Occultation event with (1208) Troilus, event index number 4177
Regions able to see the event: Australia
Geocentric closest approach at 2026/09/04 20:12:47 UTC
J2000 position of star is 05:33:49.8 +38:32:53
Equinox of date position of star is 05:35:40.0 +38:33:51
Star is 12 degrees from the moon. Moon is 44% illuminated.
Stellar brightness G=16.4, apparent brightess of occulting body is G=14.8
Use an exposure time of 1.10 seconds with the standard RECON-QHY system.
SNR of 3.2 per integration for unocculted signal
Expected flux drop is 19% with SNR of 0.6 for the occulted depth (per occulted point)
Apparent velocity is 21.9 km/sec on the sky relative to the star, or, 20.4 arcsec/hr.
Position angle of asteroid motion is 49.2 degrees
The recommended exposure time corresponds to 24.1 km per image.
The 1-sigma error in the time of the event is 1.5 seconds.
The 1-sigma cross-track error in the shadow position is 11.1 km.
The sky-plane scale is 3880.7 km/arcsec.
Diameter estimates:
92.9 km assuming a 5% albedo, maximum of 4.2 sec for a central chord
37.9 km assuming a 30% albedo, maximum of 1.7 sec for a central chord
Cross-track diameter of 100.5 km used for deployment plan.
Star training set for 1208_Troilus, (2026/09/04 20:13UT) Object RA Dec mag sep mel Aldebaran 04:37:27.3 +16:33:39 0.8 25.43 14 34Bet Aur 06:01:29.2 +44:56:50 1.9 7.99 20 21Sig Aur 05:26:28.2 +37:24:27 6.4 2.15 10 PPM 070575 05:37:23.6 +38:02:06 8.0 0.63 11 PPM 070550 05:36:25.7 +38:30:31 9.6 0.16 12 1208_Troilus 05:35:40.0 +38:33:51 14.8 12 Positions are for equinox of date
Star training set for 1208_Troilus, (2026/09/04 20:13UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 25.43 14 34Bet Aur 05:59:31.6 +44:56:51 1.9 7.99 20 21Sig Aur 05:24:39.2 +37:23:07 6.4 2.15 10 PPM 070575 05:35:33.9 +38:01:11 8.0 0.63 11 PPM 070550 05:34:35.4 +38:29:34 9.6 0.16 12 1208_Troilus 05:33:49.8 +38:32:53 14.8 12 Positions are for J2000