Occultation event with (17172) 99NZ41, event index number 1670
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/12/11 22:38:26 UTC
J2000 position of star is 03:59:04.9 -14:24:31
Equinox of date position of star is 04:00:17.0 -14:20:10
Star is 112 degrees from the moon. Moon is 49% illuminated.
Stellar brightness G=16.5, apparent brightess of occulting body is G=15.9
Use an exposure time of 0.95 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 38% with SNR of 1.1 for the occulted depth (per occulted point)
Apparent velocity is 16.2 km/sec on the sky relative to the star, or, 18.6 arcsec/hr.
Position angle of asteroid motion is 107.5 degrees
The recommended exposure time corresponds to 15.4 km per image.
The 1-sigma error in the time of the event is 0.1 seconds.
The 1-sigma cross-track error in the shadow position is 42.7 km.
The sky-plane scale is 3127.4 km/arcsec.
Diameter estimates:
40.9 km assuming a 5% albedo, aximum of 2.5 sec for a central chord
16.7 km assuming a 30% albedo, maximum of 1.0 sec for a central chord
Cross-track diameter of 34.5 km used for deployment plan.
Star training set for 17172_99NZ41, (2025/12/11 22:38UT) Object RA Dec mag sep mel Rigel 05:15:47.2 -08:10:25 0.1 19.50 93 67Bet Eri 05:09:07.6 -05:03:17 2.8 19.32 95 PPM 213613 03:57:40.3 -13:31:25 6.5 1.03 112 PPM 213694 04:00:49.3 -13:58:07 9.5 0.39 112 17172_99NZ41 04:00:17.0 -14:20:10 15.9 111 Positions are for equinox of date
Star training set for 17172_99NZ41, (2025/12/11 22:38UT) Object RA Dec mag sep mel Rigel 05:14:32.3 -08:12:06 0.1 19.50 93 67Bet Eri 05:07:50.8 -05:05:13 2.8 19.32 95 PPM 213613 03:56:27.7 -13:35:51 6.5 1.03 112 PPM 213694 03:59:37.0 -14:02:26 9.5 0.39 112 17172_99NZ41 03:59:04.9 -14:24:31 15.9 112 Positions are for J2000