Occultation event with (17171) 99NB38, event index number 3511
Regions able to see the event: Europe
Geocentric closest approach at 2026/03/26 21:58:59 UTC
J2000 position of star is 03:12:46.3 +40:37:35
Equinox of date position of star is 03:14:29.5 +40:43:24
Star is 55 degrees from the moon. Moon is 63% illuminated.
Stellar brightness G=15.9, apparent brightess of occulting body is G=16.4
Use an exposure time of 0.50 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 61% with SNR of 1.9 for the occulted depth (per occulted point)
Apparent velocity is 32.7 km/sec on the sky relative to the star, or, 28.1 arcsec/hr.
Position angle of asteroid motion is 90.6 degrees
The recommended exposure time corresponds to 16.3 km per image.
The 1-sigma error in the time of the event is 0.2 seconds.
The 1-sigma cross-track error in the shadow position is 27.4 km.
The sky-plane scale is 4179.2 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, maximum of 1.4 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 40.9 km used for deployment plan.
Star training set for 17171_99NB38, (2026/03/26 21:59UT) Object RA Dec mag sep mel Aldebaran 04:37:25.7 +16:33:36 0.8 30.08 42 Algol 03:09:53.2 +41:03:17 2.1 0.93 56 28Ome Per 03:12:59.6 +39:42:33 5.8 1.05 55 PPM 045952 03:15:47.0 +40:17:51 8.5 0.49 55 PPM 045949 03:15:46.3 +41:00:39 9.7 0.38 55 PPM 045925 03:14:12.4 +40:44:39 10.6 0.06 55 17171_99NB38 03:14:29.5 +40:43:24 16.4 55 Positions are for equinox of date
Star training set for 17171_99NB38, (2026/03/26 21:59UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 30.08 42 Algol 03:08:10.1 +40:57:20 2.1 0.93 56 28Ome Per 03:11:17.3 +39:36:41 5.8 1.05 55 PPM 045952 03:14:04.0 +40:12:05 8.5 0.49 55 PPM 045949 03:14:02.8 +40:54:53 9.7 0.38 55 PPM 045925 03:12:29.2 +40:38:50 10.6 0.06 55 17171_99NB38 03:12:46.3 +40:37:35 16.4 55 Positions are for J2000