Occultation event with (11887) Echemmon, event index number 4437
Regions able to see the event: Europe
Geocentric closest approach at 2026/10/19 04:04:07 UTC
J2000 position of star is 05:50:16.5 +16:04:25
Equinox of date position of star is 05:51:49.2 +16:04:46
Star is 145 degrees from the moon. Moon is 55% illuminated.
Stellar brightness G=16.5, apparent brightess of occulting body is G=16.1
Use an exposure time of 1.05 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 8.6 km/sec on the sky relative to the star, or, 9.4 arcsec/hr.
Position angle of asteroid motion is 15.5 degrees
The recommended exposure time corresponds to 9.1 km per image.
The 1-sigma error in the time of the event is 3.5 seconds.
The 1-sigma cross-track error in the shadow position is 22.5 km.
The sky-plane scale is 3295.2 km/arcsec.
Diameter estimates:
40.7 km assuming a 5% albedo, maximum of 4.7 sec for a central chord
16.6 km assuming a 30% albedo, maximum of 1.9 sec for a central chord
Cross-track diameter of 31.2 km used for deployment plan.
Star training set for 11887_Echemmon, (2026/10/19 04:04UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.4 +07:24:35 0.4 8.75 143 Alhena 06:39:15.6 +16:22:27 1.9 11.39 156 131 Tau 05:48:44.8 +14:29:46 5.7 1.75 144 PPM 121449 05:51:35.0 +16:01:09 8.3 0.08 145 11887_Echemmon 05:51:49.2 +16:04:46 16.1 146 Positions are for equinox of date
Star training set for 11887_Echemmon, (2026/10/19 04:04UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 8.75 143 Alhena 06:37:42.8 +16:23:56 1.9 11.39 156 131 Tau 05:47:13.1 +14:29:18 5.7 1.75 144 PPM 121449 05:50:02.3 +16:00:47 8.3 0.08 145 11887_Echemmon 05:50:16.5 +16:04:25 16.1 145 Positions are for J2000