Occultation event with (17171) 99NB38, event index number 4352
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/10/06 08:00:01 UTC
J2000 position of star is 06:21:31.8 +45:36:42
Equinox of date position of star is 06:23:30.4 +45:35:49
Star is 49 degrees from the moon. Moon is 21% illuminated.
Stellar brightness G=15.8, apparent brightess of occulting body is G=16.3
Use an exposure time of 1.05 seconds with the standard RECON-QHY system.
SNR of 5.7 per integration for unocculted signal
Expected flux drop is 60% with SNR of 3.4 for the occulted depth (per occulted point)
Apparent velocity is 9.7 km/sec on the sky relative to the star, or, 9.4 arcsec/hr.
Position angle of asteroid motion is 45.0 degrees
The recommended exposure time corresponds to 10.2 km per image.
The 1-sigma error in the time of the event is 1.2 seconds.
The 1-sigma cross-track error in the shadow position is 25.9 km.
The sky-plane scale is 3713.8 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, maximum of 4.7 sec for a central chord
18.8 km assuming a 30% albedo, maximum of 1.9 sec for a central chord
Cross-track diameter of 40.9 km used for deployment plan.
Star training set for 17171_99NB38, (2026/10/06 08:00UT) Object RA Dec mag sep mel Pollux 07:46:57.0 +27:57:34 1.1 24.15 27 34Bet Aur 06:01:29.6 +44:56:50 1.9 3.93 52 PPM 049066 06:29:51.8 +47:23:11 6.3 2.10 48 PPM 048984 06:23:44.0 +45:35:46 8.1 0.04 49 17171_99NB38 06:23:30.4 +45:35:49 16.3 48 Positions are for equinox of date
Star training set for 17171_99NB38, (2026/10/06 08:00UT) Object RA Dec mag sep mel Pollux 07:45:17.7 +28:01:33 1.1 24.15 27 34Bet Aur 05:59:31.6 +44:56:51 1.9 3.93 52 PPM 049066 06:27:50.9 +47:24:18 6.3 2.10 48 PPM 048984 06:21:45.4 +45:36:40 8.1 0.04 49 17171_99NB38 06:21:31.8 +45:36:42 16.3 49 Positions are for J2000