Occultation event with (17171) 99NB38, event index number 1445
Regions able to see the event: Europe
Geocentric closest approach at 2025/11/02 05:50:02 UTC
J2000 position of star is 02:56:51.6 +48:55:28
Equinox of date position of star is 02:58:38.8 +49:01:38
Star is 66 degrees from the moon. Moon is 85% illuminated.
Stellar brightness G=14.2, apparent brightess of occulting body is G=15.6
Use an exposure time of 0.35 seconds with the standard RECON-QHY system.
SNR of 9.4 per integration for unocculted signal
Expected flux drop is 78% with SNR of 7.3 for the occulted depth (per occulted point)
Apparent velocity is 16.2 km/sec on the sky relative to the star, or, 18.7 arcsec/hr.
Position angle of asteroid motion is 82.2 degrees
The recommended exposure time corresponds to 5.7 km per image.
The 1-sigma error in the time of the event is 0.7 seconds.
The 1-sigma cross-track error in the shadow position is 25.5 km.
The sky-plane scale is 3124.1 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, aximum of 2.8 sec for a central chord
18.8 km assuming a 30% albedo, maximum of 1.2 sec for a central chord
Cross-track diameter of 40.9 km used for deployment plan.
Star training set for 17171_99NB38, (2025/11/02 05:50UT) Object RA Dec mag sep mel Aldebaran 04:37:24.4 +16:33:33 0.8 38.17 76 Mirphak 03:26:10.9 +49:57:03 1.8 4.56 71 13The Per 02:45:58.8 +49:20:09 4.1 2.09 65 PPM 045704 02:59:41.6 +48:58:50 8.5 0.18 67 PPM 045696 02:59:07.8 +49:06:36 10.2 0.11 67 17171_99NB38 02:58:38.8 +49:01:38 15.6 67 Positions are for equinox of date
Star training set for 17171_99NB38, (2025/11/02 05:50UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 38.17 76 Mirphak 03:24:19.4 +49:51:40 1.8 4.56 71 13The Per 02:44:12.9 +49:13:40 4.1 2.09 65 PPM 045704 02:57:54.3 +48:52:42 8.5 0.18 67 PPM 045696 02:57:20.4 +49:00:27 10.2 0.11 67 17171_99NB38 02:56:51.6 +48:55:28 15.6 66 Positions are for J2000