Occultation event with (17171) 99NB38, event index number 1444
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/11/02 02:29:26 UTC
J2000 position of star is 02:56:57.8 +48:55:38
Equinox of date position of star is 02:58:45.1 +49:01:47
Star is 68 degrees from the moon. Moon is 84% illuminated.
Stellar brightness G=15.3, apparent brightess of occulting body is G=15.6
Use an exposure time of 0.60 seconds with the standard RECON-QHY system.
SNR of 5.8 per integration for unocculted signal
Expected flux drop is 57% with SNR of 3.3 for the occulted depth (per occulted point)
Apparent velocity is 16.2 km/sec on the sky relative to the star, or, 18.6 arcsec/hr.
Position angle of asteroid motion is 82.4 degrees
The recommended exposure time corresponds to 9.7 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 26.1 km.
The sky-plane scale is 3124.4 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, aximum of 2.9 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 02:29UT) Object RA Dec mag sep mel Aldebaran 04:37:24.4 +16:33:33 0.8 38.16 78 Mirphak 03:26:10.9 +49:57:03 1.8 4.55 72 Iot Per 03:10:56.7 +49:42:35 4.0 2.10 70 PPM 045704 02:59:41.6 +48:58:50 8.5 0.16 68 PPM 045696 02:59:07.8 +49:06:36 10.2 0.10 68 17171_99NB38 02:58:45.1 +49:01:47 15.6 68 Positions are for equinox of date
Star training set for 17171_99NB38, (2025/11/02 02:29UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 38.16 78 Mirphak 03:24:19.4 +49:51:40 1.8 4.55 72 Iot Per 03:09:07.3 +49:36:46 4.0 2.10 70 PPM 045704 02:57:54.3 +48:52:42 8.5 0.16 68 PPM 045696 02:57:20.4 +49:00:27 10.2 0.10 68 17171_99NB38 02:56:57.8 +48:55:38 15.6 68 Positions are for J2000