Occultation event with (5123) Cynus, event index number 1539
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/11/18 09:45:44 UTC
J2000 position of star is 11:50:44.9 +09:35:48
Equinox of date position of star is 11:52:04.7 +09:27:10
Star is 43 degrees from the moon. Moon is 3% illuminated.
Stellar brightness G=13.2, apparent brightess of occulting body is G=15.6
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 9.7 per integration for unocculted signal
Expected flux drop is 90% with SNR of 8.8 for the occulted depth (per occulted point)
Apparent velocity is 27.6 km/sec on the sky relative to the star, or, 26.2 arcsec/hr.
Position angle of asteroid motion is 106.4 degrees
The recommended exposure time corresponds to 3.3 km per image.
The 1-sigma error in the time of the event is 1.0 seconds.
The 1-sigma cross-track error in the shadow position is 30.8 km.
The sky-plane scale is 3797.1 km/arcsec.
Diameter estimates:
57.5 km assuming a 5% albedo, aximum of 2.1 sec for a central chord
23.5 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 35.4 km used for deployment plan.
Star training set for 5123_Cynus, (2025/11/18 09:46UT) Object RA Dec mag sep mel Regulus 10:09:44.9 +11:50:23 1.3 25.25 66 Denebola 11:50:22.7 +14:25:38 2.1 4.99 47 4 Vir 11:49:14.6 +08:06:07 5.2 1.52 43 PPM 158257 11:51:48.7 +09:37:59 8.3 0.19 44 PPM 158258 11:52:00.4 +09:22:20 8.7 0.08 43 5123_Cynus 11:52:04.7 +09:27:10 15.6 43 Positions are for equinox of date
Star training set for 5123_Cynus, (2025/11/18 09:46UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 25.25 66 Denebola 11:49:02.7 +14:34:16 2.1 4.99 47 4 Vir 11:47:54.8 +08:14:45 5.2 1.52 43 PPM 158257 11:50:28.9 +09:46:37 8.3 0.19 44 PPM 158258 11:50:40.6 +09:30:59 8.7 0.08 43 5123_Cynus 11:50:44.9 +09:35:48 15.6 43 Positions are for J2000