Occultation event with (17171) 99NB38, event index number 1199
Regions able to see the event: SMexico
Geocentric closest approach at 2025/07/10 10:07:10 UTC
J2000 position of star is 02:52:08.3 +40:32:40
Equinox of date position of star is 02:53:46.8 +40:38:53
Star is 128 degrees from the moon. Moon is 100% illuminated.
Stellar brightness G=16.2, apparent brightess of occulting body is G=16.3
Use an exposure time of 0.70 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 51% with SNR of 1.5 for the occulted depth (per occulted point)
Apparent velocity is 30.9 km/sec on the sky relative to the star, or, 27.7 arcsec/hr.
The recommended exposure time corresponds to 21.6 km per image.
The 1-sigma error in the time of the event is 1.3 seconds.
The 1-sigma cross-track error in the shadow position is 33.2 km.
The sky-plane scale is 4019.9 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, aximum of 1.5 sec for a central chord
18.8 km assuming a 30% albedo, maximum of 0.6 sec for a central chord
Cross-track diameter of 46.1 km used for deployment plan.
Star training set for 17171_99NB38, (2025/07/10 10:07UT) Object RA Dec mag sep mel Aldebaran 04:37:23.3 +16:33:31 0.8 32.88 145 Algol 03:09:50.4 +41:03:08 2.1 3.06 131 22Pi Per 03:00:24.2 +39:45:47 4.7 1.54 129 PPM 045476 02:48:26.8 +40:43:12 8.5 1.01 127 PPM 045605 02:53:46.7 +40:46:29 9.5 0.13 128 17171_99NB38 02:53:46.8 +40:38:53 16.3 128 Positions are for equinox of date
Star training set for 17171_99NB38, (2025/07/10 10:07UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 32.88 145 Algol 03:08:10.1 +40:57:20 2.1 3.06 131 22Pi Per 02:58:45.7 +39:39:45 4.7 1.54 129 PPM 045476 02:46:48.7 +40:36:52 8.5 1.01 127 PPM 045605 02:52:08.1 +40:40:16 9.5 0.13 128 17171_99NB38 02:52:08.3 +40:32:40 16.3 128 Positions are for J2000