Occultation event with (7641) Cteatus, event index number 3870
Regions able to see the event: SAfrica
Geocentric closest approach at 2026/07/20 17:22:08 UTC
J2000 position of star is 10:53:34.7 -22:57:12
Equinox of date position of star is 10:54:52.1 -23:05:43
Star is 34 degrees from the moon. Moon is 43% illuminated.
Stellar brightness G=15.5, apparent brightess of occulting body is G=15.2
Use an exposure time of 0.55 seconds with the standard RECON-QHY system.
SNR of 4.4 per integration for unocculted signal
Expected flux drop is 42% with SNR of 1.9 for the occulted depth (per occulted point)
Apparent velocity is 32.4 km/sec on the sky relative to the star, or, 29.2 arcsec/hr.
Position angle of asteroid motion is 89.3 degrees
The recommended exposure time corresponds to 17.8 km per image.
The 1-sigma error in the time of the event is 0.3 seconds.
The 1-sigma cross-track error in the shadow position is 46.1 km.
The sky-plane scale is 3996.5 km/arcsec.
Diameter estimates:
76.6 km assuming a 5% albedo, maximum of 2.4 sec for a central chord
31.3 km assuming a 30% albedo, maximum of 1.0 sec for a central chord
Cross-track diameter of 71.8 km used for deployment plan.
Star training set for 7641_Cteatus, (2026/07/20 17:22UT) Object RA Dec mag sep mel Regulus 10:09:47.0 +11:50:11 1.3 36.63 50 4Gam Crv 12:17:10.5 -17:41:21 2.6 20.01 14 PPM 258298 10:56:29.5 -20:48:25 6.4 2.32 33 PPM 258279 10:55:24.1 -23:19:40 8.4 0.26 34 PPM 258253 10:54:23.7 -23:19:09 9.6 0.25 34 7641_Cteatus 10:54:52.1 -23:05:43 15.2 33 Positions are for equinox of date
Star training set for 7641_Cteatus, (2026/07/20 17:22UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 36.63 50 4Gam Crv 12:15:48.1 -17:32:30 2.6 20.01 14 PPM 258298 10:55:11.6 -20:39:54 6.4 2.32 33 PPM 258279 10:54:06.7 -23:11:09 8.4 0.26 34 PPM 258253 10:53:06.4 -23:10:39 9.6 0.25 34 7641_Cteatus 10:53:34.7 -22:57:12 15.2 34 Positions are for J2000