Occultation event with (17172) 99NZ41, event index number 1307
Regions able to see the event: Europe,SAfrica
Geocentric closest approach at 2025/09/23 02:05:56 UTC
J2000 position of star is 04:28:31.9 -10:57:56
Equinox of date position of star is 04:29:44.9 -10:54:37
Star is 122 degrees from the moon. Moon is 2% illuminated.
Stellar brightness G=14.4, apparent brightess of occulting body is G=16.1
Use an exposure time of 0.40 seconds with the standard RECON-QHY system.
SNR of 9.3 per integration for unocculted signal
Expected flux drop is 83% with SNR of 7.8 for the occulted depth (per occulted point)
Apparent velocity is 11.9 km/sec on the sky relative to the star, or, 12.9 arcsec/hr.
Position angle of asteroid motion is 173.6 degrees
The recommended exposure time corresponds to 4.8 km per image.
The 1-sigma error in the time of the event is 3.2 seconds.
The 1-sigma cross-track error in the shadow position is 18.3 km.
The sky-plane scale is 3327.7 km/arcsec.
Diameter estimates:
40.9 km assuming a 5% albedo, aximum of 3.4 sec for a central chord
16.7 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 34.5 km used for deployment plan.
Star training set for 17172_99NZ41, (2025/09/23 02:06UT) Object RA Dec mag sep mel Rigel 05:15:46.5 -08:10:26 0.1 11.67 112 67Bet Eri 05:09:07.0 -05:03:18 2.8 11.37 114 PPM 214397 04:30:18.7 -12:59:37 5.6 2.09 122 PPM 214390 04:30:07.8 -11:00:12 8.0 0.13 122 PPM 214377 04:29:38.4 -10:53:37 9.4 0.03 122 17172_99NZ41 04:29:44.9 -10:54:37 16.1 122 Positions are for equinox of date
Star training set for 17172_99NZ41, (2025/09/23 02:06UT) Object RA Dec mag sep mel Rigel 05:14:32.3 -08:12:06 0.1 11.67 112 67Bet Eri 05:07:50.8 -05:05:13 2.8 11.37 114 PPM 214397 04:29:06.9 -13:02:54 5.6 2.09 122 PPM 214390 04:28:54.8 -11:03:31 8.0 0.13 122 PPM 214377 04:28:25.4 -10:56:57 9.4 0.03 122 17172_99NZ41 04:28:31.9 -10:57:56 16.1 122 Positions are for J2000