Occultation event with (5258) Rhoeo, event index number 3285
Regions able to see the event: Europe
Geocentric closest approach at 2026/02/21 22:33:45 UTC
J2000 position of star is 10:59:36.2 -01:32:16
Equinox of date position of star is 11:00:56.4 -01:40:42
Star is 137 degrees from the moon. Moon is 22% illuminated.
Stellar brightness G=14.5, apparent brightess of occulting body is G=14.8
Use an exposure time of 0.55 seconds with the standard RECON-QHY system.
SNR of 9.8 per integration for unocculted signal
Expected flux drop is 57% with SNR of 5.6 for the occulted depth (per occulted point)
Apparent velocity is 15.3 km/sec on the sky relative to the star, or, 19.6 arcsec/hr.
Position angle of asteroid motion is 110.1 degrees
The recommended exposure time corresponds to 8.4 km per image.
The 1-sigma error in the time of the event is 1.7 seconds.
The 1-sigma cross-track error in the shadow position is 29.2 km.
The sky-plane scale is 2814.8 km/arcsec.
Diameter estimates:
51.3 km assuming a 5% albedo, maximum of 3.3 sec for a central chord
20.9 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 53.3 km used for deployment plan.
Star training set for 5258_Rhoeo, (2026/02/21 22:34UT) Object RA Dec mag sep mel Regulus 10:09:45.7 +11:50:18 1.3 18.56 120 61 Leo 11:03:09.7 -02:37:33 6.1 1.10 138 PPM 178351 11:00:10.1 -02:22:37 8.1 0.72 137 PPM 178354 11:01:09.8 -02:08:09 8.9 0.46 138 5258_Rhoeo 11:00:56.4 -01:40:42 14.8 138 Positions are for equinox of date
Star training set for 5258_Rhoeo, (2026/02/21 22:34UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 18.56 120 61 Leo 11:01:49.7 -02:29:06 6.1 1.10 138 PPM 178351 10:58:50.1 -02:14:11 8.1 0.72 137 PPM 178354 10:59:49.7 -01:59:43 8.9 0.46 138 5258_Rhoeo 10:59:36.2 -01:32:16 14.8 137 Positions are for J2000