Occultation event with (11887) Echemmon, event index number 4470
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/10/24 05:46:22 UTC
J2000 position of star is 05:49:44.4 +15:45:49
Equinox of date position of star is 05:51:17.0 +15:46:11
Star is 82 degrees from the moon. Moon is 95% illuminated.
Stellar brightness G=16.5, apparent brightess of occulting body is G=16.1
Use an exposure time of 0.95 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 41% with SNR of 1.3 for the occulted depth (per occulted point)
Apparent velocity is 9.5 km/sec on the sky relative to the star, or, 10.5 arcsec/hr.
Position angle of asteroid motion is 28.9 degrees
The recommended exposure time corresponds to 9.0 km per image.
The 1-sigma error in the time of the event is 2.5 seconds.
The 1-sigma cross-track error in the shadow position is 28.3 km.
The sky-plane scale is 3248.5 km/arcsec.
Diameter estimates:
40.7 km assuming a 5% albedo, maximum of 4.3 sec for a central chord
16.6 km assuming a 30% albedo, maximum of 1.8 sec for a central chord
Cross-track diameter of 31.2 km used for deployment plan.
Star training set for 11887_Echemmon, (2026/10/24 05:46UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.5 +07:24:35 0.4 8.46 84 Bellatrix 05:26:34.2 +06:22:18 1.6 11.18 77 131 Tau 05:48:44.8 +14:29:46 5.7 1.41 82 PPM 121449 05:51:35.0 +16:01:09 8.3 0.26 82 PPM 121450 05:51:36.3 +15:40:20 9.2 0.12 83 11887_Echemmon 05:51:17.0 +15:46:11 16.1 83 Positions are for equinox of date
Star training set for 11887_Echemmon, (2026/10/24 05:46UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 8.46 84 Bellatrix 05:25:07.8 +06:20:58 1.6 11.18 77 131 Tau 05:47:13.1 +14:29:18 5.7 1.41 82 PPM 121449 05:50:02.3 +16:00:47 8.3 0.26 82 PPM 121450 05:50:03.8 +15:39:58 9.2 0.12 83 11887_Echemmon 05:49:44.4 +15:45:49 16.1 82 Positions are for J2000