Occultation event with (17171) 99NB38, event index number 1543
Regions able to see the event: SAmericaN,UAE
Geocentric closest approach at 2025/11/18 23:45:05 UTC
J2000 position of star is 02:44:18.8 +48:18:01
Equinox of date position of star is 02:46:04.1 +48:24:30
Star is 151 degrees from the moon. Moon is 2% illuminated.
Stellar brightness G=14.9, apparent brightess of occulting body is G=15.6
Use an exposure time of 0.55 seconds with the standard RECON-QHY system.
SNR of 7.6 per integration for unocculted signal
Expected flux drop is 65% with SNR of 4.9 for the occulted depth (per occulted point)
Apparent velocity is 17.1 km/sec on the sky relative to the star, or, 19.8 arcsec/hr.
Position angle of asteroid motion is 64.6 degrees
The recommended exposure time corresponds to 9.4 km per image.
The 1-sigma error in the time of the event is 1.1 seconds.
The 1-sigma cross-track error in the shadow position is 20.2 km.
The sky-plane scale is 3112.4 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, aximum of 2.7 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, (2025/11/18 23:45UT) Object RA Dec mag sep mel Aldebaran 04:37:24.5 +16:33:33 0.8 39.12 151 Mirphak 03:26:11.1 +49:57:04 1.8 6.73 148 13The Per 02:45:59.0 +49:20:10 4.1 0.93 150 PPM 045408 02:44:46.9 +48:22:27 7.3 0.22 151 17171_99NB38 02:46:04.1 +48:24:30 15.6 151 Positions are for equinox of date
Star training set for 17171_99NB38, (2025/11/18 23:45UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 39.12 151 Mirphak 03:24:19.4 +49:51:40 1.8 6.73 148 13The Per 02:44:12.9 +49:13:40 4.1 0.93 150 PPM 045408 02:43:01.9 +48:15:55 7.3 0.22 151 17171_99NB38 02:44:18.8 +48:18:01 15.6 151 Positions are for J2000