Occultation event with (1208) Troilus, event index number 1311
Regions able to see the event: SAmericaN,SAfrica
Geocentric closest approach at 2025/09/25 02:07:50 UTC
J2000 position of star is 03:41:38.4 +19:15:21
Equinox of date position of star is 03:43:07.5 +19:20:12
Star is 160 degrees from the moon. Moon is 10% illuminated.
Stellar brightness G=16.1, apparent brightess of occulting body is G=14.2
Use an exposure time of 2.00 seconds with the standard RECON-QHY system.
SNR of 5.0 per integration for unocculted signal
Expected flux drop is 15% with SNR of 0.7 for the occulted depth (per occulted point)
Apparent velocity is 9.6 km/sec on the sky relative to the star, or, 10.9 arcsec/hr.
Position angle of asteroid motion is 127.1 degrees
The recommended exposure time corresponds to 19.2 km per image.
The 1-sigma error in the time of the event is 0.6 seconds.
The 1-sigma cross-track error in the shadow position is 32.1 km.
The sky-plane scale is 3164.1 km/arcsec.
Diameter estimates:
92.9 km assuming a 5% albedo, aximum of 9.7 sec for a central chord
37.9 km assuming a 30% albedo, maximum of 3.9 sec for a central chord
Cross-track diameter of 100.5 km used for deployment plan.
Star training set for 1208_Troilus, (2025/09/25 02:08UT) Object RA Dec mag sep mel Aldebaran 04:37:24.0 +16:33:32 0.8 13.20 147 44Zet Per 03:55:45.4 +31:57:28 2.8 12.94 155 13 Tau 03:43:48.3 +19:46:51 5.7 0.47 160 PPM 119282 03:42:55.5 +19:28:10 8.3 0.14 160 1208_Troilus 03:43:07.5 +19:20:12 14.2 160 Positions are for equinox of date
Star training set for 1208_Troilus, (2025/09/25 02:08UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 13.20 147 44Zet Per 03:54:07.9 +31:53:01 2.8 12.94 155 13 Tau 03:42:18.9 +19:42:01 5.7 0.47 160 PPM 119282 03:41:26.4 +19:23:19 8.3 0.14 160 1208_Troilus 03:41:38.4 +19:15:21 14.2 160 Positions are for J2000