Occultation event with (17171) 99NB38, event index number 5011
Regions able to see the event: Europe
Geocentric closest approach at 2026/12/03 18:05:45 UTC
J2000 position of star is 06:06:00.0 +47:36:13
Equinox of date position of star is 06:08:02.2 +47:35:57
Star is 101 degrees from the moon. Moon is 25% illuminated.
Stellar brightness G=14.2, apparent brightess of occulting body is G=15.8
Use an exposure time of 0.35 seconds with the standard RECON-QHY system.
SNR of 9.5 per integration for unocculted signal
Expected flux drop is 80% with SNR of 7.6 for the occulted depth (per occulted point)
Apparent velocity is 16.6 km/sec on the sky relative to the star, or, 18.3 arcsec/hr.
Position angle of asteroid motion is 91.9 degrees
The recommended exposure time corresponds to 5.8 km per image.
The 1-sigma error in the time of the event is 0.6 seconds.
The 1-sigma cross-track error in the shadow position is 27.9 km.
The sky-plane scale is 3272.5 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, maximum 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, (2026/12/03 18:06UT) Object RA Dec mag sep mel Pollux 07:46:57.6 +27:57:32 1.1 27.48 79 34Bet Aur 06:01:30.3 +44:56:50 1.9 2.88 102 PPM 048732 06:07:55.5 +48:14:41 6.3 0.65 101 PPM 048679 06:04:47.7 +47:48:28 6.9 0.58 102 PPM 048744 06:08:38.5 +47:37:05 9.8 0.10 101 17171_99NB38 06:08:02.2 +47:35:57 15.8 101 Positions are for equinox of date
Star training set for 17171_99NB38, (2026/12/03 18:06UT) Object RA Dec mag sep mel Pollux 07:45:17.7 +28:01:33 1.1 27.48 79 34Bet Aur 05:59:31.6 +44:56:51 1.9 2.88 102 PPM 048732 06:05:52.5 +48:14:58 6.3 0.65 101 PPM 048679 06:02:45.2 +47:48:37 6.9 0.58 102 PPM 048744 06:06:36.3 +47:37:23 9.8 0.10 101 17171_99NB38 06:06:00.0 +47:36:13 15.8 101 Positions are for J2000