Occultation event with (17171) 99NB38, event index number 3211
Regions able to see the event: Europe
Geocentric closest approach at 2026/02/05 00:01:51 UTC
J2000 position of star is 02:33:59.0 +41:59:29
Equinox of date position of star is 02:35:38.9 +42:06:17
Star is 122 degrees from the moon. Moon is 89% illuminated.
Stellar brightness G=15.6, apparent brightess of occulting body is G=16.2
Use an exposure time of 0.60 seconds with the standard RECON-QHY system.
SNR of 4.7 per integration for unocculted signal
Expected flux drop is 63% with SNR of 3.0 for the occulted depth (per occulted point)
Apparent velocity is 16.8 km/sec on the sky relative to the star, or, 16.5 arcsec/hr.
Position angle of asteroid motion is 121.3 degrees
The recommended exposure time corresponds to 10.1 km per image.
The 1-sigma error in the time of the event is 0.3 seconds.
The 1-sigma cross-track error in the shadow position is 27.6 km.
The sky-plane scale is 3667.4 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, (2026/02/05 00:02UT) Object RA Dec mag sep mel Aldebaran 04:37:25.3 +16:33:35 0.8 36.47 105 57Gam1And 02:05:30.8 +42:27:13 2.3 5.58 126 PPM 045035 02:24:28.4 +41:30:47 6.1 2.16 124 PPM 045195 02:34:49.1 +41:55:53 7.8 0.23 122 PPM 045226 02:36:30.6 +42:14:37 9.7 0.21 122 PPM 045188 02:34:37.4 +42:05:23 10.4 0.19 122 17171_99NB38 02:35:38.9 +42:06:17 16.2 122 Positions are for equinox of date
Star training set for 17171_99NB38, (2026/02/05 00:02UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 36.47 105 57Gam1And 02:03:54.1 +42:19:46 2.3 5.58 126 PPM 045035 02:22:50.1 +41:23:44 6.1 2.16 124 PPM 045195 02:33:09.4 +41:49:04 7.8 0.23 122 PPM 045226 02:34:50.5 +42:07:50 9.7 0.21 122 PPM 045188 02:32:57.6 +41:58:33 10.4 0.19 122 17171_99NB38 02:33:59.0 +41:59:29 16.2 122 Positions are for J2000