exposure time of 1.55 seconds with the standard RECON-QHY system.
SNR of 10.0 per integration for unocculted signal
Expected flux drop is 50% with SNR of 5.0 for the occulted depth (per occulted point)
Apparent velocity is 6.8 km/sec on the sky relative to the star, or, 5.8 arcsec/hr.
Position angle of asteroid motion is 55.4 degrees
The recommended exposure time corresponds to 10.6 km per image.
The 1-sigma error in the time of the event is 2.3 seconds.
The 1-sigma cross-track error in the shadow position is 23.7 km.
The sky-plane scale is 4215.0 km/arcsec.
Diameter estimates:
87.5 km assuming a 5% albedo, maximum of 12.8 sec for a central chord
35.7 km assuming a 30% albedo, maximum of 5.2 sec for a central chord
Cross-track diameter of 81.0 km used for deployment plan.
Star training set for 5144_Achates, (2026/09/24 03:18UT) Object RA Dec mag sep mel Aldebaran 04:37:27.5 +16:33:39 0.8 19.39 100 Alnath 05:27:59.0 +28:37:39 1.6 3.32 113 25Chi Aur 05:34:28.2 +32:12:33 4.8 1.06 114 PPM 070525 05:34:43.9 +31:53:18 7.5 1.08 114 PPM 070377 05:29:10.0 +32:06:27 9.5 0.21 113 5144_Achates 05:29:38.3 +31:55:24 15.4 113 Positions are for equinox of date
Star training set for 5144_Achates, (2026/09/24 03:18UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 19.39 100 Alnath 05:26:17.6 +28:36:22 1.6 3.32 113 25Chi Aur 05:32:43.7 +32:11:31 4.8 1.06 114 PPM 070525 05:32:59.7 +31:52:17 7.5 1.08 114 PPM 070377 05:27:25.6 +32:05:13 9.5 0.21 113 5144_Achates 05:27:54.1 +31:54:11 15.4 113 Positions are for J2000