Occultation event with (11509) Thersilochos, event index number 4809
Regions able to see the event: Europe,SAmericaN
Geocentric closest approach at 2026/11/22 03:44:22 UTC
J2000 position of star is 06:07:58.7 +05:56:57
Equinox of date position of star is 06:09:25.2 +05:56:37
Star is 69 degrees from the moon. Moon is 92% illuminated.
Stellar brightness G=15.0, apparent brightess of occulting body is G=15.3
Use an exposure time of 0.80 seconds with the standard RECON-QHY system.
SNR of 8.8 per integration for unocculted signal
Expected flux drop is 58% with SNR of 5.1 for the occulted depth (per occulted point)
Apparent velocity is 14.9 km/sec on the sky relative to the star, or, 16.7 arcsec/hr.
Position angle of asteroid motion is 63.5 degrees
The recommended exposure time corresponds to 11.9 km per image.
The 1-sigma error in the time of the event is 0.5 seconds.
The 1-sigma cross-track error in the shadow position is 27.6 km.
The sky-plane scale is 3204.4 km/arcsec.
Diameter estimates:
55.0 km assuming a 5% albedo, maximum of 3.7 sec for a central chord
22.4 km assuming a 30% albedo, maximum of 1.5 sec for a central chord
Cross-track diameter of 50.0 km used for deployment plan.
Star training set for 11509_Thersilochos, (2026/11/22 03:44UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.7 +07:24:35 0.4 3.50 65 Bellatrix 05:26:34.5 +06:22:18 1.6 10.66 58 63 Ori 06:06:24.2 +05:24:58 6.4 0.92 68 PPM 149889 06:07:34.3 +06:01:10 8.0 0.47 68 PPM 149961 06:09:58.3 +05:47:40 8.9 0.20 69 11509_Thersilo 06:09:25.2 +05:56:37 15.3 69 Positions are for equinox of date
Star training set for 11509_Thersilochos, (2026/11/22 03:44UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 3.50 65 Bellatrix 05:25:07.8 +06:20:58 1.6 10.66 58 63 Ori 06:04:58.1 +05:25:12 6.4 0.92 68 PPM 149889 06:06:07.8 +06:01:26 8.0 0.47 68 PPM 149961 06:08:32.0 +05:48:01 8.9 0.20 69 11509_Thersilo 06:07:58.7 +05:56:57 15.3 69 Positions are for J2000