Occultation event with (17171) 99NB38, event index number 4403
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/10/15 05:32:45 UTC
J2000 position of star is 06:23:06.6 +46:00:41
Equinox of date position of star is 06:25:05.9 +45:59:45
Star is 154 degrees from the moon. Moon is 20% illuminated.
Stellar brightness G=14.3, apparent brightess of occulting body is G=16.2
Use an exposure time of 0.35 seconds with the standard RECON-QHY system.
SNR of 9.3 per integration for unocculted signal
Expected flux drop is 85% with SNR of 7.9 for the occulted depth (per occulted point)
Apparent velocity is 7.3 km/sec on the sky relative to the star, or, 7.2 arcsec/hr.
Position angle of asteroid motion is 20.7 degrees
The recommended exposure time corresponds to 2.6 km per image.
The 1-sigma error in the time of the event is 3.0 seconds.
The 1-sigma cross-track error in the shadow position is 19.7 km.
The sky-plane scale is 3625.2 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, maximum of 6.3 sec for a central chord
18.8 km assuming a 30% albedo, maximum of 2.6 sec for a central chord
Cross-track diameter of 40.9 km used for deployment plan.
Star training set for 17171_99NB38, (2026/10/15 05:33UT) Object RA Dec mag sep mel Pollux 07:46:57.1 +27:57:33 1.1 24.20 141 34Bet Aur 06:01:29.7 +44:56:50 1.9 4.27 158 PPM 049066 06:29:51.9 +47:23:11 6.3 1.61 152 PPM 048994 06:24:24.9 +46:10:46 7.2 0.22 154 PPM 049006 06:25:28.3 +45:48:55 9.7 0.19 154 17171_99NB38 06:25:05.9 +45:59:45 16.2 154 Positions are for equinox of date
Star training set for 17171_99NB38, (2026/10/15 05:33UT) Object RA Dec mag sep mel Pollux 07:45:17.7 +28:01:33 1.1 24.20 141 34Bet Aur 05:59:31.6 +44:56:51 1.9 4.27 158 PPM 049066 06:27:50.9 +47:24:18 6.3 1.61 152 PPM 048994 06:22:25.4 +46:11:41 7.2 0.22 154 PPM 049006 06:23:29.3 +45:49:52 9.7 0.19 154 17171_99NB38 06:23:06.6 +46:00:41 16.2 154 Positions are for J2000