Occultation event with (5126) Achaemenides, event index number 1023
Regions able to see the event: Europe
Geocentric closest approach at 2025/05/31 21:28:56 UTC
J2000 position of star is 09:22:37.1 +30:00:17
Equinox of date position of star is 09:24:07.6 +29:53:42
Star is 11 degrees from the moon. Moon is 28% illuminated.
Stellar brightness G=14.2, apparent brightess of occulting body is G=16.3
Use an exposure time of 0.35 seconds with the standard RECON-QHY system.
SNR of 9.8 per integration for unocculted signal
Expected flux drop is 88% with SNR of 8.6 for the occulted depth (per occulted point)
Apparent velocity is 24.4 km/sec on the sky relative to the star, or, 22.1 arcsec/hr.
Position angle of asteroid motion is 347.0 degrees
The recommended exposure time corresponds to 8.6 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 17.2 km.
The sky-plane scale is 3986.3 km/arcsec.
Diameter estimates:
45.5 km assuming a 5% albedo, aximum of 1.9 sec for a central chord
18.6 km assuming a 30% albedo, maximum of 0.8 sec for a central chord
Cross-track diameter of 45.5 km used for deployment plan.
Star training set for 5126_Achaemenides, (2025/05/31 21:29UT) Object RA Dec mag sep mel Regulus 10:09:43.4 +11:50:31 1.3 20.93 16 PPM 099676 09:34:47.2 +28:15:14 6.4 2.85 10 PPM 074383 09:18:32.1 +30:16:01 8.2 1.27 11 PPM 074489 09:27:00.1 +30:22:52 8.6 0.79 11 PPM 074447 09:24:30.7 +30:05:14 10.5 0.21 11 5126_Achaemeni 09:24:07.6 +29:53:42 16.3 11 Positions are for equinox of date
Star training set for 5126_Achaemenides, (2025/05/31 21:29UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 20.93 16 PPM 099676 09:33:18.2 +28:22:04 6.4 2.85 10 PPM 074383 09:17:01.1 +30:22:28 8.2 1.27 11 PPM 074489 09:25:29.5 +30:29:31 8.6 0.79 11 PPM 074447 09:23:00.1 +30:11:50 10.5 0.21 11 5126_Achaemeni 09:22:37.1 +30:00:17 16.3 11 Positions are for J2000