Occultation event with (8125) Tyndareus, event index number 1128
Regions able to see the event: SAfrica
Geocentric closest approach at 2025/07/11 16:21:19 UTC
J2000 position of star is 11:05:58.5 -01:43:34
Equinox of date position of star is 11:07:16.7 -01:51:51
Star is 130 degrees from the moon. Moon is 99% illuminated.
Stellar brightness G=13.8, apparent brightess of occulting body is G=16.8
Use an exposure time of 0.20 seconds with the standard RECON-QHY system.
SNR of 8.8 per integration for unocculted signal
Expected flux drop is 94% with SNR of 8.3 for the occulted depth (per occulted point)
Apparent velocity is 27.3 km/sec on the sky relative to the star, or, 23.0 arcsec/hr.
Position angle of asteroid motion is 336.7 degrees
The recommended exposure time corresponds to 5.5 km per image.
The 1-sigma error in the time of the event is 2.0 seconds.
The 1-sigma cross-track error in the shadow position is 41.9 km.
The sky-plane scale is 4265.1 km/arcsec.
Diameter estimates:
40.7 km assuming a 5% albedo, aximum of 1.5 sec for a central chord
16.6 km assuming a 30% albedo, maximum of 0.6 sec for a central chord
Cross-track diameter of 40.7 km used for deployment plan.
Star training set for 8125_Tyndareus, (2025/07/11 16:21UT) Object RA Dec mag sep mel Regulus 10:09:43.7 +11:50:29 1.3 19.81 149 Denebola 11:50:21.6 +14:25:45 2.1 19.48 128 PPM 178367 11:04:32.9 -00:53:28 6.2 1.19 131 PPM 178398 11:09:35.2 -02:02:30 7.2 0.60 130 PPM 178380 11:06:23.8 -01:56:20 8.9 0.23 130 8125_Tyndareus 11:07:16.7 -01:51:51 16.8 130 Positions are for equinox of date
Star training set for 8125_Tyndareus, (2025/07/11 16:21UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 19.81 149 Denebola 11:49:02.7 +14:34:16 2.1 19.48 128 PPM 178367 11:03:14.6 -00:45:12 6.2 1.19 131 PPM 178398 11:08:17.0 -01:54:11 7.2 0.60 130 PPM 178380 11:05:05.6 -01:48:02 8.9 0.23 130 8125_Tyndareus 11:05:58.5 -01:43:34 16.8 130 Positions are for J2000