Occultation event with (17171) 99NB38, event index number 1616
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/11/30 03:16:34 UTC
J2000 position of star is 02:36:53.1 +47:32:54
Equinox of date position of star is 02:38:36.9 +47:39:35
Star is 57 degrees from the moon. Moon is 70% illuminated.
Stellar brightness G=16.3, apparent brightess of occulting body is G=15.6
Use an exposure time of 0.85 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 35% with SNR of 1.1 for the occulted depth (per occulted point)
Apparent velocity is 16.7 km/sec on the sky relative to the star, or, 19.2 arcsec/hr.
Position angle of asteroid motion is 52.9 degrees
The recommended exposure time corresponds to 14.2 km per image.
The 1-sigma error in the time of the event is 1.4 seconds.
The 1-sigma cross-track error in the shadow position is 15.5 km.
The sky-plane scale is 3135.1 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, aximum of 2.8 sec for a central chord
18.8 km assuming a 30% albedo, maximum of 1.1 sec for a central chord
Cross-track diameter of 40.9 km used for deployment plan.
Star training set for 17171_99NB38, (2025/11/30 03:17UT) Object RA Dec mag sep mel Aldebaran 04:37:24.6 +16:33:33 0.8 39.52 69 57Gam1And 02:05:30.1 +42:27:10 2.3 7.82 49 13The Per 02:45:59.1 +49:20:11 4.1 2.07 59 PPM 045344 02:42:57.5 +47:40:52 7.5 0.73 57 PPM 045280 02:39:38.0 +48:00:25 8.7 0.39 57 PPM 045259 02:38:29.1 +47:40:56 11.1 0.03 57 17171_99NB38 02:38:36.9 +47:39:35 15.6 57 Positions are for equinox of date
Star training set for 17171_99NB38, (2025/11/30 03:17UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 39.52 69 57Gam1And 02:03:54.1 +42:19:46 2.3 7.82 49 13The Per 02:44:12.9 +49:13:40 4.1 2.07 59 PPM 045344 02:41:13.2 +47:34:17 7.5 0.73 57 PPM 045280 02:37:53.8 +47:53:46 8.7 0.39 57 PPM 045259 02:36:45.4 +47:34:14 11.1 0.03 57 17171_99NB38 02:36:53.1 +47:32:54 15.6 57 Positions are for J2000