Occultation event with (5284) Orsilocus, event index number 3619
Regions able to see the event: Australia
Geocentric closest approach at 2026/04/12 15:48:31 UTC
J2000 position of star is 12:29:07.9 +23:08:31
Equinox of date position of star is 12:30:26.7 +22:59:48
Star is 138 degrees from the moon. Moon is 27% illuminated.
Stellar brightness G=9.9, apparent brightess of occulting body is G=15.2
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 58.6 per integration for unocculted signal
Expected flux drop is 99% with SNR of 58.2 for the occulted depth (per occulted point)
Apparent velocity is 14.6 km/sec on the sky relative to the star, or, 16.5 arcsec/hr.
Position angle of asteroid motion is 100.5 degrees
The recommended exposure time corresponds to 1.8 km per image.
The 1-sigma error in the time of the event is 1.2 seconds.
The 1-sigma cross-track error in the shadow position is 31.1 km.
The sky-plane scale is 3172.5 km/arcsec.
Diameter estimates:
57.0 km assuming a 5% albedo, maximum of 3.9 sec for a central chord
23.3 km assuming a 30% albedo, maximum of 1.6 sec for a central chord
Cross-track diameter of 50.2 km used for deployment plan.
Star training set for 5284_Orsilocus, (2026/04/12 15:49UT) Object RA Dec mag sep mel Arcturus 14:16:51.7 +19:02:50 0.0 25.11 113 Denebola 11:50:23.9 +14:25:30 2.1 12.77 148 18 Com 12:30:45.7 +23:57:50 5.9 0.97 138 PPM 101969 12:33:10.7 +23:07:26 8.1 0.64 138 PPM 101950 12:31:45.9 +22:44:03 9.3 0.40 138 PPM 101918 12:29:22.8 +22:59:55 10.7 0.25 139 5284_Orsilocus 12:30:26.7 +22:59:48 15.2 138 Positions are for equinox of date
Star training set for 5284_Orsilocus, (2026/04/12 15:49UT) Object RA Dec mag sep mel Arcturus 14:15:37.7 +19:10:06 0.0 25.11 113 Denebola 11:49:02.7 +14:34:16 2.1 12.77 148 18 Com 12:29:27.0 +24:06:32 5.9 0.97 138 PPM 101969 12:31:52.1 +23:16:08 8.1 0.64 138 PPM 101950 12:30:27.1 +22:52:45 9.3 0.40 138 PPM 101918 12:28:03.9 +23:08:37 10.7 0.25 139 5284_Orsilocus 12:29:07.9 +23:08:31 15.2 138 Positions are for J2000