Occultation event with (23958) 98VD30, event index number 917
Regions able to see the event: SAmericaN,SAmericaS
Geocentric closest approach at 2025/04/20 02:08:22 UTC
J2000 position of star is 08:44:55.3 -09:19:33
Equinox of date position of star is 08:46:08.9 -09:25:08
Star is 139 degrees from the moon. Moon is 60% illuminated.
Stellar brightness G=14.8, apparent brightess of occulting body is G=15.4
Use an exposure time of 0.70 seconds with the standard RECON-QHY system.
SNR of 9.7 per integration for unocculted signal
Expected flux drop is 64% with SNR of 6.2 for the occulted depth (per occulted point)
Apparent velocity is 13.5 km/sec on the sky relative to the star, or, 15.0 arcsec/hr.
The recommended exposure time corresponds to 9.5 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 29.0 km.
The sky-plane scale is 3255.4 km/arcsec.
Diameter estimates:
55.0 km assuming a 5% albedo, aximum of 4.1 sec for a central chord
22.4 km assuming a 30% albedo, maximum of 1.7 sec for a central chord
Cross-track diameter of 55.0 km used for deployment plan.
Star training set for 23958_98VD30, (2025/04/20 02:08UT) Object RA Dec mag sep mel Regulus 10:09:43.0 +11:50:33 1.3 29.72 139 Alphard 09:28:49.8 -08:46:10 2.0 10.56 133 PPM 220578 08:47:19.7 -11:06:01 6.1 1.71 137 PPM 191633 08:44:07.1 -09:53:52 7.3 0.69 139 PPM 191661 08:46:05.9 -09:21:05 9.1 0.07 139 23958_98VD30 08:46:08.9 -09:25:08 15.4 139 Positions are for equinox of date
Star training set for 23958_98VD30, (2025/04/20 02:08UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 29.72 139 Alphard 09:27:35.2 -08:39:30 2.0 10.56 133 PPM 220578 08:46:06.8 -11:00:24 6.1 1.71 137 PPM 191633 08:42:53.7 -09:48:20 7.3 0.69 139 PPM 191661 08:44:52.2 -09:15:30 9.1 0.07 139 23958_98VD30 08:44:55.3 -09:19:33 15.4 139 Positions are for J2000