Occultation event with (17171) 99NB38, event index number 1172
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/07/27 05:51:38 UTC
J2000 position of star is 03:04:16.9 +42:19:57
Equinox of date position of star is 03:05:58.0 +42:25:52
Star is 98 degrees from the moon. Moon is 7% illuminated.
Stellar brightness G=16.0, apparent brightess of occulting body is G=16.2
Use an exposure time of 0.55 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 55% with SNR of 1.6 for the occulted depth (per occulted point)
Apparent velocity is 25.7 km/sec on the sky relative to the star, or, 23.8 arcsec/hr.
The recommended exposure time corresponds to 14.1 km per image.
The 1-sigma error in the time of the event is 1.4 seconds.
The 1-sigma cross-track error in the shadow position is 36.4 km.
The sky-plane scale is 3877.2 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, aximum of 1.8 sec for a central chord
18.8 km assuming a 30% albedo, maximum of 0.7 sec for a central chord
Cross-track diameter of 46.1 km used for deployment plan.
Star training set for 17171_99NB38, (2025/07/27 05:52UT) Object RA Dec mag sep mel Aldebaran 04:37:23.5 +16:33:31 0.8 32.41 85 Algol 03:09:50.6 +41:03:08 2.1 1.56 98 PPM 045917 03:13:51.4 +42:28:14 5.9 1.46 96 PPM 045802 03:05:23.1 +42:30:53 8.3 0.14 98 17171_99NB38 03:05:58.0 +42:25:52 16.2 97 Positions are for equinox of date
Star training set for 17171_99NB38, (2025/07/27 05:52UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 32.41 85 Algol 03:08:10.1 +40:57:20 2.1 1.56 98 PPM 045917 03:12:09.5 +42:22:33 5.9 1.46 96 PPM 045802 03:03:41.9 +42:24:58 8.3 0.14 98 17171_99NB38 03:04:16.9 +42:19:57 16.2 98 Positions are for J2000