Occultation event with (11887) Echemmon, event index number 1157
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/07/22 07:52:03 UTC
J2000 position of star is 03:02:03.3 +27:06:11
Equinox of date position of star is 03:03:34.5 +27:12:09
Star is 36 degrees from the moon. Moon is 8% illuminated.
Stellar brightness G=15.6, apparent brightess of occulting body is G=16.3
Use an exposure time of 0.40 seconds with the standard RECON-QHY system.
SNR of 3.3 per integration for unocculted signal
Expected flux drop is 64% with SNR of 2.1 for the occulted depth (per occulted point)
Apparent velocity is 23.0 km/sec on the sky relative to the star, or, 22.5 arcsec/hr.
The recommended exposure time corresponds to 9.2 km per image.
The 1-sigma error in the time of the event is 2.2 seconds.
The 1-sigma cross-track error in the shadow position is 14.5 km.
The sky-plane scale is 3679.6 km/arcsec.
Diameter estimates:
40.7 km assuming a 5% albedo, aximum of 1.8 sec for a central chord
16.6 km assuming a 30% albedo, maximum of 0.7 sec for a central chord
Cross-track diameter of 40.7 km used for deployment plan.
Star training set for 11887_Echemmon, (2025/07/22 07:52UT) Object RA Dec mag sep mel Aldebaran 04:37:23.4 +16:33:31 0.8 24.17 20 44Zet Per 03:55:44.7 +31:57:27 2.8 12.29 25 49 Ari 03:03:24.9 +26:33:42 6.0 0.64 37 PPM 092163 03:03:57.3 +26:42:26 7.1 0.50 36 PPM 092152 03:03:05.4 +27:05:29 11.3 0.15 37 11887_Echemmon 03:03:34.5 +27:12:09 16.3 36 Positions are for equinox of date
Star training set for 11887_Echemmon, (2025/07/22 07:52UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 24.17 20 44Zet Per 03:54:07.9 +31:53:01 2.8 12.29 25 49 Ari 03:01:54.1 +26:27:44 6.0 0.64 37 PPM 092163 03:02:26.5 +26:36:29 7.1 0.50 36 PPM 092152 03:01:34.3 +26:59:31 11.3 0.15 37 11887_Echemmon 03:02:03.3 +27:06:11 16.3 36 Positions are for J2000