Occultation event with (7641) Cteatus, event index number 3665
Regions able to see the event: SMexico
Geocentric closest approach at 2026/04/21 01:11:28 UTC
J2000 position of star is 10:10:13.2 -29:27:52
Equinox of date position of star is 10:11:25.0 -29:35:40
Star is 91 degrees from the moon. Moon is 18% illuminated.
Stellar brightness G=15.1, apparent brightess of occulting body is G=14.7
Use an exposure time of 1.05 seconds with the standard RECON-QHY system.
SNR of 8.8 per integration for unocculted signal
Expected flux drop is 40% with SNR of 3.5 for the occulted depth (per occulted point)
Apparent velocity is 16.6 km/sec on the sky relative to the star, or, 18.7 arcsec/hr.
Position angle of asteroid motion is 174.8 degrees
The recommended exposure time corresponds to 17.4 km per image.
The 1-sigma error in the time of the event is 2.7 seconds.
The 1-sigma cross-track error in the shadow position is 10.7 km.
The sky-plane scale is 3201.8 km/arcsec.
Diameter estimates:
76.6 km assuming a 5% albedo, maximum of 4.6 sec for a central chord
31.3 km assuming a 30% albedo, maximum of 1.9 sec for a central chord
Cross-track diameter of 71.8 km used for deployment plan.
Star training set for 7641_Cteatus, (2026/04/21 01:11UT) Object RA Dec mag sep mel Bet Cru 12:49:16.6 -59:49:55 1.3 40.15 125 Lam Vel 09:08:57.9 -43:32:23 2.2 18.69 89 PPM 287271 10:06:56.1 -31:01:13 6.5 1.72 91 PPM 257264 10:10:04.3 -29:52:45 8.5 0.41 91 7641_Cteatus 10:11:25.0 -29:35:40 14.7 91 Positions are for equinox of date
Star training set for 7641_Cteatus, (2026/04/21 01:11UT) Object RA Dec mag sep mel Bet Cru 12:47:43.1 -59:41:20 1.3 40.15 125 Lam Vel 09:07:59.7 -43:25:57 2.2 18.69 89 PPM 287271 10:05:45.2 -30:53:30 6.5 1.72 91 PPM 257264 10:08:52.7 -29:44:58 8.5 0.41 91 7641_Cteatus 10:10:13.2 -29:27:52 14.7 91 Positions are for J2000