Occultation event with (8125) Tyndareus, event index number 1068
Regions able to see the event: SAfrica
Geocentric closest approach at 2025/06/17 19:19:35 UTC
J2000 position of star is 10:54:18.0 -00:36:07
Equinox of date position of star is 10:55:36.2 -00:44:17
Star is 172 degrees from the moon. Moon is 61% illuminated.
Stellar brightness G=12.1, apparent brightess of occulting body is G=16.7
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 19.8 per integration for unocculted signal
Expected flux drop is 99% with SNR of 19.5 for the occulted depth (per occulted point)
Apparent velocity is 17.7 km/sec on the sky relative to the star, or, 15.9 arcsec/hr.
Position angle of asteroid motion is 337.1 degrees
The recommended exposure time corresponds to 2.1 km per image.
The 1-sigma error in the time of the event is 2.8 seconds.
The 1-sigma cross-track error in the shadow position is 39.4 km.
The sky-plane scale is 4014.1 km/arcsec.
Diameter estimates:
40.7 km assuming a 5% albedo, aximum of 2.3 sec for a central chord
16.6 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 40.7 km used for deployment plan.
Star training set for 8125_Tyndareus, (2025/06/17 19:20UT) Object RA Dec mag sep mel Regulus 10:09:43.5 +11:50:30 1.3 16.97 166 55 Leo 10:57:00.9 +00:36:02 6.2 1.38 174 PPM 178316 10:53:54.3 -00:20:15 7.4 0.58 172 PPM 178326 10:55:55.4 -01:03:39 9.7 0.33 172 PPM 178327 10:56:06.2 -00:43:33 10.1 0.13 172 8125_Tyndareus 10:55:36.2 -00:44:17 16.7 172 Positions are for equinox of date
Star training set for 8125_Tyndareus, (2025/06/17 19:20UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 16.97 166 55 Leo 10:55:42.5 +00:44:13 6.2 1.38 174 PPM 178316 10:52:36.1 -00:12:07 7.4 0.58 172 PPM 178326 10:54:37.3 -00:55:29 9.7 0.33 172 PPM 178327 10:54:48.0 -00:35:23 10.1 0.13 172 8125_Tyndareus 10:54:18.0 -00:36:07 16.7 172 Positions are for J2000