Occultation event with (11509) Thersilochos, event index number 4562
Regions able to see the event: Europe,SAmericaN
Geocentric closest approach at 2026/11/04 03:35:13 UTC
J2000 position of star is 06:13:27.1 +06:57:36
Equinox of date position of star is 06:14:54.0 +06:57:03
Star is 68 degrees from the moon. Moon is 26% illuminated.
Stellar brightness G=15.3, apparent brightess of occulting body is G=15.5
Use an exposure time of 1.15 seconds with the standard RECON-QHY system.
SNR of 8.8 per integration for unocculted signal
Expected flux drop is 54% with SNR of 4.8 for the occulted depth (per occulted point)
Apparent velocity is 10.8 km/sec on the sky relative to the star, or, 11.7 arcsec/hr.
Position angle of asteroid motion is 38.5 degrees
The recommended exposure time corresponds to 12.5 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 21.7 km.
The sky-plane scale is 3321.6 km/arcsec.
Diameter estimates:
55.0 km assuming a 5% albedo, maximum of 5.1 sec for a central chord
22.4 km assuming a 30% albedo, maximum of 2.1 sec for a central chord
Cross-track diameter of 50.0 km used for deployment plan.
Star training set for 11509_Thersilochos, (2026/11/04 03:35UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.6 +07:24:35 0.4 4.56 72 Alhena 06:39:15.7 +16:22:26 1.9 11.15 62 PPM 150217 06:18:25.3 +07:02:27 6.4 0.88 67 PPM 150089 06:14:25.4 +07:16:07 8.3 0.34 68 PPM 150123 06:15:20.1 +06:57:43 9.9 0.11 68 11509_Thersilo 06:14:54.0 +06:57:03 15.5 67 Positions are for equinox of date
Star training set for 11509_Thersilochos, (2026/11/04 03:35UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 4.56 72 Alhena 06:37:42.8 +16:23:56 1.9 11.15 62 PPM 150217 06:16:58.4 +07:03:08 6.4 0.88 67 PPM 150089 06:12:58.2 +07:16:39 8.3 0.34 68 PPM 150123 06:13:53.1 +06:58:18 9.9 0.11 68 11509_Thersilo 06:13:27.1 +06:57:36 15.5 68 Positions are for J2000