Occultation event with (1868) Thersites, event index number 969
Regions able to see the event: SAmericaN,SAmericaS
Geocentric closest approach at 2025/05/13 00:57:49 UTC
J2000 position of star is 08:56:03.7 +03:30:07
Equinox of date position of star is 08:57:23.2 +03:24:12
Star is 99 degrees from the moon. Moon is 100% illuminated.
Stellar brightness G=11.6, apparent brightess of occulting body is G=15.5
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 26.7 per integration for unocculted signal
Expected flux drop is 97% with SNR of 26.0 for the occulted depth (per occulted point)
Apparent velocity is 17.1 km/sec on the sky relative to the star, or, 14.9 arcsec/hr.
The recommended exposure time corresponds to 2.1 km per image.
The 1-sigma error in the time of the event is 2.6 seconds.
The 1-sigma cross-track error in the shadow position is 8.7 km.
The sky-plane scale is 4148.2 km/arcsec.
Diameter estimates:
76.2 km assuming a 5% albedo, aximum of 4.5 sec for a central chord
31.1 km assuming a 30% albedo, maximum of 1.8 sec for a central chord
Cross-track diameter of 76.2 km used for deployment plan.
Star training set for 1868_Thersites, (2025/05/13 00:58UT) Object RA Dec mag sep mel Regulus 10:09:43.2 +11:50:32 1.3 19.79 86 Alphard 09:28:50.0 -08:46:11 2.0 14.48 87 PPM 155117 08:53:44.4 +05:14:37 6.5 2.05 101 PPM 155151 08:55:07.3 +03:49:08 8.2 0.70 100 PPM 155217 08:57:37.9 +03:28:11 8.7 0.09 99 1868_Thersites 08:57:23.2 +03:24:12 15.5 99 Positions are for equinox of date
Star training set for 1868_Thersites, (2025/05/13 00:58UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 19.79 86 Alphard 09:27:35.2 -08:39:30 2.0 14.48 87 PPM 155117 08:52:24.2 +05:20:25 6.5 2.05 101 PPM 155151 08:53:47.6 +03:54:59 8.2 0.70 100 PPM 155217 08:56:18.4 +03:34:06 8.7 0.09 99 1868_Thersites 08:56:03.7 +03:30:07 15.5 99 Positions are for J2000