Occultation event with (17172) 99NZ41, event index number 1318
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/09/28 06:11:53 UTC
J2000 position of star is 04:28:33.1 -11:24:25
Equinox of date position of star is 04:29:45.9 -11:21:06
Star is 140 degrees from the moon. Moon is 34% illuminated.
Stellar brightness G=15.0, apparent brightess of occulting body is G=16.1
Use an exposure time of 0.70 seconds with the standard RECON-QHY system.
SNR of 8.4 per integration for unocculted signal
Expected flux drop is 73% with SNR of 6.2 for the occulted depth (per occulted point)
Apparent velocity is 11.7 km/sec on the sky relative to the star, or, 12.8 arcsec/hr.
Position angle of asteroid motion is 5.1 degrees
The recommended exposure time corresponds to 8.2 km per image.
The 1-sigma error in the time of the event is 3.5 seconds.
The 1-sigma cross-track error in the shadow position is 10.6 km.
The sky-plane scale is 3287.0 km/arcsec.
Diameter estimates:
40.9 km assuming a 5% albedo, aximum of 3.5 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, (2025/09/28 06:12UT) Object RA Dec mag sep mel Rigel 05:15:46.6 -08:10:26 0.1 11.77 144 67Bet Eri 05:09:07.0 -05:03:18 2.8 11.59 147 PPM 214397 04:30:18.7 -12:59:36 5.6 1.65 138 PPM 214390 04:30:07.8 -11:00:12 8.0 0.36 140 PPM 214408 04:30:51.0 -11:15:35 9.2 0.28 140 17172_99NZ41 04:29:45.9 -11:21:06 16.1 140 Positions are for equinox of date
Star training set for 17172_99NZ41, (2025/09/28 06:12UT) Object RA Dec mag sep mel Rigel 05:14:32.3 -08:12:06 0.1 11.77 144 67Bet Eri 05:07:50.8 -05:05:13 2.8 11.59 147 PPM 214397 04:29:06.9 -13:02:54 5.6 1.65 138 PPM 214390 04:28:54.8 -11:03:31 8.0 0.36 140 PPM 214408 04:29:38.2 -11:18:52 9.2 0.28 140 17172_99NZ41 04:28:33.1 -11:24:25 16.1 140 Positions are for J2000